UW case boyancy question.

[MasterGoa]

Hi all!

I have a Fantasea case for my
Nikon 4600 and was wondering about
boyancy at depth.

Since the case will resist collapsing
and that water is under more pressure as you go down,
will the case be more boyant the deeper you go
to resist the ever rising pressure and water weight?

Regards.

MasterGoa

 

[Diver Dennis]

Hmmmm. Good question. I have a large Ikelite case but I don't notice much difference and I've had it down to 190'.

 

[Mariozi]

No... althoug pressure will rise, water is not at all compressible like air.
So if the contents inside the housing dont change, buoyancy will not change either.
Pure physics from Archimedes time.

 

[Tortuga Roja]

Exactly. Buoyancy is only determined by 2 factors. The weight of the object and the weight of the water that it displaces. Neither changes with a housing at depth - unless it fl#@ds.

 

[TracyKent]

I'm not sure about anyone else, but my Canon A80 housing is negative no matter where I am. I'm thinking of adding a couple of those floating keychains to it. Might save me a camera on day.

 

[TracyKent]

I'm not sure about anyone else, but my Canon A80 housing is negative no matter where I am. I'm thinking of adding a couple of those floating keychains to it. Might save me a camera on day.

I keep a lanyard on it with a retractor, but I just don't trust it. Even though its my housing, its my wife's camera. Dont think she'd be happy with it at the bottom of a blue hole.

 

[miketsp]

Exactly. Buoyancy is only determined by 2 factors. The weight of the object and the weight of the water that it displaces. Neither changes with a housing at depth - unless it fl#@ds.

Water has a compressibility of 4.5 x 10-10 1/Pa. Because of this extremely small value, liquids are normally referred to as being incompressible.
At recreational depths you can forget the change due to water being more dense.
OTOH your casing orings will get a little more compressed so your housing will displace less water and appear to be slightly heavier.
Again the effect is negligible and you won't feel it.

 

[MasterGoa]

Thanx for all the responces!

So, I guess that since water cannot
compress, pressure rises for not
weight of the water as I go down...