A few thoughts. When I test the blue floatation next spring for yak stability, when its flooded, I will also get a good test of the watertight compartment and see if it is really watertight. I run a test when the compartment was finished but not installed, by putting water in it and turning it upside down. I got a little leakage but I later found out I wasn’t sealing the bottom edge as well as it could be sealed. If the compartment is really watertight then it might serve to stabilize a flooded kayak even more because it would become a buoyancy tank if the water got high enough to envelope it. So it would even be better to attach the compartment with the widest part of the compartment running vertically rather then horizontally as I did it so it wouldn’t take as much water in the yak to start the stabilization.

John