Reply To: foam hollow spaces.

I Have filled my buoyancy tanks up forward with sheets of 40mm thick polystryrene cut to shape. I only used foam to take up any gaps that were there. Unfortunately I did not know about builders foam being NOT CLOSED CELL. However there wasn't much used and I hope that I have got away with it. I fitted an length of rainwater tube down to the lowest point and put a small inspection hatch over the top to look down check if it gets water in. (none so far but I am not afloat yet!)