I am putting some buoyancy compartments into this Golden Bay conversion - the two main tanks will have hatches so they can be inspected inside, ventilated - and also used for a bit of light weight storage.
There are some other tanks which will be just for buoyancy only, and I am reluctant to close them in completely - also reluctant to add yet more inspection ports. (Part of the problem is retrofitting, one of the downsides of modifying an existing boat rather than starting from the beginning with an integrated design).
I have been wondering about a couple of coats of epoxy inside, then filling them with pour-in polyurethane foam and closing them off with no drainage or ventilation. Or, perhaps, leaving a cavity in the bottom and providing a drain plug. I haven't used expanding foam before, wondering if this is a good way to provide extra buoyancy - is this good practice with plywood?
Is anyone able to offer advice?