Try a cleaner with oxalic acid. My favorite is Barkeeper's Friend. Get mine at Walmart. Comes in a tall, gold foil, cylindrical, cardboard container (Like old time cleaners). I hose down the boat for moisture, put some of the cleaner on the bristles of a long handled scrub brush, and it works like magic. Joe Murphy <seagray@embarqmail.com> wrote: Andrei, Since the stains are mostly at or below the blue painted hull, which I would guess is some type of anti fouling paint, here is the approach I would take. Start with soap and water and a scotchbrite pad. The best soap I have found is "the Works", a bathroom cleaner in a green bottle. If that doesn't do it, then step up something like MaryKate On/Off hull cleaner. This will get you past normal dirt and down to stains. Then to remove the stain, I use a trick I learned at a local boat yard from an old salt. Use 3M liquid polishing compound and laquer thinner. Put the laquer thinner in a cheapo dollar store spritz bottle. Spray some laquer thinner on a terry cloth rag and pour on some 3M and lightly rub out the stain. This will take just about any stain out and will, if you are careful, not hurt the gel coat. Since you are trying to remove stains from a painted surface as opposed to a gel coat surface, you will more than likely remove some of the blue paint in the process, but you would probably give the bottom a fresh coat anyway. I use the laquer thinner/polishing compound on those really hard to remove stains like around through hulls; exhaust stains, etc. I just work very lightly and carefully. I follow up with a coat of wax on the spot I just cleaned. Joe
Andrei Caldararu wrote:
Dear members,
the boat I am looking at buying (1975 M-17) has a mysterious deposit just above the waterline, see the photo at
http://www.math.wisc.edu/~andreic/P6070387.JPG
Can anyone guess what it can be? The boat spent most of the last few summers (except for the last one) docked on a fresh water lake in Utah. What is very strange is that the deposit appears to exist only *above* the waterline. Do you think it could be some kind of minerals from the water (e.g., iron, calcium)? How hard would it be to remove such a deposit? Or a mold, that grows on humid gelcoat, but not in the water? Could it have damaged the gelcoat?
Despite the fact that the boat has been in storage for the last year and a half, I know from sailing pictures of the former owner that the deposit was there at the end of the last summer when the boat was sailed, two years ago (photo was of the boat in the water, sailing, and one could see the deposit at the bow).
Thanks,
Andrei.
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