Seaman's Handbook

PART C. Lights and Shapes : Anchored vessels and vessels aground

(a) A vessel at anchor shall exhibit where it can best be seen:
  1. in the fore part, an all-round white light or one ball;
  2. At or near the stern and at a lower level that the light prescribed in paragraph (I), an all-round white light.
(b) A vessel of less than 50 metres 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.(c) A vessel at anchor may, and a vessel of 100 metres and more in length shall, also use the available working or equivalent lights to illuminate her decks.(d) A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, where they can best be seen:
  1. two all-round red lights in a vertical line;
  2. three balls in a vertical line.
    1. (e) A vessel of less than 7 metres in length, when at anchor, not in or near a narrow channel, fairway or 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 metres in length, when aground, shall not be required to exhibit the lights or shapes prescribed in sub-paragraphs (d) (i) and (ii) of this Rule.