A ways back there was a reference to silicon products and a poster weighed in that silicon products are to be avoided like the plague on wooden boats. It seems like that is an opinion shared by guitar builders and repairers too. I recently went looking for some products to clean up my acoustic guitars. At Stewart MacDonald (Stew-Mac, as its widely known—a first class supplier of parts etc, for guitar makers) I found a discussion lamenting the widespread use of silicon in guitar polishes, waxes, etc. Their view was that silicon has no place in acoustic guitars: builds up, is difficult to remove, harms varnish, and inhibits gluing when repairs are required. They sell a silicon free guitar polish—Preservation Polish--that I bought and used on my instruments and it did an outstanding job. Not sure how economical it would be to use on small boat varnishes, but it sure did a good job on my guitars.