Probably one of your best choices would be the Trojan SCS225 battery. While it is listed as a deep cycle and Trojan doesn't label any of their current models "start batteries", it is designed to be a dual purpose battery. I learned this after a friend called Trojan before purchasing 2 of these to parallel for a house bank - he's very pleased and they do the job well. An ideal battery for a small powerboat that needs both start capability and house capability but not enough to justify multiple banks. This was apparently the use it was designed for.