Early this summer I got a boat given to me. 1971 glastron just a little 2 man fishing boat with a 50 horse evinrude stick steer. Engine ran on muffs after I got it home. Floor was rotten of course and I found not much of the stringer left. I have already thrown away the floor and all the water logged foam. Transom is also rotten down low. My plan of attack is still beind debated. The stringer fiberglass is rock solid but all the wood that they were formed around is rotted. As far as the transom I think I am going to brace the side of the boat together as it sits now and cut the back portion of the cap off to gain access to the transom. Cut out transom replace wood and refiberglass. As for the stringers i am not sure if I am going to start over or do something homebrew. But not halfa**. I thought about just removing the rotted wood if I can and leaving the stringer hollw. plan 2 cutting a slit in the top of the strings and inserting new wood inside them and refiberglassing. and crazy option 3 is to use thick wall pvc pipe with fiberglass over to make stringers. I'm sure i'll get a lot of don't do that or do option 2 and start from scratch but that is why I am posting to get a feel for what i really need to do. 
or maybe I posted it in his thread... 