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.
type of vessel |
Power driven vessel under 50m |
Sailing vessel (not under power). More common to use a tri-colour. |
Vessel at anchor- 50m or above |
Vessel Pushing ahead |
Vessel pushing ahead (stern view) |
Vessel constrained by draft- under 50m |
Towing astern- tow less than 200m |
Fishing vessel- under 50m |
Vessel restricted in ability to manoeuvre.Not making way. |
Vessel towing astern- tow less than 200m.Restricted in ability to manoeuvre. |
Vessel not under command, not making way |
Pilot Vessel |
Submarine- making way |
Hover craft (minimum displacement) |
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
meaning |
ditty |
| Vessel not under command. (e.g. engine or steering failure) | Red over Red. This boat is dead |
| Indicates a sailing boat. [not commonly used] | Red over Green. Sailing machine |
| A Fishing Boat | Red over White. Fishing tonight |
| A Trawler | Green over White. Trawling tonight |
| A tug with a tow under 200m | White over White. A short tow in sight |
| 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 |
| 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
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 |
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