Marine growth....how do you clean this stuff?

[Manipulator]

I have some funk growing on the bottom of my boat. This is some fresh water crude. Last year I left my boat in the water for six months and it grew some crude on the hull but nothing like this and this stuff was a half inch of nasty filth that grew in two weeks! Maybe there is a lot of stuff in the lake this year. It is a black funk. My boat would hardly go and they looked at it and it was from this gunk on the hull. They power washed it but some of it is still attached. It looks like black spider webs all over the bottom. <br /><br />I need to pull the boat out and somehow get this stuff to loosen so I can blast it off. Any suggestions? Bleach and water (heard this is not a good idea), how about straight lemon juice? I read somewhere that helps. Marina said to buy "lime away" and spray it on there and let it sit and then blast it off. Called it an acid wash which they don't do at this specific marina. I wouldn't imagine that is good for the gel coat.

 

[CATransplant]

Re: Marine growth....how do you clean this stuff?

The lime away shouldn't harm your boat, if it's fiberglas. Sounds like yucky stuff that's growing there.