I put a 10" sub with just a standard box up in the bow of my boat with the amp screwed to the back of the box. I stuffed it right in front of the little foot rest thing in the drivers foot area with the sub facing towards the front of the boat. I still have plent of storage in the bow, and the way the sub sits in there makes the whole bow act as a giant box that sends all the bass right out at the open area by my feet when I'm driving. It works well.
I have some pictures in this thread: