BoatLIFE LifeSeal Sealant BLACK 2.8OZ TUBE Designed specifically for fiberglass boats. A fast-curing (24 hours) polyurethane/silicone adhesive sealant. Permanently flexible, non shrinking. Outstanding adhesion to fiberglass, glass, plastic and wood. Latest technological marine sealant. Fast skinning (10 minutes). Use above or below waterline. Acid-free.