Restoring a '59 Glasspar Seafair Sedan

[deltatechx]

I recently purchased a '59 Glasspar Seafair Sedan, the floor and stringers are rotted so I'm going to do a complete restoration. I'm wanting to replace all of the structural wood (stringers, transom, and floor) with composite board for longevity. I'm also wanting to extend the hull 2-3 feet but I want to keep the transom intact so I'm thinking about fabricating a transom bracket and then build the hull around that. The main reason for extending the hull is to free up some space on the boat and to add a deck between the outboard(s) and the transom. I'm wanting the deck to be level with the wood trim pieces on the outside of the hull so we can easily get in and out of the boat when it's in the water.

My questions... What composite board should I use (I've been looking at Coosa)? Is it worth using epoxy rather than resin? Will the boat still handle properly with the extra 3 feet of length? Should I modify the bottom hull design or just copy the transom and use straight lines from transom to transom? Should I consider stepping the hull between the boat's transom and the extension? Would there be any other issues with extending the hull in this manner?

This is the basic design I'm wanting to use for the extension except the hull of the boat would extend to the rear of the extension:



Here's some pics of the boat:



Thanks,
Paul

[LMB]

Neat old boat. I'm restoring a Glasspar G-3 for a customer now. We're considering Coosa for this job. Ultimately it's up to the owner. Coosa or AirexPX (basically the same thing) is the only product I would consider as a structural replacement for wood. If you can handle the cost it's a great alternative. As far as resin, polyester, vinylester, or epoxy will work fine. There is no substitute for good prep and good workmanship when fitting up and glassing the structure of a boat. Epoxy is a superior glue and can compensate somewhat for poor workmanship. Whatever resin you choose, knowing the characteristics and working properties of that particular resin is key.

As far as extending the hull, there are certainly some on here more qualified to answer but in my on experience it is often not a good idea. It can completely alter the handling characteristics of a hull and introduce some real problems. Its going to be alot of extra work even if you can nail down a design that will work. If you decide the benefit is worth it - proceed cautiously.

[deltatechx]

Thanks for the info. I plan to do a few cheap hull extensions with different bottom designs that just bolt to the transom to test how it affects the handling. If I find one that works, I'll rebuild it using higher quality materials and fiberglass it to the boat along with bolting it to the transom. Otherwise, I'll just keep it the way it is.

[Seafair]

Just got me a Seafair Sedan few days ago and my floor and transom is all rot, wanted to see how yours turned out? if you could post pictures of the progress of the work