Re: Transom flex
Depending on how bad your rot is, that method of repair is a bandaid at best. It will only get you by for a couple of season at most. If you are planning on keeping it then you might as well do it right the first time. Replace the rotted wood.
If you fix it with rot doctor, then don't you need to disclose that repair to the next buyer when you sell it? Isn't there legal ramifcations of knowing something is wrong with a boat when you sell it?
If it where me I would just rip out the old rotten wood and fix it with new stuff. Post a couple of pics of your boat and we'll give you a good Idea of what the cost will be. or better yet, do a search on here os previous repairs to that same boat. Send them PM's asking how much it cost to fix. It's your best method of estimating the cost or repair.