33 CFR § 83.30 - Vessels anchored, aground and moored barges (Rule 30).
(a) A vessel at anchor shall exhibit where it can best be seen:
(i) In the fore part, an all-round white light or one ball;
(ii) At or near the stern and at a lower level than the light prescribed in paragraph (i) of this Rule, an all-round white light.
(b) A vessel of less than 50 meters in length may exhibit an all-round white light where it can best be seen instead of the lights prescribed in paragraph (a) of this Rule.
(d) A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, if practicable, where they can best be seen:
(i) Two all-round red lights in a vertical line; and
(ii) Three balls in a vertical line.
(e) A vessel of less than 7 meters in length, when at anchor, not in or near a narrow channel, fairway, anchorage, or where other vessels normally navigate, shall not be required to exhibit the lights or shape prescribed in paragraphs (a) and (b) of this Rule.
(f) A vessel of less than 12 meters in length when aground shall not be required to exhibit the lights or shapes prescribed in paragraphs (d)(i) and (ii) of this Rule.
(g) A vessel of less than 20 meters in length, when at anchor in a special anchorage area designated by the Coast Guard, shall not be required to exhibit the anchor lights and shapes required by this Rule.
(i) Every barge projecting into a buoyed or restricted channel.
(ii) Every barge so moored that it reduces the available navigable width of any channel to less than 80 meters.
(iv) Every barge not moored parallel to the bank or dock.
(i) Barges described in paragraph (h) of this Rule shall carry two unobstructed all-round white lights of an intensity to be visible for at least 1 nautical mile and meeting the technical requirements as prescribed in Annex I (33 CFR part 84).
(j) A barge or group of barges at anchor or made fast to one or more mooring buoys or other similar device, in lieu of the provisions of this Rule, may carry unobstructed all-round white lights of an intensity to be visible for at least 1 nautical mile that meet the requirements of Annex I (33 CFR part 84) and shall be arranged as follows:
(i) Any barge that projects from a group formation, shall be lighted on its outboard corners.
(k) The following are exempt from the requirements of this Rule:
(l) Barges moored in well-illuminated areas are exempt from the lighting requirements of this Rule. These areas are as follows: