Rule 30: Anchored vessels and vessels aground

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 than the light prescribed in sub-paragraph (i), an all-round white light.
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.
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.
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.
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.
A vessel of less than 12 metres in length, when aground, shall not be required to exhibit the lights or shapesprescribed in sub-paragraphs (d) (i) and (ii) of this Rule.