High-performance polyruethane formula stays flexible to allow for structural movement. Has excellent resistace to weathering and salt water and retains its strength above or below the water line. Effectively adheres to fiberglass, wood and metal for practically any marine application. Remains workable with a trowel or spatula up to 4 hours after application and becomes tack-free in 48 hours. Completely cures in 5 to 7 days. Will not shrink and doesn't sag in vertical or horizontal seams. White.