Fall Boat cleaning

[gb1234]

I don't know about seagull poop but my dad's fiberglass boat stays in the water all summer and gets a hard, scaley coating that won't come off with any amount of cleaner or elbow grease - except MARYKATE
On and Off Hull/Bottom Cleaner. We've tried other hull cleaners but this one has multiple acids in it and works great. Might also tackle seagull poop?

[Swartztastic]

Thanks for the comments Ole and gb. I’ll do some digging and report back.