I have a lovely little 18 foot fibreglass launch with a wine-glass transom. Light construction with 6 or 8 stringers of questionable integrity set in the hull length. Currently exploring the possibilities of using a two part "self levelling" closed cell foam to level the hull interior, without introducing a heavy weight. Finding a "self levelling" closed cell foam seems harder than it should be. Does anyone know and have experience with a suitable product?