Category Archives: Diving News

Myths and Mysteries of Mixed Diving Gases – By Aquaviews


mixed diving gasesOnce upon a time, there came a magical gas that promised deeper, longer dives. Some people flocked to this mystical world, regaling their friends with tales of increased energy and a weapon with which to battle the evil monster known as Decompression Sickness. Others were reluctant, mistrustful of the new technology, and they stayed within their regular air realms.

But that was a long time ago in a galaxy not so far away, before mixed diving gases started becoming more en vogue. Nitrox has been part of recreational diving for more than two decades and has made room for Trimix, which adds helium to the nitrogen/oxygen combo. So what are the pros and cons of using mixed gases, and which circumstances would better lend themselves to plain old air?

Nitrox contains an average of 32-36 percent oxygen (versus the usual 21 percent), and has long been purported to give you longer bottom time. Many divers also feel more energized after a nitrox dive. Science has yet to be able to pinpoint why this is, but many folks make the claim nonetheless. Nitrox also decreases your surface intervals, meaning you can get back in the water quicker. Seems great, right? Who wouldn’t want to spend more time at the bottom?

Nitrox does extend your dive but not perfectly. You’ll have to do some math in order to get the most out of your mix. For example, using 32 percent at 70 feet extends the recommended 50 minute dive time by about 10 minutes. Using a 40 percent mixture at the same depth can double your time to 100 minutes. And, like the reduction in fatigue that many users report, there is no hard evidence that it makes you bullet proof against narcosis, so be wary.

One advantage regular air has over nitrox is that you are better off using your regular 21 percent mixture if you’re going below 120 feet. A 36 percent or higher mix is actually more dangerous at depth and can lead to oxygen toxicity. Another is that nitrox users require additional training. If you are an occasional recreational diver, you may want to carefully weigh the pros and cons before making this extra investment.

mixed diving gasesSo, regular air divers have depth limits and shorter bottom times. Nitrox users risk OD’ing on O2 when they go deeper than 120 feet. For a growing number of advanced divers, Trimix is the solution to these problems. This blend of oxygen, nitrogen, and helium is definitely not for the “once in a while” diver. The mix can be custom blended to suit a particular environment, but requires additional gear and training. It is also more costly at the fill station. But if you regularly dive deep, this could be well worth it.

Bottom line, with the proper training and equipment, you can customize your mix to fit your dive and get the most out of your scuba certifications.

Stress-Relieving Tips for Nervous Scuba Newbies – by Aquaviews

scuba newbiesSo you’ve decided to take the plunge and get your scuba certification. As you study your class materials and shop for the perfect mask, your mind has probably been overflowing with visions of exotic coral reefs or crusty, sunken pirate ships. Indeed, a ton of aquatic adventures await but, before you start planning that trip to the Andrea Doria wreck, here are some great tips for nervous scuba newbies to make your introduction to this wonderful world the best it can be.

First and foremost, you’ll need an instructor you trust. If you start classes and feel uncomfortable for any reason, talk to your teacher or the dive center you’re working with. These people are professionals with years of experience and can offer you a world of advice to put your mind at ease. A good instructor will never make you feel pressured to dive when you’re truly not ready and will not push you to take unnecessary risks. These folks love to dive and want you to love it as well, but they know the learning process can be daunting and have all the tools necessary to get you past the normal mental roadblocks people encounter. You’re breathing underwater and things can go wrong. But, with a good instructor, you’ll first learn how to handle these situations in a controlled and safe environment. Then, if they happen out in the open ocean, you’ll be ready to react and take care of the problem without panic.

Knowing your own gear is essential. You will have your own mask, snorkel, and fins to begin your training and you should practice to make working with these items as involuntary as blinking. Take the time to get that perfect fit on your mask. Ask questions about how you can adjust it just right. Wear your fins in the pool to practice getting them on and off in the water and work on your strokes. Snorkel in the bathtub! The more you practice, the more these item s will feel like an extension of you rather than some foreign object.

scuba newbiesFinally, buddy up! If you have a good friend who is already a diver (maybe the one who piqued your interest in the first place), invite them along. The best dive buddy for the newbie is someone who has had a lot of time underwater already and who knows the importance of watching out for each other. You can also chat with your instructor and classmates about experienced divers whom you can meet in your area. If this person has advanced certifications or rescue experience, all the better. You’ve been trained to handle minor emergencies but having someone by your side to whom these things are second nature can, literally, be a life saver. Having the right dive buddy will be a perfect complement to your new life of underwater exploration.

Keep Your Cool: What to Do in a Dive Emergency – By Josh Norris, TDI

dive emergency
There is no way to tell what your reaction will be during an emergency until you actually go through it. For all of you out there who believe that knowing CPR and going through a three day rescue course has you prepared to face some of the horrible things that could go wrong in scuba diving, you are incorrect. Let us be honest for a moment. The rules of CPR seem to change more often than some of us change our shirts. Many people believe that giving rescue breathes in the water while dragging someone out is simply a waste of time, and there will be someone there to tell you all about the things you did wrong even if you pull someone to safety. Despite the many opinions out there, there is no way to predict when something will go bad. The only thing we can do as divers is try to be as prepared as possible for when they do. Believe it or not, under the water is not a natural place for human beings to play around. So how do you keep your cool and stay calm during an emergency situation?

Man the Hell Up!!

There are certain moments in life where you realize the universe is giving you an opportunity to prove yourself. Seeing a loved one, or regular dive buddy, trying to hold onto life while you desperately attempt to help them could be just the opportunity for you to step up and knock it out of the park. While this is obviously not an ideal scenario, the world is simply not an ideal place. After all, no one made you get in the water to begin with. The adrenaline rush and sense of adventure is what drove many of us into diving in the first place. Without that basic need to push further and further, there would be no use in wreck diving or all of cave country. We could all be satisfied by seeing the pretty reefs at 40 feet. However, no one actually watches a NASCAR race to see people drive in circles. The wrecks make it worth it right? Just like no one wants to watch a soccer match for nine hours just to see people faking knee injuries every twenty seconds. The point is that because we push further into caves/wrecks and because we dive deeper and deeper, the chance for some really bad stuff to happen increases exponentially. Finding the inner beast to do what needs to be done may just mean the difference to someone. Dragging someone out of the water half dead may be better than pulling them out a few days later and trying to collect from your dive insurance.

Do Not Hesitate!

Once you make the decision to intervene with someone to help, you better not stop until that individual is safe, killing you, or dead. There is no room for a half measure when it comes to emergencies. Wrapping your head around this notion is necessary in staying calm in the midst of something chaotic. Once you make the conscious decision that you will not stop, everything else becomes easy. Either you will succeed or you will die trying right? Either way, no one has time for you to second guess yourself. If you were wrong and misinterpreted the actions of your dive buddy as a sign of distress, then fight it out on the surface or at the bar. Maybe they should not have been acting erratically while diving to begin with. When it comes to dive professionals, there is a big line in the sand it seems. When should a pro get involved with someone? What if that person is not my student? What if the other Instructor ends up hating me? Who cares? If someone is in trouble, or you think they are in trouble, then you should probably go ahead and help out. If someone sees me stroking out in the water, please send me to the surface and help me get out of the water. I promise that I will not hate you for ruining my dive. All of that said, DO NOT be the guy who has to stick their nose into everyone else’s business at every turn. There is still a learning curve in diving and some take a bit more time to learn than others.

What is the Worst that Could Happen?

So you may have found yourself in an emergency situation, and your mind is racing with all of the information you could possibly remember. Take a moment and think about this though; what is the absolute worst case scenario for you? I always tell my students, in a very matter of fact way, that “Josh is gonna be alright.” In essence, I will go through hell trying to save you but if it comes down to it; I will walk away and be just fine. Any time there is a diving incident, there are so many people who want to point to the Instructor or dive operation and scream that it is their fault. Whatever happened to bad things just happening sometimes? No one expects for a high pressure hose to explode under water 200 feet down or 7,000 feet into a cave, but it happens sometimes. Good luck trying to sue the Chinese guy who made it. Sometimes bad things just happen. Ironically, bad things seem to happen to the nicest of people. So when you are handed the chance to help out, think about how bad it could possibly be. Try to do the right thing and everything will be alright.

So basically, there is no magic answer to staying calm during an emergency. I would say that all you need to do is pop a couple of Xanax before your dive and you will be calm no matter what. However, there are so many things wrong with that. As long as you understand that the longer you stay in diving, the more likely you are to run into a bad situation; you will become more and more prepared. That does not mean that you should bust out the red cape and start a new superhero scuba trend. All it means is that no matter what, you should have a basic understanding of what is right and what is wrong. As long as you stay on the “what is right” side of things, a bad situation will work out one way or another.

Signs and Symptoms of Decompression Sickness – by Sean Harrison

hyperbaric chamberQuestions regarding decompression sickness (DCS) are very commonly asked by divers at all levels, and answers to these questions vary depending on the experience of the diver and the level of training they have received. For a sport diver who does not plan on conducting a decompression dive, the answer can be as simple as: staying well within the no decompression limits (NDLs), controlling your ascent, and performing at least a 3 minute safety stop on every dive. For technical divers, planning decompression dives, the answers get a little more complicated but the basic theory remains the same.

A technical diver planning to perform a decompression dive has to build in more contingencies such as: additional gas supplies, multiple controlled ascent rates, variations of an optimum dive plan, and additional decompression stops, all leading to the same end result – reduced amounts of residual nitrogen in the body, off-gassed at a controlled rate. For planned decompression dives this all has to happen prior to reaching the surface.

Ideally, the nitrogen and other inert gasses that have been absorbed into our body’s tissues will return to our bloodstream and eventually be eliminated out through our lungs. However, if we do not follow our no decompression limits (NDLs) or our decompression schedules, or if we ascend too quickly, the absorbed gasses in our body will expand and form bubbles in our tissues and bloodstream. The end result being decompression sickness, also known as the bends, or “getting bent.”

What are the symptoms of DCS?

  • Joint and muscle pain – this is the most common symptom due to bubbles typically forming in and around joints
  • Confusion and unusual behavior
  • Coughing up blood
  • Difficulty urinating
  • Dizziness or vertigo
  • Fatigue
  • Headache
  • Loss of hearing or ringing in ears
  • Memory loss
  • Nausea
  • Rashes
  • Sensitive, painful, or itchy skin
  • Shortness of breath
  • Swelling
  • Tingling, numbness, and paralysis
  • Unconsciousness
  • Uncontrollable shaking
  • Visual disturbances
  • Vomiting
  • Weakness

Treatment of DCS

In most cases, DCS will require treatment in a hyperbaric or recompression facility. This helps to increase the ambient pressure surrounding the diver, shrinking the inert gas bubbles and reversing the DCS effects. The pressure is then gradually reduced to normal atmospheric pressure. The more severe the case of DCS, the more aggressive the ‘table’ is that’s used to treat it. In some cases the same table is used multiple times over multiple days. In some hyperbaric facilities a second inert gas (helium) is used in place of ambient air, this has shown to decrease the time spent in the recompression chamber and speed up the treatment. Immediate steps of treatment in the field include:

treatment center

  • Maintain blood pressure and administer 100 percent oxygen (if 100 percent is not available, administer the highest percentage available) and fluids
  • Contact your local emergency medical services (EMS)

Prevention of DCS

  • Slow and controlled ascents
  • Never exceed your NDL or your planned decompression schedule
  • Do not drink alcohol before diving, and stay hydrated
  • Avoid flying or driving to higher elevations within 24 hours after a dive

The symptoms of DCS can appear as late as 48 hours after returning to the surface, but in most cases and certainly in extreme cases, the onset of symptoms occur immediately after surfacing, if not before. There are different categories and levels of DCS, based on the severity of the above symptoms. Some cases can be very dangerous and life threatening, so if you suspect that yourself or another diver may be suffering from DCS you need to immediately: abort the dive, administer pure oxygen ASAP, and contact your local emergency medical services (EMS). Proper dive planning, staying within your NDLs, staying within your planned decompression schedule, controlling your ascent, and properly executing safety stops can greatly reduce your risk of DCS.

There are more complex physiological considerations when it comes to DCS and its symptoms, but this should provide a basic understanding, and checklist of symptoms to be on the lookout for when diving. Make a mental note, and dive safely!

Beware the Deadly Beauty of the Marbled Cone Snail – by AquaViews


marbled cone snailThe unique marbled cone snail is found from the southern tip of India to Okinawa, Japan, and southeast to New Caledonia and Samoa. It feeds on other snails, including some within its own species. When it attacks its prey, it sticks out its long white proboscis to shoot a poison-laden harpoon, sometimes attacking its prey multiple times over. The prey becomes paralyzed and its muscles begin to relax irreversibly. Once the prey lies flaccid outside its shell, the snail can begin to devour it. The species is found in fairly shallow water, typically on coral reef platforms or lagoon pinnacles, as well as in sand, under rocks, or among sea grass. The marbled cone snail is unusual among marine snails in that it is quite active during the day, and not strictly nocturnal.

Some of the peptide toxins found in the venom have been characterized, one of which is being developed as a potential drug for pain. The venomous toxins are produced in the venom duct, which is attached to a large bulb called the venom bulb. The venom bulb contracts to push venom into the harpoons, similar to squeezing a pipette to force liquid out. The longest dissected venom duct is over three feet long and came from a cone snail that was only five inches long!

The harpoons are evolutionarily modified teeth that are stored in a radular sac. The harpoon is like a disposable, hypodermic needle. Once the cone snail uses a harpoon to inject venom into its prey, it is discarded. The snail must reload another harpoon before it can strike again. Thankfully for snail, they have around twenty harpoons at various developmental stages in storage so a snail will always have another harpoon ready to load and use. The venom is made of a small number of amino acids. Cone snails have the ability to make hundreds of toxins and deliver a cocktail, or mixture of toxins, when injecting its prey with venom.

marbled cone snailIn the nervous system communication can be stopped by blocking certain ion channels. These channels open to let a chemical signal travel from neuron to neuron. Eventually the signal reaches a muscle cell that tells it to contract. This is how you can bend your finger and kick a ball. Cone snail toxins, called conotoxins, block these channels. When the channels are blocked, communication in the nervous system stops. This causes paralysis.

Different toxins stop different channels. Some channels control just our skeletal muscles, some control our heart muscles, and some control our organs. Based on the type of snail, the toxin might cause different kinds of paralysis. The moral of this story seems to be not to mess with the marbled cone snail under any circumstances when you see one, lest you become a target for its painful harpoon!

Be Prepared on Every Dive – by AquaViews

Getting hurt during a recreational dive doesn’t have to be a wreck. Occasional injuries happen, from a little water in the ears to “Hey, did you know barnacles are really, really sharp?!” But being prepared for emergencies can make for a smoother and more relaxing dive trip. Below are some simple tips that can help you be prepared on every dive.

Wearing gloves and booties: Knowing the environment into which you are diving can be one of the simplest and most effective steps towards preventing injuries. Diving near pier pilings or other long-standing stationary objects? There will be barnacles. Gloves and a full body wetsuit can help protect your body from cuts and scrapes when diving.

Carry a basic first aid kit to take care of simple injuries and discomforts. What you’ll need: a sealable plastic case or waterproof bag; assorted size band aids; gauze and gauze tape; antibiotic cream like Neosporin; antiseptic wipes or running alcohol; aspirin or acetaminophen (aka Tylenol); ear drops for swimmers ear, an ace bandage. These basic tools can take care of the little things that don’t require emergency care.

Know your C’s: The Red Cross has an easy to remember action plan for any emergency situation that even applies to divers. 1. CHECK – Gauge the severity of the injury, how much distress the person is in, and whether everyone should call the dive and get back to land or to your dive boat. 2. CALL – Get help if needed. Carry an emergency whistle in the water so you can attract attention or alert your boat’s crew that help is needed. If shore diving, call 911 if needed as soon as you are out of the water. prepared on every dive3. CARE – Care for minor injuries or, in the case of more severe situations, stay with the victim until help arrives. Provide as much information as possible to the divemaster, paramedics, or health care professionals.

As the old saying goes, an ounce of prevention is worth a pound of cure. Contact your local YMCA or Red Cross about basic first aid and CPR classes. Plan your dive and know what creatures you might encounter under the water. Making a mental run through of how you’ll react in an emergency will help you be ready should one arise for real.

Aquatic Dreams Diving Checkout Weekend – June 27-28th, 2015

Our first checkout dive weekend of the 2015 season was held June 27-28th at White Rock park in Indiana.  The weather decided to throw us a few curveballs on Saturday and we dodged a few rain showers and some less than ideal visibility, but the students worked through it and we had great weather on Sunday.  We wish to congratulate Christopher and Courtney Hellmann, Jesse Kent, Tim Brueggemann, and Dave Brewer on completing their open water diver certifications and earning their certification cards.  We’re proud to call you friends and we look forward to diving with you in the future!


New student certifications and John New student certifications.1 New student certifications.2 new student certifications.3 new student certifications.4 new student certifications.5 new student certifications.6 new student certifications.7 new student certifications.8 Welcome new divers

The History of Scuba Diving – by AquaViews

history of scuba divingFreediving is as ancient an activity as humanity itself, and the predecessor to scuba diving. More than any other sport, freediving is based on old subconscious reflexes written in the human.

For the first nine months of our lives, we humans exist in an aquatic environment very similar to seawater. If a human infant is submerged underwater, it instinctively holds its breath for up to 40 seconds while making swimming motions, although we seem to lose this ability as soon as we commence walking. Awakening these reflexes is one of the most important elements of freediving, thus giving humans better abilities to be protected at large depths.

The word Apnea derives from the Greek word a-pnoia literally meaning “without breathing.” The origin of this word doesn’t have connection to water, but in modern athletic terminology “Apnea” has become a synonym for freediving. Apnea means diving on one breath of air, without using equipment that would make it possible to breathe underwater.

In the 16th century people began to use diving bells supplied with air from the surface, probably the first effective means of staying under water for any length of time. The bell was held stationary a few feet from the surface, its bottom open to water and its top portion containing air compressed by the water pressure. A diver standing upright would have his head in the air. He could leave the bell for a minute or two to collect sponges or explore the bottom, and then return for a short while until air in the bell was no longer breathable.

In 16th century England and France, full diving suits made of leather were used to depths of 60 feet. Air was pumped down from the surface with the aid of manual pumps. Soon helmets were made of metal to withstand even greater water pressure and divers went deeper. By the 1830s, the surface-supplied air helmet was perfected well enough to allow extensive salvage work.

history of scuba divingStarting in the 19th century, two main avenues of investigation — one scientific, the other technological — greatly accelerated underwater exploration. Scientific research was advanced by the work of Paul Bert and John Scott Haldane, from France and Scotland respectively. Their studies helped explain effects of water pressure on the body, and also define safe limits for compressed air diving. At the same time, improvements in technology, including compressed air pumps, carbon dioxide scrubbers, regulators, etc., made it possible for people to stay under water for long periods!

Scuba diving has come a long way since then, but it’s still one of the most beloved and adventurous recreational activities of all time!

SCUBA Divers Lead Charge Against Invasive Lionfish – by Kerry Sheridan

Diver brings up Lionfish catch

Diver brings up Lionfish catch

Islamorada (United States) (AFP) – Clad in a gray hooded wetsuit, Eric Billips straps on his scuba tank, grabs a pole spear and nods at his dive buddy as they step feet-first off the boat and disappear with a splash into sparkling blue waters off the Florida Keys.

The lionfish hunt is on.

Billips, 42, speared his first lionfish six years ago and estimates he has since killed thousands of the invasive, venomous predators, as their numbers have exploded across the western Atlantic and Caribbean.

But he isn’t sure what he will find in this particular spot, about four and a half miles (seven kilometers) offshore.

A fisherman told him he’d snared a couple of lionfish on his hook and line there — which was unusual because they typically stalk their prey in the ocean depths and don’t chase bait on a line — and gave Billips the coordinates so he could find the area himself.

The divers descend 135 feet (about 40 meters), and see what looks like bridge debris — concrete and steel girders that someone dropped there long ago to create shelter and habitat for fish, and a custom fishing hole.

Full-grown grouper and snapper are swimming around, along with vast schools of minnows ready to be gobbled up by the lurking lionfish.

Billips kneels in the sand and begins to shoot. His weapon is equipped with a three-pronged trident tip that impales each lionfish. He pushes the speared fish into his shoulder-slung container — a narrow barrel with a one-way entry — and pulls the tip out, clean and ready to shoot again.

Twelve minutes later, Billips and his fellow diver resurface, grinning and breathless. They slide their containers onto the boat, each filled with more than a dozen fat, full-grown lionfish.

“It’s crazy. These lionfish, they have no fear,” says Billips, who owns the Islamorada Dive Center in the Florida Keys.

Two more divers go down to hunt, and soon they emerge with their own bounties. A cooler fills up with twitching red, orange and brown striped fish, some as long as 16 inches (40 centimeters).

Billips pauses for a quick review of the cooler contents, and counts about 50. Then he fires up the boat’s engine to bring his team to the next fishing spot.

– A ruthless invader –

Lionfish were first spotted off Dania Beach, Florida, in 1985. The fish are native to the Red Sea and the tropical Pacific, and are believed to have been introduced to the western Atlantic by people who let their aquarium fish go in the ocean.

Two species of lionfish — Pterois volitans, which is the most common, and Pterois miles — have officially become the first outsider finfish to establish a sizeable population in the waters off the United States.

They can now be found in an area covering more than 1.5 million square miles (four million square kilometers) in the western Atlantic, Caribbean and Gulf of Mexico.

With 18 venomous spikes that can cause intense pain, and no natural enemies besides humans, these members of the scorpionfish family scare off any would-be predators. Even sharks will not eat them.

But lionfish will eat almost anything smaller than them, including valuable species like red porgy, vermilion snapper, Nassau grouper and fish that consume algae off reefs and keep them healthy.

“It is quite alarming that a small population of lionfish can literally consume millions of prey over the course of the year, so that is one of the reasons we are very focused on control,” says James Morris, a leading lionfish researcher at the National Oceanic and Atmospheric Administration (NOAA).

– Competitive sport –

The first lionfish derby was held in 2009 in the Bahamas, according to Lad Akins, director of special projects at Reef Environmental Education Foundation (REEF), a non-profit marine conservation group.

“Derbies have spread all through the region and they are held quite frequently now,” he says.

What has given divers hope that their efforts are working is an ongoing study being led by Stephanie Green, a marine ecologist at Oregon State University.

Her team has found that killing between 75 and 95 percent of lionfish off reefs in the Bahamas was enough to help populations of local fish rebound.

For the past couple of years, Green has been traveling to South Florida, tracking derbies, counting lionfish in the waters before and after hunting expeditions, and comparing the populations to areas that have not been hunted.

She and colleagues are submitting their latest work for peer-review and publication in the coming months. So far, the news is good.

“We are finding really strong evidence that volunteers can be really effective,” Green says.

“By doing derbies on an annual basis, or possibly even more frequently, the hope is that you are keeping lionfish at very low numbers, low enough that they are not having an impact.”

– The winner is… –

After the derby off the Florida Keys, a seaside party ensues. Reggae music plays, and prizes of cash, stuffed toy lionfish and jars of liquor are handed out to the winners.

Akins, who has co-authored a lionfish cookbook, demonstrates for a small crowd how to clean the fish, cut off the spikes, and slice filets.

Volunteer chefs make samples of ceviche and fried lionfish for the crowd.

“It is a really light, flaky fish,” says Michelle Dickerson, a diver from Texas. “It tasted really good.”

Two of the five boats that entered this derby came back empty handed. One team caught just two lionfish, and another boat snared 11.

Billips’ boat, The Life Aquatic, is the winner with 86.

For Billips, it wasn’t the biggest haul ever, but it was still satisfying.

“That probably saved 20,000 little fishies, just our boat today,” he says.

“That’s huge.”


Life Ending Seconds – 3000 to Zero in 72 Seconds – Advanced Diver Magazine – by Curt Bowen

We train for equipment failures in our certification courses, practice our emergency drills, and conduct pre-dive safety inspections. We do all this in hopes that we may catch a problem before it happens or have the knowledge to remedy the situation at depth just in case one occurs. In all the preparation and drills, it always seems that an equipment failure happens at the worst time.

Advanced Diver Magazine looked into equipment failure one step further and conducted a series of tests at multiple depths in an attempt to calculate if increased depth can escalate a potential life threatening equipment failure. Afterwards, we posted the results on the technical diving forum, The Decostop (, to see what the responses and suggestions from other technical divers would be.

The test

Four different equipment failures were simulated at four different preset depths and timed for their results. Each test included a full aluminum 80 cubic foot cylinder filled to 3000 psi. The test timed how long it would take to drain each aluminum 80 from 3000 psi to 0 psi.

The equipment failures tested
1. High-pressure hose failure. Simulated by putting a pre-cut high-pressure hose on a first stage regulator. The cylinder valve was fully opened at the predetermined depths, and the time it took to drain an 80 cubic foot cylinder was recorded.
2. Low-pressure hose failure. Simulated by putting a pre-cut low-pressure hose on a first stage regulator. The cylinder valve was fully opened at the predetermined depths, and the time it took to drain an 80 cubic foot cylinder was recorded.
3. Burst disk failure. Simulated by removing a burst disk from the cylinder valve at depth. The time it took to drain an 80 cubic foot cylinder was recorded.
4. Free-flow second stage regulator. Simulated by manually purging a high performance second stage at the predetermined depths until the cylinder was emptied. The time was recorded.
Depth Tests Conducted

Equipment Failure Test Results

This test (see above results) produced clear and precise results indicating that any major equipment failure, with the exception of a high-pressure hose rupture, would result in a catastrophic gas volume loss in just a few seconds.

Applying this knowledge to real life situations.

The far right column in the chart above provides the amount of gas lost in cubic feet in 15 seconds. (The estimated time it takes for an unsuspected diver to fully analyze and shut down the failed regulator or isolation valve.) Of course with some situations, such as a ruptured burst disk or tank neck o-ring failure, all the volume in the affected cylinder will be lost.

The best reaction and solution to save the maximum amount of gas will vary according to the type of rig each diver is using from doubles with an isolation valve, independent doubles, and side mount cylinders. The ending consensus indicated that a good buddy team, especially for extreme technical diving and proper gear maintenance was of top priority.