Tad - You are 100% correct. You pass the test with an A++.
Now that we have determined you know what you are talking about please explain to us very young men and women who don't know their way, exactly how one hoists a light to the masthead. My halyards don't go that high. :unsure:
It would seem to me that the Colregs would have written "masthead" if that is what the meant. Since they didn't it must mean "where it can best be seen" for the existing situation. No one will argue over the degree or two that is blocked by the mast.
If you hoist a light above the furled mainsail and away from the mast you have what has been used by sailors for hundreds of years. That's good enough for me.
Gotta love a bit of sarcasm
Personally I think the top of the mast is a stupid place for an anchor light, way to high for my taste. I usually hang an LED from my boom at night also.
And Tom, let me guess, you use a whale oil lantern for this purpose?