Paul:
When not working on the Commander during the weekend, I spend my evenings restoring an old Wellcraft. The transom of this 19' 6" runabout has a large circle cut out to fit a particular outdrive. I want to fit a Merc outdrive to it that has a different cut out pattern much smaller. The transome appears to be two 3/4" sheets thick plus the glassing. I am thinking about cutting out two elongated diamond shaped pieces that oppose each other, epoxy and glassing them in, and then recutting the merc pattern out. What do you think? Whats the correct way?
Jerry - eternal student and wishing summer would hurry up!
Similar problems encountered restoring an old Lancer or Corsair
January 31 2008, 8:49 AM
The outdrive system has been the downfall of many a fine boat. When they're working, they work great, and they give a very efficient power delivery. You can adjust the prop to push directly behind the boat parallel to the bottom of the boat. On an inboard boat, the prop is always pushing down at an angle, and this is less efficient than the outdrive setup.
When the outdrive eventually needs service, that's when many people give up. In reality, it's no more complicated than a Paragon inboard transmission. I think it's a good alternative to replace the old obsolete outdrives that are no longer supported with replacement parts, with a new one that for all practical purposes, looks like the original. By doing so, it saves a lot of Lancers and Corsairs, and other models like yours too. So, good job with saving the boat.
My concern would be to glass in the hole, and then get a stress crack around the plug. In order to avoid this, I would consider a filler piece like you described, but I would also want to back up the joint from behind, with some sort of concentric backer block, IF the outdrive bolt pattern and size would permit something like this. The outside will take some overlapping fiberglass roving, filler, smooth out, prime and paint. The inside will take a lot of build up to be strong. Rather than use polyester for the actual bond between new and old filler, I would consider using a stronger marine epoxy product. I used epoxy to repair my 1966 20' fiberglass Sea Skiff fiberglass engine stringer support, because it had better bonding and strength than polyester did. So far it's worked great.
Those are a few thoughts to consider. Sounds like a good project you have there, good luck with it.