Rule 25 · USCG Navigation Rules
Sailing vessel — optional red over green
Any sailing vessel may add two all-round lights at the masthead, red over green, to her sidelights and 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:
- All-round red (upper)
- All-round green (lower)
- red — Port sidelight
→ Sailing vessel — optional red over green — Under sail with optional all-rounds, seen from the port bow.
Memory aid
“Red over green — sailing machine.”
What it means
Under sail with optional all-rounds
The red-over-green pair may NOT be shown together with the tricolor lantern — it is either deck-level lights plus red-over-green, or the tricolor alone.
Day shapes
No special day shape — by day this vessel is recognised by sight, not by shapes.
Light details
| Light | Colour | Arc | Position |
|---|---|---|---|
| All-round red (upper) | red | 360° all-round | Mast, vertical line (top) |
| All-round green (lower) | green | 360° all-round | 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: Under sail with optional all-rounds.
In fog, she sounds
Don’t confuse with…
Official source
Rule 25, reproduced from the public-domain COLREGs Rule 25(c) — USCG Navigation Rules. Diagrams and 3D scenes are original to boatrules.com.