The number of lights a vessel carries and the way in which these lights are displayed allows you to identify a vessel at night. They can also be used to indicate the activities the vessel is engaged in.
silhouette |
type of vessel |
 |
Power driven vessel under 50m |
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Sailing vessel (not under power). More common to use a tri-colour. |
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Vessel at anchor- 50m or above |
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Vessel Pushing ahead |
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Vessel pushing ahead (stern view) |
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Vessel constrained by draft- under 50m |
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Towing astern- tow less than 200m |
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Fishing vessel- under 50m |
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Vessel restricted in ability to manoeuvre.Not making way. |
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Vessel towing astern- tow less than 200m.Restricted in ability to manoeuvre. |
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Vessel not under command, not making way |
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Pilot Vessel |
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Submarine- making way |
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Hover craft (minimum displacement) |
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Vessel engaged in trawl fishing |
It can be seen from above that some vessels will look very similar even though they may be doing completely different things. Also, how do you tell if a vessel is underway, at anchor, or restricted in some way?
Looking more closely at the masthead and stern lights will give you a clue:
masthead lights
light sequence |
meaning |
ditty |
 |
Vessel not under command. (e.g. engine or steering failure) | Red over Red. This boat is dead |
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Indicates a sailing boat. [not commonly used] | Red over Green. Sailing machine |
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A Fishing Boat | Red over White. Fishing tonight |
 |
A Trawler | Green over White. Trawling tonight |
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A tug with a tow under 200m | White over White. A short tow in sight |
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A tug with a tow over 200m | White over White Over White. A long tow in sight |
 |
A vessel constrained by her draft | Red over Red over Red. Rudder rubbing rocks |
 |
A pilot boat | White over Red. Pilot ahead |
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A vessel restricted in its ability to manoeuvre. (e.g. survey vessels, dredgers, dive boats, tugs, aircraft carriers). | Red over White over Red. Red when restricted |
 |
Minimum displacement |
stern lights
light sequence |
meaning |
ditty |
 |
Stern lights of a tug pushing a barge. | Yellow over Yellow. A pushy inland fellow |
 |
Stern lights of a tug towing astern. | Yellow over White. My towline is tight |
