Sound and light signals

Counting blasts is insufficient for interpretation. Rule 34 concerns manoeuvring and warning under specified conditions, Rule 35 restricted visibility, and Rule 36 attention without confusion. Before counting, identify situation, vessel state, duration and sequence. The figure keeps contexts separate rather than providing audio for use at sea. Equal numbers of sounds can differ through duration and scope. A summary omitting those conditions teaches incomplete recognition. This chapter explains signals and preserves their regulatory identity without acting as an operational substitute for the complete provisions.

Rule 32 defines a short blast as about one second and a prolonged blast as four to six seconds. A whistle is equipment conforming to Annex III rather than any high-pitched noise. Rule 33 requires a whistle from 12 metres, adds a bell from 20 metres, and a gong of distinct sound from 100 metres. Below 12 metres, another efficient signalling means is required if prescribed appliances are not carried. The older “12 metres: bell” summary found on some pages should not be adopted as current normative wording; device conformity and use are separate questions.