I've read the previous threads centering on ditchable weight, and I'm wondering if anyone can confirm the following:
It seems that the minimum amount of ditchable weight one should carry (thinking of wet suit diving only, here) is the difference in the weight of the tank when full & 500psi + a bit extra to allow for the buoyancy difference between neoprene at surface & neoprene at depth.
My reasoning: total weight carried should be that to keep you neutral at 15ft safety stop @ 500psi with BC deflated completely. Any less than that, and it'll make the stop difficult & possibility of uncontrolled ascent. Now, the only difference in the total diver's weight between the beginning & end of the dive is the weight of the gas used. Therefore, at the beginning of the dive, with BC deflated completely, the weight of the gas will be the amount of weight that one must be able to ditch in order to become neutrally buoyant. Of course, as one's depth increases, the neoprene will compress & therefore a bit more weight would have to be shed to become neutrally buoyant.
I'm thinking of switching to a BP/W, and I'm wondering if my logic above is correct. It seems that I should be able to take my total weight requirement & divide that among the backplate, trim weights, and ditchable weight...with the ditchable weight being equal to the delta-tank weight + a couple pounds for potential neoprene compression if I had a failure early in the dive at depth.
Does this make sense, or am I missing something? (Relatively new diver here w/ about 60 dives, so no diving ego & just interested in learning!! Thanks!)
Jim
It seems that the minimum amount of ditchable weight one should carry (thinking of wet suit diving only, here) is the difference in the weight of the tank when full & 500psi + a bit extra to allow for the buoyancy difference between neoprene at surface & neoprene at depth.
My reasoning: total weight carried should be that to keep you neutral at 15ft safety stop @ 500psi with BC deflated completely. Any less than that, and it'll make the stop difficult & possibility of uncontrolled ascent. Now, the only difference in the total diver's weight between the beginning & end of the dive is the weight of the gas used. Therefore, at the beginning of the dive, with BC deflated completely, the weight of the gas will be the amount of weight that one must be able to ditch in order to become neutrally buoyant. Of course, as one's depth increases, the neoprene will compress & therefore a bit more weight would have to be shed to become neutrally buoyant.
I'm thinking of switching to a BP/W, and I'm wondering if my logic above is correct. It seems that I should be able to take my total weight requirement & divide that among the backplate, trim weights, and ditchable weight...with the ditchable weight being equal to the delta-tank weight + a couple pounds for potential neoprene compression if I had a failure early in the dive at depth.
Does this make sense, or am I missing something? (Relatively new diver here w/ about 60 dives, so no diving ego & just interested in learning!! Thanks!)
Jim
