This inquiry has been cross-posted to rec.boats.cruising;
rec.boats.building; and rec.boats.electronics since it seems to cover
all three areas and I am hoping to tap the widest range of experts.
If you have responded to one thread, no need to respond in the other
news groups (though, of course, you are welcome to do so).

I recently read an article in Practical Sailor about navigation
lights. It reminded me about the red over green masthead light that
is optional for sailboats. I have never seen this option used but
have wondered if it actually might be a good idea to explore.

When I am sailing or motoring at night, I enjoy trying to identify the
types of vessels engaged in various activities from the navigation
lights that are displayed. Currently I have been boating in the
eastern North Carolina area. The green over white lights of the
fishing trawlers are pretty common and also quite useful to warn you
to stay clear of their operations.

As you know, for sailboats under sails alone the regulations call for
(with regard to my 43 foot cutter/ketch) a combination port/starboard
light at the bow (or separate sidelights) and a stern light or a
tri-colored light at the peak of the mast. In other words the
configuration for power boats but without the white masthead light
showing forward. From my experience the lack of a masthead light is a
distinction that is rather subtle and could be overlooked in traffic
or poor visibility. This has led me to reconsider the value of the
red over green mast light that is an option for sailboats under sail
alone. It is so distinct that even the most casual observer would
immediately recognize that the vessel was a sailboat.

First questions are whether you have ever seen the optional red over
green lights used? Was it as distinctive as I assume that it would
be? What size vessel did you see it on? What is your opinion about
the usefulness of this option?

The second set of questions have more to do with the electronics and
building news groups. I seem to remember reading somewhere that
lights in a vertical stack should (or have to) be separated by one
meter. Since the red over green lights would be entirely optional,
you probably could get away with less separation but there probably is
a minimum separation to keep the lights from appearing to merge when
sighted at a distance. Anybody have any opinion on what the minimum
distance would have to be so that the lights would appear as separate
lights at say 2 nautical miles? The distance apart also complicates
the installation. One idea I had was to hoist two lanterns up to a
block on an upper spreader. The lanterns could be powered by their
own batteries or I could run wires down to an outlet on the deck.
What do you think of this possible arrangement? It would not be at
the peak of the mast and would be blocked from vision from one side of
the boat at times by the mast. But, it would have the advantage of
being removable and repairable easily. Such an arrangement could also
be used for displaying red over red or red/white/red when those
signals might be necessary.

Since I already have a tri-color light at the peak of my mainmast, any
permanent extension above the peak would interfere with the visibility
of the tri-color (and its anchor light) when I chose to use it. Since
I have a mizzen mast, I have considered building an extension for the
peak of that mast. The added advantage of this arrangement is that it
would not increase the overall height of my rig for purposes of
vertical clearance. But even with some kind of extension, how do I
keep the pole or extension itself from blocking the light from certain
angles? Well, experts, what do you think of all this? Of course,
would be a lot of work to design and install such an arrangement. But
if it kept me from getting run down just once, it would be well worth
the effort. Or, on the other hand, have I just lost my mind? :-)

Thanks in advance for your advice and help.

Lee Huddleston
s/v Truelove
Bruce Roberts Mauritius 43
43 foot seel hulled, center cockpit, raised poop, cutter/ketch