Canon Housing Buoyancy?

[Grajan]

Has anyone bothered to work out the buoyancy of the Canon S30/45/50 housing with camera?

I want to get a weight to compensate for the lift (it annoys me floating around) and I guess I am too lazy to calculate it and too far from the sea to do an empirical test.

Also - does anyone sell weights that screw into the tripod mount?

Thanks

Graham

 

[Spectre]

I've got the housing for the Canon A40 and the bouyancy was completely annoying. I attached a BABS [big assed bolt snap] on it, and all is good now.

 

[Grajan]

If you can, please do me a favor and weigh the BABS some time.

This is all highly scientific........

 

[pdoege]

I don't have a way to do an exact measurement at home.

I'll play around and see.

Peter

 

[Grajan]

When I get the time...

1. Close housing without camera

2. Immerse in water (saucepan) and measure displacement volume (Pi*r^2*h2-h1)

3. Multiply displacement volume by weight of seawater (64lb/cu ft)

= Gross Buoyancy (B)

4. Weigh housing and camera c/w battery

= Weight (W)

B - W = net buoyancy (N)

My guess is that a few oz heavy will be most comfortable so:

Balance weight needs to be N + 2 oz

How does that sound?

 

[Spectre]

If I have a similiarly sized bolt snap to weigh, I'll do that tonight. Otherwise you'll have to wait until I get back to town late next week; as I've got enough packing to do, I don't want to have to re-hook my bolt snap...

 

[pdoege]

I have no way of measuring the weight of the camera and housing to any meaningful accuracy....

The rest of the experiment is pretty trivial.

Peter

 

[Grajan]

I will do it and post the results.

Still have to source / make weights on a suitable bolt.

 

[Spectre]

The bolt snap I use to neutralize the housing is 68.2 grams. I'm not positive it makes it truely neutral [I've never let go of it], but I know it's not annoying anymore.

 

[Grajan]

Thanks spectre