IALACOLREG
27

Vessels Not Under Command or Restricted in Ability to Manoeuvre

Not under command — two red all-round; two balls by day.

Rule 27 prescribes lights for NUC and RAM vessels.

a
A vessel not under command shall exhibit: two all-round red lights in a vertical line where they can best be seen; sidelights and sternlight when making way.
b
A vessel restricted in her ability to manoeuvre shall exhibit: three all-round lights in a vertical line — the highest and lowest being red and the middle one being white (red-white-red); masthead lights, sidelights and sternlight when making way.

Day shapes: NUC shows two balls in a vertical line. RAM shows ball-diamond-ball in a vertical line.

d
A vessel engaged in dredging or underwater operations when restricted in ability to manoeuvre shall additionally show two red all-round lights or two balls on the obstructed side, and two green all-round lights or two diamonds on the side available for passing.

Aqui é mostrada uma ilustração 3D interativa. O mesmo conteúdo é descrito no texto da regra e nos pontos-chave abaixo.

Recognition Sequence

Classify the vessel state first: underway, making way, stopped, at anchor, aground, towing, fishing, pilotage or special condition.

Read special lights vertically from top to bottom before using sidelights and sternlight to confirm aspect.

Then confirm the answer with the day shape, vessel length and any extra signal such as towing lights, deck illumination or a cylinder.

Exam Focus

Avoid identifying a vessel from one colour alone.

Many mistakes come from spotting a red light and guessing before checking the full pattern.

If the question mentions 'making way', 'underway but stopped', 'at anchor' or 'aground', that wording usually determines which extra lights or shapes appear.

Pontos-chave

1

NUC: two red all-round lights vertically (day: two balls)

2

RAM: red-white-red all-round lights (day: ball-diamond-ball)

3

Dredging vessels show red on obstructed side, green on clear side

4

Sidelights/sternlight only when making way

Erros comuns

Confusing NUC lights (red-red) with RAM lights (red-white-red)

Forgetting that NUC and RAM only show sidelights when making way

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