Part D — Sound and light signals. Manoeuvring signals, fog signals and distress signals.

(a)The word "whistle" means any sound signalling appliance capable of producing the prescribed blasts and which complies with the specifications in Annex III to these Regulations.

(b)The term "short blast" means a blast of about one second’s duration.

(c)The term "prolonged blast" means a blast of from four to six seconds’ duration.

sounddefinitionsblast

Reference only. Always navigate using the current official publication of the regulations and any local rules that apply.