Don't use silicone... Silicone caulk really has no place on a boat. What you should probably do is make the gap around the plates a bit smaller by filling the excess gap with thickened epoxy. The gap shouldn't be 1/2" all-around. Bringing it down to 1/4" would be a good idea. If the chainplates flex more than that, you've got other problems to worry about. While you're at it, checking to make sure the deck is sound in the area, especially if the chain plate passes through a cored section of the deck, would be a really good idea. If the core is exposed, sealing it with thickened epoxy would also be a really good idea.
Making a stainless steel cover for the slot is a good idea. Make it out of the same grade stainless steel as the chainplates if you can.
Use SikaFlex 291, 3M 4200, or butyl tape to bed the stainless steel cover and seal the hole.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.
—Cpt. Mal Reynolds, Serenity (edited)
If you're new to the Sailnet Forums... please read this To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Still—DON'T READ THAT POST AGAIN.