General question about weight

[SkimFisher]

How much weight do you find yourself adding when diving saltwater vs. freshwater? I know they say you need more for salt than fresh - but how much? I don't really have the opportunity to do a "check out" dive before my first saltwater dive.

I'm 5'5" and weigh 147lbs. With no wetsuit (or gear) I naturally sink like a rock with my lungs half empty. I can dive freshwater (no wetsuit) with 8lbs and I'm thinking I can do 6lbs (maybe less) but I've yet to try that out. I am planning on wearing a 3/2 wetsuit for the salt dives.

I know it's a very general question and relative to the individual and gear, but I just thought I'd ask.

 

[Teamcasa]

Generally, (a guy your size) is going to need about two pounds more. However, because you are adding more gear (wetsuit) you should do a proper weight check on your first ocean check-out dive.

In your case, I'd suggest starting with 10lbs and adjust from there.

 

[Web Monkey]

How much weight do you find yourself adding when diving saltwater vs. freshwater? I know they say you need more for salt than fresh - but how much? I don't really have the opportunity to do a "check out" dive before my first saltwater dive.

I'm 5'5" and weigh 147lbs. With no wetsuit (or gear) I naturally sink like a rock with my lungs half empty. I can dive freshwater (no wetsuit) with 8lbs and I'm thinking I can do 6lbs (maybe less) but I've yet to try that out. I am planning on wearing a 3/2 wetsuit for the salt dives.

I know it's a very general question and relative to the individual and gear, but I just thought I'd ask.

From a physics point of view, you'll need about 2% of your total weight including equipment, in additional lead, if you were weighted correctly for fresh water.

From a reality point of view, people generally dive with different equipment going from fresh to salt (exposure protection, gloves, equipment, etc.), so the the above isn't really helpful, and you'll need to do is a buoyancy check when you get there.

From a wild-assed-guess point of view, it usually works out to an extra 4 - 6 pounds, depending on your weight, although I'd still check first.

Terry

 

[Web Monkey]

Just a quick note: SCUBA weights aren't precision instruments, and just because a chunk of lead says "5" on it doesn't mean it's really 5 pounds. They can be off by a significant amount.

If you haven't already guessed, you'll need to do a buoyancy check anyway.

Terry

 

[Steve50]

10 lb.

 

[Interceptor121]

Actually some people have done work and there is a formula
Add
Your weight
Your cylinder displacement
Your cylinder buoyancy (typically a negative number)
Your weight on the belt or integrated
Take 3.5% of this and you work out the kg to add
Example
Diver 80 KG
Cylinder 12 liters -> Displacement 14KG
Cylinder Buoyancy -2.74 Kg
Weight belt 10 Kg
Estimated displacement 106.74
Weight change 3.5% of 106.74 = 3.74

Did not make this figures up myself I read it on Diver February 2007 issue
the rational is that you can calculate the additional weight evaluating the displacement and evaluating the impact of the difference density between fresh and salt water (3.5%)

 

[waynne fowler]

my weighting changes about 20% from fresh to cold.
I ware 18# in salt... 14# in fresh (i could really take more off but its close) and I ware the same kit in both.

 

[Steve50]

Actually some people have done work and there is a formula
Add
Your weight
Your cylinder displacement
Your cylinder buoyancy (typically a negative number)
Your weight on the belt or integrated
Take 3.5% of this and you work out the kg to add
Example
Diver 80 KG
Cylinder 12 liters -> Displacement 14KG
Cylinder Buoyancy -2.74 Kg
Weight belt 10 Kg
Estimated displacement 106.74
Weight change 3.5% of 106.74 = 3.74

Did not make this figures up myself I read it on Diver February 2007 issue
the rational is that you can calculate the additional weight evaluating the displacement and evaluating the impact of the difference density between fresh and salt water (3.5%)

suggest using 2.5%

 

[Interceptor121]

density of fresh 1 density of salt 1.035 hence the 3.5%
Physics I would say

 

[Steve50]

fresh 62.4lb/cuft salt 64lb/cuft 1.6/62.4= 2.56% = going from fresh to salt...tis physics