Wood core totally rotted, options?

[Evinrude Boater]

The wood core in my 16' runabout is totally rotted. I've removed the inner layup, stringers, braces and wood core and dried and sanded the inside of the hull. I don't want to install another core material. The original construction had one center stringer and 4 cross braces. Can I get away with adding two more stringers (one on each side of the center stringer) and doubling the braces instead of a new wood core or am I wasting my time and money? Check out my Boat Restoration photos. Boat Restoration

 

[JasonJ]

Re: Wood core totally rotted, options?

Do you know how thick the hull layup is? If it is about 1/4 inch on the bottom (check the thickness at the lower hull drain, that'll tell ya), and you glass in two stringers on each side of the center, and fill the voids with 2 part foam, it will be stronger than original.

 

[BillP]

Re: Wood core totally rotted, options?

I wouldn't glass over rotten core. The hull may be too flexible and punchure easy. The stringers won't have a good foundation unless you remove the core where they sit and are glassed. Rotten core may also hold a lot of water and add weight. I'd strip the core out and glass a few additional layers on the inside for strength if you don't want core.<br /><br />I stripped the core out of a 17' boat but it was 1/2" plywood. I took it out only because it was too hard to check 100% for rot. What I found was the core was 90% ok and I did all the work for nothing! It took a couple of days to get the old core out. I used a skill saw to rip the glass off and various tools to pry it up. The hardest part was where it sat against the hull. That area needed 36 grit and a high speed grinder to smooth out. If your core is rotten it will be MUCH easier to remove and you can use low cost ply for an easy replacement. Start saving auto batteries...they are perfect weights to hold down core when gluing it down.

 

[Evinrude Boater]

Re: Wood core totally rotted, options?

Thanks JasonJ and BillP,<br />The rotted core has been removed and I'm not planning on replacing the core. The core board came out easily in fact most was washed away or removed from a previous repair. I'm planning on three stringers and several cross braces instead of core board. I think I've got to put the boat down on the garage floor because the hull is flexing so much on the trailer rollers. I might have to do the Mission Impossible thing and suspend myself over the boat while working on it so I don't flex the hull while glassing in the stringers.<br />And another problem!!! The keel is cracked in the bottom of the vee. This has been repaired before on the exterior and part of the repair has peeled off. How many layers should I apply over this area? Should I be using roving or matt? I thought I'd put one layer of matt inside the keel before glassing in a new wood stiffener then one or two layers on the exterior.

 

[JasonJ]

Re: Wood core totally rotted, options?

Definately repair the crack from both sides. Don't be skimpy, use pleny of layers. On the outside you should grind the crack down, and grind away from it creating a sort of sunken dished effect. The goal is to fill this dished area with layers of alternating mat and cloth, each layer a bit larger than the last, bringing the repair flush to the surrounding area. You can just prep and lay some layers on the inside without making it pretty, it'll be hidden anyway. Good luck...