Subject: Rotted Stringer
Date: Wed, 13 May 1998
I have a 1979 MFG Caprice with a 200Hp OMC, and recently noticed the motor dropping about 2 inches. Needless to say I found the stringers were completely rotted. I have already pulled the engine and cut away the top of the fiberglass on the stringers to show the mess. I then removed the rotted wood. Now I am left with the repair. First of all I not sure what type of wood to use or what type of fiberglass. Any pointers would be appreciated.
Yep, sounds like the standard problem. Here's what we'd recommend:
1) Make sure you've cut back on the stringers to where you're seeing
2) Go to the local home-mart and buy some fir, clean (no knots) as you
can find and as close in height/width as the stringer space. You can use
thinner multiple pieces of required.
3) Cut the pieces to fit inside the stringer. If possible they should
lap over, either by beveled cut or actual wood laps, the good wood still
in the stringer.
4) Brush the new wood with 2 coats of our Clear Penetrating Epoxy Sealer
(CPES), paying particular attention to the end grain. Give the wood all
it will take. This will help protect the wood from future rot damage. A
2-quart unit should do this just fine.
5) Place the wood in location inside the stringer, and then fill-in
around it with a thick mixture of our Layup & Laminating Resin and fine sawdust. We do sell the fine sawdust if you can't find it. You'll have to estimate how much of the resin you'll need for filling. You mix about 1 lb. (.45 kg.) of fine sawdust and 1.5 qt. (1.425 L.) of resin to make the paste.
6) Smooth off the top with a thick L&L Resin/sawdust paste.
7) Re-cover the stringer with glass cloth and resin. Here you can use
polyester resin if you want. Save a little money.
You're done. You can also help protect the
wood further up the stringers by drilling a few small access holes on
top through the glass and injecting CPES into the area. It will work its
way into the wood and help keep the rot out.
Come back if you have more questions.