> Double-sticky carpet tape makes a pretty good non-permanent means of
> holding the seat in place. Contact cement is a good permanent adheasive.

> 3M 5200 is hard too beat. Regular Silicone sealant (RTV) is pretty good
> but may fail after a while.

You might want to try one of the polyurethane calks that are now available. They seem to stick forever to almost anything and are rated for water immersion. The are several brands. PL makes a good one as does MD (Macklinberg Duncan). My own opinion is that these are much better and easier to use than the traditional 3M stuff. (They also cost half as much). My experience with the 3M 5200 is that it shrinks and cracks when drying and the joints therefore sometimes fail.