DAN Report on Diving Fatalities

[Thalassamania]

I do not disagree with Hilbert's opinion, in fact I worked at the NAUDC for years. What I object to is Dennis' misleading statement that implies that even properly conducted BB my be fatal because divers hold their breath and thus overpressurize to the point of AGE while still involved in BB. The locked glottis and AGE has ALWAYS occurred as a result of the failure of the BB activity and the subsequent separation of the buddies coupled with the inability to the perform a CESA. Hilbert would have been equally correct to say had both buddies been adequately trained and practiced in BB, then they'd (almost by definition) be alive today. The octopus is a better solution, but in many ways is also a possibly appropriate equipment solution to a skill problem.

'Breath hold' is a non technical term that opens a rats' nest of semantic problems when you try to pin down the details.

 

[debajo agua]

This is something I never understood: in the fire service, every scba has an audible alarm (bell) that automatically starts ringing at 500 psi and continues until there's no more air in the bottle.This is invaluable, not only to the firefighter, but also to there coworkers. It lets everyone know, "hey, someone is low on air, time to leave."

 

[John C. Ratliff]

Thalissamania, thanks for the clarification. All Dennis wanted was to stimulate thinking during the ITC. Putting this up has again stimulated that thinking.

debajo aqua, I have two regulators that have this type of sonic alarm. One is the original Healthways Sonic regulator, which honks when the pressure is below about 500 psig. The other is the Scubapro Sonic, which not only honks, but also puts a vibration in the second stage. Both are quite effective. They were used, but then the rumor came through that the sonic reserve attracted sharks, and they started to come out of favor. But they work well.

SeaRat

 

[debajo agua]

Without any prior experience, unless you remember to brief me pre-dive, I'd have no idea what your computer is doing. Different alarms mean different things (ascent alarms, rapid breathing alarms, BT alarms, etc.). Having never heard them before, how do I know which alarm is sounding? I'm going to look at you with a big question mark. I will also wonder if you know how to use your computer? If you're in the habit of using the rule-of-thirds, through no fault of your own, you might not have ever heard this alarm yourself. Valuable time might escape, while you're in a state-of-confusion, since you may not have any prior experience with this new sound your computer is now making.

In the fire service the audible alarm is universal. I can go to any fire dept. in the country and know when someone is low on air. The beauty of it: every trained firefighter on scene (supervisors, fellow firefighter, and the person low on air) knows what's up too... time we get the #$@% outta here!

We also have a PASS device which we can activate if we're lost, down, trapped, or entangled; hopefully, help will soon follow. The PASS device (manually activated) gives a distinct audio (annoying) sound that drives everybody crazy; therefore, somebody is going to come and find out "what the #$@% is going on because that sound is driving me nuts." :chairfight:It also flashes, which isn't very useful in smoky environments, but it does assist, once the rescuers have closed in on the down FF.

I sincerely believe, that the fire service is much more vigilant when it comes to possible OOA training and warning devices. When someone enters an environment where you simply can't pull off your protective equipment and draw a breath, it leaves me perplexed why the scuba industry doesn't incorporate some of the concepts and training found in the fire service. With a limited air-supply strap to your back, both environments are dangerous.

 

[Ayisha]

That is enlightening, debajo agua. May I add a little twist to hearing an alarm at depth: sometimes it's hard to hear with a thick hood on. Sometimes I've barely heard an alarm but the red light signals my attention as well. Sometimes more than one diver's alarm is going off and everyone looks to see if it is theirs. Some people have so many alarms set that they disregard half of them.

I set my alarms to where they matter rather than just warnings way in advance, so if they do go off, they're not an annoyance. The ascent alarm is on. I set my turn pressure at half, so if I haven't turned yet on most dives, I'd better. I set my residual gas at 500 psi expecting to not reach it. I set the depth alarm at 130 feet so I don't have to keep re-adjusting, although I don't plan to unknowingly be at any depth. It helps to reduce the quizzical looks from a buddy as to why the alarm's going off. I figure the more meaningful the alarms are that you set, if you use them at all, the more you take them seriously.

 

[boulderjohn]

Another problem is that with underwater alarms, sound travels so quickly that you cannot tell where it is coming from. On a recent trip, everyone on our boat was diving for the first time at that location. After the dive, we all reported the same thing--we were constantly hearing some kind of alarm we had never heard before. Everyone was looking at their computers, their buddies' computers, or anything else that could help them locate the source of the sound which seemed to be coming from everywhere. The dive professionals on the boat explained it for us. There was a naval base not far away, and we were hearing sonar from a submarine.

 

[debajo agua]

Wouldn't it be awesome if everyone knew the distinguishing sound for "hey, my air is low" or "hey, I'm in some sort of serious trouble over here and need assistance" vs "I'm ascending 20 fps" or " warning: with the current SAC rate, at the current depth, you have two minutes remaining BT".

What I'm getting at is, we need universal sounds in the scuba industry for high priority incidents. Something that every OW student would be familiar with, namely, "I'm close to OOA (below 500 psi)" which would be automatic activated and "I'm in serious trouble and need assistance" alarm which would be manually activated . IMHO, these two distinct sounds would be easy enough for every OW student to learn, that they should be universal on every dive computer. Take out the guess work and simplify things for both the user and the buddy! I believe it would save lives. I'm not in favor of regulations but this is a case where it might help save someone's life. If the manufactures can't agree on a universal distress call, maybe the government should step in and say, "This is how it's going to be, now you manufacturers comply, or sell you computers elsewhere".

 

[John C. Ratliff]

debajo aqua, these are concepts which have been looked at, and argued about, over thirty years ago. We used to have only one "alarm" for low air--the J-reserve valve. When that reserve was pulled, we knew that the person was below 300 psig (single tank) or 250 psig (double tank--reserve in one cylinder set at 500 psig). (You can see in the enclosed photo of U.S. Navy UDT members with twin tanks, and at least one tank has more than 500 psig, as the J-valves are in the up position; note that these two divers reversed the direction of these reserves too, so that they are not easily hit and inadvertently activated.)

We then got some sonic alarms, such as the two regulators I mentioned above. Also, U.S. Divers Company came out with a valve which would hammer a steel tank from the inside at less than about 350 psig.

However, there are two factors going against any standardization; the international competitiveness of the diving manufacturers, and the other factor I mentioned above--the fear of attracting predatory fish (sharks and barracuda). Fire services don't have to contend with the latter problem.

I am very familiar with the Incident Command System (ICS) for fire and emergency response teams (ERTs). But there are several differences--these teams train together for years, and know their equipment very well. They usually also have radio communications (which you did not discuss).

My feeling is that until we get audio communications (voice communications) between divers, we will continue to have these signal problems. These audio signals could be standardized, but may not be heard (here in the Pacific Northwest, we have thick hoods and I cannot hear my own computer). In 1972 I spent a summer as a smokejumper, hoping to take the money I made and develop a simple communications set for divers. Well, instead I had to use that money on my education. Now, we are getting to where comm gear is now available, along with FFM (full-face masks) that are at a reasonable price. This, I think, is the next great jump in diver safety.

SeaRat

 

[debajo agua]

However, there are two factors going against any standardization; the international competitiveness of the diving manufacturers, and the other factor I mentioned above--the fear of attracting predatory fish (sharks and barracuda). Fire services don't have to contend with the latter problem.

True that... but at 500 psi, my plans were to leaving the underwater realm anyways. Here's my concern, I would hate to be put into a position, as a buddy, where my buddy ignores his air-supply until he runs low or OOA. Now we have to both share mine for an emergency ascent. That's putting me at risk. What if I don't have enough air to do it? Some kind of universal audible alarm should be mandatory on all newly manufactured equipment. Some frequency that won't stimulate sharks. That way, when I hear my buddies alarm go off, not only does he know it's time to leave, but I know it's time for him to leave as well.

It can be done. We have the technology to do it. It can be done cheap. Ultimately, it could save a life.

I am very familiar with the Incident Command System (ICS) for fire and emergency response teams (ERTs). But there are several differences--these teams train together for years, and know their equipment very well. They usually also have radio communications (which you did not discuss).

LOL... our communications suck... feedback, background noise, excited personalities, etc. When you're out of breath, communicating in a mask is not easy.

Once the graduate from the fire academy, rookies are expected to know the basics of firefighting. For their first 5 years on the job or more, rookie fire fighters jerry (work with different crews, equipment, and companies) almost every shift....the low man goes.

My feeling is that until we get audio communications (voice communications) between divers, we will continue to have these signal problems. These audio signals could be standardized, but may not be heard (here in the Pacific Northwest, we have thick hoods and I cannot hear my own computer). In 1972 I spent a summer as a smokejumper, hoping to take the money I made and develop a simple communications set for divers. Well, instead I had to use that money on my education. Now, we are getting to where comm gear is now available, along with FFM (full-face masks) that are at a reasonable price. This, I think, is the next great jump in diver safety.
SeaRat

The only thing that I know about underwater voice communications are they're not cheap. Water + electronics = $$$... and a nagging wife who has better uses for the money.

---------- Post added January 2nd, 2013 at 10:56 AM ----------

That is enlightening, debajo agua. May I add a little twist to hearing an alarm at depth: sometimes it's hard to hear with a thick hood on. Sometimes I've barely heard an alarm but the red light signals my attention as well. Sometimes more than one diver's alarm is going off and everyone looks to see if it is theirs. Some people have so many alarms set that they disregard half of them.

I set my alarms to where they matter rather than just warnings way in advance, so if they do go off, they're not an annoyance. The ascent alarm is on. I set my turn pressure at half, so if I haven't turned yet on most dives, I'd better. I set my residual gas at 500 psi expecting to not reach it. I set the depth alarm at 130 feet so I don't have to keep re-adjusting, although I don't plan to unknowingly be at any depth. It helps to reduce the quizzical looks from a buddy as to why the alarm's going off. I figure the more meaningful the alarms are that you set, if you use them at all, the more you take them seriously.

I think it's great the you understand and now how to work your computer. I've come to find out, many people don't how to use their own, and are not really interested in learning how to use it!

You stated that you get quizzical looks from your buddy when your alarm goes off. I can totally relate. There's nothing more perplexing than to hear your buddies computer go off and have no idea what's gone wrong. I propose we fix this problem making two universal alarms for every dive computer sold in the future. One automatic, continuous alarm for a diver who has fallen below 500 psi and a different alarm manually activated for a diver in need of assistance. I then propose that every SCUBA training agency adopt a curriculum that teaches the student to identify these alarms and know their meaning.

If the computer manufactures will not come to an agreed upon alarm. I propose that legislation measures that will prevent, or allow them to sell their computers.

I feel that strongly about it.

---------- Post added January 2nd, 2013 at 11:04 AM ----------

Another problem is that with underwater alarms, sound travels so quickly that you cannot tell where it is coming from. On a recent trip, everyone on our boat was diving for the first time at that location. After the dive, we all reported the same thing--we were constantly hearing some kind of alarm we had never heard before. Everyone was looking at their computers, their buddies' computers, or anything else that could help them locate the source of the sound which seemed to be coming from everywhere. The dive professionals on the boat explained it for us. There was a naval base not far away, and we were hearing sonar from a submarine.

As stated, everyone was "hearing some kind of alarm". In other words, the same quizzical looks were being shot around that Ayisha was getting. If you had been trained and familiar with two distinct alarms that I propose become standardized, you could have mentally eliminated two very serious conditions: someone is below 500 psi and someone is in need of immediate assistance.

 

[Ayisha]

Debajo agua, not everyone uses a computer and the more complicated diving that people do, likely the less computers are used. It probably won't be possible to regulate computer use any more than the features of the computer, although a specific alarm might be useful. You could propose it to computer manufacturers.

If divers were always aware of their gas supply and how to manage it; could handle dive emergencies proficiently; maintained situational awareness, stayed within a fin kick of their buddy(ies) and maintained visual contact - a two-tiered alarm wouldn't be necessary, would it?