Our 310 Catalina was functioning fine. (Bought her last year, a 2005). We took it out for a sail a few weeks ago. She started fine, we shut her down and sailed. The batteries are brand new. The vessel is set up with two house batteries and a separate starter battery. All batteries are showing full charge. When we went to restart her up for the ride home, there was nothing. Luckily, we were very close to home and had just enough wind to guide her to port. We have checked the breakers, all good. We have power from the house batteries to run radio, lights, etc. The boat still won't start. The helm panel is showing no juice. We checked the starter on the port side under the engine and the connections are all firm. We have tried all configurations of using the battery switches. Could this be a fuse or the iginition switch itself? We don't know location of fuses. HELP!