Seeking algae removal tips

[itsaboat]

Our new (to us) boat was hauled to a lake closer to our house Monday (another adventure story), and is on a trailer in the yard at the local marina. The trailer owner wants to launch the boat around the first of the year, so he can get his trailer back for another job. So, considering Christmas, I basically have next week to get the hull in the best shape that I can.

When we hauled it out we were surprised that there were no blisters (not one!) and the paint for the most part was in good shape. It looks like there was a copper blue paint covered by red paint over the years. There are a few scrapes that go either down to the blue or white in some areas. I decided to leave these for another year. Is this okay?

There are basically two things I want to address next week. First is the amount of algae that I need to get off the bottom. I tried soap and a soft brush so as not to harm the bottom paint, but this is a slooooow process. I was warned not to use an abrasive scrubber, but are there some that are not so abrasive as to not damage the bottom paint, but help loosen the algae? Or does any of this matter? Is the algae going to hurt performance, or is it just cosmetic?

The second thing is that I am going to use a wash/polish on the hull above waterline with a buffer and follow by a wax. Probably carnuba based. I thought about a poly-glo or Nu-Finish type thing, but I am not sure that this would be best. I have read several posts online about hull finish, but it seems most of them are trying to sell a product. What do y'all think?

[heinzir]

Try using a strong (50%) bleach solution instead of soap on the algae. Let it soak for 15 minutes or so and then wipe off with a rag or soft brush.

Oxalic acid from the hardware store will remove any scum above the waterline. Don't let it drip on the bottom paint, though, or you will have to repaint.

[mitiempo]

The best way to clean a boat's hull is to powerwash just after hauling. Waiting until it dries makes a one hour job a lot longer.

[CorvetteGuy]

I would agree pressure washing is the way to go. Try and soak the alge to make it soft again then go to town with the pressure washer, As for the hull Nu Finish works very well easy on and off as long as there is no oxidization.

[SlowButSteady]

Pressure wash, and a plastic putty knife for the tougher stuff, right when you pull it out of the water will take almost all the fouling. For harder or more tenacious critters (barnacles, tube worms, etc.), you may have to use a Scotch-pad-like scrubber or a metal scraper.

Any fouling (algae, barnacles, whatever) will increase drag on a boat hull. You want the bottom to be as smooth as possible (if anyone mentions golfball dimpling, etc., just laugh and walk away). In addition, that thin layer of slime that first develops on the hull surface (what marine biologists call "biofilm") will actually attract and provide a suitable environment for larger algae and other fouling organisms. The best way to prevent a build-up of fouling is to have the bottom regularly cleaned by a diver using a soft cloth to wipe off the biofilm and any small fouling organisms (before they can grow into big fouling organisms).

[Lake Superior Sailor]

Plastic windshield scraper really works well! --Dale

[itsaboat]

Thanks for the input. Now that the holiday business is out of the way, I'm getting out to the boat tomorrow to try some of these things.