3M Marine Grade Silicone Sealant is formulated specifically for above-the-waterline sealing on RVs, boats and personal watercraft. Ideal for hatches, dashboard components, deck hardware, portlights and many other uses inside or out, it features a non-shrinking formula that forms a strong elastomeric bond and stays firm, tough yet flexible even in tough environments. Apply this silicone sealant to paint, fiberglass, bare metal, glass and non-oily wood as well as many plastics and abraded rubber. It resists all types of weather including high temperatures, and fights the growth of mildew which can cause degrading and discoloration. It also wont turn yellow over time, preserving the sharp, professional look of your boat or other watercraft. It wont sag, making it easy to apply even on vertical surfaces. It requires no mixing and applies right from the container. This boat sealant becomes tack-free in as little as 20 minutes, and fully cures in 24 to 48 hours so you can get right back out on the water.