Frame Rot... Where to start?

I have a 75 Glastron 15 ft boat- its a fiberglass hull with an outboard.
Got it for free and hoping to restore it.

The problem is it held water for the last year, and the floor is rotted and so is the frame. I want to replace the whole frame but im not sure how to start. It looks like a 2x4 framing wrapped in fiber glass- completely to mush. There is also what looks like foam shoots- running along the wood. Do I take it all out first? or do I have to do it one piece at a time to keep the structure intact?

Is there an instructonal site anyone knows of?

Whos done this before?
Is it even worth doing?

 

When you rip out all the floor and ribs the boat will be flimsy. I did this to my dad's 1973 Chrysler trihull. I used a couple 2x4s screwed to the gunwales to help keep her shape. I built new stringers and cross ribs out of 2x4's and 2x6s. The original design was flimsy plywood stringers with foam fill everywhere. The foam was water logged and the plywood rotten. Once the frame was built I glassed the whole thing with regular polyester. The boat sits several inches higher, is faster and much stiffer than it was when new. Of course without the foam it is no longer unsinkable.

 

That model boat has little value, if the engine is in good condition, remove it and find a donor hull to slap it on, that doesn't require it to be completely disassembled, rebuilt and reassembled. If the engine isn't very good, it's better to just drag her to the landfill and be done with it.

Not that it can't be saved, it sure can, but if you have little 'glass work under your belt, it may be a bucket to toss money in until you've had enough. This type of repair isn't the most pleasant work and the boat probably has other issues (like a soft transom) that also need attention. If you feel comfortable working with polyester and the little bit of wood working involved, then go for it, but you'll still have a 30 year old boat of little value with new stringers, floors and transom.

 

so after quite a bit of research we decided to go for it.

I ripped out the floor and spent 2 days cleaning out everything. I came to find the wood underneath had little to no structural importance. it was just for the foor. I purchased some marine grade plywood and had some white oak cut to the correct sized and what I am waiting on right now is the glass for the white oak. Once that is done I am sistering the fiberglass wrapped wood. The floorboards I could not remove that are wrapped in the hull I am drilling holes and filling with get-rot. Once this is done I have a cross beam for the final support for the floor. Everything looks like it will go well I just didn't realize the wait time for the fiberglass coating on the oak.

Until then.....

thanks for the help