What's the best wood to use for stringers replacement.

[newtons law]

Recently acquired 1984 Galaxy conquest has bad flooring. While cutting it out,I realized that the two stringers on either side of the ski storage are rotted. Cutting the top cap to remove the rotted wood. Noted the outer fiberglass shell that incases the stringers will only allow three quarter inch thick board. Should I cut the side walls,so I cauld use two by boards,or stick with three quarter that are sealed in resin? Thanks

 

[Pmt133]

3/4 exterior plywood is probably what it was built with. (I've seen from friends that OSB was used in cheap boats at the factory) So yes, you'd have to cut that shell, adhere the board or float it then glass up around and over it back to the hull.... I used a local lumber yard, told them what I was doing and they delivered excellent quality wood to my location for the same price as the cheap stuff at HD and the like and it was already dried! So look around. Chances are you're going to have to go through everything on the hull if the stringers are gone...