1. Whistles (a) Frequencies and range audibility The fundamental frequency of the signal shall lie within the range 70-700Hz. The range of audibility of the signal from a whistle shall be determined by those frequencies, which may include the fundamental and/or one or more higher frequencies, which lie within the range 180-700Hz (+/-1%) for a vessel of 20 meters or more in length, or 180-2100Hz (+/-1%) for a vessel of less than 20 meters in length and which provide the sound pressure levels specified in paragraph 1(c) below.The range of audibility of the signal from a whistle shall be … [Read more...]
Rule 33 – Equipment for sound signals
Rule 33 : Equipment for sound signals a. A vessel of 12 m or more in length shall be provided with a whistle and a bell and a vessel of 100 m 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 of 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.b. A vessel of less than 12 m … [Read more...]