"Joe" wrote
Here are a few running lights I've seen in the past.

(1). While entering Galveston bay from the Gulf of Mexico late one
night I thought I was seeing things! After the jetties and close to
Point Bolivar I saw a strange arrangement of running lights. The boat
was coming straight towards us and I could see the standard running
lights. The strange thing was the Blue over White lights on the mast.
What did I meet head on? And what side should I pass on.

Good question Joe. Is this an area of naval operations?

Naval vessels in convoy duty may display, during such activity, a
blue light located near the stern, with the same characteristics as,
but in lieu of the normal white stern light. However, this doesn't
match your description of a vessel approaching you.

Naval vessels may display, as a means of outlining the contour of the
delivery ship during night time underway replenishment operations, red
or blue lights at deck edge extremities. These lights are all being
switched
blue. But what is the point of doing replenishment operation close to
shore unless it is too large to dock? Again your description indicates
a light on a mast not contour lights.

My next thought was that this was a trick question and in fact the light
was on land in line with the vessel. In any case, I did a search on the
"Light List" for Galveston Bay and Blue Light and found nothing.

In another post you mention it is an International rule, while
clearly you are located in inland waters. That reinforces the fact
that it is. It is all very confusing as I know of no rule for a solid blue
light, only a flashing blue for law enforcement.

I'll take a wild guess and say it is a widebodied vessel and the purpose
of the blue light is to draw attention to a special situation like this.


(2). In the Straits of Gibralter I meet another boat at night. This
time I could also tell it was coming strait at us. You could see the
standard runnings lights, but on the mast and forearms there was a
triangle of green lights over a white light. What did I meet head-on
and what side can I pass by close-by?

Pretty easy one--Minesweeper engaged in minesweeping operations.
If this is an excercise, and there are no mines, there are still things in
the water you don't want to hit--vanes and cable. Which side to pass
cannot be determined from this information. Close by would not be a
good idea. In most passing situations, I'd "give you one blast, passing
port-to-port, but the smart thing to do is give a call on the radio and
ask for advice, or else turn around.