Buoyancy Check Methods

[eastnorri]

The PADI OW book says the way to check your buoyancy is to get in the water, take a deep breath, hold it, let out all the air from your BC, and you should float at eye level.

Is this the best way to test my buoyancy?

Are there any other methods?

Is it better to be a bit over weight or a bit under weight?

My diving is varied from cold water diving in Pennsylvania in the summer and fall with wetsuit, and
warm water diving in the Caribbean once per year.

 

[spectrum]

The PADI OW book says the way to check your buoyancy is to get in the water, take a deep breath, hold it, let out all the air from your BC, and you should float at eye level.

Is this the best way to test my buoyancy? That's over simplified but it can evolve into a decent starting point.

Are there any other methods? Yes, in the shallows, 10-15' deep at the end of the dive.

Is it better to be a bit over weight or a bit under weight? Never under. Right on per the check or a little more if surge or other conditions suggest. If you have the hang of it 2-4 occasional extra pounds becomes trivial.

My diving is varied from cold water diving in Pennsylvania in the summer and fall with wetsuit, and
warm water diving in the Caribbean once per year.

The long version of how and why is here.

Pete

 

[Bob DBF]

Are there any other methods? Yes, in the shallows, 10-15" deep at the end of the dive.

I believe 10-15" might be possible, I try for 10-15' myself.

I do my weight check at the end of the dive at 15' with 500#, then always add a couple of pounds in case I get to the stop with less than 500# or want to continue the dive shallower @ 500#.




Bob
-----------------------------------
"No matter what happens, somebody will find a way to take it too seriously" -Dave Barry

 

[spectrum]

I believe 10-15" might be possible, I try for 10-15' myself.

I do my weight check at the end of the dive at 15' with 500#, then always add a couple of pounds in case I get to the stop with less than 500# or want to continue the dive shallower @ 500#.




Bob
-----------------------------------
"No matter what happens, somebody will find a way to take it too seriously" -Dave Barry

Oh yea....' (Feet)

 

[TMHeimer]

Of course, you are always somewhat overweighted starting the dive. If underweighted you will struggle to or be unable to descend. If you are able to get down and your wetsuit compresses, you'll be OK down there for a while until you use up some air. The idea is to be neutrally buoyant at the end of the dive (in the shallows) or at a safety stop if boat/deep diving. Since you are continuously using tank air your total weight is always lessening, so you are never really perfectly weighted, save for an instant in time.

You can go horizontal on the bottom and dump ALL BC air and do a fin pivot. If you need any more than 1 or 2 short puffs of air to rise you are overweighted.

 

[redacted]

A weight check at a rest stop is a good start, but if there is neoprene involved, you just don't get a very accurate answer. What is the buoyancy of your neoprene at 1.5 atm? I prefer to do it at the surface (usually at the end of my dive). I hand weights off until I can not comfortably descend again. I prefer the end of the dive, not because the tank is low (I can adjust for the weight of the gas), but because I'm pretty sure there is no gas still trapped anywhere in my gear. I keep a log of the buoyancy of all my neoprene so adjusting for exposure protection is not difficult. But check it again occasionally as it does change with age.

 

[Hawkwood]

The PADI OW book says the way to check your buoyancy is to get in the water, take a deep breath, hold it, let out all the air from your BC, and you should float at eye level.
...

Close. The book does not say to take a "deep" breath. It says to hold a "normal" full breath. There is a difference and it will make a big difference in how you end up weighting yourself.

 

[WhiteSands]

I'm curious, does the PADI method work? If so why does it work?

I agree that the correct method should be to do your check at 5m with 30bar or 500PSI left in your tanks.

Can someone explain how that translates to the PADI method of testing at the start of the dive on the surface with a tank full of gas.

 

[DevonDiver]

Options for buoyancy check/weighting confirmation are here: Scuba Weighting | 4of9 | Scuba Buoyancy Masterclass

The 'PADI method' is only really good for a rough approximation at the beginning of the dive, should your equipment etc have changed. There's no substitute for a real weighting check, conducted in the shallows, by holding a neutral hover at safety stop depth with no air in your BCD (superfluous weight removed incrementally until the hover is achieved).

 

[Eric Sedletzky]

I've been saying exactly this for years until I'm blue in the face seemingly to a deaf crowd.
I would add, the check needs to be done after a full length dive at depth because wetsuits cool off and also compress further with more time at depth. Just going straight into the shallows from shore with a warm plump wetsuit with a near empty tank doesn't approximate the real thing.

Options for buoyancy check/weighting confirmation are here: Scuba Weighting | 4of9 | Scuba Buoyancy Masterclass

The 'PADI method' is only really good for a rough approximation at the beginning of the dive, should your equipment etc have changed. There's no substitute for a real weighting check, conducted in the shallows, by holding a neutral hover at safety stop depth with no air in your BCD (superfluous weight removed incrementally until the hover is achieved).