Gel Coat White Marks; Transom Holes

[Igor]

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

[jimh]

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.

[jimh]

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

[Igor]

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!

[jimh]

Wood usually does not rot in saltwater.

[biggiefl]

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.