The buoyancy foam I’m using in my AUV is a polyurethane based closed cell foam. while it is rated for 100m of depth, it will still absorb water over time. to fix this I’m looking at the similar Blue Robotics foam, and while they do have a depth rating, has there been any testing done to study water ingress over time?
The foam i have here currently was at 1m for 48 hours and gained 7% of its mass in water. not ideal for an AUV.