Paragraph (a): At anchor
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 lower than the forward light, an all-round white light.
COLREGs trainerPart C: Lights and Shapes
Rule 30
Anchored Vessels and Vessels Aground
Anchored: all-round white(s); aground: anchor lights + two reds.
Wording follows the International Regulations as printed in the US Coast Guard Navigation Rules handbook (2024), with British spelling, and is shortened in places. Download the rules
Read the whole of Rule 30 on one page
Paragraph (a): At anchor
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 lower than the forward light, an all-round white light.
Paragraph (b): At anchor, under 50 m
A vessel of less than 50 m in length may exhibit a single all-round white light where it can best be seen, instead of the two lights in paragraph (a).
Paragraph (c): Illuminating the decks
A vessel at anchor may, and a vessel of 100 m or more shall, also use available working or equivalent lights to illuminate her decks.
Paragraph (d): Aground
A vessel aground shall exhibit the anchor lights of paragraph (a) or (b) and, in addition, where they can best be seen: (i) two all-round red lights in a vertical line; (ii) three balls in a vertical line.
Paragraph (e): Small vessels at anchor
A vessel of less than 7 m in length, when at anchor not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate, is not required to exhibit the anchor light(s) or ball of paragraphs (a) and (b).
Paragraph (f): Small vessels aground
A vessel of less than 12 m in length, when aground, is not required to exhibit the two red lights or three balls of paragraph (d)(i) and (ii).
A training aid, not the official text. The COLREGs are an IMO convention, and your national authority publishes the version that applies in its waters. Check the rules themselves before you rely on them at sea. Download the rules.