All Ground Up
“I am repairing an older 19-foot daysailer that has a slow but persistent drip from the bottom of the keel; the drip comes from an area about 6 inches square. The ballast is 400 pounds of iron, encapsulated in the fiberglass shell that is part of the outer hull. When I ground down the laminate, I could see that some of it had delaminated.
I ground the surface as smooth as possible and drilled holes in the glass to help drain the water; I can plug them when it’s drained out. But water still seems to work out through the glass surface, and, since the bilge also seems to be damp, I’m beginning to think the entire keel may be waterlogged.
I’ve been advised to dry out the keel with heat, refair the iron foil with putty, and then reglass the damaged area. But since I’m not sure what the underlying problem is, should I patch and hope for the best or continue to diagnose and hope I find the answer? “
— Paul Sirotta , D’Iberville, Minnesota
Don Casey replies : There are two issues here. First is the actual keel repair. The right way to proceed is to clean the iron and then repair the fiberglass encapsulation. Since you plan to do the glass layup anyway, you should continue to grind down the worst of the drip site(s), which will let you take a closer look at the actual keel. It should also let out more water.
Whenever you laminate fiberglass over an iron surface like a keel, always grind the surface bright and then immediately cover it with resin. While the resin is still wet, use a wire brush to lift off any rust that may still be on the surface. Rust will compromise the bond between iron and glass.
You must also keep the cavity from refilling with water, so the ballast must be well sealed at the top. First get the bilge dry, perhaps by applying heat, and then seal the ballast with several layers of fiberglass. This will take both time and money, so you first have to decide how large an investment of both you want to put into this boat.