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Rule 30: Anchored vessels and vessels aground
Anchored and aground vessels must display unmistakable status signals, with limited small-vessel exemptions.
Detailed Explanation
(a) At anchor: (i) fore all-round white or one ball by day; (ii) at/near stern, lower level, second all-round white.
(b) Vessel <50 m may show one all-round white instead of two anchor lights.
(c) Anchored vessel may, and vessel ≥100 m shall, use working/equivalent lights to illuminate decks.
(d) Aground vessel shows anchor signals plus: (i) two all-round red vertical; (ii) three balls vertical.
(e) Vessel <7 m at anchor outside narrow channels/fairways/anchorages/normal traffic areas may be exempt from anchor light/shape.
(f) Vessel <12 m aground may be exempt from red-red and three-ball aground additions.
Key Points
- Anchored: all-round white forward + lower aft (≥50m: both)
- Aground: anchor lights + two red all-round + 3 balls by day
- <12m anchored: not required if not in/near narrow channel
- ≥100m: deck lights to illuminate outline
Examples
- At night you see a vessel showing two all-round white lights in a vertical line — fore and aft — at anchor. Per Rule 30(a), a vessel 50 m or over at anchor shows a white light in the fore part and a second lower one near the stern.
- You approach a vessel displaying anchor lights plus two all-round red lights vertically and three black balls by day. Per Rule 30(d), this vessel is aground — you give her a wide berth.
- A vessel under 50 m at anchor displays a single all-round white light where it can best be seen. Rule 30(b) permits this simplified arrangement for smaller anchored vessels.
Common Mistakes
- Forgetting to show the additional two red lights and three balls when a vessel is aground, not just anchor signals.
- Not displaying anchor lights on a vessel of 100 metres or more in length, which must illuminate its decks.
- Assuming a vessel under 50 metres at anchor can omit the black ball by day.