Negative housing - need help to make it neutral

[Misa]

Hey again,

After flooding the camera and the housing in November i`ve decided to move forward and buy electronic housing with sensors and buttons, etc. But, when all was installed and the test was performed, underwater the housing was way too heavy. I cant hold trim, my front side goes down, arms go down, lol.

The only place i can install some float arms or some floating "thing" is under the housing between the canisters. The kit weights around 9 kg

I was thinking to buy 2 or 4 x INON Mega Float Arm M and mount`em somehow under the housing...arms wont fit on my arm...different mount. Each Float arms is +640g. I have a feeling that only 2 wont do the job, maybe 4 will do it right.

Do you guys have other solutions ?

 

[Wookie]

Syntactic foam is your friend. Won't crush under water pressure like strobe arm foam will. Get a small block and form it to fit between the battery pods. Makes the housing neutral, but tends to be top heavy, which is OK by me, because I dive with a steel tank, so I tend to be top heavy too, but it takes some getting used to.

 

[Kilili]

If you mount the floats under the housing, the entire system will want to flip upside down. It would be very difficult to control and impossible to keep stable for shooting. Similar problems if the floats are not properly positioned over the housing body mass. I tried it once...

The Inon Megafloats are great though, if you can figure out how to attach.

Take a scale, like for fish, and weigh your rig whilst it is suspended in the water. That's how much buoyancy you need. If you do in fresh water, subtract 2% of the housing body weight [dry, not submerged] to compensate for the difference in salt water density. If you want true negative buoyancy, you can offset the difference with the float arms you use by adjusting with StiX arm floats [Backscatter has] and lead fishing weights.

No idea what your rig looks like, so cannot further comment.

 

[Misa]

what do you mean looks like ?

ya, floating thing has to be uptop on weight center.

 

[Misa]

oh, this. thanks. will look.

Backscatter : Underwater Camera, Underwater Video Housing, Underwater Photography, Waterproof Camera

 

[Misa]

Syntactic foam is your friend. Won't crush under water pressure like strobe arm foam will. Get a small block and form it to fit between the battery pods. Makes the housing neutral, but tends to be top heavy, which is OK by me, because I dive with a steel tank, so I tend to be top heavy too, but it takes some getting used to.

You were right. With this block of foam the housing is almost neutral. I`ve called a friend and he came to my place with this foam. Problem is almost solved. I will put pictures in few days with all things attached. I need to cover this block into something cool and resistant.

Thanks!

 

[Wookie]

You were right. With this block of foam the housing is almost neutral. I`ve called a friend and he came to my place with this foam. Problem is almost solved. I will put pictures in few days with all things attached. I need to cover this block into something cool and resistant.

Thanks!

I've seen it painted, but plasti-dip is your next best friend. If you decide to drill holes in the foam to mount it, drill them slightly larger then plastidip it. I had a machinist make a dog that slides in the rail of my Gates, then I use a bolt to hold the foam to the dog. I think it's notable that I only need the foam when I have the lights mounted. Without the battery pods, the housing is only about 1 pound negative. With lights and batteries, it's about 4 pounds.

 

[Misa]

If lights are not mounted, then housing is -400g negative, so i dont need foam. It will be attached exactly between the housing and the batteries so it wont be hard to hold it there.

Do you think the foam will last at top 6atm ? Usually i dive max at 4atm.

 

[Wookie]

If lights are not mounted, then housing is -400g negative, so i dont need foam. It will be attached exactly between the housing and the batteries so it wont be hard to hold it there.

Do you think the foam will last at top 6atm ? Usually i dive max at 4atm.

Ummm. We put Syntactic foam on ROV's and mini-subs diving to 2-3,000 meters. Should be fine at 6 atm.