Re: navigation lights why do this?
maybe the blinker fluid is low
Actually I kinda agree with what your PO was trying to do, in the stern. I think that in busy water the single white light is dangerously insufficient and there should be more light on the stern and, for many boats, for anchoring. the white light on a sailboat mast is truly worthless in an area with lots of lights.
however, the reason it is illegal to add lights is that the other lights send confusing messages to other boaters; the red/green plus white when use correctly tell the other boaters what is going on. Yours would tell other boaters that someone drove his car off the ramp.
Illlegal or not, I sometimes hang a blinking flashlight off the stern. In your case another plain white light back there (not a spot) would be helpful and not interfere with your night vision, and wouldn't cause problems.
The front light should be turned off unless you are within 20' of your own dock. Better to learn to drive without them.