EDUCATIONAL blog

<< First  < Prev   1   2   3   4   Next >  Last >> 
  • November 22, 2021 8:11 AM | Howard Ratsch (Administrator)

    What To Do When You Run Out Of Air While Scuba Diving | Scuba Diving

    By Scuba Diving Editors

    This article represents the views of the authors.  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.

    What should you do if you run out of air? This has always been one of the most frequently asked and significant questions for new and experienced divers. Even more so today. Not because the answers have changed, but rather because our understanding of the out-of-air situation and the way divers are equipped has evolved. As a result, the choice of which ascent you make and how you make it may be different today than it was years ago.

    Are You Really Out of Air?

    Probably not. What you sense as an out-of-air situation is usually a low-on-air situation. Indeed, in nearly all scuba accidents, the victim still has air and the regulator still functions. What usually happens is that a diver breathes his air supply down so low that the regulator can no longer provide air at the effort level required by the diver. In theory, this occurs when ambient (surrounding) pressure equals tank pressure. At 100 feet, this would be about 60 psi. Regulator studies and diver experience have shown that because of the mechanics and maintenance of regulators, diver breathing habits and rates, and the inaccuracies of submersible pressure gauges, the diver will feel out of air at a tank pressure higher than ambient pressure and that this disparity increases with depth. It's not as simple as that, though, because regulators reduce cylinder pressure in two stages, and because of breathing habits, exertion levels and so on. These are among the reasons why the current practice is to surface with 500 to 800 psi remaining rather than 300 psi.

    Equipment or Human Failure?

    Equipment can fail, but does so rarely. With a regulator, failure usually takes the form of an air leak, a water leak or a free flow. If there is a problem with the regulator, it usually still delivers air, creating an inconvenience rather than a serious situation. In spite of what textbooks and instructors might say, we do not learn to make emergency ascents because of the possibility of equipment failures, but because 99% of the time the errors are human errors. This significant fact does not change the ascent options available, but it may change which options the diver chooses and how that ascent is performed.

    The Power Inflator

    The use of power inflators and alternate or octopus regulators has become nearly universal. Both have a significant bearing on emergency ascent choices. A little-known fact about power inflators is that they will continue to function at a lower tank pressure than that at which a diver can comfortably continue to breathe from a regulator. At low tank pressures and greater depths, the flow rate is slower, but the power inflator still works even when the demand-valve regulator produces an out-of-air sensation for the diver. It's important to note that if you're at or nearly neutral, you don't need BCD air added anyway. As soon as you start up, buoyancy increases just like on any ascent. You may however need to orally inflate once at the surface to get enough buoyancy.

    Don’t Forget To Inhale

    Another misunderstood rule concerns breathing during ascents. It sounds so simple in the textbooks: “Always exhale while you ascend.” But this is only half the story. The only way you can hold your breath during an ascent is to do so forcefully, as what happens in a state of panic.

    Otherwise, a relaxed diver is continuously venting. Excess air will flow out of the lungs as long as the airway is kept open through inhaling or exhaling. Continuing to breathe in and out is the best possible way to surface, as it is closest to a normal ascent. Ideally, you do not want your lungs to approach being either full or empty.

    Speed Rules

    In low-air or out-of-air situations, the speed of ascent is not nearly as important as was once thought. With healthy lungs and a clear airway (normal breathing/exhaling), divers can ascend at remarkably high speeds without significant risk of lung overexpansion injury. Today the recommended normal ascent rate is 30 feet per minute. Yet during out-of-control ascents performed while testing BCs, members of ScubaLab have achieved rates of 540 feet per minute, and the Royal Navy has achieved even higher rates, both with no harm to the divers. The point: ascent rate is more critical to avoiding decompression sickness than lung overpressure. While avoiding it should always be a concern, DCS is less of a danger than having no air to breathe at depth. Of course, using a buddy’s alternate air source can eliminate the need to ascend quickly.

    Out-of-Air Options

    Whether you take independent action or dependent action depends primarily on three factors: your gear configuration, your depth and your proximity to a properly equipped buddy.

    INDEPENDENT ACTIONS

    Option 1: NormalAscent

    Or as normal as possible. This is the easiest and safest way to surface when low on air. You can push off the bottom, kick and use the power inflator on your BC. Remember, more air will become available from the tank, from the regulator and from within your body as you ascend. Also, your buoyancy will increase as the air in the BC or dry suit expands, or as your neoprene suit expands. With the additional air that becomes available, you will be able to continue breathing on the way to the surface. With the additional buoyancy, you may even need to dump air from the BC and/or flare (stretch out your arms and legs as wide as possible and arch your back so you face the surface) to slow the ascent. The ascent should be made with as much control as possible.

    Option 2: Emergency Swimming Ascent

    An emergency swimming ascent is similar to the normal ascent, but faster, so you have less control.

    Option 3: Emergency Buoyant Ascent

    If for any reason you feel you can’t make the surface by swimming and using the BC, then simply ditch your weights. The ascent now becomes an emergency buoyant ascent. You will go faster and have less control, yet you can still breathe in and out, dump air from your BC and flare as necessary. Emergency buoyant ascents are a faster and surer method, but they are not nearly as fast as some divers believe. You can still slow down (but not stop) and you do not pop out of the water as you arrive at the surface. With all these ascents, the key is to look up, relax and continue breathing in and out.

    DEPENDENT ACTIONS

    Option 1: Redundant Air

    Redundant air systems, such as a pony bottle or Spare Air, eliminate the need to share air and can be used by more than one octopus. If you or your buddy has one, it should be your first choice.

    Option 2: Sharing Air

    If your buddy has an alternate air source, is closer than you are to the surface, and you have an agreed-upon plan, then go to your buddy and share air. You may also need to use an alternate air source because of an obstruction preventing a direct ascent to the surface, such as swimming in a wreck, under heavy kelp, inside a cave, under ice, needing to decompress, or being at great depth. Remember your power inflator will still work while you are using your buddy’s alternate air source, so each of you can become neutrally buoyant and then make a controlled ascent using buoyancy to assist you.

    Option 3: Sharing Air (Buddy Breathing)

    Buddy breathing should be your last resort. This is an obsolete skill that is still taught in some classes. Many divers do not understand how much easier it is to make an independent ascent (normal, emergency swimming or emergency buoyant) or to use an alternate air source or redundant system. The skill of buddy breathing is far too difficult for most divers to be able to remember and use under stress while ascending. Accident reports indicate that we’d be better off if we never have to attempt buddy breathing in an emergency. Divers have an obligation to equip themselves properly, and that means having access to an alternate air source on every dive.

    Subscribe to Scuba Diving (buysub.com)

  • October 22, 2021 1:12 PM | Howard Ratsch (Administrator)

    Tips for Scuba Diving in Low Visibility

    How to improve your skills and make the most out of poor viz.

    By Eric Michael June 22, 2019

    Pro Tips for Low Visibility Scuba Diving | Scuba Diving

    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.

    Perfect is a shifting ­base line, ­especially when it comes to ­diving. Despite the challenges of ­raging current, bone-aching cold or snotty ­visibility, some among us can find the best in even the worst. Those silver-lining divers can be an envied bunch, enjoying the messiest of conditions like it was a screensaver fantasy. However, this relentless optimism isn’t necessarily an innate ability. Perspective is completely relative. And making the most of the marginal can be a learned skill. Just ask Glen Faith.

    “The first two years of my diving ­career, I didn’t know you could even see underwater,” says the former ­Illinois ­Secretary of State Police diver, who now owns and operates Mermet Springs, a popular quarry site and full-service ­scuba ­training facility in southern Illinois. “I thought a mask was just something to keep the mud out.”

    Becoming a certified search-and-recovery diver meant feeling his way through murky farm ponds and performing skills in near-blackout situations.

    “It was diving by Braille. You couldn’t see a thing,” Faith says. “I guess the instructor trusted us when we did our skills because I don’t think he could see us.”

    Thankfully, almost 24 years of finding guns, stolen cars and sometimes ­bodies in highly challenging marine environments from lakes to the Mississippi River didn’t ruin his enthusiasm for diving. Today, his former limestone quarry, which features sunken attractions—­including a 727 passenger jet from the 1998 film U.S. Marshals, a full-size train car, a fire truck, a pedal-powered submarine and a submerged petting zoo—draws more than 6,000 divers annually to get certified and share the love of diving.

    Tips for Scuba Diving in Low-Visibility or Silt-Out Situations

    “The first time I breathed ­underwater, I never wanted to come back up,” Faith says. “It was one of the most addictive things I’ve ever done in my life. If I could live underwater, you’d never see me again.”

    Faith is definitely a glass-­perpetually-overflowing type of diver, a living example of the adage that the best diver is the one having the most fun—even if he can’t see much. From his example, we can all learn lessons about how to prepare for and get the most enjoyment from less-than-­optimal conditions. So, when the pristine, 100-foot visibility you anticipated turns out to be a cloudy, can-barely-see-your-hand-in-front-of-your-face kind of day, try these simple hacks.

    Pack a positive attitude

    The most important piece of your ­foul-visibility kit is your own attitude. Disappointment can kill a good vibe ­instantly, so shedding the burden of expectation can make the difference ­between diving under a dark cloud or laughing through your regulator. Rather than obsessing so heavily on what might have been, focus on the possibilities—the challenge of operating in poor visibility will not only make you a better diver, it also might actually be fun.

    “Anybody can dive in 100-foot ­visibility, but the challenge of diving where you can barely see your fins or you have to use a light to see your gauges—that’s another level,” Faith says. “People who ­practice in reduced visibility are really opened up to a lot more diving opportunities. ­Sometimes when the viz is blown out, that’s when some of the coolest marine life come out of hiding.”

    According to Faith, the right training can seriously improve your outlook. A night diving or limited visibility ­specialty course will not only improve your skills and preparation, but it will also raise your level of comfort in poor conditions, which will deliver greater enjoyment.

    Dive the right gear

    Often the solution for a difficult problem is having the right tool for the job. Diving in poor visibility is no different.

    A quality dive light is paramount for navigating, reading gauges and ­other critical tasks in ­limited-visibility ­situations, along with a trusty backup that can be safely stowed and easily accessed. Faith advises not to be blinded by power when choosing a torch because sometimes lumens can be outshined by ergonomics. Make sure your light fits comfortably and securely in your hand. And beyond the point-and-shoot ­varieties, consider a strobe for your tank.

    “Not just a tank light, but a strobe light, so if you get displaced from your buddy, they can see that blink underwater and make their way back to you,” says Faith.

    Color is another key factor when ­arming for low viz. “I dive yellow fins and a yellow mask for a reason,” he says. “When visibility is reduced, I need my students or my buddy to see me, and light colors that reflect light underwater make a big difference.”

    Dive computers typically offer some type of illumination; recent advances in LED and OLED technology deliver bright, colorful displays that are highly ­effective in low-viz situations, as well as more ­affordable.

    Slow it all down

    The excitement of exploration can often drive divers to dangerous speeds underwater. Just like on the road, speed can quickly escalate challenging ­low-visibility conditions into a dangerous ­situation. Planning for a reduced pace on your dive—and being mindful of it during your dive—can be the difference between ­surfacing with a smile on your face or ending up in the back of an ambulance. Besides being safer, slowing down offers other benefits.

    “Most divers, as a rule, swim too fast,” Faith says. “Low-visibility diving forces people to slow down—and even stop—to appreciate the little things along the way.”

    Slowing down can also facilitate better discipline and increased performance in other important aspects of diving. Buoyancy is easier to control when you’re not kicking like mad. Your air consumption will improve. And you’ll get lost less often.

    “Navigation is key in limited visibility because you can’t look out and see ahead of you for 100 feet, so your compass skills have to be absolutely proficient,” Faith says. “Sometimes you’ll have to make a midwater swim back to the dock or the boat, and you won’t be able to see anything. In aviation, it’s called flying by your instruments—and that’s exactly what you’ll be doing underwater.”

    Overall, a successful dive in poor ­visibility requires a combination of the right equipment, the ability to slow yourself down, and an attitude optimized to make the best of less-than-optimal conditions. It might seem like a difficult equation, but the payoff will be that silver lining we all covet.

    The Hack: Best Buddies

    Buddy diving is fundamental. But when conditions are pristine and you can seemingly see forever, how many of us really stick to strict buddy protocol? ­Increasing your discipline to stay within easy reach of your buddy, communicate more often, and truly dive like a team is crucial to a successful dive in low visibility. When conditions are challenging, the added safety and redundancy that optimal collaboration provides is well worth the effort. ­Because if two eyes are better than one—wouldn’t you really rather have four?

    Subscribe to Scuba Diving (padi.com)


  • September 22, 2021 11:00 AM | Howard Ratsch (Administrator)

    Educational Blog

    Dive Training: Save Your Breath | Scuba Diving

    By John Francis

    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.

    Diving Tips: Save Your Breath

    During the surface interval, the divemaster makes his rounds, recording each diver's air consumption. You admit to having only 300 psi left, which is cutting it a little close, though you made a slow, safe ascent and a complete safety stop.

    But most of the other divers have 600, 800 even 1,100 psi left! What's up with that? Are they hanging out at the surface for half the dive? Sipping from a hidden pony bottle? Stealing from your octopus?

    More likely, they've learned not to waste air. But cheer up: We can get you back in the game and save you as much as 500 psi. You need only follow three simple diving tips: 1. Think slow. 2. Think slippery. 3. And act sleepy. Now, how hard can that be?

    1. Think Slow

    Water is some 800 times denser than air, and your speed is proportional to the square of the energy it takes to produce it. You already know how hard it is to wade across a swimming pool, even slowly. Doubling your speed requires about four times as much energy. Or turn that around: Wading across the pool half as fast takes one-fourth as much energy.

    So go slow. Swim slow, turn slowly, reach slowly for your console--do everything in slow motion.

    Several changes to your normal pattern will save energy and air, but swimming slowly is the obvious air-saver. Also, don't forget to move your hands, arms, head and torso slowly. Unless you pay attention, you'll try to make movements at "normal" speeds, which, having been learned in air, are too fast under water.

    Other Ways To Go Slow

    • Duck currents. They're usually weaker at the bottom or along a wall.
    • Use your hands. Where appropriate, pull yourself rock-to-rock, hand-over-hand, across the bottom. (Don't touch coral and other living things, of course.)
    • Stay warm. Your body burns calories and consumes oxygen to generate heat, so conserve it. Wear a hood or beanie, even in warm water.
    • Make short fin strokes. Besides finning slowly, keep the strokes short. Wide fin strokes move a lot of water but give only a little more propulsion.
    • Get better fins. Some fins are more efficient at translating muscle power into movement. A good pair means you'll kick with less effort, and less often.
    • Be physically fit. When even a slow speed is an all-out effort, you'll burn more energy than a fit diver for whom the same speed is easier. The more fit you are the more energy-efficient (and air-efficient) you'll be.

    2. Think Slippery

    Save energy and air by reducing drag. It's no coincidence that fish, whales and seals have smooth bodies with very few appendages. Divers, by contrast, start out with long, lanky appendages, then load themselves down with lots of bulky gear. Masks, BCs, tanks and the rest of it present rough, complicated shapes that cause lots of turbulence and drag.

    There are many steps you can take to streamline yourself, but if you do only one thing, do this: Fine-tune the amount of lead you carry and where you carry it. Your goal is neutral buoyancy with minimum BC inflation and a perfectly horizontal position. This will allow your torso, hips and legs to follow through the "hole" made in the water by your head, shoulders and the end of your tank, while enlarging it as little as possible.

    If you are negative, for example, you will have to fin yourself upward a little, as well as forward, to maintain a constant depth. You'll look like a "tail-dragger" airplane taxiing on the runway: Your feet and legs will be lower than your shoulders, enlarging the "hole" in the water and causing drag. If you are positively buoyant, you'll have to fin downward, with the same result.

    Carrying the minimum amount of weight is important because if you are heavy (the usual case), you'll have to inflate your BC to compensate for the extra lead. The inflated BC is physically bigger and enlarges the "hole" you make in the water.

    Once you have the right amount of weight, you'll need to distribute it so that, without moving or finning, your body will assume a horizontal position. That's correct "trim." Many divers are heavy at the head and shoulders and light at the hips and legs, so they swim in a bent-waist, butt-up posture or with their fins high to drive their hips down. In either case, they're pushing more water aside than necessary, causing drag and wasting air.

    Other Ways To Reduce Drag

    • Clip your console and octopus close to your body. Keep as much gear as possible in the slipstream of your body.
    • Adjust hose routings. Choose different ports and shorter hoses to keep hoses close to your body. Just don't make them so short they restrict your head movement or your ability to read your console.
    • Get a better BC. Look for the combination of fit and just the right amount of buoyancy. A BC that's too large or has excess lift will create a surprising amount of drag. An oversized model will also tend to shift, throwing off proper trim.
    • Fin with short strokes. Not only are shortened fin kicks more efficient, they keep your fins inside your slipstream.
    • Keep your hands to your sides. And keep them still.
    • Hide your snorkel. Strap it to your calf, tuck it under your BC, put a foldable snorkel in a pocket, or leave it behind.
    • Put small accessories in BC pockets. Small objects like lights, whistles and safety sausages cause disproportionate amounts of drag when fluttering in the "breeze."

    3. Act Sleepy

    Here, we're talking about your breathing pattern — not your sleeping habits. If you do only one thing to make your breathing pattern more efficient, do this: Breathe almost as if you were asleep — slowly and deeply. This saves air by promoting the most complete exchange of oxygen and carbon dioxide.

    You might think that taking shallow breaths, as if sipping from your tank, would conserve air. In fact, it wastes air. Every breath first brings to your lungs the "dead air" that remained in your throat and trachea from your last exhalation. This dead air has a high concentration of carbon dioxide and a low concentration of oxygen. The high carbon-dioxide concentration triggers the urge to take another breath, even before you need more oxygen.

    Deep breaths, on the other hand, dilute the dead air with fresh air and deliver more oxygen to the lungs. That not only promotes quicker gas exchange, it also delays the urge to take another breath. A tank lasts longer when you take deeper breaths because you need fewer of them.

    Breathe slowly too. That increases your uptake of oxygen and your discharge of carbon dioxide simply because each breath stays in your lungs longer. It gives more time for gas molecules to pass between the air sacs in your lungs and your bloodstream.

    Other Ways To Breathe Sleepy

    • Exhale completely. This reduces the "dead air" volume and eliminates as much carbon dioxide as possible, thus delaying the urge to take another breath.
    • Pause after inhaling. Use your diaphragm to hold air in your lungs a few extra seconds while keeping your throat open. This allows even more time for gas exchange. Your breathing pattern should be: Exhale, inhale, pause. Exhale, inhale, pause.
      Note: Every time we describe this breathing pattern, someone writes us, "Isn't this skip breathing?" It's not. Skip breathing involves holding your breath by closing your epiglottis (like when you grunt) and holding it for much longer. Closing your throat creates a closed air space that is vulnerable to embolism if you ascend. Keeping your throat open avoids that risk. Besides, skip breathing doesn't work. Holding your breath too long means retaining too much carbon dioxide, triggering the urge to breathe sooner than necessary and resulting in rapid shallow breathing. The net result: You use more air by skip breathing, not less.
    • Buy a high-performance regulator. With the best models, considerable engineering has gone into reducing the work of breathing induced by the regulator itself.

    Comparing Gauges
    If you finish the dive with less air than the next diver, does it really mean you aren't as skilled or experienced or in tune with nature?

    Maybe, but it's just as likely you're bigger than the other diver. Or that you followed a slightly deeper profile or carried a camera. Or that you have different genes. It might even mean that somebody's pressure gauge is inaccurate, or that somebody's tank got a better fill.

    Sure, if you use 1,000 pounds more than your buddy on the same profile, you've got a problem you should correct. But a 200- or 300-pound difference? It's meaningless.

    And when faced with a choice between cutting into your 500-psi reserve or cutting short a safety stop — cut into the reserve. A safer profile is more important than a well-intentioned guideline. Just do a better job of gas management on the next dive.

    Subscribe to Scuba Diving (buysub.com)


  • August 23, 2021 2:08 PM | Howard Ratsch (Administrator)

    How To Identify Decompression Sickness — AKA The Bends

    By Scuba Diving Editors

    This article represents the views of the authors.  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.

    "I'm bent." They're the two hardest words any diver ever says. But denying the symptoms of decompression sickness (DCS) could mean you end up with the four hardest to hear: "Can never dive again."

    Relaxing at the pool after a morning of diving, you notice a nagging ache in your shoulder. Is it DCS or a muscle strain from lugging gear bags? Time for a little self-diagnosis:

    Do I have any symptoms of DCS?

    These include but are not limited to:

    • Joint or limb pain
    • Itching
    • Skin rash
    • Nausea and vomiting
    • Dizziness
    • Ringing in the ears
    • Extreme exhaustion

    Clearly, these symptoms are not specific to DCS, so move to the next question:

    LEARN MORE: The ABCs of DCS

    How Likely Are These To Be Symptoms of DCS?

    You did only a single half-hour dive to 40 feet that morning — how could it be DCS? Easy: during the last five days you’ve done 15 dives. The more diving you’ve been doing, the more likely it is to be DCS. The more you’ve pushed the edge of no-decompression status, the more likely it is DCS. The more safety stops you’ve blown off, the more likely it is to be DCS. Any of those apply?

    I'm Still Not Sure. What Can I Do?

    This is easy: Call DAN’s emergency number (+1-919-684-9111) if you need some expert assistance

    in deciphering your symptoms. DAN has doctors on call 24 hours a day who can help you arrive at a decision about your symptoms.

    I Know I Have The Bends. What Should I Do?

    Start breathing oxygen and have someone call DAN’s emergency number immediately: (919-684-8111). The DAN staff can help you arrange for transportation to the nearest chamber. DAN will help you even if you have not purchased DAN insurance, but you won’t like the five-figure bill you may have to pay. Or the possible delay in emergency evacuation because the helicopter company wants its money up front since you don’t have insurance, Considering how little we actually know about the mechanism of DCS, anyone diving without dive accident insurance is taking unnecessary health and financial risks.

    Subscribe to Scuba Diving (buysub.com)


  • July 22, 2021 2:54 PM | Howard Ratsch (Administrator)

    Educational Blog

    Safety Tips for Diving During COVID-19 | Scuba Diving

    Advice from PADI and DAN on how divers can get back in the water safely.

    By Alexandra Gillespie

    This article represents the views of the authors.  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.

    Stay six feet apart on land.

    Maintaining social distancing while topside will help reduce the risk of transmitting coronavirus when diving.

    Scuba divers around the world are eager to get back in the water. As operators reopen globally, PADI is encouraging divers to #DiveLocal.

    To help divers prepare for the new reality of diving during COVID-19, PADI and the Divers Alert Network (DAN) each recently issued advice to dive operators on how to safely resume operations.

    While this guidance gives divers an inkling of what they can expect when returning to their dive shop—reduced boat capacity, a possible disappearance of communal rinse barrels and simulated air sharing in training courses—the best practices also include ideas for what divers can do to keep the industry healthy and operating.

    Please note: While these actions can reduce the likelihood of coronavirus transmission, the risk cannot be entirely eliminated when interacting with other people.

    Stay distant at the surface

    Stay six feet away from other divers until you are underwater, such as when riding a boat out to the drop, checking your buddy’s kit or renting equipment. This means, for example, you should inspect your buddy’s equipment visually before getting in the water, but not reach out to adjust any of their straps.

    Keep at least six feet between you and other divers when in the water as well until you are securely below the surface. Once submerged, “breathing from scuba substantially reduces respiratory transmission concerns,” says PADI in the best practices document posted on the PADI Pros website. “This is obviously important underwater because close contact is important for safety, control, skill conduct and maintaining buddy contact.”

    Kit up solo

    Putting on all of your equipment by yourself enables social distancing and minimizes the number of people who touch your gear. Sitting on a bench or putting on your BCD once you are in the water will make this easier. It may become a necessary skill—tour operators, usually happy to help you wrangle equipment into place, are being advised not to touch customers or their gear if it can be avoided.

    Diving with a member of your household allows more interaction with your buddy, like kitting up or sitting by each other on a boat, as “couples, families and others already socially exposed to each other have more latitude in distancing/contact restrictions,” says PADI on the basis of broadly accepted best practices.

    Breathe through regulators in close quarters

    Some situations require proximity to other divers when at the surface, like dealing with a panicked diver or doing a tired diver exercise. While a regulator does not protect those around you from your exhalations, warns PADI, breathing through your regulator allows you to pull from your tank air, reducing the chance of inhaling respiratory particles floating around you.

    Wash or sanitize hands while topside

    “Divers should avoid touching each other's gear, but sometimes it is necessary before, during or after a dive,” says PADI. “The best practice is for divers to wash/sanitize hands before and after touching their own and someone else's gear, meaning before and after the dive in most instances.”

    Exercise caution with sanitizer around canister fills

    Frequent disinfection of hands and equipment is key to limiting transmission. But DAN warns divers to keep alcohol away from canister fills in order to avoid accidentally igniting a fire.

    “Note that alcohol-based hand sanitizers are incompatible with compressed gas,” DAN says in its online FAQ. If you are filling your own tank, “alcohol-based substances should not come into contact with...cylinders and fill whips that are used with any compressed gas but especially oxygen-enriched gas. This would increase the risk of fire and explosion due to the high volatility of alcohol and its ability to ignite at relatively low temperatures.”

    Washing hands with soap and water is a far preferable route. If hand sanitizer must be used, DAN urges divers to make sure their hands are “completely dry and all alcohol has evaporated.”

    Smear defog, not saliva

    Some divers swear spit clears a mask better than any defog. That debate will have to wait. Spitting nearby other people—especially into a rented mask—could increase the risk of transmitting coronavirus. Rely on defog for the foreseeable future to get a clear view underwater.

    Watch where you’re pointing that snorkel

    Coronavirus can pass through respiratory droplets carried through the air. PADI advises keeping an eye on where the wind is blowing and in what direction other divers are breathing. After surfacing, divers should separate to at least six feet before switching from a regulator to a snorkel, which should only be used when pointed away from other divers. When on a boat, wear a mask over your mouth to mitigate the spread of coronavirus from wind off the water or from the movement of the boat.

    Limit trying on rentals

    If the operator is properly sanitizing rentals, they should be safe to use. Nothing is foolproof, however, so only try on multiple pieces of rental equipment when strictly necessary. This restricts how much rental equipment you are exposed to, and, respectively, how much equipment you contaminate that could expose other divers.

    Dive conservatively

    Diving beyond your limits or absentmindedly can cause an emergency. Common emergency procedures, like sharing air or performing CPR, bring divers in close contact and swaps saliva, increasing the chance of transmission. Dive well within your limits to avoid forcing a close encounter.

    Subscribe to Scuba Diving (buysub.com)


  • June 22, 2021 8:36 AM | Howard Ratsch (Administrator)

    Educational Blog

    In which part of the scuba diving industry should I invest? | by Darcy Kieran | Scubanomics | May, 2021 | Medium

    This article represents the views of the authors.  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.

    Updated on May 31, 2021.

    The scuba diving industry has been hit hard by the coronavirus pandemic and was already facing copious challenges before this ordeal. But running for the hills is not always the only choice in difficult times! In many cases, problems are opportunities — for real! I believe it is the case in the dive industry.

    Our biggest opportunity lies in redesign the scuba diving industry business model using a blue ocean strategy. It’s also a big challenge!

    But it will happen, so… Where should I put my money to be ready to benefit from a ‘new’ dive industry? Better yet, in which part of the scuba diving industry should I invest if I want to be part of the solution and cash in on a renewed growth trajectory?

    Disclaimer

    Before getting any further into this discussion, let’s clarify that the information contained in this article is not intended as, and shall not be understood as construed as, financial advice. I am not an attorney, accountant, or financial advisor, nor am I holding myself to be. The information contained here is not a substitute for financial advice from a professional who is aware of the facts and circumstances of your individual situation.

    Furthermore, in this article, I am looking at investments in different parts of the scuba diving industry, at the macro level, not in particular companies, even if I use some of them as examples of general concepts.

    Macro-Trends That Will Lead Growth in The Scuba Diving Industry

    For real growth to happen in the dive industry, we need a renewed focus on the experience of scuba diving and much less on c-cards (certification courses) and dive gear which is simply a means to an end.

    Currently, our business model relies on local dive shops as the entry door into scuba diving. And for dive store owners to be able to pay the rent and buy groceries for their family, they must sell courses and dive gear. It explains why the dive industry focus has been so much on selling courses and scuba equipment. Local advertising for dive shops is usually about dive certification courses, and competition between dive centers is usually on the pricing of courses and gear.

    This model doesn’t work anymore for all the reasons we’ve discussed numerous times in Scubanomics. For the dive industry to grow, we need to adapt to today’s consumers' expectations and deliver experiences worth reliving over and over again instead of peddling c-cards to people who wanted to cross that off their bucket lists.

    In fact, we shouldn’t be so focused on the words “scuba diving.”

    Hiking doesn’t advertise itself as “walking.” In our case, scuba diving is like walking — it’s a way to do something else. And that “something else” may be many different activities, including discovering reef fish (the equivalent to bird watching) or visiting deep wrecks (much more adventurous).

    The market is not homogeneous. People have different interests and aspirations. There may be many different reasons why people would be drawn to experiencing the underwater world. And strictly promoting the act of breathing underwater (which is what scuba diving is) will leave a lot of potential clients behind.

    We need to identify these motivations and advertise them — not “scuba diving” — just like bird watching is not promoting walking and breathing. Scuba diving needs to become an “oh, by the way, we need to be scuba diving to do that.”

    Similarly, we should stop talking about “the dive industry” and talk about “the underwater world industry.”

    In such a renewed focus, where will current stakeholders stand? Who will gain and who will lose?

    Scuba Diving Certification Agencies

    As we analyzed before, dive training agencies currently maintain a chokehold on the rest of the dive industry. In our Porter’s Five Forces Analysis of the Scuba Diving Industry, we concluded that dive training agencies were extracting and pocketing an inordinate proportion of the dive industry value chain.

    It is unlikely that they can maintain such a position and even less likely improve on it. No matter how much we squeeze a lemon, there is a limited amount of juice in it! That’s why we see dive training agencies fighting over market shares in a desperate attempt to please their shareholders during this fiscal quarter. They are not growing the industry.

    On top of that, we believe that a renewed dive industry can only be built on a much lesser focus on issuing certification cards. It is not inconceivable to think of a world where there wouldn’t be much more than an entry-level certification course in recreational diving (not talking of tech diving).

    The rest of the dive abilities could be developed by spending more on experience and less on the training material.

    All arrows point toward dive certification agencies losing their grip on the industry. In fact, it may be a requirement for significant growth for the rest of us. It’s the last place I would currently invest money. We’ve seen numerous private equity firms rushing to throw money at them, but that was based on a very traditional look at past results.

    Footnote: These observations are based on the certification part of dive training agencies. These companies could do well if they diversify away from relying on selling course material and online access to training. We see PADI heading in that direction with their acquisition of Bonnier publications and Diviac. They appear to be focused on pocketing more profits from the “activity” of scuba diving by selling dive experiences directly to consumers in competition with local dive shops. I think we can expect further developments in that direction.

    Dive Gear Manufacturers and Brands

    In a world where our focus is on a wider segment of the population casually experiencing the underwater world, selling dive gear to scuba diving fanatics will no longer be front and center.

    Our traditional core market in the dive industry has been — and to a certain extend, remains — the baby boomers. For them, scuba diving was a lifelong dream, and once they learned to scuba dive, they defined themselves as scuba divers. They went on dive trips in which there was nothing else to do but scuba diving and drinking beer.

    The younger generations tend to “do” scuba diving without “being” a scuba diver.

    They could be interested in visiting the underwater world once or twice in a trip that also includes hiking and stand-up paddling.

    This new generation will not travel around the world with a huge duffel bag of heavy scuba gear for a day or two of diving here and there.

    We already see a trend toward fewer dive gear sales. On top of a reduction in the number of dive certifications, we see fewer dive gear sales per new student diver trained. Therefore, the future is as bleak for dive gear manufacturers as it is for traditional dive training agencies — if they do not adapt.

    But there are new opportunities on that front.

    First, we can expect a growing demand for dive adventure operators to provide quality rental gear. We will come back to the importance of consistency in the quality of the experience in the next section, and what opportunities it will create for dive gear brands.

    Second, I would invest in a company focused on redefining dive gear to help bring more people to experience the underwater world.

    Future dive gear needs to be lighter, easier to use, and much more “cool”.

    Nothing has really changed in the basic configuration of the scuba unit in years. Well… Somebody, somewhere, will innovate — and cash in.

    One glaring example is surface-supplied air (SSA) that we discussed recently. It looks pretty good on the Eliminate-Reduce-Raise-Create Blue Ocean Strategy’s grid. And with the introduction of the battery-operated surface-supplied air units, SSA gives us a very convenient way of providing air to people underwater for them to experience “the first atmosphere” (up to 10 meters/30 feet), which is where most underwater tourists will find interesting stuff to see and do.

    It means that a good investor would keep an eye on innovative companies like Brownie’s Marine Group. It is notable that they had a 53.5% increase in revenues in 2020 — unlike the dive industry! And just like the rest of the outdoor industry!

    A good way to make money, in the long run, has always been to invest in innovative companies at the start of their innovation cycle. Remember Apple? Google? Just saying!

    In parallel to that, we have companies providing very specialized dive gear like rebreathers and other tech diving equipment. This market should remain a valid one. It’s the casual recreational scuba diving segment that is most likely to witness significant changes in the short term.

    With that kind of pressure on recreational dive gear brands, we can expect further diversification and consolidation — which has already been happening very aggressively over the last 10 years.

    Diversification is like the recent acquisition of the triathlon wetsuit company Aquaman by French dive, snorkeling, and freediving brand Beuchat. Consolidation is like the acquisitions of Atomic Aquatics, Zeagle, Bare, Hollis, Stahlsac, and Oceanic by Huish Outdoors in Salt Lake City, Utah.

    What does it mean in terms of investment?

    Whenever a company acquires another one, the shares of the acquiring one drop while the shares of the acquired one jump up in value. We see that in the stock exchange almost every day.

    Therefore, a good investment strategy in dive gear brands would be to place money into smaller dive gear manufacturers, especially if they provide something unique — like SSA and dive computers — something that a larger dive gear brand would benefit from adding to their product line-up.

    Another option is investing in regional dive gear brands. For instance, a Huish Outdoor is firmly established in the USA but lacks a solid presence in Europe. I would not be surprised to see Huish acquiring a company well-positioned in Europe but with a weak presence in the USA. This could be a Beuchat or a Poseidon, for instance.

    Disclaimer: I have no financial investments in any of the companies mentioned above, and I used them only to represent a general idea and direction.

    Dive Travel

    Dive travel is very segmented at the moment. Numerous travel agencies are specializing in scuba diving adventures. The destination can be one of many dive resorts or liveaboards. Local dive shops also sell dive travel. And any tourist resort or regular travel agency can add scuba diving to their offerings.

    Scuba diving can be done anywhere there’s water, and therefore, the dive operators will most likely remain a series of independent operators. The biggest opportunity on this front is not on consolidation or vertical integration.

    The two biggest opportunities on this front are related to diversification and branding.

    Diversification means offering more than scuba diving, as we discussed above. Growth would come if we manage to offer the experience of the underwater world to a wider segment of casual divers. This can be achieved by providing the experience in more destinations outside the traditional dive-focused resorts. Surface-supplied air units could be a useful tool to achieve this goal, as is the development of a reliable brand.

    Consistency in the quality of the experience has been a recurring problem in the dive industry. It fuels a huge drop-out rate, as we have seen in a recent Scubanomics survey on scuba diving and snorkeling.

    Therefore, the biggest opportunity in dive travel — and the dive industry as a whole — is the development of a trusted brand offering consistency in the quality of the experience at all locations operating under its flag. I do not see any company currently investing in that direction. That is what I will keep my eyes (and wallet) open for!

    Dive Gear vs. Dive Travel

    Consistency in the quality of the experience means that I would expect quality dive gear at every location. Not only that, I would expect the gear to be pretty much the same so that I know how to best operate it — and I know that a size ML Tall is what I always fit best into.

    That requirement for increased reliability in the quality of the experience and the fact that younger generations tend to be more casual divers, open up an opportunity for a dive gear brand willing to satisfy these needs. For instance, here is one: a rental dive gear system allowing divers to have access to the same gear everywhere they dive, without having to travel with it and without having to take care of the annual maintenance.

    Time to think outside the box!

    Local Dive Shops

    Traditionally, local dive shops have been the entry door to scuba diving. Yet, they’ve also been the weak link.

    I don’t want to insult anybody here! I owned and operated dive shops, and I know how difficult it is to offer quality in all six of the business units we try to operate under one roof: a school, a retail store, a travel agency, a fill station, a garage for dive gear, and a rental business.

    A local dive shop is a tiny business, and that level of diversification naturally leads to sub-par performance in all 6 business units.

    On top of that quality issue, these small businesses do not have the financial means to maintain a level of dive gear inventory that would satisfy today’s consumers.

    Therefore, the opportunity on this front relies on a complete re-design of the business model.

    Purchasing or investing in a local dive shop is not a smart money move at the moment — if it ever was!

    If I want to offer scuba diving in an urban (non-tourist) location, I would invest in developing my personal dive instructor brand around the quality of the experience and forego selling dive gear.

    Eventually, training agencies and dive gear brands will all be selling directly to my clients. Therefore, the investment should be in my personal brand (my name), not on promoting PADI, SSI, Aqualung, 10W30, or XYZ.

    Once a global brand has established itself as the one providing consistency in the quality of the experience (as discussed under dive travel), that is the brand I would want to operate under and invest into.

    The only big investment needed in this local diving scenario is a fill station, but we can skip the heavy gear inventory and the expensive commercial lease. And if the market is too small for a full-blown fill station, I would look at surface-supplied air units and/or portable compressors.

    Summary: Investing In The Dive Industry

    I would not invest in:

    ·      Traditional dive training agencies

    ·      Large, established, and non-innovative dive gear brands

    ·      Local dive shops

    ·      Dive resorts offering only scuba diving

    I would invest in:

    ·      Innovative dive gear brands

    ·      Specialized dive gear brands

    ·      Dive gear brands with a strong presence in a region not well serviced by large brands

    ·      Locally: My personal dive instructor brand (my name)

    And the big investment would be in a project to develop a global experience brand offering consistency in the quality of the experience.

    Let’s make a good living out of our passion for scuba diving!

    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.

    Be our dive business buddy on LinkedIn | Twitter | Facebook | Elsewhere

    Check our list of suggested business management books for dive professionals.

    Sign up for Scubanomics: Scuba Diving Industry

    By Scubanomics

    The dive industry is facing many challenges and exciting opportunities. Let's redefine our business model around today's consumers expectations. We will let you know when new topics are available. Take a look.

    Get this newsletter


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

    Educational Blog

    DOES SCUBA DIVING AFFECT MENTAL HEALTH

    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. 

    Mindfulness

    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.

    Fitness

    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. 

    Conclusion

    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

    THE DIFFERENCE BETWEEN “THEN AND NOW” IN TECHNICAL DIVING

    By Michael Thomas

    https://www.tdisdi.com/tdi-diver-news/the-difference-between-then-and-now-in-technical-diving/?fbclid=IwAR2f60R2T2YkRUV0GssuOaso7lqtAQOMm2SKU8HdNuNA59-uW2a4ks81XO4

    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. 

    Trimix 

    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. 

    Lights 

    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. 

    Decompression 

    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 (dtmag.com)

    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 debersole@watsonclinic.com.

     

    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:

    1.

    Lifestyle/risk factor screening

    2.

    Dietary intake counseling

    3.

    Diabetes screening and management

    4.

    Physical activity counseling

    5.

    Smoking/tobacco cessation

    6.

    Weight management

    7.

    Blood pressure control

    8.

    Blood lipid measurement and control

    9.

    Global risk estimation with tools such as Framingham Risk Score

    10.

    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.

    Recommendations

    1.

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

    2.

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

    3.

    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

    4.

    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.

     


<< First  < Prev   1   2   3   4   Next >  Last >> 

© Copyright Under Sea Adventurers Dive Club 2021

Powered by Wild Apricot Membership Software