Signals to Attract Attention
If necessary to attract attention, a vessel may make light or sound signals that cannot be mistaken for any prescribed signal.
Rule 36 allows any vessel to make light or sound signals to attract the attention of another vessel, provided such signals cannot be mistaken for any signal authorized elsewhere in these Rules, or for any aid to navigation.
Signal Workflow
Decide the context first: manoeuvring in sight, restricted visibility, or distress. The same whistle can mean very different things in a different context.
Check both the pattern and the interval. For fog signals, the time spacing is part of the rule, not just the blast sequence.
When in doubt about another vessel's intentions, use the prescribed warning signal early rather than waiting for the situation to deteriorate.
Exam Focus
Three short blasts are astern propulsion, not a fog signal.
In restricted visibility, think 'every two minutes' for underway signals and 'every one minute' for anchor bell signals.
Key Takeaways
Any signal may be used to attract attention
Must not be mistakable for a prescribed signal or navigation aid
Searchlights may be directed towards a danger
Common Mistakes
Using signals that could be confused with distress signals
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