BCD requirements for Drysuit

scubajo007 · Jul 6, 2012

Hello all,

I may begin and do some dry suit diving in the North Sea. I have a BCD (travel light) which can only lift around 20lb which I'm afraid is not enough. Would it be acceptable/safe to pump the dry suit a bit when surfacing in order to compensate for the lifting capacity of the BCD at least until I get some of the weights handed up to the boat crew?

skankpile · Jul 6, 2012

There is no scuba law which says you cannot. You can dump weight in you rip open your suit.

I imagine now that you are joining the dry crowd you will soon have a plate/wing as well... a slippery slope

hypertech · Jul 6, 2012

I would not. If you have a suit failure, you want to be able to be positive at the surface. If its true that your BCD cannot keep you positive at the surface itself, you need to do something about it. Preferably, you get something with more bouyancy. If you are constrained size wise, a BP&W is pretty compact. If there is no other choicce, be sure to carry a lift bag or a SMB or something so you can be sure to be positive if needed. Don't be afraid to dump weights, but I'd rather fill a bag than lose them if I can.

elan · Jul 6, 2012

You can dive your 20 lb bcd safely. The only thing is the weight of your gas and ditchable and non ditchable weight on the ncd should be less than the lift capacity of the BC for a shell suit. If you have a neoprene suit you also need tp account for the suit buoyancy change with depth and the gas weight + the buoyancy change should be less than the BC lift capacity.
The rest of the weight must go to the weight belt.
Leave a safety margin - keep more weight ditchable.

hypertech · Jul 6, 2012

That's another good point. You need to make sure your rig will float on its own so if you have to take it off in the water, it doesn't sink to the bottom.

Peter_C · Jul 6, 2012

You also want to make sure if you ditch your kit underwater that you won't go shooting up to the surface, which means putting enough weight on your body to offset the suits positive buoyancy, which is known as a weight belt.

I would recommend a 30lb wing with a stainless steel backplate eventually.

NE_SSI_Diver · Jul 6, 2012

I was taught when drysuit diving to not use your BC for buoyancy purposes. When I dive dry my BC only serves the purpose of holding my tank and extra accessories. What you should do is use your drysuit for buoyancy. This should not be an issue unless you have trouble maintaining horizontal trim. On the surface inflate your BC fully and if extra lift is needed add air to your drysuit. Between the two you should be able to float on the surface.

FoxHound · Jul 6, 2012

I completely disagree

Drysuit is to keep you dry, you inflate it a bit enough to take the squeeze off and be comfortable.....the buoyancy compensator is for buoyancy compensation.

this becomes especially true with steel tanks and doubles.......you will have too much gas in your suit and it will become unmanageable and extremely difficult to maintain trim

j yaeger · Jul 6, 2012

just enough air bubble to keep the kids warm and not toooo snug!
too much air in the suit makes things funky...
i use a bcd with singles and bp/wing with doubles
whatever works for you is the best advice-dive,try it,dive some more...
now THAT is a slippery slope!!!!
have fun
yaeg

rhwestfall · Jul 6, 2012

another word of caution about using the suit for buoyancy... the valve is NOT as fast as one on a BC... Despite the teachings by a couple agencies, I still do not believe a DS is for buoyancy.

BCD requirements for Drysuit

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