What is it? Black streaks, sometimes just a nasty dark gray color all over the boat. I have heard all manner of opinion on what it is. I had one conversation that stated it was mold. In another, the substance was pollution. I have even heard that its what’s left over form the teflon based cleaner that I used once before. I don’t know what it is. But I know if it dries on the hull it is extremely hard to remove.
This past weekend I decided to get the grey off of my boat with a power washer. I used your standard 6.5 hp Briggs & Stratton based pressure washer from my favorite big box store. A word of caution for those that haven’t used one yet. Do not use the high pressure setting on wood, ropes/lines or cloth. It will remove software wood between the grain, cut covers and strands of those lines and eliminate the cloth it touches. Be careful, work slowly and be careful. I power washed a the top of the cabin trunk and worked my way down to the hull. The stuff did not come off easily but it mostly came off. The only difficulty I had was cleaning the stuff off the molded in non-skip and my cockpit sole painted with Kiwi Grip. Owners that have used kiwi grip will be happy to know that the highest setting on the pressure washer did not damage the non-skid surface provided by kiwi grip. Its tough.
But so is the grey stuff. Neither non-skid types came completely clean (the decks mostly did). Some of the patterns have deep groves that the pressure washer could not touch or the microbes in those spaces had enough grip to thwart them. I used a mild solution of white vinegar and water, which did not work. Then I used Clorox and water. That worked.
The question now becomes how to keep this from happening. I read online (Sailnet), that if I wipe the boat down each morning before the dew dries its not a problem. Well, I don’t live on my boat and don’t see it each day, so that is not an option and I suspect its not an option for the vast majority of boat owners. So what else is out there to take care of this problem? I think I will try rewaxing the hull, then:
- collinate boat cleaner
- a gutter at the rub rail
Any thoughts? Let me know.