Vessel towing astern
Two masthead lights in a vertical line plus yellow towing light above the sternlight. Two white masthead lights in a vertical line and a yellow light above the sternlight: towing astern. Three in a line when the tow exceeds 200 m.
Drag across the scene to walk around the ship. Tap a light to see its name.
Lights (Rule 24)
| Light | Colour | Sector | Height above water |
|---|---|---|---|
| white masthead light (lower of the vertical pair) | white | masthead, 225° (from right ahead to 22.5° abaft the beam on each side) | 13.5 m |
| white masthead light (upper of the pair; three when the tow exceeds 200 m) | white | masthead, 225° (from right ahead to 22.5° abaft the beam on each side) | 15.5 m |
| green sidelight (starboard) | green | sidelight, starboard, 112.5° | 8.7 m |
| red sidelight (port) | red | sidelight, port, 112.5° | 8.7 m |
| white sternlight | white | stern, 135° (around the stern) | 3.5 m |
| yellow towing light above the sternlight | yellow | towing, 135° (around the stern) | 5.5 m |
Model: a 32 m vessel. Heights and positions follow COLREG Annex I (positioning of lights).
Day shapes
- diamond · diamond (when the tow exceeds 200 m)
Shapes are black and hoisted where they can best be seen: a ball at least 0.6 m in diameter, vertical spacing at least 1.5 m (Annex I, section 6). Set the trainer above to day to see them.
Fog signal
One prolonged and two short blasts (Rule 35c). A manned tow answers: one prolonged and three short (Rule 35e).
A short blast lasts about 1 second, a prolonged blast 4 to 6 seconds (Rule 32). The play button is in the trainer above.
What to watch for
The yellow towing light (same arc as a sternlight) sits above the white sternlight. The towed object itself shows only sidelights and a sternlight.
With a tow over 200 m: add a diamond by day and a third masthead light in the line.
Quick answers
What lights does a vessel towing astern show at night?
Two masthead lights in a vertical line plus yellow towing light above the sternlight. In full: white masthead light (lower of the vertical pair); white masthead light (upper of the pair; three when the tow exceeds 200 m); green sidelight (starboard); red sidelight (port); white sternlight; yellow towing light above the sternlight.
What day shapes does a vessel towing astern show?
By day she shows: diamond (when the tow exceeds 200 m).
What is the fog signal of a vessel towing astern?
One prolonged and two short blasts (Rule 35c). A manned tow answers: one prolonged and three short (Rule 35e).