I am currently putting the finishing touches on a 16' driftboat (no
engine) and ran across another driftboat this past weekend that had a
stereo system in it. He had a battery in it that appeared to about
half the size of a car battery to power the stereo. So now I want to
put a CD/MP3 player in my boat and a couple of speakers and was
wondering what size of battery I can use that would provide a minimum
of 6-8 hours of playback time.

Thanks.