Question 1

Annex III of the COLREGS covers technical details of sound signalling appliances. What frequency range does it specify for whistles on vessels of 20m and above?

Accepted Answer

70-700 Hz overall: 70-200 Hz for 200m and above; 130-350 Hz for 75m to under 200m; 250-700 Hz for under 75m.. ANNEX III SOUND SIGNAL FREQUENCIES: vessels of different lengths require whistles of different frequency ranges, lower frequencies carry further in fog, which is why large vessels use lower-pitched whistles. VESSELS 200m+: fundamental frequency 70-200 Hz. VESSELS 75-200m: 130-350 Hz. VESSELS under 75m: 250-700 Hz. The audible range of human hearing: ~20-20,000 Hz. The specified ranges ensure that: large vessels have low-pitched, long-range fog signals; small vessels have higher-pitched signals. Two or more fundamental frequencies may be used simultaneously. The stated frequency bands refer to the whistle's fundamental frequency.

Question 2

Per COLREGs Annex III, the fundamental frequency of a whistle on a vessel of 200m and above shall lie in the range:

Accepted Answer

70 to 200 Hz. Annex III/1(a): vessels 200m+ have whistle fundamental in range 70-200 Hz; 75-200m: 130-350 Hz; under 75m: 250-700 Hz.

Question 3

Annex III specifies whistle fundamental frequency by vessel length. Larger vessels are required to have:

Accepted Answer

Lower-pitched (lower frequency) whistles. Annex III, section 1(a): the fundamental frequency of the signal must lie within the range 70-700 Hz. Vessels 200m or more must use 70-200 Hz, 75 to less than 200m use 130-350 Hz, 20 to less than 75m use 250-525 Hz, and less than 20m use 250-700 Hz. Larger vessels carry deeper-pitched whistles, audible at greater range.

Annex III, questions and explanations

Annex III of the COLREGS covers technical details of sound signalling appliances. What frequency range does it specify for whistles on vessels of 20m and above?

Per COLREGs Annex III, the fundamental frequency of a whistle on a vessel of 200m and above shall lie in the range:

Annex III specifies whistle fundamental frequency by vessel length. Larger vessels are required to have:

Practise this properly

Annex III, questions and explanations

Questions

Annex III of the COLREGS covers technical details of sound signalling appliances. What frequency range does it specify for whistles on vessels of 20m and above?

Per COLREGs Annex III, the fundamental frequency of a whistle on a vessel of 200m and above shall lie in the range:

Annex III specifies whistle fundamental frequency by vessel length. Larger vessels are required to have:

Practise this properly