On the cable, usually at the engine end, maybe a couple feet from the nut, is stamped the number of the cable and the length. If you don't see it there, sometimes they put it at the other end. Any marina should be able to get it for you or order it online
Thanks so much for the reply. After digging and digging on the web I actually came across some Sea Ray documentation that indicated the proper length is 15’. I’m alway from home and couldn’t physically check the boat but I wanted to get it ordered up with the season fast approaching. Thanks again. Rob