Float Arm Bouyancy Rating

[addohm]

When calculating bouyancy for a camera rig, float arms often list their weight as well as their bouyancy. Is the bouyancy value calculated after the weight consideration? By that I mean, when Im adding up all my "weight in the water" values, can I just refer to the bouyancy rating, or do I need to add the weight AND subtract the bouyancy?

 

[MidOH]

Buoyancy is all that matters. My camera is 4# negative.

So two 1.5# buoyancy floodable Krakin arms, and one Backscatter Jumbo Foam cross brace, does the trick.