eelnoraa
Contributor
26(on belt) +15(for head)= 41 pounds.
Not sure why he needs that 26 pounds, but then I've never worn a 5mm suit. I wore a 7mm once and don't think I used that much weight. How much buoyancy is lost with depth with a wet suit? Using Boyle's law, @33 ft you've lost 50%, At 66ft, you've lost %66, @ 99ft, you've lost %75 and so on. With a dry suit, you have to worry about a total loss of buoyancy. This isn't like weight. I want a little buffer with my lift, 'just in case'. There is no real benefit to having "just enough" lift to get by. In reality, you will probably limit the dives you can accomplish with this false economy.
It doesn't sound so crazy when you start crunching the numbers. Does that explain my rationale?
I don't think that number should be added. When a diver is properly weighted, he/she is only negative by the weight of the gas he/she is carrying. So at the beginning of the dive, with full kit, full tank (AL80), he/she is 6lb negative. He/she is never 26lb negative. If so, he/she has a much bigger problem. Now +15lb for head. He needs 21lb of lift in that situation.
Since he/she is with AL80 with 26lb. AL80 is +4lb empty, he is suit can't have more +22lb buoyancy (which is on the high side), so it can't lose more than 22lb. So he/she needs 22lb for this situation. With a wetsuit, you never had a case where you lose all suit's buoyancy and need head above water. So in this case, I will say get a 30lb wing.
I also agree the "no benefit to just have enough lift" part if the additional lift doesn't cause a drawback. IMHO, single wings at 30-35lb are still very streamline. Most 40lb start to get flappy and taco-ee unless it is Oxycheq MkV. So there is a cost going too big too