CONTINUOUSWAVE

I own a [1997—always use four digits for years] Montauk 17 which I'm planning to restore. The boat is generaly in good condition. The gel coat has a problem I have never seen before. When I rub my fingers over the gel coat a chalk-like layer which is easily washed away with water appears.

I did some patching with new gel coat resin and painting on few spots. [The repair has held] for a few years now without a problem.

I sanded away a bit of gel coat to see what would happen. At first the gel coat looks okay. But after some time the same [problem] happens.

Give me advice.

Is there a better solution than sanding and painting all over?

Also, the previous owner tightened the engine bolts too much and indented the laminate. And he also did not use sealant. I have applied Sikaflex 291 after drying [the damaged area of the transom] properly, but I'm afraid the plywood inside is a bit rotten already.

Tell me how to patch this.

(English is not my native language.)

Thanks — Igor

A gel coat surface that has a white chalk-like top layer is probably oxidation. Badly oxidized gel coat can be removed by wet-sanding with very very fine grit emery cloth.

Before resorting to sanding away the oxidation, try a less abrasive gel coat “restorer” compound.

Re wood rot in the internal transom reinforcement: was the boat run in saltwater or in fresh water?

boat was run in salt water only. All this rotten material must be removed but I'm not sure how to patch it after in order to re-install engine in the same place.

Thanks!

Wood usually does not rot in saltwater.

Your chalking problem is due to lack of wax. Easily cured with wax. Transom is probably not rotten. Repair and use a spreader bar to cover the small cracks and spread the stress over a larger area. They are like $20 or so.