I think I've decided to go home and drain the water out of the boat. Scratch the antifreeze. I've also ordered one of these.... http://www.boatownersworld.com/xtrem...emeheaters.htm
.... just so that if I do wanna go put the boat in the water during the day in the early season I don't have to worry if it gets below freezing during the night. Thanks for the advice all!!