3M Marine Grade Silicone Sealant - Clear

A sealant is critical for any fastener that penetrates your wood or wood-epoxy hull.  Water penetration into screw holes for deck rigging, footbraces, sailboat hardware, etc. is the primary cause of stains and damage to wooden boat hulls.  (Okoume is particularly susceptible to water staining if the epoxy envelope is pierced.)  A small dab of this high quality marine-grade silicone beneath each fastener is required.  It forms a seal that remains flexible even after years of exposure. Bonds to wood, epoxy, fiberglass, gelcoat, glass, rubber and vinyl.  Keeps footbrace screws on kayak watertight for years.

A tube of this is indispensable in the boatshop---we use ours almost daily as we maintain and upgrade the CLC demo fleet.  We find it has a pretty good shelf life as long as you get the cap on tight and keep it at room temperature.