Rule 24 · USCG Navigation Rules
Vessel towing astern (tow 200 m or less)
Two masthead lights in a vertical line, sidelights, sternlight — and a yellow towing light above the sternlight.
Viewpoint
Display
Drag to orbit freely, scroll or pinch to zoom — or use the viewpoint buttons above (keyboard friendly).
From the port bow you see:
- white — Masthead light (upper of two = tow ≤ 200 m)
- white — Masthead light (lower of two)
- red — Port sidelight
→ Vessel towing astern (tow 200 m or less) — Tow ≤ 200 m, seen from the port bow.
Memory aid
“Two whites up the mast + yellow over white at the stern = short tow astern (200 m or less).”
What it means
Tow ≤ 200 m
Tow length is measured from the STERN of the tug to the AFTER END of the tow. A towing vessel of 50 m or more must also carry the normal second (after, higher) masthead light.
Day shapes
No special day shape — by day this vessel is recognised by sight, not by shapes.
Light details
| Light | Colour | Arc | Position |
|---|---|---|---|
| Masthead light (upper of two = tow ≤ 200 m) | white | 225° forward | Mast, vertical line (top) |
| Masthead light (lower of two) | white | 225° forward | Mast, vertical line (2nd from top) |
| Port sidelight | red | 112.5° to port | Port side, deck level |
| Starboard sidelight | green | 112.5° to starboard | Starboard side, deck level |
| Sternlight | white | 135° aft | Stern |
| Yellow towing light, above the sternlight | yellow | 135° aft | Aft, raised above the stern |
2D profile
Labelled side view — works without WebGL and in print. Variant shown: Tow ≤ 200 m.
In fog, she sounds
Don’t confuse with…
Official source
Rule 24, reproduced from the public-domain COLREGs Rule 24(a) — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.