Some one on a automobile board mentioned these devices, which may be useful on a boat if you run out of switches: http://www.autoswitch.com/ It is installed in a existing switched circuit. When that circuit is switched on and off for roughly one second, the relay picks up. There is a second version that switches if you cycle power twice in the time interval. Thus one switch can control three circuits. steve Steve R. M-15 #119 Lexington, KY