Rule 34(a) — Whistle Manoeuvring Signals
POWER-DRIVEN vessels in sight of one another use whistle signals to indicate helm actions (Rule 34(a)): (1 short, 1s) = "I am altering my course to...
Scenario briefing
POWER-DRIVEN vessels in sight of one another use whistle signals to indicate helm actions (Rule 34(a)): (1 short, 1s) = "I am altering my course to STARBOARD"; (2 short) = "to PORT"; (3 short) = "operating ASTERN PROPULSION". You are altering course to PORT to avoid a crossing give-way situation. Which signal must you sound?
Applicable COLREG rule(s)
Key teaching points
- Rule 34(a)(i): one short blast = "I am altering my course to starboard".
- Rule 34(a)(ii): two short blasts = "I am altering my course to port".
- Rule 34(a)(iii): three short blasts = "I am operating astern propulsion".
- Rule 34(b): the signals may be supplemented by light signals (one/two/three flashes) of at least 5 seconds each.
Common mistakes to avoid
- Using two short blasts to mean "stop" — wrong. Two = port turn. There is no whistle signal for "stop".
- Skipping the signal because "we agreed on VHF". The whistle is the legally-required signal in the in-sight rules.
Why it matters
Exam relevance
Rule 34 manoeuvring signals are a recurring oral exam item in RYA Coastal/Yachtmaster and STCW OOW exams — candidates must produce the signal verbally and explain when it applies.
Related scenarios
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