Black is a hard color to match. Are the scratches visible? Where are they located? If they are under the boat and not visible without getting under the boat then I wouldnt worry too much about them unless they were down into the fiberglass. If they are that bad, then you would probably be better off letting a professional take care of it. If youre thinking about a sharpie then I wouldnt think they are that bad and a fiberglass man can fix them fairly cheap.
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