How do I know Which battery for my boat to get?

Someone stole my boast battery. How do I replace the battery that some thief took out of my boat. Since now I don't have the old one to know what size to get. I have a two stroke 1999 60hp yamaha outboard. The boat is a 2000 17ft Carolina Skiff. Would appreciate some help. Thanks.|||You should get a 70 AMP Group 24 marine battery. They are made to handle both starting and normal boat electrical needs. Good luck!.