The deep-cycle battery that starts the '95 Mercruiser 5.7L (GM) TBI EFI in my direct-drive inboard tournament tow boat has been sluggish of late and finally crapped out yesterday. I've always bought deep-cycle batteries, but then I read the diff between those and a marine starting battery. My ski boat that is constantly being stopped and restarted as we cut the engine every time we pick up a skier and restart to pull the next. Run time between these events is less than 10 minutes. So which battery? Or does it matter? Many thanks for your help, PW