Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I assume the holes go all the way through. Use a very good tape to cover the holes in the interior and fill the old holes with fiberglass resin with microbaloons or epoxy. Sand down when set if needed and touch up the repair.
Are you putting the new clutches in about the same place? If so, use as many of the existing holes as possible. That'll save ya some filling work.
Mix epoxy with colloidal silica and fill the holes you aren't using. Actually it's a good idea to drill the holes you are using oversized, fill with the epoxy mixture and, after it sets, redrill the correct size.
If any of the filled holes will be exposed after remounting, the epoxy needs to be covered with polyurethane paint or gel coat. I've read somewhere, though, that gel coat doesn't like to go over epoxy, or that there's some trick to doing it.
Here is what I have done in your situation. Make up some 1/4" thick stainless steel plates the appropiate size for your hardware to sit on, and drill and tap them so your hardware can be bolted to it. Then drill holes in the plate to match the holes thru the deck and use flat head screws to bolt the plate to the deck (with the proper sealant under it). Then lock-tite the hardware to the plate with the proper screws. Since everything is in a shear load, the short engagemnet of the threads is no problem. No holes to fill, and everything looks pretty neat with the stainless backer, especially if you give it a high polish.
to patch holes on my 22 I first filled up the holes with west epoxy. Some of the epoxy absorbed into the wood. This left about 1/4" on top which I patched with Gel Coat patch manufactured by Sprectrum. I purchased this material from Catalina Direct. It works great and matches the deck perfectly. Catalina Yachts even uses this product
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.