Attaching grill to swim platform

Peg_O_My_Heart

I am planning on mounting a plate for a pedestal mount grill on my swim platform.  My question is what size bolts should I use to secure the mounting plate to the swim platform.

Stodge

Just did this.  I used stainless 1/4x20 bolts.  I also followed the advice of many on here and another forum and made the holes around 3/8 inch, then filled them with penetrating epoxy, let dry, then drilled 1/4 inch holes in the epoxy for the mount.  

Cableguy Greg

I also used 1/4x20 bolts.

craigswardmtb

I was lazy and used SS screws with 5200 in each hole. Hasn't moved or loosened up in 2+ years.

Stodge

I was going to go the same route Craig, but I was told that the problem was that the core (wood) had to be properly sealed or water would sneak in.  It seemed that the popular thought was that the only way to properly seal the core was with penetrating epoxy.  

craigswardmtb

That makes sense I suppose, and the safer route.  But it seemed to me no different than how the mfg handled attaching the swim platform supports with lag bolts and 5200 right into the transom.

Stodge

Except I don't think those bolts go through any core.  The thinner areas of the platform, I believe, are just fiberglass.