I gotta tell ya, this stuff is phenomenal, fantastic, unbelievable, A local marina told me about Slimy Grimy. My boat has to sit in the lake all summer, inside my boat dock. It’s a 1987 boat, which I purchased 6 years ago so it had YEARS of brown crud covering the bottom. I tried using a scouring powder last year but after an hour I had only the rear transom cleaned and I gave up. I just finished washing the entire bottom with Slimy Grimy and in about an hour I was finished and the bottom of the boat is as white as it was new. I could not believe it!!!!!! There aren’t enough expletives to describe how good Slimy Grimy is.