Near miss diving doubles for 2nd time

[rongoodman]

What kind of tanks did you have, how much lead, SS or aluminum BP?

 

[tonka97]

SmpleGreen,

Bottom line....Congrats for surviving and posting such an eloquent tale, that many of us can relate to.

Your incident reminds me a bit of 'Into Thin Air'....mountain climbers who were conditioned to obey their leaders....some to their deaths. (Leaders died too).

You could have easily bought the farm on your dive.

Glad you walked away....a lot more knowledgeable AND self dependent!

 

[SmpleGreen]

What kind of tanks did you have, how much lead, SS or aluminum BP?

Steel 100s's (diving Doubles). I want to say the backplate was stainess steel....but I don't know that for sure.

No lead. The tanks made me ridiculously negatively buoyant without any added weight. I added 1.5 pound ankle weights on each leg, which helped a lot with orientation in the water, but obviously not so much in terms of being overweighted.

 

[Garth]

You still haven't told us when the next class is. Have you spoken to the instructor yet?

 

[Gombessa]

Steel 100s's (diving Doubles). I want to say the backplate was stainess steel....but I don't know that for sure.

No lead. The tanks made me ridiculously negatively buoyant without any added weight. I added 1.5 pound ankle weights on each leg, which helped a lot with orientation in the water, but obviously not so much in terms of being overweighted.

Depending on the particular type of 100s, it's pretty easy to see that you were significantly overweighted. I don't know exactly how much buoyancy an old, worn 5/7 wetsuit affords at the surface, but it's possibly in the range where the weight of the gas in the tanks alone matches it. Add on the steel backplate, ankle weights, regs, tank buoyancy, and rest of your rigging, in fresh water...and a wing failure at the surface (let alone at depth when what little buoyancy the suit provides is significantly diminished) could have left you in dire straits, and without any significantly ditchable weight.

Whenever you're renting equipment, especially if it's unfamiliar, you should try to do the math and make sure everything balances out. Doing so here would have very quickly raised a red flag, which you could then investigate further.

After sitting down and going through these calculations on your own, I highly suggest that you approach your instructor and ask him, respectfully, how he would calculate your total ballast and buoyancy, and how he feels this setup was appropriate for the dives you were doing that day.

 

[TSandM]

SimpleGreen, I really empathize with you about relative passivity in the face of an instructor who, one hopes, knows more than you do. I took a class last year where I allowed an instructor I viewed as being extremely knowledgeable and even eminent, to overrule me on some matters where I actually DID know what I was doing, and he did not. I also changed a lot of gear to "please" him, and caused myself all kinds of issues by doing that. And I did not ask for things I wanted to make the class go better for me, because I didn't want to irritate him. The net result was not a serious safety issue, but a class which was more stressful and less productive than it could have been. So I understand the phenomenon where an otherwise assertive person takes an more passive role while under instruction. Unfortunately, in diving, it isn't always true that the instructor knows better, even if he is a superb, knowledgeable and experienced diver. And one of the lessons I learned from the class is not to let someone misguide me, when I know that's what they are doing.

I'm glad I didn't have to learn my lesson from something as potentially dangerous as your class is learning through.

 

[cool_hardware52]

Depending on the particular type of 100s, it's pretty easy to see that you were significantly overweighted. I don't know exactly how much buoyancy an old, worn 5/7 wetsuit affords at the surface, but it's possibly in the range where the weight of the gas in the tanks alone matches it. Add on the steel backplate, ankle weights, regs, tank buoyancy, and rest of your rigging, in fresh water...and a wing failure at the surface (let alone at depth when what little buoyancy the suit provides is significantly diminished) could have left you in dire straits, and without any significantly ditchable weight.

Whenever you're renting equipment, especially if it's unfamiliar, you should try to do the math and make sure everything balances out. Doing so here would have very quickly raised a red flag, which you could then investigate further.

After sitting down and going through these calculations on your own, I highly suggest that you approach your instructor and ask him, respectfully, how he would calculate your total ballast and buoyancy, and how he feels this setup was appropriate for the dives you were doing that day.

+1


The sad fact is that very few divers, students, instructors etc. have any idea about how buoyant their exposure suit is, or how to estimate how much ballast their "rig" will provide.

I need these numbers when I'm making a wing capacity or plate material recommendation.

Maybe 1 in 20 have any idea. Many are ready to tell me how much "lead" they use, but can't tell me what cylinders they were using at the same time. (Ballast is everything that does not float)

This is a *HUGE* hole in current diver education.

I cringe every time I see "What wing do I need with XX tanks?"

The anecdotal answers that inevitably follow typically contain *Zero* information regarding exposure suit buoyancy.

Over weighting not only makes diving more difficult it makes any buoyancy failure much more difficult to cope with.

Tobin

 

[Garth]

SmpleGreen,

Bottom line....Congrats for surviving and posting such an eloquent tale, that many of us can relate to.

Your incident reminds me a bit of 'Into Thin Air'....mountain climbers who were conditioned to obey their leaders....some to their deaths. (Leaders died too).

You could have easily bought the farm on your dive.

Glad you walked away....a lot more knowledgeable AND self dependent!

I can't disagree more. Thank god I can't relate to his situation. As far as walking away more knowledgable that is at best questionable.
Ankle weights don't solve trim especially on you 2nd day in doubles. DIR equipment doesn't make you a DIR diver. Buoyant ascents are bad. Predive briefings are necessary. Post dive discussion is necessary. Cold water changes everything. . . I could go on and on.
I think it's up to time to see if he's/she's figured these out.

As far as your into thin air comment I totally agree.
But what does self dependent mean? Did you mean self sufficient? I can't agree.
Did you mean self reliant? Hope not

Anyway. I will await further info on the progress of the class and whether he fails you or you find another instructor.

 

[TSandM]

Garth, I think you're being a bit harsh to the OP. Except for a bit of defending his instructor, I haven't seen him trying to excuse his own failings here. To the contrary; I think he has been quite gracious in accepting a great deal of criticism.

Although I would agree with you that ankle weights are not, perhaps, the best solution to a trim issue when you are new to doubles, I can see someone using them for a day in class, to be able to balance better and not have all their skills practice confounded by severe static imbalance. I think people with heavy wetsuits and neutral or positive fins CAN have much more severe problems with going head-down than those of us with dry suits and Jet fins. Static weighting problems get solved with posture first and weight changes second, but if they're really severe, you either condemn the diver to 45 degree head-up trim for a while, or constant swimming. I'd rather see somebody throw on a set of ankle weights for today and then work with adjusting their gear and their weighting at the end of the dive, so the next one might not require the weights. They aren't the devil's spawn -- they just aren't the optimal, long-term solution to the problem.

At any rate, I think SimpleGreen HAS learned a big lesson about not passively following an instructor. And since I had to learn the same lesson, I have perhaps a bit more empathy for him.

 

[Garth]

My apologies to the OP. I'm really not a harsh person believe it or not. When I read theOP's discussion here it concerns me though.