Wetsuit buoyancy

[broncobowsher]

There is a lot more material in an XL than an XS. That will also be a huge factor.
If you know the difference between no suit and the 3mm, 7mm is about 133% more material. But there will also be differences in Neoprene density (ratio between the rubber and the bubbles in it). So no matter what it is a guess.

 

[TMHeimer]

I have a 7mm farmer john and jacket with mitts and hood. I'm 5'10", 160lb and with aluminum 80 tank I need 30lb lead in sea water.

Same wetsuit, tank but 6 feet tall and 185 pounds.
42 pounds salt water
with shorty--18 pounds salt water
with body suit ("rash guard', whatever)--10 pounds salt water
Take off 5-6 pounds for fresh water.
Does that help?

 

[MichaelMc]

A more elaborate version of a mesh bag, weights, and 2’ of water.

Equipment:
- hand held luggage scale, or fish scale if prone to dropping it
- More lead than suit has lift
- line with way to attach lead at bottom, suit above (mesh bag), and scale at top.
- pool with a deep end

Rig weights at end of line.
Attach empty mesh bag to line above that.
Attach line to scale.
Lower weights into deep end.
Record weight of that setup, with mesh at depth you want to measure suit!

Pull up, put suit 1 in mesh bag, lower, record how much lift suit added at its depth.
Do with suit 2.

Now you know both suits' buoyancy in fresh water.

Separately weight both suits dry on land to do conversion fresh to salt.

Alternatively, put loops in line at different depths, use clip to hook mesh bag at different loops of line to measure buoyancy at different depths. Hang scale from diving board or arm of pool exit ladder.