Weight ~ just curious...

[AJ McFinnagain]

Yeah I wouldn't trust that calculator. I dive in skins, AL80, in salt water and use 6#, yet that says I need 12# +/-. This doesn't take into consideration BC type our or anything else. Get out and dive to figure out what you need.

 

[LariatAdvance]

OP was probably using Estimated Diving Weight Calculator | DiveBuddy.com. Seems like a typo, 14 lbs. is with an AL80, 8 lbs. is with a stell 80.

Yeah that's it. But no typo. I did it again just to make sure. Says 14lbs.
I guess I'll just have to go find out for myself and let you know.

They say I'd need a whopping 21 pounds with an AL80!
"In Salt water, weighing 200 lbs, with a 3mm one-piece wet suit and Aluminum 80:
You will need an estimated 21 lbs of weight (+/- 2 lbs)."

They also say I'd still need 19 lbs even if I lost 20 pounds in body weight with an AL80. So no need for me to bother to lose weight. Not that much of a savings. I can still be fat and dive.
"In Salt water, weighing 180 lbs, with a 3mm one-piece wet suit and Aluminum 80:
You will need an estimated 19 lbs of weight (+/- 2 lbs)."

 

[LariatAdvance]

Yeah I wouldn't trust that calculator. I dive in skins, AL80, in salt water and use 6#, yet that says I need 12# +/-. This doesn't take into consideration BC type our or anything else. Get out and dive to figure out what you need.

Yeah but I thought it might get me in the ballpark. 6 vs 12 I wouldn't call in the ballpark. It obviously doesn't take into account body mass. A 200 lbs fat boy will have more buoyancy than a 200 lbs solid body builder. Fat floats, muscle doesn't. How much difference in buoyancy, I don't know. Probably not enough to make a mentionable difference. That's probably where their +/- factor comes in.

 

[DevonDiver]

A 200 lbs fat boy will have more buoyancy than a 200 lbs solid body builder. Fat floats, muscle doesn't. How much difference in buoyancy, I don't know.

What makes the biggest difference, based on body composition, is the volume of the body for a given weight (mass). It's simple Archimedes principle.

A more muscular person, at the same weight, displaces less water than a more fatty person. This is because of the relatively density (volume versus mass) - muscle being more dense than fat.

Also, body density/composition can directly influence the size of the wetsuit worn, which has a much more direct impact on buoyancy. Obviously, the volume of an individual influences their surface area. Cover that surface area with highly buoyant neoprene and we can see a definite variation in buoyancy.

Obviously, there are other factors that dictate the size of a wetsuit needed. Height, for example, may dictate a larger wetsuit size, rather than waist or chest measurement.

 

[RainPilot]

If you are talking about a corpse, then yes, buoyancy of a newbie and an experienced diver are the same. However, buoyancy is a factor of mass and volume, and an inexperienced diver almost always has a slightly higher volume than the same diver once they relax in the water.

As @DevonDiver said, the new diver tends to breathe in the top half of the lung volume, I find that its REALLY hard to get the guys to exhale fully at all for the first while. So if I am neutral with half lungs and can pick up 4-5 lbs easily with a full inhale, then if I was breathing around the 2/3 mark instead of the half-mark I would need an extra 2 lbs or so to be neutral. Almost every diver Ive known has dropped a pound or two every few months as they get more experienced, more so if they were overweighted by a sausage-machine instructor to start with.

 

[Derelict]

That online buoyancy calculator is a joke. For my 5mm wetsuit for warm water, with al100 it says 16#. I wear half that.

 

[urbaneve71]

I dive a full 3mm suit and use 14lbs of weight. So I'm think the calculator tou used may be a bit off. I'm 5'8" & weigh 140 lbs. With you being 200. Is would call your LDS and ask them.

When I talked to mine..he told me right on the money with 14lbs of weight. Of course my upper torso will DD a bit of buoyancy for me ....lol

 

[Derelict]

I dive a full 3mm suit and use 14lbs of weight. So I'm think the calculator tou used may be a bit off. I'm 5'8" & weigh 140 lbs. With you being 200. Is would call your LDS and ask them.

When I talked to mine..he told me right on the money with 14lbs of weight. Of course my upper torso will DD a bit of buoyancy for me ....lol

14lbs seems too much for you? As per above I dive with 8lbs on a 5mm and I'm 5'10 150lbs

 

[urbaneve71]

When I wore a 5mm farmer john I needed 26lbs of weight lol but I am not as lean as I was 15 yes ago.

 

[Jim Lapenta]

If you look at some of the numbers it is clear that the calculator is not doing much more than saying 10% of your body weight plus or minus a pinch depending on suit and some experience. The latter of which is also subjective since I have seen divers with a few hundred dives that were clueless when it comes to weighting. Same info is found in many OW student manuals as a starting point.
The only way to know how much weight you are going to need with any kind of accuracy is to get in the water and check.