I did post this in another forum, sorry for the repeat, just hoping for more people (experts) to chime in.

In the picture below you can see and old Cape Charles that I'm repairing. As you can see in that photo, the top layer of the plywood has come up. My thought for a repair was to cover it up. The rudder just flops around up there when not in use, so I made this "keeper" to sit on top of that area. It was made from a glue-up of solid oak. Started out at about a 2 1/2" cube, then roughly shaped to the sketch in the next post.

The question is. How do I properly prep that area of the deck for the thickened epoxy to glue on the keeper? Do I just need to sand the varnish off in that area and glue & clamp? I planned on putting 2-3 coats of epoxy on the keeper.

The next question is then related to the finish. I would like to put a few new coats of varnish on. What is the preper prep for existing varnish? Simply wet sand with 400 then start brushing the new stuff it on? Should I sand everything first and then do the keeper thing, then the varnish?
Thanks,
Jerry