Equipment for sound signals
In plain language
A vessel of 12 m or more shall carry a whistle; of 20 m or more, a whistle and a bell; of 100 m or more, a gong in addition. A vessel of less than 12 m must carry some other efficient means of making a sound signal.
Full text of Rule 33
A vessel of 12 metres or more in length shall be provided with a whistle, a vessel of 20 metres or more in length shall be provided with a bell in addition to a whistle, and a vessel of 100 metres or more in length shall, in addition, be provided with a gong, the tone and sound of which cannot be confused with that of the bell. The whistle, bell and gong shall comply with the specifications in Annex III to these Regulations. The bell or gong or both may be replaced by other equipment having the same respective sound characteristics, provided that manual sounding of the prescribed signals shall always be possible.
A vessel of less than 12 metres in length shall not be obliged to carry the sound signalling appliances prescribed in paragraph (a) of this Rule but if she does not, she shall be provided with some other means of making an efficient sound signal.
Reproduced from the COLREGs 1972 (as amended) for study. Always verify against the official IMO publication.
Key points
- 1
12 m and over — whistle.
- 2
20 m and over — whistle and bell.
- 3
100 m and over — whistle, bell and gong.
- 4
Under 12 m — some other efficient sound signalling means.