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Near Misses and Lessons LearnedHere is a forum to discuss those incidents that ended well but could easily have ended badly, and the lessons learned from them.
Please note: The last reply in this thread was more than 1 month(s) ago.
Was on a dive with my regular buddy and a new guy last week. The new guy was a less experienced diver, and we knew going into it that he was going to be an air hog. Newbie had an AL80. Regular buddy and I both use a larger tanks plus ponies.
We picked a conservative profile, max depth 50ft, and what we thought was a good turn pressure for the newbie. He hit his turn pressure even earlier than we anticipated. On the way back in (long bottom swim back to shore), newbie was getting too low on air. (We had discussed this possibility before the dive -- didn't think it would actually happen.) So he took my buddy's regulator and they swam back in sharing air until we were at 20fsw. Newbie went back to his own reg.
A few minutes later, he held up his gauge with big eyes and was at about 200psi. I instantly gave a big thumbs up, and we did a safe ascent from less than 15fsw. He had enough air to inflate his BC at the surface and all was fine.
I consider this a successful failure. No one deployed a pony bottle (all contigencies are planned as if we did not have the pony tanks.)
A few minutes later, he held up his gauge with big eyes and was at about 200psi. I instantly gave a big thumbs up, and we did a safe ascent from less than 15fsw. He had enough air to inflate his BC at the surface and all was fine.
I consider this a successful failure. No one deployed a pony bottle (all contigencies are planned as if we did not have the pony tanks.)
So, some lessons learned, any thoughts?
Yes. Plan your reserve gas to handle whatever kind of hoover you're diving with and be sure to reserve enough gas to get you both to the surface from any point in the dive.
Also there should be no reason to be sharing anything. If you're taking on the responsibility of diving with a new diver, you should be aware of their tank pressure at all times and turn the dive when appropriate. If anybody surfaces OOA or you need to share air, it means that both divers screwed up. He didn't watch his air and you didn't watch his air either.
Quote:
We picked a conservative profile, max depth 50ft, and what we thought was a good turn pressure for the newbie. He hit his turn pressure even earlier than we anticipated. On the way back in (long bottom swim back to shore), newbie was getting too low on air.
That would be bad gas planning and/or bad dive planning and execution. How did you choose the turn pressure, and how did you expect to know when it happened without monitoring his SPG?
Give the newbie the bigger tank to start with. It will help them relax and be less of an airhog. The psychological impact of having more air available is significant for new divers.
You should have taken over as the donor (after your buddy stopped being donor) until you were ready to ascend.
This member has said "Thank you." to electric_diver for this useful post:
I personally dont use this air management rule unless I am in a cave but it would probably work well with a new diver to prevent that from happening. Use the 1/3 in 2/3 out rule. That would be 1/3 for the dive, 1/3 to surface and that leaves 1/3 for an emergency. At least when he turned the dive you would not be caught off gaurd but it sound like you handled it well.
Give the newbie the bigger tank to start with. It will help them relax and be less of an airhog. The psychological impact of having more air available is significant for new divers.
You should have taken over as the donor (after your buddy stopped being donor) until you were ready to ascend.
My experience with new divers is never plan on the dive lasting more than 20 minutes. If it does, terrific, but it rarely happens. Also, stay away from deep dives or long surface swims and keep looking at their air pressure.
I am always surprised how quick they get better however. Here is my rule of thumb. <10 dives = 20 min plan, <20 = 30 min plan, <30 they get pretty good by then, watch closely. And so on.
Don’t worry about it, just be calm and tell them count to 4 during the inhale, count to 5 for the exhale, they will just keep getting better.
Remember, diving is fun!
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Dave
Lack of preparation on your part will most certainly lead to an emergency on my part. Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you're a mile away and you have their shoes. Join us on the Great Escape, Jan 17, 2009
This member has said "Thank you." to Teamcasa for this useful post:
My thoughts are that you set him up.
Tank sizes should be about the same, whereas you had a huge disparity.
And you also failed to check his gauge, knowing that he would run OOA before you did.
So this was the blind leading the blind.
I do not believe you had a very good teacher yourself.
Wow, that was harsh.
I didn't expect so many responses so quickly. Some clarifications:
1. Newbie couldn't use my tank or the other buddy's tank without a lot of complications. I will spare the details unless you really want to know. As a result, I fully expected to have a shortened dive and far more air. Tank size was not the problem. The turn pressure wasn't conservative enough, and perhaps the dive plan itself was flawed and we should've done a 30ft dive at the Cove instead of a 50ft dive at the Shores (San Diego).
2. We were checking gauges frequently. We turned at the agreed upon pressure. In hindsight, the turn pressure should have been higher. At 15fsw, he did surprise me with how low he got so quickly. I should have checked it more in the shallows.
Quote:
Originally Posted by teamcasa
My experience with new divers is never plan on the dive lasting more than 20 minutes. If it does, terrific, but it rarely happens.
Thank you. Good response, tactful delivery.
So . . . the consensus seems to be that in addition to the obvious need for better gas planning, we should have thumbed the dive rather than share air. Lesson learned, thanks.
Practicing sharing air on the underwater swim back to shore is fine if both divers are calm and well trained and confident. I consider it good practice as long as the recipient reserves enough air in his tank to make it to the surface easily.
I did this exact same thing with my 9-yr old a few weeks ago when he was sucking down his 63 cu-ft tank faster than I used my 149 cu-ft tank.
However, it sounds like you did not know the guy and have no way to judge his comfort threshold. Thus, I think it was probably poor judgement and dangerous idea to do what you did to the new diver.
I would have aborted the dive and done the swim on the surface.
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