Estimating weight requirements for new drysuit, from FW to SW

[Gdon]

I would like to get an estimate of the weight I will require using a new drysuit in salt water. I have used the .025 method* with my wetsuit kit and it worked out well, but I wonder if the drysuit will have more volume and therefore require more weight than this method of estimation would predict. Interestingly the out of the water weight of my dry kit is within a pound of my wetsuit outfit.

Using a White’s Fusion I have established my minimum fresh water weighting at 17 lbs. This was with empty suit and BC at 18 feet.

With my gear and an empty tank I weigh 276 lbs. Based on fresh water weight of 62.4 lbs per cubic foot, I am displacing 4.4 cubic feet of fresh water. Based on average salt water weight of 64 lbs (1.6 more per cubic foot than fresh), I need 4.4 times 1.6 lbs, or 7 lbs more.

* Or if you prefer .025 x 276 = 6.9

Thats 24 lbs total.

Do you think this is a fair estimation or will the suit require more in actual use due to volume changes with inflation?

 

[ERP]

It's probably about right, I'm somewhat lighter than you are and I add or remove about 6 lbs.

 

[Gdon]

Well I went ocean diving last week and I was able to get by just fine with at least three pounds less than I estimated. There really is no substitute for in water buoyancy checks. Too bad it’s harder to find a place in salt water to do them.