repairing hull

I am a new guy on the forum but nobody has answered you yet so I'll give you my opinion. I planned to restore my 87 SN this winter so I purchased some books for information.

Anyhow, from what I have learned, if there is any kind of penetration through the hull, it should be repaired from inside. Grind the area so it is cupped. Pre-cut three pieces of fibergla$$ mat each larger than the other. Gla$$ them in and roll out all the air bubbles. Then, on the outside, you can use a fibergla$$ filler, sand and paint to match.

Small scratches can be buffed out or wet sanded then buffed. I have used Marine-tex to fix little gouges.

Good luck.

That damage can and must be repaired from the outside. Use a dremel and grind out the damaged gelcoat and any loose or damaged fibergla$$. If the outer layer(s) of fibergla$$ are damaged, then you must build out with thickened epoxy (or similiar). Leave the repair low to keep room for the gelcoat. Grind the surrounding good gelcoat to a feathered (tapered) edge. Clean well with acetone. Applied the color matched and catalyzed gelcoat so that it is proud of the surround gelcoat. Cover the repair with clear packing tape overnight. Once the patch has cured, remove the tape and wipe the repair with acetone until the rag remains clean after wiping. Mist the area with black paint. Using 220 sand paper, sand the patch down until the black paint is gone. If you are left with a few low spots, get the black paint off with acetone and repeat the patchign process. Re-trace and sand again. Avoid sanding in one small area or you will be left with a depression around the repaired area. With each higher grit of paper, you must sand a larger area. You should trace between each paper grit up to 400. sand to 800 or 1000 grit then compound.

Hope that helps.

Yes, good point. NEVER EVER use a rubber sanding block. On a small repair such as yours, a 4" long block works great. Personally, I use a 4" long piece of oak corner moulding. It has radiused edges and a built in handle, plug you have two sanding surfaces.