Triggers of Dive Accidents

[cruisensnooze]

Hi Ken
Maybe the rule we have at our club would help. If you get down to 50 bar (sorry am english) you are fined £5 and down to 25 bar is £25. The money goes to the local decompression unit to help with the running costs. It sure sharpens the mind and makes most divers very careful.
Chris

 

[Ayisha]

I wonder why a typical OW course doesn't require you to plan and execute a dive with a buddy without an instructor. OW is supposed to prepare you to dive independently but it's the one thing you're guaranteed not to do in the course.

Excellent point. It might take a little more time before the fourth dive, if not the third and fourth, for each buddy pair to plan a first and consecutive dive and have the instructor approve it. The flex skills would probably best be done within the first 3 dives. If the instructor needs to hover right beside each buddy pair, then he or she can give the students parameters to work within and still see if the students planned and executed it well.

If you had a fifth dive in one weekend, one dive might have to be quite late or a night dive because that is apparently the only way to get three training dives in on one day. Or once everyone has completed the o/w, get them to do a third dive of the day that they plan and execute, including navigation, gas management, etc.

If you read the standards for PADI, at least, OW students are supposed to participate in the dive planning for their OW dives, with the supervision of the instructor.

I am very certain that I did not participate in planning any of my OW or AOW dives, with or without an instructor. I am very certain that none of my classmates did either. I was around and participated when several of my friends got certified in the following years as well, and I am very certain that they also did not participate in dive planning during their OW or AOW dives. We were told what depth we were going to and what skills we would be performing, and we followed. After the dives, we used the figures that were recorded when we entered and exited plus any info we wrote down to log our dives, and the logs were checked by the instructor.

I am wondering how much planning goes into dives with newer students today who may not have even learned to use the RDP. Many dive shops no longer teach the tables, but use the eRDP. Many divers spend little or no time working with tables and go straight to a computer, where they may or may not plan the dive beforehand. I wonder how the students who did not learn tables do in an EANx course where it presupposes a solid understanding of working with tables - unless the course no longer uses tables? I imagine there's more to learn at once in the nitrox course if you haven't worked with tables.

Many divers simply run their dives on the fly as a multilevel computer dive and let the computer tell them when to ascend, when the dive is over, when they can do another dive or fly. Do divers plan and execute their dives the way they used to?

 

[boulderjohn]

I am wondering how much planning goes into dives with newer students today who may not have even learned to use the RDP. Many dive shops no longer teach the tables, but use the eRDP.

Dive planning is easier with the eRDPml than the tables. You can easily plan a multi-level dive with them as well. A multi-level plan is possible with the tables if you really know what you are doing (and it is not taught), but it is a piece of cake with the eRDPml.

I wonder how the students who did not learn tables do in an EANx course where it presupposes a solid understanding of working with tables - unless the course no longer uses tables? I imagine there's more to learn at once in the nitrox course if you haven't worked with tables.

The nitrox course has similarly changed.

 

[drbill]

Ken, I decided you were crazy some time ago so I'm not surprised! Seriously, your post is meat for some real thought.

In almost 50 years of diving I've unintentionally run OOA three times. Once was in the days when we had no SPGs and the tank I pulled from the "filled" rack wasn't. Second time was when my dip tube clogged with debris and the valve stopped delivering air despite there being 2800 psi in it. The third time was due to my own stupidity... not checking my gauge to ensure the shop had actually filled my tank (it hadn't... twice in a row for that shop jock). I've intentionally run OOA a few times when I wanted to get every bit of video I could of a subject in shallow water.

First, it astounds me that ANY trained diver would run OOA (but I did it once). I know my profiles pretty well and can estimate my remaining air fairly accurately without even looking at my gauge. However I DO look and have been amazed at how many divers don't check their SPG with sufficient frequency.

Second, I believe that it is essential to teach various OOA drills to beginning divers with the stipulation that they have it drilled into them that this shouldn't happen... but if it does... I think back to the late 1960s when I finally got certified and Ron Merker used to sneak up on us and shut off our valves to see how we responded as part of our OW course. I'm not suggesting instructors do that today. However, I think having a student and an instructor actually see how a diver responds to an unexpected OOA situation can be very informative. Do they panic or address the situation calmly. Personally I think that is one of the most important things a diver can learn about themselves.

I agree with Lynne that gas management should be a part of early training. OW courses these days are so minimal (compared to the three week course I rook with Ron), that it doesn't leave much room for adding what I think should be taught. I see this as a failure in our training procedures.

As for training re: avoiding DCS, I think embolism is a greater risk to most beginning divers. Both should be covered relative to gas management though.

 

[Q1988]

Dr. Bill, Ken et al.
running out of air because your tank has plugged or was not filled or was mt and put in the filled rack seems to be a possibility when you arrive at a new dive shop for the first time, have just got off the plane and are ready to dive for the week.

These are not your fault but the outcome, OOA, is your problem. Hopefully it the situation presents itself very early in the dive or before you hit the water.

Not checking your gauge, not having a spare supply, not making sure your buddy is carrying a little more air and he knows it is for you if something, anything happens and you run OOA is reckless. If you solo dive then you better cover your a.. If you dive with a group then know their equipment and yours, just in case.

Good pilots don't run out of gas. Good divers shouldn't either.

Randy

 

[davidbaraff]

It's an excellent suggestion and one (when I was teaching OW regularly) that I would do as the final dive for all my classes. The students had all already done the required number of dives and demonstrated skills up to snuff for me, and then the final thing was to plan/do a dive on their own with their buddy, while I stayed up on the boat and supervised.

- Ken

I did my O/W with a NAUI instructor two years ago. His standard practice is that the fourth dive is the students, who have been working together throughout the first three dives, to go out without the instructor. They form the same buddy teams they have been using throughout the course, plan the dive, then dive it.

I think it's highly valuable --- you suddenly realize, wow, we better know what we're doing. I can't believe this isn't standard.

Needless to say, he doesn't let people he has doubts about to that. The instructors are still up on the shore, watching.

When I came back to watch newer students going through this, I was amused to find that (though hidden well), the instructor was more nervous watching students go out than (most) students were doing the dive!! But he did a good job of not letting us know that at the time.

I think it was one of the most valuable parts of the course.

 

[MXGratefulDiver]

I did my O/W with a NAUI instructor two years ago. His standard practice is that the fourth dive is the students, who have been working together throughout the first three dives, to go out without the instructor. They form the same buddy teams they have been using throughout the course, plan the dive, then dive it.

I think it's highly valuable --- you suddenly realize, wow, we better know what we're doing. I can't believe this isn't standard.

Needless to say, he doesn't let people he has doubts about to that. The instructors are still up on the shore, watching.

When I came back to watch newer students going through this, I was amused to find that (though hidden well), the instructor was more nervous watching students go out than (most) students were doing the dive!! But he did a good job of not letting us know that at the time.

I think it was one of the most valuable parts of the course.

Whatever the merits of such an approach may be, it's a violation of NAUI Standards ...

The NAUI policy, as stated on page 2.14 of the S&P, under the heading Supervision states that ...

No instructor shall knowingly permit any student to leave the immediate in-water training area without supervision or attendance of an instructor or certified assistant.

If an accident should occur, this instructor is wide-open to liability and sanction from NAUI for violating written standards.

If, after the students have completed the course curriculum satisfactorily, the instructor decided to do this, then I could see the value ... and he'd be covered. But it would have to be after the mandated five dives and all skills have been successfully completed.

... Bob (Grateful Diver)

 

[John C. Ratliff]

Dr. Bill, Ken et al.
running out of air because your tank has plugged or was not filled or was mt and put in the filled rack seems to be a possibility when you arrive at a new dive shop for the first time, have just got off the plane and are ready to dive for the week.

These are not your fault but the outcome, OOA, is your problem. Hopefully it the situation presents itself very early in the dive or before you hit the water.

Not checking your gauge, not having a spare supply, not making sure your buddy is carrying a little more air and he knows it is for you if something, anything happens and you run OOA is reckless. If you solo dive then you better cover your a.. If you dive with a group then know their equipment and yours, just in case.

Good pilots don't run out of gas. Good divers shouldn't either.

Randy

Randy,

You apparently haven't been diving for over 25 years (actually, it's over 50 years now for me). There was a time before submersible pressure gauges (SPGs), when we had to use a hand gauge before putting on the regulator to check tank pressure. Sometimes, in the situation described by Dr. Bill above, these kinds of things did happen. Before we dove aluminum tanks, there was the potential for large pieces of rust to jam into the valve, which is why many of the valve tubes have the end crimped and lateral holes drilled in them. So there was always that potential too with open-ended valve tubes.

Yes, you are right that we shouldn't run out-of-air (OOA). But remember, if you are at depth, and your scuba stops breathing for some reason, you are not OOA if you can head for the surface. Air expands, and even in an OOA situation, there is enough air in your lungs to get you to the surface (assuming on overhead or decompression problems exist).

NWGratefulDiver (Bob), very good points!

SeaRat

PS--good pilots do sometimes run out of gas, from contaminated fuel, broken lines, weather, etc. I've been in rescue long enough to have seen that several times.

 

[Peter Guy]

Re planning/executing dives as a brand new diver:

As Boulder John wrote, within the PADI system, the OW Student is supposed to be involved with the dive planning for the dives. I'll confess that I've probably not been as good on this as I should be (although I have presented the students with the general profile several days prior to the dive and told them to do their NDL calculations AND, to a limited extent, gas consumption calculations). It is certainly something I could do better.

I have told students that for dive #4, which is mostly a "let's go tour dive" that they are to be the leader and that I'll be off doing something else (but they ARE with a DM who is supposed to be only an observer or, just a buddy). I wave good-bye, watch them leave and then shadow then -- DFO (Death From Above -- i.e., above and behind them so I can see them well but they can't see me). But this can be, and should be, done in a better and more organized manner.

Now if I can remember to do it when I have my next OW class!

 

[TSandM]

Now if I can remember to do it when I have my next OW class!

I'll remind you . . .