I'm sure this question has been asked before...but...<br /><br />I have insane growth on the bottom of my boat and on the engine (I/O). It's only been kept in the water since June, but the bottom of the boat is not painted. I've used a product called "In and Out" to get all the growth and stains off the sides of my boat, but I'm having a tougher time with the bottom. Any suggestions? I've heard that it's not good to use acid based cleaners on boat bottoms that are not painted. HELP!