I have found that Boat Life Life-Caulk is the bee's knees for permanent underwater applications (e.g. installing a cutlass bearing or through hulls) and topside mounts. Silicone is not appropriate unless you need something flexible and/or temporary. I tried 5200, but it is the most amazingly difficult stuff to remove if you flub the application (as Bert suggests), and it does not waterproof or last any better. Tom Jenkins On Mar 12, 2012, at 9:06 AM, Flickasf wrote:

I don't like using 5200 because it is hard to remove. I like using Life Seal above the water line and 4200 below.

Bert Felton