Dive Op Self Defense

[redacted]

When I went on my first set of ocean dives I had not dove with an al tank in a long time. All of mine are steel. I borrowed an al 80 from the shop that was down to 1000psi. Took it in the pool with my 5 mil which was what I would be using and took it down to 400 psi. I then spent a few minutes adding weight til I got where I wanted to be. This was what I started with plus 8lbs for salt water. It worked for my first ocean dives on the spiegel grove but was a tad heavy. I knew this going in. But better to be safe than sorry.

Why didn't you just research the bouyancy characteristics of each tank and make the necessary adjustment?


1 new
2 not much experience
3 lacking in the training dept
4 not willing to work on basic skills
5 lazy.
6 Why pass up the chance to get wet?

 

[Meng_Tze]

I don't get it, I'm sorry. Could you explain what you mean by that?

People assume that weight is in a bulk park figure. Different people have different weighting requirements. But it seems that the focus predominantly is on 'overweighted' people. Having not enough weight is equally (and arguably even more-) dangerous.

 

[redacted]

The "augmentation" process as it happens with me is not some published set of rules, its a case by case assesment of each diver, and is conducted mostly in my mind. If there is enough "evidence" it leads to a few subtle and private questions and most likely some in water attention by me or some other in water personnel. It's all about knowing (or educated guessing) about who's going to need you the most down there.

I agree that the DM's screening of his divers for who might need special attention is an informal additional process to control problems with qualified divers. But I thought the OP was looking from a dive operation standpoint for indications that the diver is qualified to make the dives.

 

[mikerault]

All,

I have tried to condense the comments and suggestion made here into an article of 600 words or less (web site requirement) have a look and see if I have missed anything vital within this restriction:

http://scuba-diving.suite101.com/article.cfm/judging_a_divers_qualifications

Thanks!

Mike

 

[Land Locked]

Nice work Mike!

 

[vel525]

All,

I have tried to condense the comments and suggestion made here into an article of 600 words or less (web site requirement) have a look and see if I have missed anything vital within this restriction:

http://scuba-diving.suite101.com/article.cfm/judging_a_divers_qualifications

Thanks!

Mike

Nice article Mike. I think you got it right on. Of course you want to look at all those things such as certification, log book (if they have it) etc, but nothing can substitute actual experience on a "check-out" dive.

With that said, if I was on a short weekend trip to the FL keys and only have two days of diving, it would suck for my first dive to be a easy reef dive if I'm down there to do the wrecks...just a thought...

 

[Fish_Whisperer]

Way to go, Mike. Nicely written summary and article. I wonder if Dive Training Magazine or DAN would be interested in it... In my opinion, it is as good as anything I've read in any of the dive rags.

 

[Scubakevdm]

People assume that weight is in a bulk park figure. Different people have different weighting requirements. But it seems that the focus predominantly is on 'overweighted' people. Having not enough weight is equally (and arguably even more-) dangerous.

I see your point, and I agree that being underweighted can be quite dangerous, especially in situations where there is any kind of deco obligation incurred. However, I think, in the context of this thread that it's the the overweighted diver that causes alarms in the diver experience department. I'll tell you why; Typically it's been my experience that instructors that either don't care or don't know weight their students so that they will sink, even with lungs completely filled with air. In water buoyancy control is handled with a combination of a negative coarse adjustment to the BCD, an upward attitude and finning and sculling. This is the most natural response to sinking, and requires zero instruction. A horizontal, streamlined attitude, as I'm sure you are aware is not natural, and can even be uncomfortable. Buoyancy control through breath control requires some time and effort by both the student and the instructor, and in my opinion is both the most important and sorely neglected skill in diver instruction. Anyway, either to avoid extra work and time, or because the instructor themselves don't understand how this works, the diver is weighted to be negative in any percentage of lung inflation at the surface. This problem is aggravated at depth with the compression of the wetsuit, and even more air has to be added to the BCD. So now you have a new diver trying to get the feel for neutral buoyancy swimming around with a giant air bubble in their BCD. Because there is so much air, the expansion and compression of the bubble has a much greater effect on the diver's buoyancy and out of control ascents are very common.
In contrast, being underweighted generally prevents the diver from leaving the surface in the first place. I understand that the air in the diver's tank has weight, and that it's conceivable that they would be able to descend at the beginning of the dive, however, for a single 80 foot tank, you're looking at about a five pound swing between full and empty, so no matter what, if they descend they're less than 5lbs underweighted. Furthermore, in this scenario, they would have no air in their BCD, and the extra weight of the air is lost gradually, and so they gradually drift upwards to the surface.
One could argue that the diver could swim down and maintain depth with propulsion, and though certainly this is somewhat risky, the fact of the matter is that most divers will not do this, or get tired of doing it very quickly, or burn through their tank quickly. In any event it certainly limits the time spent at depth.

 

[wedivebc]

I don't think a dive operator should make a judgement nor are many qualified to judge a diver's ability. I like Diver Choice Charters approach to this issue and when they book a shop they offer a comp spot for a DM. The shop then takes responsability for the safety of the divers in the water and the boat assumes the role of a taxi driver. Admiralty law assumes the boat operator is only responible for divers while they are on the boat, and possibly on the dock.

 

[Scubakevdm]

I agree that the DM's screening of his divers for who might need special attention is an informal additional process to control problems with qualified divers. But I thought the OP was looking from a dive operation standpoint for indications that the diver is qualified to make the dives.

Ahh, I see. It's interesting that you pointed this out.
I am writing from a fairly unique perspective in that I am the dive operator and the divemaster, so the two proccesses kinda flow together from my standpoint. I do recognize that the way you saw the situation is probably much more common, and makes sense.