Stained Boat Bottom

[Tim Bromund]

I'm sure this has been discussed before, but I just had my boat (fiberglass) in a transient slip (freshwater, Olcott Harbor, Lake Ontario) for the month of July (usually trailered, so no bottom paint) and it is now badly stained below the water line. I have power washed the hull and it is still pretty nasty looking.

I plan on permanently slipping the boat next season and will be having barrier coated and bottom painted before that happens, but what's the best way to clean the staining off the hull right now. Is there a hull cleaner that works better than others that you folks would recommend?

Thanks

Tim Bromund