Lift for doubles?

[DA Aquamaster]

Steel 72's are near neutral when empty compared to a set of AL 80's that are about 8 lbs positive when empty. Both steel 72's and AL80's trim well and both feel very stable in the water so they are good starter doubles.

If you are usign a heavy 7mm wet suit or dry suit, a more negative tank is better. If you are diving a 3mm wet suit, more bouyant tanks are preferrable.

Start with your weigth requirements now, then adjust for the bouyancy change due to the empty extra tank. (-1 for a steel 72 and +4 for an AL 80) to ensure you can stay down at a safety stop at the end of your dive. Then consider the swing weight (-10 lbs of gas) to ensure you have enough lift for the gas and the wet suit compression at depth. 40 lbs is more than enough for either set of doubles as long as you are not badly over weighted.

 

[Couv]

Before you settle on which set of doubles you like, put together the rest of your kit less the manifold. Once you have decided on everything except the tanks and manifold, rent, borrow, steal, etc. the various double sets you are interested in. Dive them as independent doubles until you have your mind made up. The only thing you will have left over after your decision is an extra SPG. Who knows, you might even like keeping them as independent doubles and would have no worries if you were to travel without them and needed to rent a set.


couv