COLREG / ARPA / AIS Bridge Rule 27(b)(i) Rule 27(b)(iii) 🔒 Course / Premium

Rule 27(b) — RAM NOT Making Way / At Anchor

NIGHT. A vessel shows three all-round lights in a vertical line where they can best be seen: RED-WHITE-RED.

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Scenario briefing

NIGHT. A vessel shows three all-round lights in a vertical line where they can best be seen: RED-WHITE-RED. She shows NO masthead light, NO sidelights, and NO sternlight. Anchor whites are also visible. What is her status?

Applicable COLREG rule(s)

Rule 27(b)(i) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

Rule 27(b)(iii) — referenced in this scenario. Practising this scenario reinforces correct application under realistic time pressure.

📸 Night recognition — 8 aspects

The same vessel rendered every 45° of aspect — bow, starboard bow, beam, quarter, stern, port quarter, beam, bow. Use this strip to learn how the lights present from each approach angle. Click any image to view full size.

Vessel restricted in ability to manoeuvre, at anchor viewed head-on (bow aspect) — COLREG Rule 27(b) night-recognition diagram — Bow

Vessel restricted in ability to manoeuvre, at anchor viewed from her starboard bow — COLREG Rule 27(b) night-recognition diagram — STBD bow

Vessel restricted in ability to manoeuvre, at anchor viewed from her starboard beam — COLREG Rule 27(b) night-recognition diagram — STBD beam

Vessel restricted in ability to manoeuvre, at anchor viewed from her starboard quarter — COLREG Rule 27(b) night-recognition diagram — STBD qtr

Vessel restricted in ability to manoeuvre, at anchor viewed dead astern (stern aspect) — COLREG Rule 27(b) night-recognition diagram — Stern

Vessel restricted in ability to manoeuvre, at anchor viewed from her port quarter — COLREG Rule 27(b) night-recognition diagram — Port qtr

Vessel restricted in ability to manoeuvre, at anchor viewed from her port beam — COLREG Rule 27(b) night-recognition diagram — Port beam

Vessel restricted in ability to manoeuvre, at anchor viewed from her port bow — COLREG Rule 27(b) night-recognition diagram — Port bow

Key teaching points

Rule 27(b): RAM = three all-round vertical lights RED OVER WHITE OVER RED, plus sidelights/sternlight if making way.
A RAM at anchor shows the Rule 27(b) lights AND the Rule 30 anchor lights (Rule 27(b)(iii)).
A diving operation (RAM) shows red-white-red PLUS a rigid replica of the international "A" flag (Rule 27(e)).
A cable-layer, dredger or vessel transferring stores at sea will indicate the safe side via additional pairs of red and green lights (Rule 27(d)).

Common mistakes to avoid

Reading the Rule 27(b) three-vertical pattern as a long-tow tug (also three vertical, but those are masthead lights, not all-round red-white-red).
Approaching the side of a dredger marked with red/red lights instead of the green/green safe side.

Why it matters

A RAM at anchor or stopped sometimes adds Rule 30 anchor lights on top of the Rule 27(b) RAM identifier — a busy three-vertical-plus-anchor pattern. Diving operations and cable-laying ships are typical examples and the lights tell you exactly what is going on below the surface.

Exam relevance

Stopped/anchored RAM and the Rule 27(d)/(e) special signals are an advanced topic in STCW OOW orals and a probing item in Yachtmaster Offshore.

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