34
Manoeuvring and Warning Signals
One short blast = altering to starboard. Two short blasts = altering to port. Three short blasts = operating astern propulsion.
Rule 34 prescribes manoeuvring and warning signals for vessels in sight of one another.
a
When vessels are in sight of one another:
- One short blast: I am altering my course to starboard
- Two short blasts: I am altering my course to port
- Three short blasts: I am operating astern propulsion
b
Any vessel may supplement whistle signals with light signals: one flash = one short blast, two flashes = two short blasts, three flashes = three short blasts.
d
When vessels in sight of one another are approaching each other and either vessel fails to understand the intentions of the other, or is in doubt whether sufficient action is being taken, the vessel in doubt shall immediately indicate such doubt by giving at least five short and rapid blasts on the whistle.
Key Takeaways
1
1 short = starboard, 2 short = port, 3 short = astern propulsion
2
5 or more short rapid blasts = doubt/danger signal
3
Light signals can supplement whistle signals
4
These signals only apply when vessels are in sight of each other
Common Mistakes
Using manoeuvring signals in restricted visibility (these are for in-sight only)
Confusing three short blasts with fog signals
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