Update on the portside bow navigation light- I hooked a volt meter to the wires, and it read 11.97 volts! :) So I changed the bulb (it was blackened, but the filament was intact). And the light still doesn't work, even with the new bulb... Very strange. The wires look good, the meter says it's got 12v, so I'm not sure what I'm missing here... I'm not very experienced with volt meters, but I know enough to read the display!
Did you check the voltage inside of the socket itself? Might try cleaning the inside of the socket.