Re: transom repair help
Hi Kerome --
There are a few options, depending on the exact layout of your boat, ranging from most to least involved:
1) For most hulls, replacing with a new wood transom will require separating the top part of the hull (the "cap") from the bottom part. These two pieces are generally held together by a line of rivets or screws under the rub rail that goes all around the boat. Taking the cap off is a chore, but it greatly improves access. Then, cut out the whole transom from the inside, replace with new plywood sealed in fiberglass, tabbed in to the sides of the hull and the stringers. Replace the cap.
For an exquisitely detailed tutorial on this process, including a handy crane for pulling the cap, click on Oops!'s link in his signature (he posted above). It's 160-something pages, but if you read through the first 20 pages of that thread, you will come out 8,000% more knowledgeable about what you're up against than you are now. (and with an uncanny thirst for Corona)
2) In some hulls, it is possible to pull and replace the transom from under the splash well without taking off the cap. In one sense, this seems easier, not having to pull the cap, but the working area will be much more awkward.
3) Remove the metal brace and cut off the fiberglass on top of the transom, carve out all the wood (not just the soft stuff -- it's all rapidly on its way to being soft stuff) and pour in Seacast or a similar material.
There is an immense wealth of knowledge here, and many detailed threads about transom replacement projects. My very sincere recommendation is that you read through several of them, and then come back with whatever questions remain unanswered.
Good luck with this project!