Weight VS. Lift How much will be to much but can't get under

[fire5man]

My last dive (cold water) 7mm suit and Zeagle Brigade BCD 35lb wing and 34lbs of weight. (Pot Belly Diver).

35 lbs seams like a lot to me but it was not enough to get me to sink with all the air out of my BCD. I ended up having to swim down kind of pushing and kicking hard down to about 15ft before I was sinking on my own. This ended up making the later safety stop challenged.

I wear 15 lbs on my belt and the rest in my BCD. I feel this way if I have to take off my BCD for some reason I will not surface in a hurry.

Anyways could I be doing something wrong? Should I add more weight? How much weight will be to much for the wing?


Thanks for the help!

 

[LeadTurn_SD]

Your wing need to compensate for the buoyancy your wetsuit loses at depth, and also needs to be able to float your rig (tank & regs, integrated weights, and anything attached to it) on the surface if you need to take it off.

If 35 lbs of weight was not really enough to get you down at the beginning of the dive, that means your bouyancy (wetsuit, residual buoyancy in BC, and your body's buoyancy) exceeded 35 lbs.

Are you doing anything wrong? The only answer I can think of is you need to be sure you've completely vented your BC. Any air trapped in the wing will make it tough to descend. Also, there is a tendancy for many new divers to fin and move their hands unconsciously on the surface, which also makes it very hard to descend; and also to hold too much air in their lungs when they first try to descend. But if none of these is the problem in your case, then you probably need to add some more weight.

The only way to really know how much to add is to do a weight check at the beginning of the dive... add weight until you float at eye level with a normal breath (make sure your feet and hands are still when doing this check, and all air is out of your wing). Then add some weight to compensate for the weight of the air used during the dive.... for example, with an AL80, if you do the weight test with a full tank, you'll need to add around 4-5 lbs to compensate for the air you use during the dive. At the end of the dive, check to make sure you can hold a 15' safety stop with around 500lbs in your tank. It may take some trial and error to get it just right.

Is 35lbs enough lift? It should probably be fine for a single tank. Your wetsuit cannot lose more buoyancy than it started with, and you wont lose your "personal buoyancy" ... Remember that at the beginning of the dive, properly weighted, you are only going to be around 5 lbs negative or so (at the surface), at at the end of the dive you'll be close to neutral at the surface. Your wetsuit will compress as you descend and it will lose a good bit of buoyancy, but you will not lose all of it, and will not lose the "pot belly" buoyancy

Good luck.