Rule 24 · USCG Navigation Rules
Pushing ahead or towing alongside
Two masthead lights in a vertical line with sidelights and a sternlight — Inland swaps the sternlight for two yellow towing lights.
Viewpoint
Display
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From the port bow you see:
- white — Masthead light (upper of two)
- white — Masthead light (lower of two)
- red — Port sidelight
→ Pushing ahead or towing alongside — Pushing ahead / towing alongside (International), seen from the port bow.
US Inland difference
Inland Rule 24: when pushing ahead or towing alongside she shows TWO YELLOW TOWING LIGHTS in a vertical line at the stern INSTEAD of the sternlight. On the Western Rivers (except below the Huey P. Long Bridge) she shows only sidelights and the two towing lights — no masthead lights.
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Memory aid
“Pushing looks like a short tow up the mast — but no yellow light (International). Inland: TWO yellows aft.”
What it means
Pushing ahead / towing alongside (International)
No yellow towing light internationally — that belongs to towing ASTERN. A pusher rigidly connected to its barge is a composite unit and is lit as one ordinary power-driven vessel (Rule 24(b)).
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) | 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 |
2D profile
Labelled side view — works without WebGL and in print. Variant shown: Pushing ahead / towing alongside (International).
In fog, she sounds
Don’t confuse with…
Official source
Rule 24, reproduced from the public-domain COLREGs Rule 24(c) — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.