Ex-Calif, your rotary switch design will do the job.
David, In this application an appropriate diode should last just about forever. The only threat would be lightning
, and I suppose that's a reasonable thing to worry about. Of course, the OP is using LED nav lights, and these are probably vulnerable as well. OK, a short at the light fixture, or a failed bulb could also stress the diode. Perhaps your worry isn't so far-fetched...
I personally prefer the lights to be on four separate switches (I've got circuit breakers): Tricolor, Anchor
, Steaming, Deck-level Running. It just seems simpler, and I can light up my boat like a Christmas
tree if I want to -- those five plus the spreader lights.
However, my new LED tricolor will switch between tri and anchor
, depending on how I connect the pair of power leads: +/- = tri, -/+ = anchor. I had to build a little relay board to interface it to my existing breakers.
Finally, LED running lights can have a huge impact on your energy budget
. If you don't have them, you might want to run the numbers.