Must I have ditchable weight? And if so, how mucShould I go with the heavier or ligh?

[a4lod]

I dive using a 7mm wetsuit and require 18lbs of weight. I plan on buying a new BC with a FredT plate that weighs 9lbs (the heavy SS one). Since I dive singles (Al80's), I can buy a FredT STA that weighs 5lbs or 1.9lbs. By doing this, I would only need 4-8 lbs on my belt. Would this be reccommended? Should I go with the heavier or lighter STA? Please respond. Thanks.

 

[scubasean]

I prefer to have a small amount of ditchable weight and wear six pounds on my belt.

It is highly unlikely that you'd have to remove any weight at depth, and you'd probably only want to remove enough to become buoyant in any case.

At the surface, if you can't remove enough to be buoyant, you risk drowning if your B/C fails...

 

[Karl_in_Calif]

With a 7mm wetsuit now requiring 18 lbs, assuming he is neutral at the surface at the end of a dive, this must be for fresh water. Some people weight themselves neutral at the end of a dive at 15 ft depth. That allows you to creep up on the 15 ft stop, but you are not really neutral at the surface, and you would then have to kick down if near the end of the dive, with an almost empty tank. But at least that would be erring on the safe side.

So it depends what is going on here.

Everyone who wants to minimize their ditchable weight needs to figure out how much weight they can comfortable kick up with.

If the answer is -0-, then you would want to weight yourself as neutral at depth, so that in case of a B/C wing failure, you can ditch the ditchable weight and be neutral or positive.

Now for the calculations.

We dont really know enough to answer this question.

 

[Karl_in_Calif]

scubasean once bubbled...
I prefer to have a small amount of ditchable weight and wear six pounds on my belt.

It is highly unlikely that you'd have to remove any weight at depth, and you'd probably only want to remove enough to become buoyant in any case.

At the surface, if you can't remove enough to be buoyant, you risk drowning if your B/C fails...

6 lbs would compensate for the change in the ballast of the tanks as the air is breathed down.

0.06 x 80 = 4.8 lbs

But what about the change in ballast of the wetsuit going to depth? How much weight would that entail, in addition to your 6 lbs?

 

[Spectre]

a4lod once bubbled...
By doing this, I would only need 4-8 lbs on my belt.

IT all depends on what you can swim yourself.

To save repeating myself, check post at this link. The thread also has some great info

http://www.scubaboard.com/showthread.php?s=&postid=129684#post129684