Hey fellas I need some input on getting a bad waterline mark out of a boat hull. The boat has been in a slip for six months. I took it to the car wash and that got all of the algae off but its like the fiberglass is stained. I'm afraid I may have to get it off with a buffer and buffing compound or wrap the boat. Any ideas?

Go buy cheap toilet bowl cleaner at the Dollar Store. It did a great job on my white Nitro. It wasn't in a slip but stained a little.

This is the best I have ever used.

http://www.academy.com/shop/pdp/star-brite-32-oz-hull-cleaner#repChildCatid=14066

Be sure to wear gloves and then wash it off your driveway.

This stuff works! But...as soon as it's clean, rinse it really well and apply a wax.

This!

I'll give it a try.

If you have an aluminum trailer cover it with a tarp or something. This stuff will leave some oxidize it badly then you'll be buffing it out as well. Ask me how I know...

Another vote toilet bowl cleaner like Sno Bowl. Works great and inexpensive.

I have to go with the toilet bowl cleaner also.

Kaboom

For small spots the magic eraser works pretty well.

Well it�s the whole bottom of the boat where it was sitting in the lake. Will the hull cleaner or toilet bowl cleaner hurt the carpet on the bunks?

+1 for Magic Eraser

I did the Star Brite hull cleaner like others have suggested at the car wash. Spray it on, let it soak then use the foam brush, then rinse. It worked great on my white hull and did not affect the carpet on the trailer. I have an painted trailer and it was not affected by it either but I did rinse everything off after using the foam brush to scrub the bottom. If it does not come off the first time do it a second time. It works very well.

I have never tried the toilet bowl cleaner.

Liquid Vanish is the only thing that I have found that will take cypress sap off down here at the lake, If that don't work you may haft to wet sand it.