Trexmdr
Registered
I plan on test my new gear setup in a freshwater pool. How much more weight will I need beyond neutral buoyancy when I go into the ocean.
thanks
RT
thanks
RT
How much buoyancy does salt water add
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Grocio
Contributor
If you use exactly the same equipment, you may need to add 2 kg approximately.
The technical answer is the average weight of seawater is 64.1 Lbs/Ft³ and pure fresh water is 62.297 (rounded) Lbs/Ft³ Fresh Water @32° F. That’s about 2.89% more displacement.
That doesn’t mean you need 3% more lead than the weight of your belt in salt water. Assuming you are neutral in fresh water and your total geared-up dry weight is 200 Lbs., then you displace 3.21 Ft³ (200/62.297). It would take 5¾ Lbs more lead to make you neutral is sea water or a total dry weight of 205.761 Lbs (3.21 x 64.1)... give or take
That doesn’t mean you need 3% more lead than the weight of your belt in salt water. Assuming you are neutral in fresh water and your total geared-up dry weight is 200 Lbs., then you displace 3.21 Ft³ (200/62.297). It would take 5¾ Lbs more lead to make you neutral is sea water or a total dry weight of 205.761 Lbs (3.21 x 64.1)... give or take
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Kharon
Contributor
Posts above are leaving out what I feel is a very important consideration. I use 12# in both fresh and salt. The reason - I dive steel tanks, with as minimal neoprene as possible enhanced by polyolefin under suits (0 buoyancy) in fresh water. I dive aluminum tanks with no neoprene (only shorts and a nylon t-shirt in salt water). Unless you are diving the exact same type & size of tank and the exact same insulation you need to do an aproximate weight check at the beginning and a good weight check at the end of your first dive.
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