Bottom paint is the paint applied to the part of the boat that is always in the water. Many things can grow on that part of the boat. On Earthling's bottom we had an barnacle bed growing after we left Luperon in Dominican Republic. This caused the motor to over heat and slowed us down at least a knot in average. It took a few weeks of underwater scraping till it completely was cleaned. On the propeller there was an barnacle an inch wide! First time I looked at the barnacle bed, the bottom of the boat looked like a breathing dinosaur, it was so gross and disgusting, but it had to be cleaned, and I was the one to do it! I was so disappointed that the paint we applied less than a year ago didn't survive this situation. I guess you have to use paint with a lot of
poisonous chemicals in it to not get any growth on the bottom. But then again, the very strong paints are banned in many countries, and this is probably hurting the nature! This is a dilemma many boaters have. For the last 3 days we have been scraping off the oyster bed's residue and light sanding and then it's ready to paint. We heard of other boats that had the same experience in Luperon. A lesson learned to not anchor for a long time in isolated mangrove areas. If you do, make sure to keep her bottom clean.
Love from Spanish town