Bats in the boathouse
 

I have a bat problem every year the weather starts getting warm. I have sealed up the smallest cracks and holes I can find, and they still get in and crap all over my boat cover and garage.. what can I do? I've tried rat poison, bugbombs etc...

Honestly, I would try building a few bat houses on the outside of your boathouse. Maybe if you can give them something to go to other than the boathouse, they'll go in there. That way you can keep the benefit of having the bats around (no bugs), but keep your boat and garage clean. I built one at my parents house as a kid and it worked great to keep the bugs down in our yard. They are super easy and you can find all kinds of different plans online.