Paragraph (b) of Rule 30 of both the International and Inland Rules of
the Road reads as follows
A vessel of less than 50 meters in length [at anchor] may exhibit an
_all-round_ white light _where it can best be seen_ instead of the
lights prescribed in paragraph (a) of this Rule [emphasis added].
An "all-round light" is defined elsewhere (Rule 21, paragraph (e)) as "a
light showing an unbroken light over an arc of the horizon of 360
degrees." To comply with the requirements of the Rules for vessels of
less than 12 meters in length, such lights must be visible for 2 miles
(Rule 22, paragraph (c)). NB Read "may exhibit" in the quoted paragraph
as "shall exhibit either an ... or the lights prescribed in paragraph
(a)...."
It would appear, therefore, that while not explicitly required, an
all-round white light fixed to the masthead would be the best way of
complying with the requirements of the Rules.
A "dysfunctional" light, wherever located, is of course no better than
no light at all. It is also unlikely that any light fixed to "the front
of the mast" would show "an unbroken light over an arc of ... 360
degrees," as required by the Rules.
This said, it is worth noting that paragraph (e) of Rule 30 exempts
vessels of less than 7 meters in length "when at anchor, not in or near
a narrow channel, fairway or anchorage, or where other vessels normally
navigate," from the requirements of paragraph (b) of that Rule. (A
further provision, found only in the Inland Rules, also exempts vessels
of less than 20 meters in length, "when at anchor in a special anchorage
area designated by the Secretary."
A further caveat: Vessels whose operations are confined to waters
located entirely within the boundaries of a state, not designated U.S.
navigable waters, are regulated by applicable _state_ navigation law.
The provisions of state law may not agree in all respects with those
contained in the International and Inland Rules.
Confused? For a definitive statement of the Rules, supplemented by much
helpful commentary, see _Handbook of the Nautical Rules of the Road_, 2d
ed., by Christopher B. Llana and George P. Wisneskey. For state
regulations, see the navigation provisions of the consolidated laws of
your state.
Forrest Brownell
South Colton NY
forrest@slic.com