COLREG / ARPA / AIS Bridge
Rule 27(a)
Rule 27(b)
🔒 Course / Premium
Rule 27 — NUC / RAM Lights
NIGHT. You observe a vessel showing at her masthead THREE all-round lights in a vertical line: RED WHITE RED.
This scenario is part of the full library.
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Scenario briefing
NIGHT. You observe a vessel showing at her masthead THREE all-round lights in a vertical line: RED WHITE RED. She is making way through the water and also shows sidelights and a sternlight. What is she?
Applicable COLREG rule(s)
Rule 27(a) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.
Rule 27(b) — 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.
Both run in any modern browser, on desktop or mobile. No install, no plugins.