Rule 24 · USCG Navigation Rules
Vessel or object being towed
The tow shows only sidelights and a sternlight — plus a diamond by day when the tow exceeds 200 m.
Situation
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:
- red — Port sidelight
→ Vessel or object being towed — Tow ≤ 200 m, seen from the port bow.
Memory aid
“The tow lights up like a sailboat: sidelights and sternlight, nothing white up top.”
What it means
Tow ≤ 200 m
No masthead light, no all-rounds — from ahead a towed barge shows only red and green. The fog signal (one prolonged + three short) is sounded only if the tow is manned.
Tow > 200 m
Same lights, plus a diamond shape where it can best be seen by day.
Day shapes
Tow > 200 m
Diamond
A diamond where it can best be seen — tow length over 200 m.
Light details
Tow ≤ 200 m
| Light | Colour | Arc | Position |
|---|---|---|---|
| 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 |
Tow > 200 m
| Light | Colour | Arc | Position |
|---|---|---|---|
| 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 |
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(e) — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.