COLREG / ARPA / AIS Bridge Rule 35(c) 🔒 Course / Premium

Rule 35(c) — NUC / RAM / Sailing / Fishing Fog Signal

FOG. You hear, at intervals of not more than 2 minutes, one prolonged blast followed by two short blasts: .

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Scenario briefing

FOG. You hear, at intervals of not more than 2 minutes, one prolonged blast followed by two short blasts: . Under Rule 35(c), which of the following vessels might this be?

Applicable COLREG rule(s)

Rule 35(c) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

Key teaching points

Rule 35(c): a vessel NUC, RAM, CBD, fishing, sailing or towing/pushing sounds ONE prolonged + TWO short blasts at ≤2-minute intervals.
Same signal whether making way or stopped — the priority of these vessel types is built into the COLREG identification.
A vessel being towed (if manned) sounds ONE prolonged + THREE short blasts (Rule 35(e)).
A vessel at anchor in fog (length ≥100 m) sounds bell forward + gong aft every ≤1 minute (Rule 35(g) modified).

Common mistakes to avoid

Treating Rule 35(c) as fishing-only — it covers NUC, RAM, CBD, fishing, sailing and towing collectively.
Forgetting that the towed vessel (if manned) has its own distinctive signal under 35(e).

Why it matters

A vessel not under command in fog has a distinct sound signal — three blasts in sequence — that signals her inability to manoeuvre. The signal exists so that nearby vessels know to give wide berth, exactly as in clear visibility her red-red lights would convey.

Exam relevance

Rule 35(c) and (e) sound-signal distinctions are an STCW OOW oral classic — candidates must distinguish which signal applies to which vessel category.

Related scenarios

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