COLREG / ARPA / AIS Bridge Rule 34(d) 🔒 Course / Premium

Rule 34(d) — Doubt / Disagreement Signal

POWER-DRIVEN vessels in sight of one another, when in DOUBT whether sufficient action is being taken by the other to avoid collision, shall indicate suc...

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This scenario is part of the full library. Unlock all 54 COLREG scenarios with the Skipper Refresher Course (€99.99, lifetime + certificate) or a Premium subscription (from €29.99/mo).

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Scenario briefing

POWER-DRIVEN vessels in sight of one another, when in DOUBT whether sufficient action is being taken by the other to avoid collision, shall indicate such doubt (Rule 34(d)). A crossing vessel on your starboard bow is not altering as required; you are uncertain of her intentions. What signal must you sound?

Applicable COLREG rule(s)

Rule 34(d) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

Why it matters

COLREG knowledge is the foundation of safe ship handling. Most maritime collisions happen because watchkeepers either misidentified the situation, applied the wrong rule, or acted too late. This scenario lets you train pattern recognition + correct response under time pressure — the exact skill the rules are designed to support. RYA, Yachtmaster, STCW and most national exams expect you to apply COLREGs reflexively, not just recite them.

Related scenarios

About SkipperCheck simulators

SkipperCheck offers two browser-based maritime training simulators:

ARPA · AIS · COLREG Bridge Simulator — 54 scenarios covering Rules 2, 5–10, 12–19, 23–30, 34 and 35.
VHF SRC Radio Simulator — 15 scenarios: voice Mayday, DSC distress, Mayday Relay, Pan-Pan, Sécurité, routine.

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