Wow, so many follow-up questions for such a simple question!! -Thank you Scott for answering the original question.
Yes, I have to bring up dead bodies to the surface. Yes, they don't weigh much under water, but when you get to the surface, they weigh what they weigh on the surface, and you better be prepared to float both you and them on the surface while the tender boat makes it's way over to you. Yes, you can use a lift bag, but have you ever? I have. It's pretty traumatic for the family to see Uncle Jimmy shoot to the surface like a Trident missle. Then the bag tips over (because Uncle Jimmy had some momemtum), the air burps out, and Uncle Jimmy goes back down to the bottom again, and you have to go find him a second time. Never tried one of those fancy body bags with the lift bag built into it, but would love to try it. How hard is it to get a body into, underwater and in zero vis? I know a closed bag would help with the tip-over problem, and a tag-line helps with finding them a second time. All lessons learned the hard way.
"What does altitude have to do with it? "
At altitude, atmospheric pressure is lower than at sea level. If it takes 36 pound to get you under at sea level, it's gonna take a bit more to get you under at altitude (my experience, about 42 lbs). Underwater, the neoprene compresses, and you now need more air in your BCD to remain neutral. Add the weight of your steel tank (full, not empty), and you are over 45 lbs. I am 6'5" and wore a 3XLT shirt, that's a lot of neoprene.
Granted, in 23 years of diving (certified in '87) I've only been "stuck" on the bottom once, and the fact that I mostly dive with a drysuit now, make this scenario unlikely anymore. But, how many near death experiences do you have to have?
The type of diving I do, is most likely not the same kind of diving YOU do. We dive heavy, because we have to. It's not easy being the pivot man in a circle search when you have "just enough" weight. Even with a couple extra lbs it can be a challenge to stay put.
The reason I pointed out that 55lbs capacity is more than 45lbs of lift, is because I've helped train enough students to know that if you CAN stuff 55lbs of lead in a BCD, at some point, a student or newer inexperienced diver WILL stuff 55 lbs in it. Seems like a liability to me. Maybe it hasn't happened yet, but can you say it WON'T ever?
Bottom line is, it's my BCD, and if I want a 65lb bladder, and they have one to sell me, that's what I'm gonna get!!
Scott- Bought my first BCD - A Zeagle Ranger back in the early 90's (it has the original cloth RANGER patches)- Have hundreds of dives on it in all kinds of water ranging from nasty to crystal clear - It still looks mostly brand new. I loved it! The only reason I got a new BCD was because my Ranger no longer fit me (went from 3XL to XL ). I hope this one holds up as good as my first!!
