Navigation Lights

[pbryant]

The vertical separation requirement is in Annex I:

§ 84.03 Vertical positioning and spacing of lights
(...)
(i) When the Rules prescribe two or three lights to be carried in a vertical
line, they shall be spaced as follows:
(1) On a vessel of 20 meters in length or more such lights shall be
spaced not less than 1 meter apart, and the lowest of these lights
shall, except where a towing light is required, be placed at a height
of not less than 4 meters above the hull;
(2) On a vessel of less than 20 meters in length such lights shall be
spaced not less than 1 meter apart and the lowest of these lights
shall, except where a towing light is required, be placed at a height
of not less than 2 meters above the gunwale;

Rule 3 defines....

(i) The word “underway” means that a vessel is not at anchor, or made fast
to the shore, or aground.

A vessel not underway should display:

1) When anchored an anchor light.
2) When aground, two red lights in a vertical line (the same as "not under command"). We were taught: "Red over red -- this boat is dead."

That's Rule 30, and there is no distinction between power driven or sailing vessels since - if the vessel isn't moving - its usual method of propulsion is irrelevant -- it's not being propelled by anything.

There are some exemptions to the requirement for anchor lights on small vessels.