One long, two short
Fog signal identification. Advanced level, about 2 min. COLREGs Rule 35(c).
The situation
Still in fog. A different signal comes from your port bow. Play it and decide what kind of vessel could be sounding it.
Which vessel could be sounding this signal?
- A vessel fishing, sailing, not under command, restricted, constrained or towing: One prolonged followed by two short blasts.
- A manned vessel being towed: One prolonged followed by three short blasts.
- “I intend to overtake you”: A manoeuvring signal in a narrow channel.
Lookout: This signal groups several vessel types with limited ability to keep clear. Treat its source with particular care.
The sound answer
A vessel fishing, sailing, not under command, restricted, constrained or towing
Rule 35(c): vessels not under command, restricted in their ability to manoeuvre, constrained by their draught, sailing, engaged in fishing, or towing or pushing sound one prolonged followed by two short blasts at intervals of not more than two minutes.
Why the other options fall short
A manned vessel being towed
A manned vessel being towed sounds one prolonged followed by three short blasts, immediately after the towing vessel’s signal. This signal had two short blasts.
“I intend to overtake you”
Overtaking signals in a narrow channel are for vessels in sight of one another, and begin with two prolonged blasts. In fog, vessels are not in sight and Rule 35 signals apply.
Rule 35(c) · Signals of vessels with limited manoeuvrability
In or near restricted visibility, a vessel not under command, restricted in her ability to manoeuvre, constrained by her draught, sailing, engaged in fishing, or towing or pushing sounds one prolonged followed by two short blasts at intervals of not more than two minutes.