i'll chime in with everyone else, its what you need for 12v, but you can buy 2 interstate or deka for 1 optima, so, for 24v a set of good trolling batteries will do...

sure is nice to be able to beat that optima around and take it back for up to 2 years, though i have taken one back before, i got a free replacement and the 2 year guarantee was renewed

the blue top optima is your best bet if you are definitly leaving it in your boat(12v), but if it is going to be a multi purpose, i would get a yellow top... i have used my yellow top in my boat, truck, racecar, and tractor... no doubt the most versitile battery out there