Log in


  • May 23, 2021 11:54 AM | Howard Ratsch (Administrator)

    Educational Blog


    By Oyegoke Motolani Oluwakemi

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    Presently, the concept of mental health is under investigation. What we know for sure, regardless of your age, size, or societal status — it can affect anyone. Therefore, it’s tasking for medical professionals to give concise advice on this issue. The ideal mental health involves a natural ability to live out individual potential; this includes facing the usual stress associated with being human, productivity, and daily work. The ideal mental health is not limited to being productive; it involves being socially balanced, professional, and socially engaged, etc. 

    Mental health levels can be described based on a spectrum ranging from healthy to adverse or ill. Hence, there’s usually a variation — short-term and long-term mental illnesses. Still, the effects may vary in individuals such that a person with a poor mental health condition like anxiety disorder could be fully functional in their daily lives. To cushion the effects of adverse mental health, professionals advise socializing. In adherence to such opinions, people embrace physical interactions with the environment, and other individuals, thus embracing scuba diving. 

    Scuba diving does not take place in a natural human environment, so taking precautions is necessary. While the thrill of diving into the water brings out people’s adventurous side, divers usually overlook their mental health. However, due to the impact outdoor activities have on an individual’s overall well-being, people with mental health concerns naturally embrace the activity. 

    A study conducted by the University of Sheffield’s Medical School supports the claim that diving impacts levels of anxiety, depression, and social functioning. The report also claims that scuba diving can provide several therapeutic benefits to improve social dysfunction and depression. The study sheds light on scuba diving as a potential therapeutic aid, while demonstrating the positive impacts it poses. How does it work? 

    Physical activity

    Anyone who recognizes that they have mental health challenges must have spoken to a professional and counselor. It is, therefore, not uncommon to receive recommendations of participating in physical activities. 

    However, for many people, running and other kinds of physical activity turn out boring. It doesn’t take too long for discouragement to set in, and so, physical activity comes to an abrupt end. Local sports or Zumba classes make nice alternatives, but you tend to expend more energy. 

    Scuba diving is essentially moving slowly underwater. As you begin to dive, you put your muscles into work by swimming and slight body adjustments. But, in the end, you’re doing something that improves your mental health. 


    Breathing is the core of diving, just as it is for living. It happens instinctively, so that movement in water is seamless. What you’re doing in the real sense is focusing on your breath and its rhythm. Diving has more merits than demerits. All divers actively engage their minds in the activity while underwater. They make clear decisions and effectively manage events. None of this is possible without involving the mind. 

    Since breathing is the biggest part of diving, you learn to focus your breathing by inhaling and exhaling in a meditative way. Meditation is a fundamental aspect of yoga which comes in handy and helps your mind retain calm. When underwater, you’re surrounded by a peaceful kind of calm and silence that allows you to flow with the current environment. Your mind presently drifts away from external concerns so that you can enjoy your space and sport.

    Easy Socialization

    A major symptom of adverse mental health conditions is the affected person’s inability to talk to people or maintain social interaction. Networking for such people is almost impossible because they tend to hide and isolate themselves. Sometimes, changing environments is tough since it equals a potential association with new people.

    Scuba diving is an easy way to come out of this state. It brings people of different races, classes, and calibers together without fear or judgment. Regardless of where you’re from or when you’re diving, you speak one language — the language of the sea. The amazing part is that you don’t have to say a word. There is a common ground and an avenue for people to bond and enjoy the sport.

    Socializing while underwater is easier with the various diving hand signals people use to communicate. Furthermore, it excludes the anxiety that often comes with speaking to people because you only need to communicate with a partner. Generally, diving is done with someone else, so you find yourself with them. Since you only need to ease into the conversation, you soon find yourself talking about other stuff and sharing without any pressure. Additionally, as these interactions grow, you begin to trust people more

    The Marine life encounter

    If you have ever watched fishes in an aquarium, you will agree that there’s a feeling of satisfaction with that simple act. Life underwater brings a calming effect to the heart and brain. The burst of colors and different species of aquatic life brings you delight and calm. Colors naturally lift the human mood by increasing serotonin and dopamine levels produced in the brain. Both neurotransmitters stimulate happy chemicals in the brain, hence improving the mood.

    A kind of therapy

    Scientists like Dr. J.C. Lilly, a neuro-physiologist, agree that water therapy is both relaxing and rejuvenating. The flotation therapy proves that weightlessness is a way to put the body in a state of total relaxation. Since scuba diving is akin to submerging the body in water, it helps clear the mind and release stress.

    The human body comprises 70% water, the same percentage of water covering the earth’s surface. Saltwater opens the pores on the skin and enhances the absorption of essential water minerals. So, in addition to aiding mental health, scuba diving looks great on the skin too.


    Although the weather conditions of the location you use for your diving activity may be subject to peculiar changes, the struggle against any water body improves your strength. Often, divers move through currents and avoid collision against water reefs. These build physical fitness and improve endurance. The water workout helps your mind stay sharp and ready. Also, it helps the muscle and joints. 


    Scuba diving is relaxing and encompassing. It fosters self-reliance and therefore, it is good for individuals with mental health challenges. So, does scuba diving affect mental health? Yes, and positively too. It’s time to explore the numerous advantages of scuba diving. If you intend to go all out and embrace something new, scuba diving is a great idea. I recommend you try the waters of Miami and have all preparations taken care of beforehand. Here’s a chance to sharpen your senses and retain your vitality while having fun too. Enjoy! Happy Diving!

  • April 22, 2021 8:49 AM | Howard Ratsch (Administrator)

    Educational Blog


    By Michael Thomas

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    “Have you got a light, guys?”

    Many years ago, surfacing from a cave or sump dive and hearing the cry “have you got a light, guys?” was not uncommon. Diving light failure happened a fair bit, as lighting was not as reliable or bright as we have now. A team member’s light was either out or producing lumens not much better than a glow worm in a jam jar! Not really a problem if you are back at the entrance to the cave, but more of a problem if you have surfaced beyond a sump inside the cave. 

    Sitting at my desk, passing the time in Coronavirus lockdown, I started thinking about the equipment and techniques we used back in the 90s compared to what we use now. Was it all the bad old days? Did the skills we developed then and problems we had to overcome put us in a better place for dealing with modern long exposure technical diving on rebreathers and mixed gas today? The list of differences is long and would be very tedious to the reader. I’ve chosen eight subjects to compare that have had major changes since my diving life started in 1987. 

    Deep Air 

    This is the one old school technique every diver today knows is a bad thing — the skill set that really needs to be in the diving dustbin. A breathing gas at depths below 30m gives increasing narcosis and increasing PP02. Both of these are bad, and combined with increased work of breathing, increasing gas density, and C02, it really does not have much to offer. 

    So why did we use it as a deep gas? 

    Firstly, it was readily available and cheap. Oxygen and nitrox were not easy to get for divers, let alone helium. Plus, so few divers within the sports diving and fledgling technical diving world knew how to produce decompression tables for helium. So, for most, air was the only option for inquisitive divers that wanted to explore deeper. Exploration is a powerful driving force for some. 

    Now you also need to consider the attitudes of the time: going deep was deemed cool. It proved something to your peers. This was an attitude that killed many and the rest of us just got lucky. But what did we learn from deep air diving? The TDIstandards of today are based on sensible diving limits learnt the hard way by many, and I, being one of the lucky ones who survived, can teach with first-hand experience about what narcosis and gas density are all about. Deep Air: just don’t do it. 


    This gas, with a combination of Oxygen, Helium and Nitrogen, has become the go-to gas for deeper diving on open circuit and now, more commonly, on rebreathers. With the correct gas mixture for the planned depth, low narcosis, low work of breathing and gas density are achieved. Today, many dive computers can compute for any gas mixture and your mobile phone contains gas mixing and decompression planning apps. The understanding behind the Decompression theory is at an all-time high, with multiple papers and blogs explaining the current thinking. 

    If we go back to the mid-1990s, trimix diving was very different. 

    We were still at the point of hiding nitrox cylinders to get them on dive boats. The primary agencies of the time, BSAC and PADI, had declared nitrox a devil gas that would kill everyone, and both the US Navy and British Navy said recreational/technical divers did not have the knowledge or backup to use trimix safely. However, we persevered. A few brave divers took the plunge, resulting in some success and also tragedy, but we carried on. Bill Hamilton would supply trimix diving tables to technical diving expeditions for a price, and eventually, Sheck Exley released a decompression planning software program called Dr X. Other notable divers followed suit around the same time and technical diving agencies were born, producing trimix manuals complete with decompression tables. 

    Now, our knowledge then was very different from today. When I did my open circuit trimix course in 1997, the general consensus was the need to get off the helium as deep as possible on the way up. Our lack of understanding about how helium reacts led us to believe the lighter gas, helium, would cause decompression illness if we stayed on it at shallow depths. We did some gas switches to air at around 50m after 85m trimix dives! Now, during deep CCRdives, the diver will stay on the helium in the loop all the way to the surface. 

    Another big change is the use of dive computers, either in open circuit mode or real-time monitoring of your CCR, with divers carrying a backup computer to give the all-important decompression information. 

    Now back in the 90s, we had pockets full of laminated decompression tables for the planned depth and time. We also had multiple variations of depth and time, such as deeper and longer and shorter bailout tables if you missed the wreck or had a problem on the descent. The time and depth were either recorded on bottom timers or divers would use a standard air computer and just bend the air computer on surfacing. More than once, I remember dive partners surrounded by decompression tables on decompression stops, as the homemade laminated tables fell apart and alarming air dive computers in a bucket of water on the dive deck to muffle the sound.

    Independents Doubles 

    A twin set is now a fairly common and basic entry requirement into the technical diving world. In Europe, the standard is generally a 12l (cylinder size may vary elsewhere) steel set with an isolation manifold fitted. Regulators with longhose on the right, a single pressure gauge to the left and primary donate being the preferred option. A backplate and wing making up the complete system. Most divers preferring a Hogarthian system, keeping it clean and simple. 

    Back in the 90s, a lot of twin sets were independent cylinders with no manifold at all, either banded together with traditional stainless bands as you see now, or using temporary cam bands to join two cylinders together. In the early years, most independent twinsets had two right-handed cylinder valves, giving you no chance to shut down the left-hand cylinder. It took a while for the technical diving community, especially in Europe, to start thinking about shutdowns and using a left-handed valve on the left cylinder. Being able to shut down the gas supply on your own at that time was not high on the list of things-to-do. Eventually, manifolds started to become more popular, and finally, manifolds with an isolation valve became the norm, making diving safer and divers more skilled. 

    Fixed Sidemount 

    I started sidemount diving in 1992. The day I started cave diving, I was loaned a 1980s style sidemount harness. The cylinders were clamped at a single point, about a quarter of the way down the cylinder. We had different size clamps for different size cylinders. The cylinder and clamp was then threaded onto the harness belt loop along with the weight needed to dive. Regulators were then attached to cylinders. We had standard length high-pressure hoses wrapped around the first stage and valve, held down with bungee loops. The diver then had to lay the sidemount harness out on the ground, complete with cylinders, then step over it and pick it all up to get it onto their waist! With large cylinders, help was generally needed. The harness had no built-in buoyancy, so a modified open water BCD was used and worn over the top of the harness. When diving this system, back pain on long dives was very common, as the entire weight of the harness, cylinders, and lead rested on your lower back, pushing the diver into shallow V shape. 

    Compared to todayʼs modern sidemount harness choices, some of which are superb, with built-in BCDs, weight running down the spine and the ability to attach cylinders after the harness is on, the harness we started with is a world away. Sidemount diving is easy and enjoyable now, once you have the modern harness set up correctly. The techniques we developed have been ever-evolving. But gas management, rule of thirds and balancing cylinder pressure was done from the early years. 


    Having good lighting is one simple yet expensive way to improve the overall dive experience. From caves to wrecks, ocean dives to photography, lighting can make or break the dive. The other thing Iʼve learnt over many years of diving is if you donʼt want a dive light to fail during the dive, leave it at home safely in storage and make sure you have a backup light. Iʼve seen lights fail in every conceivable way, from floods to cable breaks and blown bulbs. 

    Modern lighting is generally very good now, with LED bulbs, high lumen output and battery technology thatʼs improved every year, giving longer burn times and smaller and smaller battery packs. Compared to what we used to use in the 90s: lead-acid battery packs that weighed around 3kg and were the size of a small diving cylinder, generally mounted on the twin set or on the right hip. Unlike todayʼs canisters, it was like having an extra stage cylinder on your harness. Large unwieldy light heads with, if you were lucky, a 50-watt halogen bulb to brighten the darkness. Between halogen bulbs and the LED bulbs of today, we had the HID bulb, which gave a greater light output but were very fragile and rather expensive to replace. They were not great for a light unit designed to be used by divers exiting a busy dive boat deck or cave diving. 


    Ever since divers have started diving, decompression has played a large part in the sport and working environment for all divers. The act of allowing your body to adjust back to surface pressure after diving is still as crucial now as it was then. We canʼt beat physics and physiology. 

    What has changed and continues to change is our understanding of decompression and the techniques of conducting decompression dives. Understanding that all dives put you, the diver, under pressure and require at least a minimum safety stop to choose the most effective decompression gas to return from deep open-circuit dives, or what fixed partial pressure and gas to run on your rebreather, is important. A lot of technical diving expeditions now conduct post-dive medical studies on divers to build the knowledge of decompression and papers are written fairly regularly with updated knowledge. A good diver will constantly update his knowledge on decompression and make use of the information available to stay as safe as possible. 

    Boat Lifts 

    I had just finished nearly an hour of decompression after a dive in 1998 in the English Channel. The wreck was at 80m and previously unexplored. On surfacing, I floated, talking to my dive partner, whilst waiting for the dive boat to come alongside and pick us up. The sea conditions were worsening, and the skipper indicated he wanted us on board as quickly as possible. Working my way along the line on the side of the dive boat and reaching the ladder to get back on board, I placed a regulator in my mouth and started to climb. A 12l steel independent twinset on my back canister, a dive light under each arm , and 10l steel decompression cylinders are a heavy load to climb a ladder with, especially after a deep dive. On this occasion, I really struggled to climb the ladder and only realized at the top of the ladder that I had put my trimix regulator back in and not the decompression gas regulator. Not only was I trying to climb a ladder with four cylinders in a heavy sea, but I was trying to do it with a reduced oxygen percentage. Spitting the regulator out and breathing air really helped. 

    Today most dive boats that I use all have diver lifts. When the dive boat pulls alongside, the lift is dropped into the water, the diver swims in and places feet down and hands-on handrails, clear of the boat. A nod to the skipper and you are raised like a god to the dive deck. You have to love boat lifts. But, if a dive boat has no lift or the lift fails, then years of ladder use make this no problem, as long as the diver has good strength and fitness. 

    Fitness and Attitude

    Back when I started diving in 1987, I was using a single cylinder, a wetsuit, and an ABLJ buoyancy compensator. It took years to progress up to twinset diving and drysuits and finally caves, rebreathers, and instructing. However, those years were not wasted. They allowed us to gain the experience and also follow the changes within sport and technical diving. We found out what worked and what did not work, sometimes the hard way. We crash-tested the standards that are the norm today. 

    Along the way, we realized diver fitness was crucial to stay safe in a sometimes unforgiving environment. Today diving is possible with much faster progression. Equipment is pretty much available to do most things, and the training is available to use that equipment. Whatʼs missing now is the attitude of slowing down and building on that training before launching on the next quest. A diver with a solid skills platform and experience at one level is ready to tackle the next with much more confidence and safety. 

    I sat at my desk writing this during very strange times. Iʼm aware that I probably wonʼt dive for some time due to coronavirus stopping the world. What Iʼm doing is keeping my physical fitness up and keeping my mind sharp by reading, research and planning some dives for when we can get back in the water. These dives will not be teaching dives. They will be easy dives to refresh myself and rebuild muscle memory for the art of diving. Stay safe guys and remember, when we can, build up slowly again.

  • March 22, 2021 9:24 AM | Howard Ratsch (Administrator)

    Educational Blog

    Scuba Q & A: Common Questions Asked By Nondivers | Scuba Diving News, Gear, Education | Dive Training Magazine (

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    When you tell friends and co-workers that you’ve recently been certified to scuba dive, their immediate reaction is likely to be an incredulous, “Wow. You did? I’m not sure I could do that!”

    This knee-jerk response is often closely followed by a rash of questions indicating intense curiosity mixed with a touch of apprehension and perhaps a fair amount of misinformation. This article answers several of the questions most commonly asked by those who haven’t tried scuba yet. You can consider it a primer for the would-be diver, the friend, co-worker or family member who you think might enjoy our sport. By acting as a scuba steward, you might help turn a nondiver into a new diver — and maybe your dive buddy.

    Is it hard to learn to scuba dive?

    As active recreational pastimes go, scuba diving is one of the easiest to learn. While you’re gliding around enjoying the underwater sights, you’re engaged in only three basic skills: floating, kicking and breathing. Of course, there’s more to it than that — becoming proficient at using the equipment and developing knowledge of scuba concepts and safety procedures — but if you can breathe through your mouth, chances are you can learn to scuba dive.

    The necessary skills are not tough for most people to master. During scuba certification class, you’re taught the effects of increased water pressure and safe diving practices. You rehearse equipment-related skills in a controlled water setting until you feel comfortable, as well as practice what to do if things don’t go as planned.

    The bulky scuba gear worn by many divers may seem intimidating, but learning to use it is straightforward. If you’ve snorkeled, you’re already familiar with the mask, snorkel and fins. The scuba unit consists of an air cylinder containing compressed breathing gas, buoyancy compensator (BC) jacket to help you float on the surface and maintain your desired depth underwater, and a regulator for you to breathe through. The exposure protection keeps you warm when diving in cool-water environments.

    You don’t need to be a strong swimmer or an athlete to scuba dive, but some degree of comfort in the water certainly helps. Even if you enter scuba training with less than total confidence in your water skills, by the time you receive your first certification card, your comfort level will be greatly increased.

    Learning to scuba dive is mostly a matter of attitude. If you are motivated to step through the door into an exciting new world, then the experience will prove both energizing and confidence-building.

    Doesn’t it hurt your ears?

    This question comes mainly from folks who have snorkeled and tried to dive beneath the surface — free dive. They swim headfirst down to about 6 feet (2 m) and suddenly develop a stabbing pain in their ears, sending them shooting back to the surface. The unknowing assume that they have an ear problem that precludes them from scuba diving.

    On the contrary, the problem is due to a lack of knowledge about the effects of pressure and is easily prevented. If you fly in a plane without serious ear discomfort, then your ears should not present an impediment to diving.

    Increasing water pressure pressing inward on your eardrums as you descend, compressing the surface-pressure air within your middle ear, causes the pain. The remedy is to equalize the pressure on both sides of the eardrums by opening the eustachian tubes, which run from the back of your throat to the middle ear. This is done by pinching your nostrils shut, lifting your chin and gently trying to blow out through your nose. Try it now. You should hear a slight crackling sound — the eustachian tubes opening. Some divers can equalize by simply moving their jaw or tongue.

    It is typically easier to equalize the ears when scuba diving than when doing a headfirst surface dive. The reason is that scuba divers are taught to descend feetfirst (air moves up more readily than down) and to equalize “early and often.” Unless your ears are stuffed by cold or allergy symptoms or you are one of the very few people born with narrow eustachian tubes, ear pain is not an issue. Trained scuba divers know that if they do occasionally have trouble clearing their ears, it’s time to skip diving until the congestion eases.

    What is there to see down there?

    A whole new world of incredible sights awaits the scuba diver, no matter what the underwater environment — fresh or salt water; tropical or temperate; ocean, quarry, lake or river.

    It shouldn’t be hard to envision yourself gliding effortlessly through a crystal-clear tropical ocean, marveling at rainbow-hued fishes flitting about a vibrant coral reef. We’ve all been treated to underwater scenes such as this on TV, in movies or perhaps a friend’s underwater video. You may even have caught a firsthand glimpse when snorkeling in Florida or the Caribbean.

    But unless you’ve spent time underwater, you can’t appreciate the wealth and diversity of life on a coral reef. Fishes are the most recognizable inhabitants, however, they represent only a fraction of all reef animals. Sponges grow in bizarre shapes, often resembling vases or organ pipes; anemones and feather stars extend scores of tentacles like delicate flowers; soft corals imitate bushes waving in a breeze. Even the rocklike reef-building corals are actually colonies of thousands of individual animals. And that’s not to mention the cryptic crabs, undulating sea snails and spiraled Christmas tree worms.

    What most nondivers don’t realize is that there is plenty of life in non-tropical environments as well. The temperate waters along both coasts of North America support many times more life than warm seas. The nutrient-rich waters are thick with the microscopic creatures that form the basis of the entire food chain. Kelp forests are nature’s underwater jungle, and the chilly Pacific Northwest is home to the massive Metridium anemone and the gentle giant octopus.

    While freshwater diving venues don’t support the diversity of life found in the oceans, the fish population can be impressive, especially where they’ve been nurtured. Whether it’s migratory salmon, intrusive bluegill or the elusive paddlefish, there is bound to be something to entertain divers. Also, by concentrating your gaze in a small area, you’ll find a variety of snails, plants and other attention-getters right at the tip of your nose.

    Living creatures are not the only underwater attractions for divers. Man-made features are also popular. The Great Lakes and the entire East Coast of the United States are known for shipwrecks, many sunk during World War II. Realizing the potential for tourism, more and more communities are cleaning, preparing and sinking wrecks — commercial jets as well as mothballed ships — strictly for the pleasure of scuba divers. And lakes formed by damming rivers often hold the remains of flooded villages and drowned forests.

    Nondivers often believe that it is dark underwater. Certainly this is not the case in most warm-water areas, where visibility commonly exceeds 100 feet (30 m). Water does absorb and scatter sunlight; reds are the first to disappear, turning underwater scenes to shades of blue, or in areas with extensive suspended particles, to emerald green. Many divers routinely carry lights — both to restore natural colors and to peek under shaded overhangs.

    Although there are plenty of interesting and unusual sights to hold the attention of scuba divers, some enthusiasts dive for the sheer pleasure of floating weightless in an environment as close to outer space as the majority of us will ever experice.

    Aren’t you afraid of sharks?

    Of the almost 400 species of sharks inhabiting our oceans, only a handful are known to be aggressive toward man; none of these are typically encountered by divers. Despite their position at the top of the ocean’s food chain, sharks’ reaction to a diver’s presence in their domain is commonly one of disinterest. Half of shark attacks are to surfers, whose appearance on the water’s surface approximates that of seals or sea lions, a major food source for some species.

    The “Jaws” movies were largely responsible for the image of sharks as man-eating killing machines, and the media attention surrounding last year’s shark attacks in U.S. waters unfortunately reinforced that impression. The truth is that only 76 unprovoked shark attacks occurred worldwide in 2001, five of them fatal. Just 11 of the attacks, all nonlethal, involved divers or snorkelers. In other words, your chances of getting injured by a shark while scuba diving are minute.

    Many scuba divers actually seek out shark encounters. The Galapagos Islands of Ecuador, Cocos Island off Costa Rica and the Flower Garden Banks in the Gulf of Mexico are popular destinations for diving with schooling hammerheads. A few dive operators offer open-ocean encounters with more aggressive shark species in the relatively safe confines of a shark cage.

    Diving venues around the world routinely engage in shark-feeding dives, in which guides hand-feed reef sharks or anchor giant “chumsicles” — frozen balls of fish — near the bottom, as fascinated divers watch from a respectful distance. Although the wisdom of such activities has recently been called into question, these thrilling dives have been increasingly popular in places like the Bahamas. No injuries to participants have been reported in several years of shark feeding, and the educational value of observing sharks up close helps spread the truth: Sharks are an indispensable part of the ocean’s natural balance.

    The fact is that sharks are in far more danger from humans than we are from them. It is estimated that up to 100 million sharks are killed each year as bycatch to commercial fishing activities as well as for disproven medicinal remedies and shark fin soup. Several species are actually in danger of becoming extinct — an eventuality that would have serious, irreversible ecological consequences.

    Why do you need to wear weights?

    Believe it or not, the human body is quite buoyant. With your lungs full of air, you’d be hard pressed to sink, especially in salt water. That’s why most people have no trouble snorkeling — when you lie flat on the surface with your head in the water, your weight is easily supported, whether you weigh 100 pounds or 300 (45 kg or 136).

    Add scuba equipment and you become even more buoyant. Even though scuba tanks will sink when full, divers wear buoyancy compensators (BCs), vests that not only secure the tank to the diver’s back but also contain inflatable air bladders to provide flotation on the surface. Wetsuits are made of neoprene, a type of rubber that contains thousands of tiny air pockets. These air cells provide insulation to prevent heat loss and in addition add considerable buoyancy.

    Even with all the air vented from a BC, a diver usually cannot sink without weights. Lead can be strung in blocks on an easily ditchable weight belt worn around the waist or bagged as tiny beads in a removable weight pouch. Divers strive to wear as little weight as necessary to allow them to descend from the surface without struggling, and remain slightly negatively buoyant throughout the dive. (Divers add a small amount of air to their BC while underwater to maintain neutral buoyancy while at depth.)

    The amount of weight worn varies from a couple of pounds (1 kg) to more than 30 pounds (14 kg) depending on a variety of factors. Salt water, for instance, is more buoyant than fresh water, so about 2.5 percent more weight is required. The type of exposure protection worn, specific scuba equipment, dive conditions and an individual’s body composition also affect the optimum amount of weight. Divers regularly re-evaluate the amount and placement of their weighting system.

    How deep do you go?

    The industry standard depth limit for recreational divers is 130 feet (39 m) at sea level. During the basic scuba certification, students experience depths of 30-60 feet (9-18 m), and a “deep” dive is considered more than 60 feet (18 m).

    “Going deep” is not an end in itself for scuba enthusiasts. Science has shown that the vast majority of marine species live at depths less than 60 feet (18 m). Within the limits of their training, divers go as deep as necessary to see the points of interest at a particular dive site. That may mean 110 feet (33 m) along a coral-covered wall, 90 feet (27 m) on a wreck or 20 feet (6 m) in a river.

    Staying shallow holds several advantages. One is that your air lasts longer. The deeper you go, the greater the water pressure. The scuba regulator works by automatically providing the diver air at the same pressure as the surrounding water. Therefore, the air in the cylinder is used faster the deeper the dive. For example, at 100 feet (30 m), air is used four times as fast as at the surface. If it takes a diver an hour to become low on air at or near the surface, all else being equal, it would take the same diver only 15 minutes to deplete his air on a 100-foot dive.

    Another advantage of remaining shallow is that the diver’s body accumulates less nitrogen in a given amount of time. This allows him to stay down longer without needing to make a mandatory decompression stop. Decompression diving is beyond the scope of standard recreational dive training.

    Recreational divers primarily breathe filtered air compressed into the scuba cylinder. Nitrogen, which comprises 79 percent of “plain old” air, is not metabolized, but accumulates in the tissues when breathed under increased pressure as you dive. This is what causes decompression sickness, or the bends; when the absorbed nitrogen is released too quickly, it forms bubbles in the tissues. The same percentages as above apply: A diver absorbs nitrogen four times faster at 100 feet than at the surface. There is a definite trade-off between how deep you go and how long you can stay down.

    Some recreational divers expand their skill range through additional training in technical diving disciplines. These include courses in deep diving and use of mixed breathing gases — gases other than plain old air. 

    Are my kids too young? Am I too old?

    Scuba diving is a nondiscriminatory activity. Anyone with the physical ability to handle the equipment and the emotional maturity to comprehend the rules and take responsibility for his or her safety and that of his dive buddy, can scuba dive safely and enjoyably.

    There is no upper age limit on learning scuba. Prospective scuba students are asked to have a standard medical questionnaire completed by a doctor — preferably one knowledgeable in hyperbaric, i.e., pressure-related, medicine. Certain conditions may preclude those of any age from diving, temporarily or permanently, especially conditions associated with lung functions or anything that may impair your ability to perform effectively underwater. As long as you maintain relatively good physical and mental conditioning, it’s never too late to learn scuba. Many divers continue into their 70s and 80s.

    Minimum age restrictions do apply, although these have recently been lowered by some scuba certification agencies with the development of noncertification programs for children as young as 8 years old. These programs allow enthusiastic kids to get a taste of scuba diving under strict supervision and depths not exceeding about 6 feet (2 m).

    In general, children must be 10-12 years old, depending on the agency, to be certified as “Junior” divers, who may dive only under restricted conditions (i.e., limited depths and supervision by a scuba professional or certified adult diver). At 15 or 16 years old, students receive the same certification as adult divers. Of course, children mature at varying rates and only parents can decide whether their child is emotionally and physically ready to shoulder the responsibility inherent in scuba diving.

    Handicapped individuals can also participate in diving activities with the help of specially trained buddies.

    How do I get certified? How long does it take?

    All scuba instructors are affiliated with one or more of several scuba training agencies that operate in North America and worldwide; each with its own curriculum designed according to the training philosophy of its governing body. Despite this diversity, the industry has responded to the need for cross-agency consistency by implementing a set of minimum standards for the basic level of scuba certification.

    Therefore, at least at the entry level, what you are taught is similar, no matter which agency you certify through. Agencies allow their instructors sufficient leeway to incorporate additional material specific to local dive conditions as is necessary to produce competent divers. Local scuba centers are often associated with one or more scuba training agencies to assure their customers maximum flexibility in learning opportunities.

    Find a dive center near you –>

    The basic scuba certification course, commonly called Open Water Diver, is divided into three sections: academics, confined water and open water. The academics portion develops the knowledge base necessary to understand the principles behind diving rules and procedures. Traditionally, this involved several classroom sessions spread over days or weeks, but with the advent of interactive computer technology, a combination of self-paced lessons and/or amplification and testing by a scuba instructor has allowed academic training to fit just about anyone’s busy schedule.

    You practice dive procedures and learn to use the equipment in the confined water section, usually consisting of several instructor-led sessions in a pool. The open-water section consists of four or more supervised dives, during which you’ll demonstrate your mastery of scuba skills in an actual dive setting. When you earn your certification card you’ll be qualified to dive in conditions similar to those in which you were trained.

    Open Water certification can take anywhere from three days to a year to complete, depending on your preference and schedule. Your local dive center may offer a variety of training options, mixing classroom and home-based computer training with pool sessions and local open-water checkout dives. Another option for those in cold-water areas, especially in the winter, is to complete the first two sections and then accompany your dive center on a trip to a warm-water dive destination to complete the open-water portion. Still another possibility, after completing the academic and confined water sections, is to request referral papers, which allow you up to a year to complete the open-water dives with a qualified referral instructor at a resort location.

    Dive centers want to make scuba certification work for you. Some offer two-weekend “executive” courses, and many resort areas offer a three-day intensive certification for those on vacation. These latter options are most appropriate for those with good water skills and the willingness and ability to assimilate the material quickly.

    Isn’t it expensive?

    Costs for scuba diving compare favorably with those inherent in other active recreational pursuits.

    Pricing for Open Water scuba training varies widely according to the local market, but should include the cost of training materials. Use of scuba equipment for the duration of the course, other than mask, snorkel and fins, which are considered personal and supplied by the individual, may also be included.

    Once certified, scuba diving can cost as little as renting a scuba tank or having your own filled — an expense characteristically less than $10 per tank — and traveling to an area lake, quarry or river, or diving from a public beach entry. Compare this with the price of lift tickets at ski resorts, or a round of golf.

    One thing that these activities have in common is the need for equipment. Purchasing a set of scuba gear — BC, regulator, exposure protection — is no more expensive than getting started in skiing or golf. For the infrequent diver, renting equipment may be an attractive alternative. Of course, as in all worthwhile pursuits, you may choose to expand your scuba “must have” list with items such as a dive computer, underwater camera and other accessories.

    Similarly, scuba vacations are available to suit every budget, from weekends in bunkhouse accommodations with shore diving, to luxury dive resorts in exotic locations. The price of airfare is a major factor in considering vacations to any faraway destination, whether it’s for sightseeing or diving, or a combination of both. Live-aboard dive boats offer the opportunity to visit remote dive destinations and do as much diving as you desire for an all-inclusive price.

    Do I need to renew my certification periodically?

    Recreational scuba certifications do not have to be renewed periodically; they are good for life. A certification card is required in order to rent scuba tanks or have tanks filled, and also when renting gear or booking space on a dive boat.

    However, many dive operators also require proof that the individual has been diving within the past six months or a year. A logbook showing completed dives within the required time frame is usually adequate proof. Lacking such documentation, the operator may require a checkout dive with a scuba instructor to verify that your skills are sufficiently current to dive safely without supervision.

    Like any skill, scuba training will become rusty if not used for long periods. It is wise to take a refresher course, offered by all dive stores, after a hiatus from diving. Even after an interval of several months or when using different equipment, it is highly recommended to schedule time in a pool to practice basic scuba skills and re-familiarize yourself with the equipment.

    The best way to maintain scuba skills is to dive regularly and continue training. Scuba proficiency is a continuum — you can’t learn it all in one basic course. Dive centers offer a whole range of courses to improve your skills and comfort level underwater, as well as specialty courses to expand your horizons. You can learn additional navigation techniques, how to identify the fantastic creatures you’ll see, the excitement of diving at night, the intricacies of capturing all of it in still photos or video, and much more.

    If you are interested in assisting other divers or teaching scuba yourself, a variety of leadership courses will turn you into a scuba professional. The possibilities for a lifetime of enjoyable diving are practically endless. You just have to get started.

    By Linda Lee Walden

  • February 21, 2021 7:25 AM | Howard Ratsch (Administrator)

    Educational Blog

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that that might otherwise be infringing.

    Scuba Diving and Coronary Artery Disease - Advanced Diver Magazine

     By Dr. Douglas Ebersole, he is a cardiologist specializing in coronary and structural heart interventions at the Watson Clinic LLP in Lakeland, Florida.  He is also an avid technical, cave, and rebreather diver and instructor.  He can be reached at


    It is estimated that there are about 3 million certified scuba divers in the United States.  A large number of these individuals are middle-aged or older and at risk for coronary artery disease. Cardiovascular disease is the third most common cause of death while diving and remains the principal cause of death in the general population. The development of symptoms of angina, pulmonary edema, or sudden cardiac death underwater carries with it a much higher mortality than would the same event on land.  This article will review the workloads related to scuba diving, ways to assess risk in those with or at risk of developing coronary artery disease, and make recommendations to make scuba diving safer.

    Scope of the Problem
    In 2008, Denoble published a paper showing the annual death rate for scuba divers was 16.4 per 100,000 persons (1).  This was similar to the rate of 13 jogger deaths per 100,000 participants each year (2) or the risk of driving where motor vehicle accidents result in 16 deaths per 100,000 persons per year (3).  Thus, while the likelihood of dying scuba diving is quite small, understanding how and why these deaths occur is imperative.  Unfortunately, the ultimate cause of death while scuba diving is drowning, This does not give us a great insight into what led to the drowning.  Denoble reported on the causative process of 947 fatalities in an attempt to better define scuba diving fatalities (4).  He divided this into sequential components:  trigger, disabling agent, disabling injury, and cause of death.  Cardiac events constituted 26% of disabling injuries and these events were frequently associated with a history of cardiovascular disease and age greater than 40 years.   Thus, it looks like underlying cardiovascular disease is a major component in scuba diving deaths. 

    Workloads Associated with Scuba Diving
    It is clear that exercise itself is a cardiovascular stress and that the majority of non-traumatic deaths during exercise are cardiac in origin.  In most situations, diving is not particularly physically stressful.  However, there are times that due to current, waves, wind and other environmental stressors that demands during diving can reach 20 ml/kg/min (6-7
    METS).  Exercise capacity is reported in terms of estimated metabolic equivalents of task (METs). The MET unit reflects the resting volume oxygen consumption per minute (VO2) for a 70-kg, 40-year-old man, with 1 MET equivalent to 3.5 mL/min/kg of body weight.

    In the standard Bruce protocol, the starting point (ie, stage 1) is 1.7 mph at a 10% grade (5 METs). Stage 2 is 2.5 mph at a 12% grade (7 METs). Stage 3 is 3.4 mph at a 14% grade (9 METs)n and Stage 4 is 4.2 mph at 16% grade (12 METs).  This protocol includes 3-minute periods to allow achievement of a steady state before workload is increased.

    Thus, a diver with a steady state exercise capacity of 6-7
    METS can expect to manage most diving contingencies without concern for cardiovascular complications.  In most occupational exposures requiring increased physical activity, guidelines recommend maintaining workloads below 50% of maximal oxygen consumption.  Based on this relationship, a diver who is expected to minimize safety concerns related to environmental contingencies should have a maximum oxygen consumption of 12-13 METS – or about 12 minutes on a standard Bruce protocol exercise test.  Divers with peak exercise capacity below that level could expect to dive safely in low stress conditions such as warm water, minimal currents, and calm seas but could develop cardiovascular limitations under stressful diving conditions.

    Who is at risk?
    For divers older than 35 years, the dominant risk for sudden death is from coronary artery disease.  Although the incidence of coronary artery disease death is falling, the rising incidence with age makes this diagnosis the most important consideration when clearing divers who are middle-aged or above.

    One strategy to lower the risk of cardiovascular deaths would be to screen all adult participants prior to certification as most exercise-related cardiac events in adults are due to atherosclerotic cardiovascular disease. 

    The Framingham Risk Score is one of a number of scoring systems used to determine an individual's chances of developing cardiovascular disease. A number of these scoring systems are available online (5,6).  Cardiovascular risk scoring systems give an estimate of the probability that a person will develop cardiovascular disease within a specified amount of time, usually 10 to 30 years. Because they give an indication of the risk of developing cardiovascular disease, they also indicate who is most likely to benefit from prevention. For this reason, cardiovascular risk scores are used to determine who should be offered preventive drugs such as drugs to lower blood pressure and drugs to lower cholesterol levels.

    The population risk for divers could be predicted by using tools such as the Framingham Risk Score and potential participants with a specific score could be identified and excluded.  The problem with this approach is that atherosclerotic cardiovascular disease is prevalent among lower-risk subjects.  Also, extremely high-risk subjects are only a small part of the total population.  Consequently, the largest absolute number of acute events occurs not in the highest-risk subjects, but in the moderate- and lower-risk groups.  Excluding the highest-risk group likely have little effect on the total number of deaths.

    A Framingham risk score lower than 10% ( less than 1% per year risk) is considered a low score.  If a subject is assessed to be at low risk in general, that individual is not likely to have an acute coronary event while diving.  On the other hand, high-risk individuals (Framingham score > 20%) could be at considerable risk and should have further evaluation to evaluate whether diving will be safe.  Intermediate-risk individuals with a Framingham score between 10% and 20% should have further risk stratification to assess their risk for an acute coronary event while diving.

    In all individuals, regardless of risk, we should practice primary prevention of coronary artery disease.  The recommended performance measures for primary prevention are:


    Lifestyle/risk factor screening


    Dietary intake counseling


    Diabetes screening and management


    Physical activity counseling


    Smoking/tobacco cessation


    Weight management


    Blood pressure control


    Blood lipid measurement and control


    Global risk estimation with tools such as Framingham Risk Score


    Aspirin use in selected individuals

    Implementation of these measures requires performance of a careful history and physical examination, laboratory testing for lipids, and formal assessment of cardiovascular risk. 

    Performing stress testing in selected individuals, such as those with intermediate or high-risk Framingham score, is also an approach.   In comparison to younger individuals, far less attention has been paid to designing screening programs for older, usually recreational, athletes.  Few detailed pre-participation guidelines exist, and there is little reported experience in this age group.  Instead, most authorities focus on strategies used in clinical medicine for the early detection of atherosclerotic diseases, as these are the most common cause of death in this age group. 

    Since most individuals are asymptomatic, the history is often more helpful in identifying risk factors rather than symptoms.  Similarly, there may be few detectable abnormalities at rest or even with exercise as events are often due to spontaneous rupture of non-obstructive plaque.

    The American Heart Association issued recommendations for preparticipation screen in older athletes in 2007 (7).  This document recommends that older competitive athletes (>35 to 40 years) be “knowledgeable” regarding their personal history of coronary artery disease risk factors and family history of premature coronary artery disease.  Further, stress testing should be preformed selectively for individuals engaging in vigorous training and competitive sports, and who meet the following criteria: men > 40 years or women > 55 years with diabetes mellitus, or at least two risk factors or one severe risk factor other than age.  Finally, the document recommends education regarding prodromal cardiac symptoms, such as exertional chest pain.

    What about patients with established coronary artery disease?
    Patients with known coronary disease often have been subject to revascularization either by coronary artery bypass surgery or by percutaneous coronary intervention, usually with implantation of one or more coronary artery stents.  The degree of revascularization can determine safety in diving.  With complete revascularization, low-stress diving can be accomplished successfully, but diving in rough seas, fast currents or cold water could be risky.  There are many divers who have returned to diving after either coronary artery bypass surgery or stenting.  Success in return to diving is based on restored exercise capacity without ischemia after revascularization and choosing diving environments that do not produce excess stress on the cardiovascular system.

    Patients with significant reduction in left ventricular systolic function (LVEF < 35%) are at risk for exacerbation of congestive heart failure while diving.  Water immersion itself results in approximately 700 cc of fluid shift into the central circulation.  This could provoke congestive heart failure in patients with impaired left ventricular systolic function.  Additionally, most patient with LVEF < 30-35% will have impaired exercise tolerance when diving as outlined above.  For these reasons, patients with significant left ventricular systolic dysfunction should be advised against scuba diving.



    All adults should be evaluated for their risk of coronary artery disease prior to scuba diving


    Selected individuals with intermediate to high-risk Framingham scores should be referred for additional evaluation, such as treadmill testing prior to scuba diving.


    All individuals should practice primary prevention strategies to decrease their risk for the development of coronary artery disease

    1. Smoking cessation
    2. Blood pressure screening and management
    3. Weight control
    4. Physical activity counseling
    5. Cholesterol screening and management
    6. Diabetes mellitus screening and management


    Patient with coronary artery disease may begin (or return to) diving as    long as they have been revascularized with no ischemia on treadmill stress testing, have good exercise tolerance (defined as a maximum exercise capacity of 13 METs or an ability to sustain a workload of 6 METs), and have relatively preserved left ventricular systolic function.


  • January 22, 2021 9:30 AM | Howard Ratsch (Administrator)

    Educational Blog

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    5-Year Trends in The Dive Industry: Scuba Gear, Dive Travel & Certifications | by Darcy Kieran | Scubanomics | Oct, 2020 | Medium

    DEMA recently published the results of its 2020 ‘Dive Behavioral Research Project’ from a survey conducted in 2019. A previous dive behavioral research was conducted in 2014.

    We have reviewed the results of both the 2019 and the 2014 studies to identify key pieces of information to help you manage your dive business. We are especially interested in changes between these 2 reports to identify trends in the scuba diving industry.

    About DEMA’s Dive Behavioral Research Project

    The goal of the project to analyze and understand the demographics and psychographics of scuba divers as it pertains to dive travel, scuba diving equipment purchases, and scuba courses.

    DEMA is the Diving Equipment & Marketing Association commonly referred to as our dive industry trade association.

    The data collection for the DEMA Dive Behavioral Research Project was done through an online survey.

    In 2014, 24000 divers responded to the survey with more than 2000 from Canada, about 13000 from the USA, and the remainder from countries across the planet.

    In 2019, only 9700 scuba divers responded to the survey with about 1000 from Canada, almost 5000 from the USA, and the rest from countries around the globe.

    Available Data Sets and Reports from The Dive Behavioral Research Project

    So far, DEMA released 2 sets of data from the 2019 survey:

    ·                      2020 results from all responding countries

    ·                      2020 results from USA participants

    A Canadian report is forthcoming.

    Shortcomings of DEMA’s Reports on Scuba Diver Demographics and Psychographics

    There is a serious issue with the 2019 survey besides the fact that the data set was significantly smaller (about 9000 respondents vs. 14000 in 2014).

    In the 2019 survey, more than 40% of the respondents were dive professionals: divemasters, assistant instructors, and scuba diving instructors. If we are interested in understanding the behavior of ‘scuba divers’, the 2019 data set is highly unreliable as almost half of the respondents were scuba diving professionals.

    We know dive professionals have a behavior that can be significantly different than that of the average Joe Diver. For instance, typically, scuba instructors dive more frequently and purchase more dive gear.

    Furthermore, when comparing the two sets of data (2014 vs 2019), we are facing a double problem in regards to dive professionals. In the 2014 study, less than 10% of the respondents were scuba diving professionals (divemaster and up) while there were more than 40% in the 2019 survey

    Therefore, we are facing the following 2 serious issues with this DEMA study on scuba diver demographics and psychographics:

    ·                      We can’t use the results to understand the behavior of a ‘scuba diver’ as both reports include dive professionals that are much more committed to scuba diving than the average scuba diver — which is especially true in the 2019 set of data with more than 40% of the respondents being dive professionals.

    ·                      We can’t fully rely on trends identified in changes from 2014 to 2019 since we would be comparing oranges to electric cars.

    It is fair to assume that dive professionals are more ‘core’ divers than ‘casual’. In fact, we see that the average number of dives completed by 2019 respondents is higher than it was in the 2014 study. Learn more about core and casual divers on Scubanomics.

    We’ve contacted DEMA to request a version of both reports (2014 and 2019) excluding all dive professionals, so we can better understand the behavior of scuba divers in regards to dive travel, scuba gear, and dive certification courses. Tom Ingram, head of DEMA, assured us that they “have plans for additional segmentation of the consumer data, including based on certification levels”.

    We hope DEMA will quickly produce 2014 and 2019 reports excluding dive professionals as this would be highly valuable to its members trying to understand the behavior of scuba divers.

    In the meantime, let’s see what information we can extract from the currently available reports mixing scuba divers and dive professionals.

    Key Scuba Diver Demographics and Psychographics 2014 vs 2019

    Two interesting trends identified in our review of these 2 studies relate to eLearning and rebreathers.

    Scuba Diving Certification Courses at Home, in a Resort, and via eLearning

    An assumption often discussed in the dive industry is that online learning is hurting local dive centers because it becomes easier to bypass the local dive center by completing the ‘theory’ part of the course and then flying to an exotic dive destination to complete the ‘pool’ and ‘open water’ parts of the scuba diving certification course.

    This appears to be partially true but not as major as we usually assume it to be.

    ·                      The number of scuba divers who have completed the ‘theory’ part of the course online with no interaction with a local dive shop before flying to a dive resort to complete the ‘pool’ and ‘open water’ parts of the course has increased by less than 1%: from 6% to 6.89%

    Meanwhile, we observe more significant changes in the following modes of completing the entry-level open water diver certification:

    ·                      The number of scuba divers who have completed all parts of the scuba course while in a vacation setting has declined from 23.9% to 18.7%.

    ·                      The number of scuba divers who have completed the ‘theory’ and ‘pool’ parts of the course before going on a trip has increased from 14.6% to 17.6%.

    Therefore, it appears there is no reason to fear that eLearning is encouraging scuba divers to bypass the local dive shop. On the contrary, eLearning seems to have increased the number of people completing the ‘pool’ part of the course at home before going on a trip.

    It may be more accurate to assume that the online high visibility of eLearning is actually encouraging people to find a local dive shop to complete their pool sessions locally. It’s reducing the number of people going straight to a dive resort to complete the entirety of the entry-level open water certification course.

    Increased Interest for Rebreather, Sidemount, and Freediving

    There is a huge shift between 2014 and 2019 on the next courses respondents were most interested in taking.

    In 2014, the courses in which respondents were most interested in taking next were rescue diver, wreck diver, divemaster, and underwater photographer. This significantly changed in the 2019 survey.

    Not only the list of courses has changed but the level of interest has skyrocketed.

    We must urge caution with these numbers. As mentioned earlier, the 2019 sample included more than 40% of dive professionals who are much more committed to scuba diving than the average Joe Diver.

    Typically, scuba diving instructors have been a good target market for tech diving as they are looking for more challenges after reaching the pinnacle of recreational diving. Therefore, it is unlikely that there is an 84% interest in rebreathers in the general population of scuba divers.

    However, these numbers do indicate a significant increase in interest toward tech diving (rebreather, side-mount, other mixed gas) and freediving.

    Freediving has seen steady growth over the last few years. Dive gear manufacturers carrying freediving equipment have reported growth in their freediving line of products even when scuba gear sales were down. Both Mares and Aqualung have made significant investments in developing their freediving line of products.

    It appears freediving is appealing to the newer generations. It is challenging without requiring you to carry all the cumbersome equipment required for scuba diving. It also makes for great Instagram look-how-cool-I-am pictures!

    Role of The Scuba Diving Instructor

    The most significant information source for scuba divers to decide what they want to do next remains the dive instructor and divemaster. Instructor/Divemaster gets a score of 4 on 5 while the local dive shop gets a 2.9.

    As we’ve stated before, there is a continued need for local scuba diving activities but the focus should be on the action of scuba diving, not on trying to sell dive gear in an understock retail store. We believe that in the years to come, the role of local dive instructors will become more significant while local dive shops redefine their mission and business model.

    Related article: A New Paradigm for the Scuba Diving Industry: It’s about diving!

    What’s Next?

    Once DEMA releases the 2014 and 2019 survey results for ‘scuba divers’, excluding dive professionals, we will be able to get more valuable information out of these reports.

    Subscribe to Scubanomics to be informed when this data becomes available.

    Don’t be left out: Subscribe to be the first to know about dive industry news and market data.

    Continue reading: Scubanomics Table of Content.

    Connect, to be our dive business buddy: LinkedIn | Twitter | Facebook

    Sign up for Scubanomics: Scuba Diving Industry 2021

  • December 20, 2020 8:13 AM | Howard Ratsch (Administrator)

    Educational Blog

    Coronavirus FAQs: What Is A Pulse Oximeter? Why Are So Many People Buying One? : Goats and Soda : NPR



    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.


    Each week we answer some of your pressing questions about the coronavirus and how to stay safe. Email us your questions at with the subject line: "Weekly Coronavirus Questions." This week, we're considering questions about pulse oximeters.

    As the coronavirus continues to spread, a small medical device called a pulse oximeter has started to fly off the shelves. In fact, demand has spiked to such an extraordinary degree that you may not be able to buy one right now in your local pharmacy or online.

    What is the value of the device during this pandemic? Do you need to have one at home? The first question is relatively easy to answer. The second is a little more complicated.

    What is it?

    A pulse oximeter is a small electronic device that estimates the saturation of oxygen in your blood. You want a number in the 95% to 100% range. If the number drops to 92% or lower, that's a cause for concern. That's generally the level where a doctor might put you on supplementary oxygen and keep you in the hospital for observation.

    To come up with that percentage, the device clamps onto your finger or earlobe and shoots different wavelengths of light through the small capillaries, explains Dr. Richard Levitan, a New Hampshire-based emergency room physician who specializes in airway management. (For a more thorough scientific explanation, read this.)

    The term for low blood oxygen levels is hypoxemia. In this condition, your body's organs may not work right. Severe cases can interfere with heart or brain function.

    You've likely had your blood oxygen monitored by a pulse oximeter already. It's used during some physical exams and is considered essential during operations and intensive care. The devices also give your heart rate.

    Why are these devices suddenly getting so much attention?

    COVID-19 can bring on what's called COVID pneumonia — an infection in which the lung's air sacs fill with fluid or pus. And it's possible that someone infected with the novel coronavirus might be in the early stages of COVID pneumonia – including a drop in blood oxygen level — without experiencing any difficulty breathing.

    In such cases, a pulse oximeter might signal that you're in trouble before you realize it. That's what Levitan saw when he spent 10 days working in the ER at Bellevue Hospital in New York City earlier this month: Many COVID patients were already very sick with COVID pneumonia by the time they arrived. They were breathing rapidly, their blood oxygen levels dangerously low. Like mountain climbers, the patients had grown accustomed to gradually decreasing levels of oxygen and didn't realize they were in distress.

    Many of them said they only recently started feeling short of breath though they had experienced symptoms of COVID-19 for days. By the time the patients went to the hospital, says Levitan, the virus had already damaged their lungs, and many were in critical condition. He saw COVID pneumonia patients with oxygen saturation levels as low as 50 percent.

    "These COVID patients have adapted to this slow, insidious drop in their oxygen and they don't know it," he told NPR. "Then when they come in with shortness of breath, it is late in the process." In his opinion, a pulse oximeter could have caught the warning sign of low blood oxygen level earlier on.

    The disease "kills by silently causing [a decrease in] oxygen. When you come in late in the disease, which is basically everybody who we now have coming to the E.R., there is a high mortality," he says.

    Levitan says that in medicine, earlier treatment leads to better results — "and that's true of COVID, as well."

    Should you get one?

    Levitan thinks that in the midst of a respiratory pandemic, it makes sense to have a pulse oximeter at home – just as you might have a thermometer to track fevers. If you have symptoms of COVID-19, he says, like weakness, muscle aches or fever, you could use the device to measure blood oxygen levels.

    That 92% figure (or lower) is a sign that "you should get evaluated because this disease kills silently and you don't have to have significant shortness of breath" to be at risk. (Although people at high altitudes might have levels "in the low 90s and be fine," he adds.)

    Dr. Elissa Perkins, a professor of emergency medicine at Boston Medical Center, doesn't necessarily think everyone needs to buy a pulse oximeter. She worries that people will depend on the device's reading rather than calling a doctor if they're feeling sick.

    "I think it's a bit of a stretch to say that people should all have these at home," says Perkins, though she understands why people would want them.

    "In general, I think honestly, if people are starting to feel symptoms or feel even a little bit short of breath, they should probably contact their physician, if possible," she says. "Most places or many places at this point are offering telemedicine visits, telehealth visits and that can give a more thorough picture of what somebody is experiencing than just one number on a pulse oximeter."

    But she's not completely opposed to home pulse oximeters. She says if you have symptoms consistent with the novel coronavirus, using a pulse oximeter and consulting with a doctor can be a good strategy.

    She is concerned about one risk: People could be falsely reassured by good numbers into thinking they're not very sick. People with COVID "can get incredibly dehydrated, people can get very weak," says Perkins. "We've seen people fainting or passing out, who don't have particular respiratory symptoms and don't have shortness of breath. So it's another piece of data, but it's certainly not the only piece of data."

    There are other concerns. The reading can be less accurate if a person is wearing nail polish or artificial nails, has cold hands or poor circulation.

    It's possible to accidentally read the numbers upside down and panic over a seemingly eye-popping number. Or the device itself could be inaccurate.

    The American Lung Association chief medical officer Albert Rizzo issued a statement on Thursday advising against "buying pulse oximeters unnecessarily."

    "[U]nless you have a chronic lung or heart condition that affects your oxygen saturation level on a regular basis, most individuals do not need to have a pulse oximeter in their home," Rizzo said. "Most importantly, if you're interested in purchasing a pulse oximeter for home use, please discuss the necessity and use of the device with your health-care provider. A medical professional can determine if it would be helpful and also provide direction for interpreting the readings in the context of how you are feeling. Your pulse oximeter reading should be used along with your other symptoms such as shortness of breath, fever, fatigue, as parameters that would prompt a call to your doctor."

    Abraar Karan, internal medicine doctor at the Brigham and Women's Hospital and Harvard Medical School, is a proponent of caution as well when it comes to pulse oximeters for home use. He says it remains to be seen how predictive low oxygen levels are at correctly identifying patients who will have a severe course with the disease. He points to a recent study looking at 5,700 patients hospitalized with COVID-19 in New York City, which found only 27.8% needed supplemental oxygen at triage.

    And he shares Perkins' concern about people being either falsely comforted or unnecessarily alarmed.

    "What we don't want to happen is that people are in real distress but think that because their home pulse oximeter reads normal, that they are fine," Karan writes via email. "We also need to make sure that patients are using the pulse oximeter properly and that it is reading correctly — otherwise, you could have more people coming to the emergency room that may not need to be there."

    But Levitan says that kind of strain on ERs already happens when people interpret home blood pressure monitors or thermometers incorrectly. A much bigger concern, Levitan says, is people dying suddenly from COVID. And he doesn't worry that the device will just make people more anxious: "You know what? We've got fear. We've got anxiety. We need reassurance."

    Where do I buy one — and how worried should I be if there's a delay in getting it?

    If you do think a pulse oximeter would be valuable, Levitan suggests buying one from a medical source like a pharmacy rather than a random site on the internet – and it's a good idea to look for one that's been FDA-approved, if possible. You can go to the FDA's 510(k) Premarket Notification page here and search for "oximeter."

    It's possible to buy devices that haven't been approved for medical use, and such devices may be less accurate.

    Just a few months ago, it would have been easy to find consumer models costing about $30 typically on pharmacy shelves. They are often used by people with chronic lung disease who are taking supplemental oxygen to make sure they were getting the right amount of oxygen.

    With many pharmacies sold out, people are turning to sites like eBay and Amazon, where devices can be found in the $60 range.

    But Levitan says you shouldn't fret if you have to wait a few weeks to get one: "You know what? We have 12 to 24 months of this [coronavirus]," he predicts.

    He says in an age of respiratory pandemics, there is very useful health monitoring that people can do form home, in concert with a phone call to a medical professional.

    "We need to change the public perception of what health monitoring means in this age of respiratory pandemics," he says. "When you combine heart rate measurement, oxygen saturation and temperature, which are all three things you can do at home — and especially if you combine it with a phone call to your doctor or to your local emergency department ... that's incredibly informative."

  • October 21, 2020 7:08 AM | Howard Ratsch (Administrator)

    Educational Blog

    A New Business Model for a Redefined Local Dive Center

    COVID-19 accelerated changes happening in the scuba diving industry. How to be ready.

    By Darcy Kieran

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    Retail, education, and travel industries are going through a severe transformation that started before the coronavirus pandemic. But the speed of change has accelerated in a COVID-19 world, and we need to keep up — or better yet, get ahead of the curve. The dive industry has been resisting changes to its business model for a while but can no longer withstand a tsunami of changing customers’ expectations and behavior.The global pandemic has reset the gameboard. How can dive businesses emerge stronger?

    I will look at the historical ‘distribution channel’ used to provide scuba diving lessons, dive gear, and scuba diving travel to scuba diving consumers. Then, I’ll look at how it is changing and how the current coronavirus pandemic is accelerating this evolution. Finally, I’ll look at what it means for your scuba diving business.

    Traditional Distribution Process for Scuba Diving Products & Services

    Historically, dive gear and scuba lessons have been provided to the consumer by ‘local dive shops’ (in ‘origin’ dive centers) and ‘dive resorts’ (in dive destinations). And way back then, dive travel was mainly sold by local dive shops.

    We’re talking, here, pre-internet. But the dive industry business model barely changed after the arrival of the internet. Consumers have changed, but not the scuba diving industry.

    Bear with me for a minute.

    Pre-internet, it was difficult for a newly certified scuba diver to independently select the best dive destinations for his/her annual vacations. The dive instructor in the local dive shop was the principal source of information. Scuba divers would come to the local dive center to check pictures of previous trips to different scuba diving destinations. And group travel was arranged by the dive instructor.

    Dive gear manufacturers, scuba diving training agencies, and dive resorts (dive destinations) were relying on local dive shops to reach consumers.

    The local dive shop was both ‘the front line’ and the gatekeeper.

    This model doesn’t work anymore, and you can expect this fact to be even more apparent post-COVID19.

    Noticeable Dive Industry Trends

    I will be looking at ‘trends’ but only as it relates to the distribution channels used to reach scuba diving consumers.

    Trends in Dive Travel

    Dive travel was the first scuba diving industry sector to bypass the local dive shop significantly. Knowledge about dive destinations is now available to all, on the internet — with much more in-depth knowledge than what the local dive instructor could provide.

    A local dive professional can’t be knowledgeable about every dive destinations in the world. In that sense, the internet is providing more value to the scuba diver. And ‘providing value’ is vital for a business to be sustainable.

    The next dive industry segment to bypass the local dive shop (in ‘origin’ locations) is scuba diving training.

    Trends in Scuba Diving Training

    Initially, online education (eLearning) was introduced as a means to let dive instructors do what they love best — be in the water — while the ‘boring’ part of teaching in-class could be done at home ‘in the comfort of your pink slippers.’

    What eLearning also created is an additional way to bypass the local dive shop. It is quite simple and convenient to proceed with the ‘dive theory’ part of learning to scuba dive at home — or at work! And, then, you get to your dream vacation destination where you will go underwater with a dive instructor, first in a pool, then in the magical ocean.

    I do not believe this provides the best value to the consumer. You end up with rushed ‘confined-water’ (pool) training sessions because there are just so many more exciting things to do under sunny tropical skies! Cutting corners is no way to fight our excessive dropout rate. But it is a challenge to be communicating to future scuba divers that it is more valuable to them (in the long run) to be learning to dive at their local dive center before going on vacation. Therefore, the trend toward going to a dive resort after eLearning is continuing to grow.

    With COVID-19, learning online instead of in-person has become the norm rather than the exception. It means that selling online courses will simply be easier than ever before. The coronavirus pandemic has accelerated the trend toward eLearning.

    Within the dive industry, we’ve seen training agencies rush to launch new online learning programs — about anything and everything.

    This eLearning trend is here to stay, and it means that it is becoming even easier to bypass the local dive shop.

    “The shift of learning from outside the home to inside has blurred the lines between learning and leisure.” McKinsey & Company

    To counteract this trend, local dive shops would need to reach local consumers while they are researching ‘scuba diving in Fiji’ or ‘PADI certification in Cozumel.’ Even with an unlimited online marketing budget, this would be a tough challenge. And local dive shops barely have any marketing budget!

    Trends in Scuba Gear Distribution

    This was the last leg on which local dive shops could still hope to stand. And there would be a lot to say about this! But I will move as quickly as possible to discuss ‘what to do about these trends.’

    Selling scuba diving equipment is the way most local dive shops have kept the lights on. The cycle of extracting money from clients in a local dive shop has, for the most part, be in this order:

    1.                     get them in with cheap scuba lessons,

    2.                    sell them overpriced dive gear, and

    3.                    book them on a dive trip to sell them more courses and equipment.

    With the beginning (training) and the end (diving) of this cycle bypassing the local dive shop, it is making it hard for local dive shops to keep their lights on! Scuba divers going straight to the dive resort are often not even aware of the existence of a local dive shop.

    And that’s only one trend.

    Another significant trend with dive gear has been a reduction in “sales per diver.” New scuba divers tend to buy less scuba equipment than their male baby boomer predecessors. This could be an entire post in itself. Make sure to subscribe to Scubanomics at the bottom of this article.

    Otherwise, a crucial development in retailing, of course, is eCommerce. That’s another trend we’ve seen surging during this worldwide pandemic. If you are not convinced, look at this graph from McKinsey & Company, a renowned US-based management consulting firm that advises on strategic management to corporations, governments, and other organizations.

    Just like eLearning is now part of everyday life, eCommerce is now more accepted than ever before. The dive industry can’t continue to ignore this fact.

    Why has eCommerce been so slow at being implemented in the dive industry?

    There are numerous reasons why eCommerce has been slow at penetrating the scuba diving industry.

    For one, dive industry leaders have continued to maintain that the local dive shop was, and ought to, remain the focal point of the industry. This was based more on nostalgia than on sound business principles.

    Can local dive shops operate an eCommerce site in a way that will satisfy today’s consumers? No. It would require an investment far superior to what a local dive shop owner could afford.

    When shopping online, consumers expect speed and convenience. Delivery has to be tomorrow, or earlier! And convenience means that a scuba diving equipment website should have all models in all sizes and all colors. Our internal distribution issues are none of their concern! On this front, as for dive travel, the internet is providing more immediate value to the scuba diving consumer than the local dive shop with its limited inventory and product knowledge.

    By pretending that local dive shops were able to continue to satisfy evolving consumers with a small, undercapitalized store, the dive industry has simply delayed the inevitable.

    Direct to consumer’ is how most dive gear manufacturers will try to offset a reduction in scuba gear sales in local dive shops. We can already witness it on Aqualung’s USA website, which is now a full-fledged eCommerce website.

    You can’t blame dive gear manufacturers from bypassing local dive shops — they were the last to do it after scuba diving certification agencies and dive travel.

    New Distribution Process for Scuba Diving Products & Services

    The local dive shop is no longer ‘key’ in reaching scuba diving consumers, and it is facing an existential challenge: What is the new raison d’être of the local dive center?

    A Redefined Local Dive Center

    First, let’s address the elephant in the room.

    I can hear you yelling at me through your smartphone screen! “Local dive shops are crucial for the diving community. They provide air fills as well as access and information on local dive sites.”

    Yes. I know.

    In fact, the current coronavirus pandemic is contributing to making local dive shops more of a dive destination than merely an ‘originator’ of clients for dive resorts in the tropics. But here’s the thing… That’s about scuba diving (the activity), not selling gear.

    Local ‘dive centers’ can still bring value to scuba diving consumers. Dive ‘shops’ provide very little value nowadays.

    Shaming people into buying dive gear from you because you are providing air fills was always a non-sustainable business scheme, and it is now utterly disconnected from reality.

    local dive shop sells six different products and services to scuba divers:

    ·                      Education / Training

    ·                      Equipment / Toys

    ·                      Experience / Travel (the activity of scuba diving)

    ·                      Rental Dive Gear

    ·                      Repair and Maintenance

    ·                      Refills

    The first 3 are the big ones. They are known as the 3Es or the 3 Ts.

    We’ve already discussed them. These products and services no longer need the local dive shop to reach end-users. And in many cases, the scuba diving consumers find more value when shopping outside the local dive shop. ‘Value’ includes convenience, product knowledge, and availability.

    We need to face reality: the 3 Es (or 3 Ts) are bypassing local dive shops, and that trend is intensifying.

    So, now what?

    You can only swim against the current for so long!

    The way to be successful in any business is by bringing value to consumers. And that could be in the last three services listed above. They can more hardly be remotely provided.

    It is conceivable that repair & maintenance and rental gear could eventually be provided from a centralized and remote location. But for now, these are services for which scuba divers may directly benefit from your local services.

    In other words, the local dive shop should drop the word ‘shop’ and work on being a quality ‘dive center’.

    Find a location near an appropriate local dive site. Setup a fill station for air, nitrox, and possibly trimix. Maintain quality rental dive gear to be used at that dive site by scuba divers and dive instructors. And offer repair & maintenance on scuba diving equipment.

    That is a ‘local’ business.

    I bet you’ll find that your profitability may even go up! Maintaining a retail store can be expensive.

    At that new dive center location, the focus is on scuba diving. That’s why you want to be near a proper local dive site. You may also select a pool, especially if it’s deep enough for scuba divers to practice their skills outside of scuba lessons.

    Of course, you may offer scuba diving lessons at that location, but the focus has to be on promoting ‘scuba diving’. The rest is just there to support the activity.

    And now is a good time to do it. People are looking for adventures close to home.

    Operating under this new business model requires that each of these services be profitable in itself. You can no longer rely on selling overpriced dive gear to subsidize the rest of your operations. It is not sustainable. It is preventing evolution in the dive industry.

    Promotional & Visibility Issue

    I know the owner of a local dive shop in an urban area who will be transforming his local dive business into such a dive center, dropping the in-store retailing of dive gear.

    The first problem you will encounter if you proceed like him is with dive training agencies and scuba gear manufacturers.

    To be listed on their website as a retailer or training center, you must be operating a store. Scuba diving training agencies and dive gear manufacturers are forcing us to maintain this non-sustainable model of a ‘local dive shop’ operating 6 businesses under one roof.

    So… The h*** with them!

    Your main source of new clients is likely to be Google and word of mouth.

    Word of mouth and good reviews will be easier to get if you concentrate your energy, money, and time at providing what you are good at, instead of trying to be everything to everybody. You got into diving because you love diving. Focus on that! That’s how you will be able to offer consistency in the quality of the experience under your personal craft brand.

    This is how you can plan to make a good living out of your passion for scuba diving.

    Furthermore, soon, the most significant part of your revenues should come from repeat business because your focus is on the adventure of scuba diving. Your business model is based on people diving locally. It is no longer based on quickly churning new entry-level scuba diving certifications to please the PADI and SSI of this world.

    Otherwise, Google is not like your dive training agency. You do not need to operate a retail store to be listed as a business on Google map. The same principle applies to Facebook. Take advantage of that!

    It will be good for you — and for the dive industry.

    It’s always been ridiculous that consumers searching how to ‘learn to dive’ on Google where being directed to ‘retail stores’ selling gear, while the actual location to take the scuba lessons was often miles (kilometers) from there!

    This is a business opportunity for your local diving business, and it can be an exciting transformational time for the scuba diving industry.

    A Future Scuba Diving Brand Based on The Experience

    The scuba diving industry is lacking a reliable worldwide brand. Scuba diving is a global activity, no matter where you live. And the experience you encounter under Brand A in dive destination X is usually totally different than the experience you discover under the same Brand A in dive destination Y.

    Since scuba diving is an activity where safety matters, scuba diving consumers need to have ‘trust’ in the quality of the experience they will encounter, everywhere they go.

    Eventually, we will see a scuba diving brand establishing itself as a provider of a consistent scuba diving experience at all locations. The focus will be on the consistency of the quality of the activity of scuba diving.

    Keep an eye out! That is the brand under which you would want your reborn ‘local dive center’ to be operating.

  • October 11, 2020 8:59 AM | Howard Ratsch (Administrator)

    Educational Blog

    Sunken Treasures: What Makes Divers Love Wreck Diving

     For some divers it’s...

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    By Dive Training
    November 2, 2019

    The sport of scuba diving is certainly diverse, with something for everyone — at every depth and all experience levels. For some divers it’s captivating coral reefs with rainbows of colors and fascinating tropical fish. For others it’s the excitement of encountering sharks, rays and other large animals. Cave diving is another pursuit driven by the quest for discovery and an attraction to uncharted tunnels and passageways. But just what is it about shipwrecks? The interest in wreck diving seems to have increased, as evidenced by the greater number of wrecks deliberately sunk as “attractions” for divers to enjoy. Whether they’re sunk intentionally as artificial reefs or recently discovered archaeological treasures hidden in their watery graves for centuries, for whatever reason, shipwrecks draw divers.

    Wreck Diving and the ‘Why’

    Ships end up on the bottom of the ocean, lakes and rivers due to navigational errors, collisions, storms, wartime casualties or as a result of onboard mishaps such as fires or explosions. Also, there are more and more ships now being sunk intentionally to create artificial reefs. In general, shipwrecks in shallow waters and close to shore are the easiest to access and dived the most. Deeper wrecks and ones in more remote areas are dived the least. Many remain undiscovered or undived. With technological advances in sonar and magnetometer technologies, new wrecks are found every year in all oceans of the world. And more and more ships are also being sunk purposely to form reef environments to benefit divers and fishermen.

    The fact that shipwrecks offer a habitat for marine life is especially important in areas that have few natural reefs. The many flat, featureless areas of the Gulf of Mexico’s continental shelf make it prime for artificial reefing. The USS Oriskany sunk off Pensacola, Florida, in May 2005 and the Texas Clipper put to rest in Texas waters off South Padre Island are two examples of ships-to-reefs.


    Serious wreck divers seem to have an innate sense of exploration. It’s part of their core being. They live to venture where few if any have been. They yearn to unravel information and to discover what has not been known. To penetrate and explore the interior of a wreck, especially if few or none have done so, is a thrill that fuels the passion for discovery.

    For some that pursue wreck diving, historical interest is the driving force. Shipwrecks are like windows into the past. Researching the background and circumstances that led to the tragedy and then visiting the wreck site years, decades or perhaps centuries later can be like taking a journey through a time warp. Other divers are simply fascinated by the size of many wrecks and the major components and machinery that can be approached and viewed in a way that would never be possible before it sank. To swim past a colonial-era fluked anchor or to see an old crusty cannon laying in the sand can conjure thoughts of another era. Or to swim through an engine room, a bridge or crew quarters may make one wonder about the life on board the vessel years ago when it was underway plying the seas. Shipwrecks also offer many divers an environment to simply advance and hone their diving skills. A very large wreck upright in warm, clear water provides a perfect environment for several levels of development from Advanced Open Water, to various specialties and technical diver ratings.

    Serious wreck divers seem to have an innate sense of exploration. It’s part of their core being.

    Here are responses from several seasoned wreck divers when asked the “Why” question: “It’s the challenge and exploration of the unknown,” says Gary Gentile, famed wreck diver and author. “I always feel excited heading down the anchor line as I think about what I might discover inside the wreck, even if it’s a wreck I’ve dived before.” For Great Lakeswreck expert David Trotter, “It’s the desire to discover, explore and solve the mystery of ‘ships gone missing.’” Author of “Shipwrecks in the Sunshine State,” Michael Barnette says, “The factors that compel me to explore shipwrecks are curiosity, a fascination with maritime history, and a natural love of the ocean.” Barnette prefers “particularly deep or unidentified shipwrecks — places no one has been before.” United Kingdom wreck diver and explorer Leigh Bishop uses mixed gasses to “venture to areas where no dive charter has been before.” Leigh considers now “the Golden Age of shipwreck discovery around England” where he says there are more wrecks per square mile than anywhere in the world.

    Wreck Diving Training and Safety

    Wreck diving poses a unique array of hazards for any diver. Because so many wrecks constitute snags and obstructions on the seabed, trawler nets and high-test monofilament fishing lines are commonly strewn across wheelhouses and hulls. Now factor in low or no ambient light and an overhead environment that can easily trap a diver and prevent free ascent to the surface. Inside there may be sharp edges, loose cables, structurally unsound bulkheads, and a maze of passageways. Many wrecks fill with silt or mud that can easily stir, resulting in reduced visibility and serious orientation challenges. A diver trained only to an Open Water level has no more business penetrating a shipwreck than entering a cave.

    Wreck diving is an advanced skill and requires special training and equipment. But the necessary skill sets for wreck diving vary widely depending upon the specific circumstances: depth, water temperature, condition of the wreck, sea or lake conditions, and the degree of penetration, if any. Whereas an Open Water certification is adequate training to dive outside and around a shallow, tropical-warm water, well-lit, “trap-free” wreck in, say, Bermuda, to safely dive a deep, coldwater wreck like the Andrea Doria is the other extreme that requires special equipment and a training and experience level way beyond Open Water. Many wrecks at recreational depths are intermediate-level dives most of the time but as conditions change, namely current or visibility, they can transform into very advanced dives.

    The best advice is to do plenty of homework on wreck diving and get additional training before attempting wreck penetration.

    §                             Talk to the dive operator about the wreck or wrecks to make sure you have the proper skill level, experience and equipment for the dive.

    §                             Make certain you are properly outfitted for wreck diving and your gear is streamlined and snag free. Check for proper hose lengths and dive with only essential gear. Essentials while wreck diving may include two knives or cutting tools, primary and spare lights, reel and line, lift bags, alternate and redundant air supplies or more depending upon the dive.

    §                             Divers making repeat dives to a wreck need to be cognizant that the sea is constantly taking its toll. A section or a wreck that was sound and stable a few months ago may have become unstable over time.

    §                             Also, even after completing advanced and wreck diving courses, always take one step at a time in your progression as a wreck diver. Never make a dive changing more than one new variable. For example, if you are accustomed to warm-water diving, start with a wreck in warm water and begin by exploring only the outside of the wreck. Attempting a first-ever dry suit dive coupled with first-ever penetration is taskloading, and the load might just be too much too handle in one outing.

    Penetrating a wreck is a serious decision and should never be done on a whim without solid preparation, proper equipment and a well-thought-out plan. Wreck diving holds a wealth of opportunity for exploration and discovery. From the Great Lakesto Great Britain, and from North Carolina to the South Pacific, there’s a near endless list of wrecks waiting to be explored. Start training now and you’ll have a lifetime of adventure waiting for you as a wreck diver.

    Maritime History

    In all likelihood, the first boats built go as far back as the Stone Age when dugout canoes were used for fishing. Ancient civilizations relied upon rivers and seas for fishing, transportation and trade routes. As early civilizations developed, man realized that the most practical method for moving large quantities of materials or large numbers of people long distances was by floating them in a vessel. Ships clearly affected the course of our civilization. Historical records have tremendous value but artifacts provide a different insight to where we came from and how our ancestors lived their lives. Shipwrecks really are portals to the past. Many clues to where we came from remain hidden in ancient wrecks in the sea.

    The use of navigational methods dates back at least 5,000 years. In 3000 B.C. the ancient Egyptians developed the first vessels powered by wind. Egyptians used their wooden-hulled ships to explore the far reaches of the Red Sea. But the Aegean Seagets the credit for being the cradle of maritime history in the Western Hemisphere.

    “Before there were shepherds or farmers in Greece, there were sailors,” says George F. Bass, pioneer and father of underwater archaeology. In the early Bronze Age (3000 B.C.) sailors moved copper and bronze materials between Crete, Asia Minorand the Greece mainland. But by 2000 B.C. the Phoenician civilization had developed a maritime trading economy that spread across the entire Mediterranean Sea. They moved along the northern African coast returning with riches from Spain and Great Britain in ships with sickle-shaped hulls and straight-rising stem and stern posts. By the end of the first century and after a series of wars, the Romans became a major maritime power that controlled the Mediterranean, or “Inner Sea.” They were the most powerful empire in the Western Hemisphere and their elite demanded silk, spices and other exotic goods from the far reaches of that time, namely Egypt and Arabia.

    During the Middle Ages, Norsemen from Scandinavia used their vessel-building prowess to raid Britain and Ireland from the sea. Their double-ended designs with dragon-headed prows were constructed of overlapping oak planking and were powered by both oars and wind. When the wind was inadequate to fill the massive square sail, up to 20 oarsmen took over to power these sleek, efficient troop carriers.

    By the 15th century, Europeans were venturing out to sea establishing new commerce routes and trading partners. Soon after the historic Columbus voyage in 1492, European sailors recognized the wind patterns in the North Atlantic caused a clockwise sailing route to and from the New World. At that time the Europeans were in heavy economic competition for natural resources and were establishing colonies to secure their country’s power and wealth. The British, French, Portuguese and Dutch were all flexing maritime might to stake their claims. In 1578, Sir Francis Drake became the first to circumnavigate the globe in a galleon-design merchant ship. Later the sleeker, faster clipper ships were used to further expand trade between the West and the East.

    Maritime commerce in America’s Great Lakes has its roots in the days of the French fur trade. But it wasn’t until after the War of 1812 that permanent settlements flourished and commercial shipping expanded. Ship traffic picked up during the Civil War era and increased steadily through the early 20th century. Schooners, paddlewheelers, freighters, and passenger cruise liners crisscrossed the often treacherous waters of the Great Lakes. Over the years, thousands never made it to their final destinations.

    America’s first Continental Navy was established in 1775 with only six frigates. Naval ships and their designs were crucial in the early years of the United States, from the Revolutionary War and through the War of 1812 and the Civil War. Ship design progressed from sail and oar power to steam engines. Although prototype submarines date back to the late 1500s, it was during the 19th century that submarine designs were advanced for effective use in warfare. The famed battle of the ironclad CSS Virginia and the USS Monitor at Hampton Roads in 1862 had a major effect on the future of naval ship design and warfare.

    In the 1900s, modern internal combustion engines replaced steam engines and steel-hulled ships gradually replaced the wood-hulled fleets. Ocean liners replaced sailing vessels while the navies retooled their fleets with destroyers and armored cruisers. The Germans used submarine warfare in 1917 to strangle the Allied shipping commerce and World War I saw the first use of aircraft carriers.

    By the time the United States entered WWII, German U-boats were stalking and sinking Allied ships along the East Coast of the United States and Canada as well as in the Gulf of Mexico and the Caribbean. German submarine technology and production advanced rapidly. More than 1,100 U-boats were launched during World War II, but by 1943, the Allies were producing ships at a rate faster than the U-boats could sink them. Eventually new detection technologies and improved naval tactics resulted in fewer U-boat casualties. In the Pacific Ocean between 1942 and 1945, hundreds upon hundreds of ships were sunk in hard-fought battles across the Pacific southwest region.

    In July 1956, the Italian passenger liner Andrea Doria collided with the MV Stockholm near Nantucket, Massachusetts. It went down in 250 feet (76 m) of water that rarely is above 48 degrees Fahrenheit (9 degrees Celsius). In 1991 the maritime tragedy was the Salem Express and in 2006 it was the Al-Salam 98. Both were Egyptian ferries heavily loaded with workers and pilgrims that capsized in the Red Sea. Every year trawlers, tankers, ferries, cruise ships and even submarines end up wrecked underwater.

    Marine Archaeology

    Part historian and part scientist, archaeologists thrive on painstaking efforts to locate, retrieve, identify and catalog artifacts. They are trained to discover and preserve the lost and forgotten, whether buried in the ground or hidden on the bottom of the sea.

    Most marine archaeological sites are shipwrecks but some are the result of earthquakes. There are also ancient villages once located near the sea that are now underwater due to rising sea levels since the last Ice Age. For shipwreck sites, the ship, the cargo and the crews’ personal effects are all important for better understanding the social, economic and political conditions of the past.

    The chemical composition of the water environment, depth, temperature and level of light are all factors that can affect the condition of a wreck over time. Deeper wrecks tend to be better protected whereas shallow wrecks can be subject to commercial activities such as shipping, fishing, and oil and gas development. Shallow wrecks can also be affected by wave action from hurricanes and storms or from surf action. Salt water will rapidly corrode iron-based wrecks and artifacts. Sea organisms like the teredo navalis worm destroy wood and other organic materials. Fresh water is significantly less hostile than seawater. The cold, freshwater wrecks in the Great Lakes are incredibly well preserved, and many are almost fully intact after hundreds of years of submersion. The unusually low deterioration rate in this environment sustains an underwater museum for schooners, side-wheel steamers, passenger freighters and brigantines. Wooden barkentines from the 1800s remain upright with standing masts and secured yard arms.

    In the sea, a cover of sediment can preserve an old wreck by protecting it from organisms and oxidation. The dilemma many underwater archaeologists face is weighing the cost of a proper archaeological investigation with the potential value of the recorded recovery, and knowing that as the clock ticks, the underwater records are further deteriorating. Wrecks and artifacts removed from the ocean need to undergo a very special and lengthy preservation process. It can take years to fully stabilize materials that have been in the ocean. In 1960, George Bass, professor emeritus from Texas A&M University, was the first person to lead an excavation of an ancient shipwreck in its entirety underwater. But not all historically significant shipwrecks are excavated underwater. The French explorer Sieur de La Salle lost one of his ships in a shallow Texas Bay in 1685. More than three centuries passed before it was discovered buried in mud at a depth of 12 feet (4 m). The archaeologists devised a plan to excavate the wreck in place “dry.”

    From the antiquities to the modern era, shipwrecks are time capsules waiting to be opened. Some lay upright, while others upside down or resting on their sides. Over time many become buried in the silt and protected. Ones left exposed to the harsh elements of the sea eventually break into pieces, crumble and become a scatter of parts and pieces.


    Marine archaeologists and treasure hunters have been at odds for years. Archaeologists complain that treasure hunters disturb and often destroy wreck sites. They say treasure hunters often diminish their ability to systematically obtain knowledge from the remains of the ship. Marine archaeologists are especially critical of treasure hunters seeking financial gain over historical recovery and knowledge. Archaeologists often accuse treasure hunters and collectors of depriving them of finds and destroying critical information contained in the wreck. At best the treasure hunters are deemed ignorant of proper recovery and cataloguing techniques and, at worst, they are called looters.

    Many treasure hunters make the simple argument of “finders keepers” and rely on Admiralty Laws to support their salvage claims and treasure finds. With the spirit of adventure and itch for mystery fueling countless hours of research followed by costly searches of the depths, the finders argue they paid their dues and deserve the spoils for the risks taken. They claim that archaeologists overplay the “historically significant” card. They insist that many shipwrecks are no more than wrecked trucks or buses that had hulls instead of wheels. And it doesn’t have to be a gold or silver find. It may be an artifact as simple as an old bottle or a brass spike. Purist wreck divers argue for leaving everything as it is for others to see and for the next generation to enjoy, yet collectors often argue that if they don’t take it now, the sea eventually will. Teddy Tucker, Bermuda’s pioneer wreck salvor, once said that marine archaeologists “want to control everything.” He contends that many archaeologists recover important artifacts only to load them in warehouses instead of making them accessible to the public. Another complaint is that the marine archaeologists don’t do enough to educate the layman on the significance of wreck artifacts. The “treasure hunter versus archaeologist” arguments continue but it is inarguable that the search for artifacts of the past inspires many.


    A significant event in U.S. history occurred off the coast of Texas on January 11, 1863. The USS Hatteras, a 210-foot-long iron-hulled side-wheel steamer sent south to blockade the port of Galveston, sighted a suspicious set of sails in the distance. After a four-hour chase, the Yankee gunboat armed with four 32-pound cannons caught up to an unidentified black-hulled square-rigger. Initially the vessel in pursuit identified itself as the Spitfire under British flag but as soon as the USS Hatteras commander Homer C. Blake let his guard down, the black-hulled ship announced its true identity as the CSS(Confederate State Steamer) Alabama and blindsided the Hatteras with a point-blank broadside gun blast. In 13 minutes the USS Hatteras was on the bottom in 40 feet (12 m) of water. The Alabama suffered no damage. Two Union crewmen were killed. Today most of the ship is buried beneath the sand and mud 28 miles (45 km) due south of Galveston. Parts of its 500-horsepower walking beam steam engine and the tops of both of her paddle wheels protrude from the bottom. The Hatteras is a direct link to the Civil War and it has great historical significance as a naval wreck that sank under battle off the coast of the United States.

  • September 17, 2020 3:30 PM | Howard Ratsch (Administrator)

    Challenging The “Rules” of Scuba Diving: Because Not Everything is Black and White

    By Dive Training
    September 7, 2017

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    If you’re like most divers, you’ve heard of — and perhaps adhere to — procedures that are considered “normal” within our sport. A few classic “always and nevers” include: always dive with a buddy; always do your deepest dive first; always wear a snorkel; never put your mask on your forehead; always end your dive with at least 500 psi remaining in the tank and — perhaps the number one scuba diving “never” of all time — never hold your breath.

    At first glance, these might seem like black-and-white concepts. Except, guess what? They’re not. At least not entirely.

    This might sound like I’m on the verge of committing scuba heresy, but please take a couple of deep breaths and keep reading, because in this article we’ll examine — and even challenge — several widely accepted “rules” of scuba.

    Rulemaking 101

    Human beings are social creatures. We essentially want to be accepted in society, to be viewed as normal. Without diving deep into sociological terminology, the concept of norms provides a key to understanding social influence in general and conformity in particular. Social norms are the accepted standards of behavior of social groups. Behavior that fulfills these norms is called conformity. Social norms often evolve into rules, which are defined as explicit or understood regulations or principles governing conduct within a particular activity. Rulemaking is one of the basic impulses humans have for organizing and simplifying actions.

    Norms — and the rules that often evolve from them — provide order in society. These are some of the reasons why most people, most of the time, conform to social norms and abide by certain rules.

    The thing about rules is that sometimes they are based more on folklore than fact. And sometimes rules change when new facts are revealed. Take Nitrox diving, for instance. When it was first introduced decades ago there was a big hubbub about it being a dangerous “voodoo” gas that could potentially kill divers. It was condemned by the major scuba diving magazine at the time and banned at popular dive destinations. Now we know differently and divers everywhere are safely using Nitrox.

    Those who challenge social norms and set out to bend or even break the rules sometimes find themselves at the center of controversy. They often get branded as troublemakers and might even find themselves at odds with the law. However, these people also tend to be significant change makers.

    Let’s examine some commonly accepted scuba rules regarding equipment and dive practices that might be worthy of bending. If nothing else, they’re worth pondering.

    Equipment-Related Rules

    Always wear a snorkel.

    The snorkel is a required accessory for scuba diving students and their instructors to wear during training dives. But once certification requirements are fulfilled there are instances when wearing a snorkel attached to the mask can prove problematic. For instance, it presents a potential entanglement hazard when scuba diving in overhead environments, such as wrecks or caverns. In addition, it can create drag when diving in a current.

    Still, a snorkel is a useful accessory when at the surface. In recent years several innovative scuba equipment manufacturers have developed flexible snorkels that roll up small enough to fit in your buoyancy compensator (BC) pocket and/or fold into their own “shell” carrier that clips to the BC. For this reason, I’d like to edit the “always wear a snorkel rule” to read, “always carry a snorkel.” When the dive is done and you’re ready for a surface swim, locate your snorkel, attach it to your mask and you’re good to go.

    Never put your mask on your forehead.

    Okay, this one is a pet peeve of mine. I wrote about it in the May/June 2016 Final Check column, titled, “What It Looks Like When … Safety is Your Best Practice.” Somehow, somebody got a whole bunch of divers believing that placing the mask on the forehead is the international signal for “diver in distress.” Except, that’s just plain wrong.

    It is not uncommon for a panicky diver to jettison the mask and regulator. This action is a panic response, which is an indication, or a sign, that the diver is experiencing a problem. However, it is not a signal, as in “if you are having a problem, put your mask on your forehead to signal you are in distress.” If you surface from a dive and need help, signal, “I am in distress and need help” by waving one or both arms above your head. (It’s also a good idea to use an audible signaling device such as a Dive Alert™ or whistle.) There are plenty of instances when a completely happy, non-panicky diver might place the mask on his or her forehead without incident. That said, there are times when placing the mask on the forehead might not be a good idea, like when you’re in choppy seas. If your practice is to prop your mask on your forehead upon surfacing from a dive instead of leaving it in place, you run the risk of having the mask dislodged by a wave — and getting lost to the deep.

    No gloves allowed.

    Believe it or not, this is actually a hard-and-fast rule in many tropical dive destinations. In some locations, divers caught wearing gloves while scuba diving, face stiff penalties. (Fines may also apply to dive operators.) The idea behind this rule is that wearing gloves encourages divers to grab — and subsequently damage — delicate corals, whereas barehanded divers will think twice about doing so because they risk being cut by sharp coral or stung by stinging marine creatures.

    I wholeheartedly support the environmentally conscious intent behind this rule. However, I do not agree with the practice of strictly prohibiting divers from wearing gloves. Some divers have medical issues requiring them to protect their skin from exposure to sunlight, have clotting issues that turn a simple cut into a medical crisis or run risk of infection due to a cut. These folks shouldn’t need a note from their doctor in order to be allowed to wear gloves while diving.

    This month’s Final Check column, “What It Looks Like When … You Are Careful What You Touch,” addresses the potential danger of grabbing a marine-life encrusted mooring line during a safety stop. While no one associated with this magazine promotes the wanton destruction of marine life, we think the ban on dive gloves goes a bit too far. Instead, we’d like to see industry stakeholders continue to promote environmentally safe scuba diving practices that encourage divers to avoid touching corals, while still allowing them to wear gloves when needed. For instance, a diver can easily stash a pair of gloves in a BC pocket and retrieve them for use when grasping an encrusted mooring line during a safety stop.

    Always turn the tank valve back a quarter- or half-turn.

    This one’s been around forever. And it’s wrong. Don’t do this. Instead, always turn the valve all the way on and leave it that way. Do not turn it back at all.

    Apparently, the reason this practice got started is because someone decided that divers might inadvertently “strip” the valve by attempting to turn it on after it was already on. Tank valves are pretty hardy. The chances that you’ll damage a valve are slim. However, if you partially close the valve and then descend to a deep depth, the partially closed valve could restrict the airflow from the valve, making it difficult for you to breathe while on a deep dive. To avoid having problems with restricted airflow at depth always turn the valve all the way on. You are more important than a tank valve. Never turn it back a quarter- or half-turn.

    Ruling How We Dive

    Never dive alone. Always dive with a buddy.

    When recreational scuba diving first started, the relatively crude nature of early dive gear made it necessary for divers to help each other out. The buddy system was born of common sense. It’s hard for many new divers to imagine going on a dive without a BC, submersible pressure gauge (SPG), alternate (or redundant) air source or a dive computer, but all these devices were absent from early dive training. They simply hadn’t been invented yet. Keeping this in mind it’s easy to imagine why having a buddy was considered mandatory. In fact, buddy breathing — sharing one tank and regulator between two divers — was a critically important skill taught in early scuba classes. Over several decades, equipment advances have enabled divers to become safer. And more self-sufficient. Thanks to the development of alternate air sources and redundant air delivery systems, and the fact that buddy breathing itself could be inherently dangerous, the buddy breathing skill has been purged from today’s scuba diving training courses.

    Where it was once considered risky and even foolhardy to solo dive, the practice is slowly gaining acceptance. Several major scuba-training agencies offer Solo Diver and/or Self-Sufficient Diver certification courses aimed at increasing diver independence and reducing an individual’s dependence on the buddy system.

    However, despite advances in equipment and training, the issue of solo scuba diving remains controversial. Some industry experts argue that buddy diving can carry with it greater potential risks than solo diving. Some recreational divers agree, complaining about being randomly paired with a buddy they’ve just met. Some dive operators prohibit solo diving, insisting that their customers be in buddy pairs or teams, often on guided dives. Still other dive operators allow solo diving for those qualified and equipped to do so.

    A word of advice for those who wish to solo dive on a charter: reach out to the dive operator in advance to discuss your solo diving preference. Be willing to provide proof of your solo diving experience. Recognize that the dive operator has the right to deny your request to dive solo and insist that you abide by their stated operational policies. If this is the case, you have the option to seek the services of a dive operator that welcomes solo divers.

    It’s also important to note that in certain areas, such as city, county, state or national parks, solo diving might be prohibited. It pays to read the fine print when planning a solo dive inside park waters.

    On a personal note, I’ve made my share of solo dives, usually on shallow sites not far from shore. I have enjoyed the freedom and solitude of solo diving without any problems. I think those who are willing to accept responsibility for their own safety as a solo diver should be respected rather than viewed as reckless.

    No matter where you stand on the issue of solo diving, I think we all can agree that every diver should train and equip for self-sufficiency and be able to handle potential problems that might arise during a dive.

    Always do your deepest dive first.

    This rule was considered law for many years, and it is still widely practiced today despite the development of sophisticated dive computer algorithms and new research into decompression sickness. Dive Training’s Senior Editor Alex Brylske revisited this topic earlier this year in an article titled, “Deepest Dive First? The History and Science Behind How We Plan Our Dives,” which ran in the January/February 2017 issue. Here is an excerpt from Brylske’s article:

    “The issue of reverse profiles is sometimes confusing because the term actually can have two meanings. First, a reverse profile can refer to a series of repetitive dives where the deepest is not the first in the series. On the other hand, it can also describe a single multilevel dive that doesn’t follow the ‘stair-stepping’ procured described earlier; and the diver finds him or herself in the deeper phase of a dive after completing a shallower segment. Both procedures violate the deep-first rule.

    It may surprise you to learn that the deep-first rule is a relative newcomer to the diving liturgy, traceable only back to the 1970s. The story is also an interesting lesson in the history of scuba diving.

    A popular assumption is that the recreational scuba diving community simply adopted the deepest-first rule from the US Navy. Such an assumption seems entirely reasonable given that the USN Tables were the first standard for recreational scuba diving. The problem is, it’s not true. The US Navy does not now, nor did it ever, have any prohibition against reverse profile diving. In fact, one of the example dive table problems an older version of the US Navy Diving Manual involved a reverse profile. Likewise, there is no such prohibition in commercial scuba diving. So where did the rule come from?

    The first suggestion to make the deepest dive first appears to have been offered in a relatively obscure reference — and only as a suggestion — by a researcher named Dennis Walder in 1968. His rationale was that by making the deeper dive first, one might crush “silent bubbles” — assumed progenitors of decompression illness — making the development of bends less likely on that and subsequent repetitive dives. But this was based primarily on theory and informed speculation, not empirical evidence. Moreover, no reference to any deep-first guideline appeared in any recreational diving literature until 1972, when the following statement was published in PADI’s Basic Scuba Course Manual (a curriculum segment of the then-current PADI Instructor Manual): ‘One very important rule — WE ALWAYS MAKE OUR DEEPEST DIVE FIRST when using the dive tables.’ No rationale was provided, though examples were often included during training showing the aforementioned advantage of avoiding decompression stops.

    By the 1980s ‘deep dive first’ was growing beyond a recommendation.

    By the 1990s, the mantra of-deep first was firmly ensconced in diver training materials as well as in the psyche of divers; and no prudent diver even considered violating the warning. But by this time dive computers had become standard equipment, and whether by accident or intention, divers were making — and getting away with — repetitive and multilevel reverse profile dives.”

    Brylske sums it up by saying, “In all probability, the deep-first rule might never have been challenged had it not been for the widespread use of dive computers. Although the rules say otherwise, no dive computer in existence explodes, calls the police or ceases to function if the user engages in a reverse profile dive.”

    Always end the dive with at least 500 psi remaining in your tank.

    This statement is uttered during practically every pre-dive briefing in locations all over the world. The rationale behind it is solid; divers should plan their dives well and monitor their gauges carefully to avoid running low on — or out of — air. And responsible dive guides should remind divers to monitor their air supply to avoid an out-of-air emergency.

    However, in some instances, well-meaning but overzealous divemasters might take it a bit too far. I’ve heard divemasters jokingly “threaten” divers with penalties, like, “You’ll owe me a 6-pack,” if they surface with less than the mandated 500-psi.

    If a diver is nearing the end of a dive and needs to consume air below the 500-psi mark in order to complete a safety stop, the diver should feel comfortable doing so without fear of reprisal by the dive crew, because there’s simply no place for shaming in scuba diving.

    Never, ever make contact with the bottom.

    If you haven’t wanted to burn me at the stake by now, here goes. Over the years we have occasionally published photos of divers kneeling onthe bottom. This usually results in a flurry of reader letters calling Dive Training out for promoting bad diving practices. Most recently, in the July/August issue, we ran cover photos that feature two divers standing/kneeling on a sandy bottom while on a shark dive at the famous “Tiger Beach” dive site off Grand Bahama Island. I am one of the divers pictured in the photo. I’m not sure where or when the “never touch the bottom” rule got started, but I can assure you there are several instances in which kneeling in the sand is an accepted practice. Tiger Beach is a perfect example. The site is shallow (less than 30 feet [10 m]), there’s usually a moderate current running — and the water is filled with sharks.

    For these reasons, attempting to stay neutrally buoyant, kicking hard against a current while hovering a few feet off the seafloor and keeping an eye on the sharks would be impractical — and potentially dangerous. Here, kneeling in the sand is the best practice. Dive operators in other parts of the Bahamas, Fiji, Tahiti, the Maldives and other popular dive destinations follow this practice.

    Those who teach underwater photography know it is better to position beginning photographers in a sandy patch adjacent to a reef than to have them crashing into the coral while just starting out with a camera. Yes, the sand biome contains marine life, but in most instances it is not as delicate as fragile corals. A diver who carefully settles on a sandy area will have minimum impact on the environment.

    In parts of the world where strong currents are common, dive operators instruct divers in the use of “current hooks” as a means of having minimum impact on the environment. A current hook, as its name implies, is a large hook attached to a short length of line with a clip at the other end. The clip attaches to a D-ring on a diver’s BC. Divers learn to hook into an area of coral rubble in order to stay put in a strong current. By using the hook, they avoid grabbing the bottom with their hands.

    Here’s one more real-world “contact” scenario: If a diver accidentally ventures too close to the reef, rather than kicking to attempt to move farther away, using a one-finger touch of a dead or algae-covered section of reef to carefully push up and away from the reef is likely to prevent the diver from damaging living coral.

    The “look but don’t touch” mantra is ideal, but there are instances when it’s not always practical. What I’m suggesting here is careful and conscientious contact with the bottom (and with dead sections of coral) when conditions warrant it.

    Always breathe continuously. Never hold your breath.

    As I mentioned earlier, this is arguably the “number one rule” of scuba because breath holding while scuba diving can lead to serious injury, even death. However, there’s a however here.

    I bring it up in honor of a diver I met years ago. We’ll call her Janet. I guided Janet on her first recreational dives after she got certified. She bought a weeklong dive package and her first day of diving with the dive center where I worked went flawlessly. The conditions were perfect and Janet appeared comfortable in the water. I took a few underwater photos of her, smiling and signaling “OK.” She said she had a great time.

    The following morning, she was waiting at the dive shop very early when I showed up for work. She told me she wanted to cancel her dives. When I asked why, Janet explained that she’d been awake most of the night because she was worried that she might have accidentally held her breath at some point during the dive the previous day. She said, “My instructor drilled it into our heads, ‘If you hold your breath, you will die,’ and I’m just afraid. I can’t remember if I held my breath or not, but I don’t want to die.” I explained in great detail why divers should breathe continuously and avoid holding their breath. When I was finished, Janet decided not to give up on scuba diving after all. She sat out the morning dives in favor of some sleep, but was back out on the boat later that afternoon.

    So, here’s my little secret about breath holding while scuba diving. I often do it when taking underwater photos. I admit this not to encourage any diver to adopt the practice of holding their breath while on scuba, but rather to add some clarity to the breath-holding issue. If you’re like me and you sometimes briefly hold your breath while stationary, it is unlikely you will risk a lung-expansion injury. The key here is the word “stationary,” as in remaining in place and not ascending. If you hold your breath while ascending, you do indeed put yourself at risk of a potentially serious and possibly fatal lung-expansion injury. This is why scuba instructors drill it into students’ heads to “breathe continuously and never hold your breath.” But if you’re like Janet and you might have briefly forgotten to breathe continuously just for a second, say, when posing for a photo underwater, chances are, you’ll be okay. Still, do as your instructor insists. Breathe continuously and avoid holding your breath.

    A Question for You

    If you’ve read this article all the way to the end, thank you. I hope you found it thought provoking. However, the take-home message I wish to leave you with isn’t about following rules. It’s about asking questions. Asking why we divers do or don’t do certain things is important. It’s how we learn and understand and it’s also how we grow. Not everything is black and white. I want to encourage you to ask the questions and find the answers and then question the answers if they don’t sound right. This is ultimately how we advance our sport, making it safer and more enjoyable for all.

  • August 22, 2020 8:32 AM | Howard Ratsch (Administrator)

    Educational Blog

    Health for Diving: A Primer on Diabetes

    By Robert N. Rossier
    February 13, 2018

    This article represents the views of the author.  The article has not been fact checked by myself, the Board of Directors or any member of the USA Dive Club.

    Copyright Disclaimer under section 107 of the Copyright Act of 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education and research. Fair use is a use permitted by copyright statute that might otherwise be infringing.

    We all know there are medical factors that can prevent people from diving. Epilepsy, various heart conditions, loss of consciousness, pneumothorax, some chronic diseases and even some forms of anxiety can spell trouble that may be incompatible with diving. But over the years, the list of contraindications has narrowed, allowing more to enjoy exploration of the underwater world.

    One condition that has prevented some people from becoming divers is diabetes. Diabetes affects the body’s ability to produce or respond to insulin — a hormone controlling the metabolism of carbohydrates. The result is abnormal carbohydrate metabolism leading to elevated glucose levels in the blood and urine.

    While this might sound innocuous, the long-term effects of diabetes are dead serious. Diabetes takes more lives than AIDS (acquired immunodeficiency syndrome) and breast cancer combined, claiming one American life every three minutes. Diabetes is a leading cause of blindness, kidney failure, amputations, heart failure and stroke. What’s more, the incidence of diabetes is growing. According to, the number of reported cases of people living with diabetes has jumped nearly 50 percent in the past decade and it now affects more than 29 million Americans. On a global scale, diabetes afflicts more than 380 million people, and the World Health Organization estimates that by 2030, the number of people living with diabetes will more than double. Clearly, diabetes is a growing health risk and one that could affect our ability to dive safely. But, at least for some, the door has been opened for scuba diving with diabetes — that is, if the proper conditions are met and the proper protocols are followed.

    Diabetes is categorized into two primary types, referred to as Type 1 and Type 2. In those with Type 1 diabetes, the pancreas does not produce insulin or it produces insufficient insulin to meet the body’s needs. Individuals with Type 1 diabetes must receive insulin injections regularly in order to metabolize blood glucose (blood sugar). In the more common Type 2 diabetes, the body may not produce enough insulin or the insulin does not trigger the cells to allow proper metabolism of glucose.

    Type 1 and Type 2 diabetes are the most common forms of the disease but other forms exist. Many individuals are also diagnosed with pre-diabetes, a condition in which blood sugar is high but not significantly enough to warrant treatment. Unless changes are made to diet and exercise, those with pre-diabetes are likely to join the ranks of individuals diagnosed with diabetes.

    To understand the effects of diabetes, we need to have an understanding of some basic human biology. In a normally functioning body, a number of metabolic reactions occur in response to eating. First, the digestion process in the stomach breaks the food down into glucose (a form of sugar), which enters the blood stream and is transported to cells throughout the body. The hormone insulin is secreted by the pancreas, which triggers the cells to allow glucose to enter. Through a process called glycolysis, the glucose is broken down in the production of a molecule called ATP (adenosine triphosphate), which is the source of energy in the cell. Also in response to eating, the cells also synthesize and story fatty acids and proteins. These are all critical functions for a normal, healthy body.

    For the person with diabetes, this process simply does not work properly. Type I diabetes is actually an autoimmune condition. The immune system destroys the beta cells in the pancreas, which are responsible for the production of insulin. And without that insulin, glucose does not enter the cells and they run out of energy.

    For Type I diabetes, those affected must receive injections of insulin at the appropriate times to control blood glucose levels and allow cells to receive the needed glucose. Eating the right foods at the right time can also help control blood sugar by controlling how much glucose is produced through digestion. Other factors including exercise, stress and general health also affect the body’s need for insulin, so getting the correct timing and dosage for insulin injections can be a challenge.

    In Type 2 diabetes, the pancreas has a deficiency of beta cells that create insulin, making it unable to supply enough insulin to the body. In addition, insulin receptors at the cellular level may not respond properly to insulin, limiting the amount of glucose entering the cells and allowing blood glucose to remain elevated. Controlling diet is also important for those with Type 2 diabetes to prevent spikes in blood glucose. Medications are available to help maintain an appropriate low level of blood glucose. For some, additional medications may be available to increase insulin production by the pancreas.

    The factors that determine blood glucose levels fluctuate greatly throughout every day, so for a Type 1 diabetic, determining the proper dose of insulin to take can be a complex and sometimes delicate balancing act. Too much insulin means the body consumes too much glucose, which can drive blood glucose to a dangerously low level. This low blood glucose condition, referred to as hypoglycemia, can sometimes be fatal if prompt corrective action is not taken.

    With too little insulin, blood glucose can soar to dangerous levels while at the cellular level the body is starved of energy. This condition is referred to as hyperglycemia and it poses a risk of long-term complications.

    The goal, then, is to take the necessary steps to maintain a relatively constant blood glucose level as we eat and perform various activities throughout the day. One way that those challenged with diabetes can help avoid the spikes that can come, is to pay attention to what they eat and when they eat it. If such an individual doesn’t eat at the right time or eats too much of the wrong thing (or right thing) at the wrong time, the system can easily be thrown out of balance. In addition to proper eating and dietary habits, other natural remedies have also been widely used to help keep blood sugar levels in check. For example, Gymnema sylvestre is an herb used for centuries in India to help control blood glucose by stimulating pancreatic function.

    Numerous factors affect blood glucose levels, as well as overall health for all of us. These are of particular importance to those with pre-diabetes or diabetes. One factor that contributes to elevated blood glucose is stress. The stress hormone adrenaline increases blood glucose, releasing it into the blood to provide a needed boost of energy to meet the fight or flight needs. In a situation such as being chased by a shark, we would react physically by fighting or fleeing and that glucose would soon be used up. But what if instead we remain stationary? Many of us deal with stress on a daily basis, but we don’t deal with that stress by engaging in physical activity. Instead, we are forced to sit and deal with it. One result of that inaction can be elevated blood glucose levels.

    Cortisol is a hormone generated by the adrenal glands that can elevate blood glucose. Under conditions of high stress, cortisol provides the body with glucose by tapping into protein stored in the liver. This energy can help an individual in a fight or flight situation. However, if we’re constantly subjected to stress, the resulting chronic elevated cortisol can lead to increased blood glucose levels. To help reduce the effects of stress, we need to find ways to prevent or cope with it. Strategies include everything from exercise to nutrition, hydration, music and meditation.

    Sleep is not a luxury — it is a necessity that also has an impact on blood glucose. In fact, a chronic lack of sleep is another form of stress that can result in elevated blood glucose, according to an article in the December 2015 issue of Diabetes Therapy. The National Sleep Foundation recommends seven to nine hours of sleep every night to enjoy its restorative health effects.

    Another factor that can predispose individuals to Type 2 diabetes is a chronically low level of Vitamin D. A study reported in Scientific American in 2009, found that 45 percent of Americans are deficient in Vitamin D and more recent studies corroborate a rising trend in Vitamin D deficiencies. But here is the kicker: a Tufts-New England Medical Center study found that those who are chronically low on Vitamin D had a 46 percent increased risk of Type 2 diabetes. While the mechanism of Vitamin D with regards to diabetes is not crystal clear, researchers suspect that Vitamin D enhances the cells’ response to insulin.

    As it turns out, precautions against skin cancer may actually be depressing our levels of Vitamin D. In a 2009 Article in Scientific American, co-author Adit Ginde, an assistant professor at the University Of Colorado Denver School Of Medicine, reveals that using a sunscreen with as little as an SPF 15 reduces the skin’s Vitamin D production by 99 percent.

    As divers, we understand that hydration is a factor in decompression illness but it is also a factor when it comes to blood glucose levels. As fluid in our circulatory system is decreased due to dehydration, blood glucose becomes more concentrated. This causes an increase in urine production, which worsens the dehydration. The key message here is the importance of maintaining a healthy hydration level through consumption of water and other non-sugary beverages. Drinking water can reduce blood glucose, reduce insulin resistance and reduce hunger. If plain water isn’t enticing enough, try garnishing it with a citrus wedge, cucumber slice or fresh mint leaves.

    Exercise is a double-edged sword when it comes to those with diabetes. In general, exercise is an important ingredient in maintaining health for those with diabetes. But for those with Type 1 diabetes, some precautions are in order. Vigorous physical activity should be avoided when blood glucose level is too high (hyperglycemia) and insulin level is too low. Not surprisingly, this precaution is reflected in the diabetic diving protocols.

    While the long term effects of diabetes are daunting, the short term effects for a person with Type 1 diabetes can be downright frightening, especially if that individual should be underwater. The effects of hypoglycemia include confusion, blurred vision, impaired judgment, physical impairment, seizures and loss of consciousness. Such conditions are dangerous not only to a diver, but also the diver’s buddy. What’s more, if the symptoms aren’t recognized and properly treated, the diver could be in grave danger.

    Steve Prosterman is a Dive Safety Officer at the University of the Virgin Islands and a Hyperbaric Chamber Operator at the St. Thomas Hospital. Diagnosed with Type 1 diabetes in 1967, he became a dive instructor in 1982 and has made well over 10,000 dives with no complications. As he points out, “The main risk of diving and diabetes is the sudden loss of consciousness or altered state of consciousness due to hypoglycemia (low blood sugar). Hypoglycemia generally begins to develop symptoms when the blood sugar falls to 60-70 mg/dl and lower and can also lead to impaired judgment, physical impairment and seizures. For this reason, anyone with a history of reactions with these symptoms should not dive.”

    At first blush, we might think that diabetes is an absolute contraindication to diving due to the risk of losing consciousness underwater. But according to the Divers Alert Network (DAN), individuals with diabetes who wish to dive, can dive safely in many cases. In fact, protocols for diving with diabetes have been around for more than a decade now. The caveat is that medical screening and safety protocols must be observed.

    According to DAN, the first step for the prospective diabetic diver is to undergo the same medical fitness evaluation as other candidates to ensure no other disqualifying conditions exist. These include such conditions as epilepsy, pulmonary disease, heart disease and others. A person who has advanced diabetes and suffers from secondary complications may also be excluded.

    Next, it must be determined that no complications of diabetes exist that may increase the risk of injury while diving. DAN’s guidelines also note that candidates should be 18 years or older (≥16 years if in special training program), with a well-established treatment history and the ability to maintain blood glucose levels efficiently throughout the course of changing demands of daily activities. Those who do not have the ability to control their diabetes (read more here) can be at risk and may not be good candidates for diving. Candidates and divers with diabetes should undergo a mandatory annual medical examination and, if over age 40, should be regularly evaluated for silent cardiovascular disease.

    General precautions for diving with diabetes include limiting depth to 100 feet (30.5 m), limiting bottom time to one hour and not diving beyond the no-stop limits. It’s also recommended that diabetic divers buddy up with non-diabetic divers and that their buddy be aware of both their condition and the proper procedures to recognize and deal with a hypoglycemic episode.

    Since the primary risk comes when a diabetic diver experiences a low blood glucose condition, one key to safe diving is ensuring the blood glucose is at minimum safe level — and stable — at the beginning of a dive (see sidebar). The blood glucose must be high enough prior to starting a dive that the dive can be completed without experiencing an unsafe drop in blood glucose. Measuring blood glucose is quick and easy using one of the many blood glucose monitors available on the market today. Continuous glucose monitors (CGMs) are also available to help monitor blood glucose levels and trends.

    Good nutrition is important to everyone’s health and can help prevent the onset of such diseases as Diabetes. For those who suffer with Diabetes or pre-diabetes, staying healthy is, in part, a matter of making the right choices when it comes to dietary intake.

    Sugars and other carbohydrates are readily converted to glucose, but the rate at which that occurs is measured by something called glycemic index. A high glycemic index indicates a food will rapidly be converted to glucose, causing a rapid spike in blood sugar. A low glycemic index means that the digestive process for that food is slower, meaning a slow production of glucose and a slower rise in blood sugar. For example, white rice rapidly converts to glucose and has a glycemic index of 72, whereas an apple, which converts much more slowly, has a glycemic index of only 36. However, the glycemic load, which includes the effect of typical portion size, may be an even better measure of a particular food’s effect on blood glucose. 

    Another factor that contributes to the rise in blood sugar is the quantity of food eaten. Eating smaller portions results in lower spikes in blood sugar. For those with pre-diabetes or Type 2 diabetes, simply eating smaller portions more frequently can improve the body’s ability to maintain blood sugars in the proper range. Choosing foods with a lower glycemic index and eating healthy portions, can help keep blood glucose in the normal range.

    One area of conflicting research centers on the effects of caffeine on blood glucose. A study published in the June 2016 issue of the European Journal of Nutrition found that the risk of developing Type 2 diabetes was reduced for healthy, regular coffee drinkers consuming three to four cups of coffee per day. However, previous evidence suggests that high doses of caffeine can cause blood glucose to spike. The Mayo Clinic suggests that consuming up to 400 milligrams (mg) of caffeine (about four 8-ounce cups of coffee) is safe for most people, but it can cause trouble (spikes or lows) for those with diabetes. Limiting caffeine intake is a likely a good strategy for improved health.

    Considering the health effects of Vitamin D, all divers should strive to maintain healthy levels of this vitamin. Many foods are Vitamin D-enhanced and may have a naturally high dose of Vitamin D. These include salmon, tuna, mackerel and vitamin D-fortified dairy products. Taking Vitamin D supplements is another health-wise strategy that could help maintain pancreatic function and help control blood glucose. The advice of nutritionists is to take Vitamin D3 with a meal that contains fat, since Vitamin D is fat-soluble and this enhances uptake. Foods rich in healthy fat include fish, nuts, avocado and olive oil.

    The more we learn about human physiology, health and the effects of the underwater environment, the better prepared we are to make safe adaptations to explore the underwater world. Unfortunately, not everyone can safely enjoy scuba diving, but for many of those with diabetes, the door has been opened with safe diving protocols based on solid scientific research.

    While the criteria for diving with diabetes may vary from one certification agency to another, some of the basic criteria for safe diabetic diving include good control of blood glucose levels and freedom from severe secondary complications of diabetes. As University of the Virgin Islands Dive Safety Officer and Instructor Steve Prosterman points out, “A candidate for diving should have an understanding of the relationship between the disease and exercise, be able to recognize early and handle low blood sugars on their own and not have had a serious hypoglycemic (low blood sugar) episode within the last 12 months.”

    One way that diabetics can measure their ability to control the disease is with a hemoglobin A1C test, which provides a 90-day lookback at blood glucose levels and is a good indicator of how well blood glucose is being controlled. Most doctors will recommend that this test be performed at least twice a year. For diving, it may be suggested that the test results be within 30 percent of the normal range. Results that fall outside that range may indicate that better control of blood glucose is needed before a person undertakes underwater activities such as scuba diving.

    Also important to safety is the person’s ability to recognize the early warning signs of hypoglycemia. Divers with diabetes must have a clear insight into the relationship between diabetes and exercise and be able to recognize and respond properly when a low blood glucose situation is developing.

    Safe diving for diabetic divers requires strict protocols, as well as the development and use of good practices and habits. DAN recommends that divers make a general self-assessment of their fitness for diving on the day of the dive, as well as maintaining good hydration throughout the days of diving. Specific protocols* for glucose management on the day of diving include the following:

    §                             Before entering the water, blood glucose (BG) must be stable or rising with a value greater than or equal to 150 mg dL-1 (8.3 mmol L-1). Divers should complete a minimum of three pre-dive BG tests — performed at 60 minutes, 30 minutes and immediately prior to diving — to evaluate BG trends. It is noted that alterations in the dosage of oral hypoglycemic agents (OHA) or insulin on the evening prior or day of diving may help.

    §                             Divers should delay the dive if BG is less than 150 mg dL-1 (8.3 mmol L-1) or greater than 300 mg dL-1 (16.7 mmol L-1).

    • Divers must carry readily accessible oral glucose during all dives and have parenteral glucagon available at the surface.
    • If hypoglycemia is noticed underwater, the diver should surface (with buddy), establish positive buoyancy, ingest glucose and leave the water.
    • Check blood sugar frequently for 12-15 hours after diving to ensure safe levels.
    • In order to establish best practices for future diving, diabetic divers should log all dives and include BG test results and all information pertinent to diabetes management.
    • For more information, contact DAN and consult your physician.

    * Divers Alert Network, Guidelines for Diabetes and Recreational Diving, Proceedings Summary | DAN/UHMS Diabetes and Recreational Diving Workshop.

    Also available from DAN: Pollock NW, Uguccioni DM, Dear GdeL, eds. Diabetes and recreational diving: guidelines for the future. Proceedings of the UHMS/DAN 2005 June 19 Workshop. Durham, NC: Divers Alert Network; 2005.

    Hypoglycemia is a condition where blood glucose (blood sugar) is low. When levels fall to 60 to 70 mg/dl or less, a dangerous condition exists. Some signs and symptoms of hypoglycemia of which diabetic divers, their buddies and instructors should be aware include:

    §                             Excessive hunger

    §                             Weakness or dizziness

    §                             Confusion

    §                             Unresponsiveness or inappropriate responsiveness

    §                             Blurred vision

    §                             Glazed eyes

    §                             Sudden mood changes

    §                             Irritability

    • Loss of consciousness or altered state of consciousness
    • Seizures

    Diabetic divers who display these symptoms should follow established protocols. This includes exchanging hand signals to identify the problem, ascending and stabilizing at the surface (both the affected diver and the buddy) and ingestion of carbohydrates by the affected diver. The divers terminate the dive and return to the boat or beach where a blood test is performed. Such events, along with blood glucose results and other details of the event, should be recorded for future reference.

    The glycemic index is a measure of how rapidly a food is converted into glucose through digestion. A high glycemic index means a food converts quickly. The glycemic load is a measure of the impact of a typical portion of the food on blood glucose, taking into account the typical portion size.   Numerous online sources are available to provide values for a broad spectrum of foods.

© Copyright Under Sea Adventurers Dive Club 2023

Powered by Wild Apricot Membership Software