Removing a Porta Bracket

This may sound strange, but I actually want to remove a Porta Bracket that was on my 1970 20SF when I bought it a couple of months ago. The problem is that I have never undertaken any kind if fiberglass repair/rebuild. I'm pretty handy, but I will need to come to you guys with a lot of questions - many will seem pretty dumb!I have been so impressed with everyone on the forum and the help they provide that I am willing to give it a try.

I'm going to post a few pictures tomorrow of what it looks like right now and then start. I know right off the bat that I want a 25 inch transom not the 20 inch that the boat came with. I am assuming right now that the full transom on it now was built up from a 20 inch.

So here is the first really dumb question - measuring the 25 inch transom. Is it from the dead bottom of the hull to the lip of the transom?

By the way - the Porta Bracket works perfectly. I would need something for it if anyone is interested - to help me pay for this effort because this just might end up being a whole transom rebuild. If you are interested and live close, you can come help me remove it so you know you got it off the boat with no damage!

Here is the bracket and transom arrangement. That is 1/4 inch plate stainless steel and it overlaps the top of the transom down about 10 inches.