Red, white, red
Restricted in her ability to manoeuvre. Advanced level, about 2 min. COLREGs Rule 27(b).
The situation
Night. Fine on your port bow you see three all-round lights in a vertical line: red, white, red. Near them is a white masthead light, and lower down a green light.
What are you looking at?
- Restricted in her ability to manoeuvre, making way, showing her starboard side: Red, white, red plus masthead and green.
- Constrained by her draught: Three all-round lights in a vertical line.
- Not under command: Red all-round lights.
Lookout: Count the vertical lights and read their colours from the top. Three lights mean something different from two.
The sound answer
Restricted in her ability to manoeuvre, making way, showing her starboard side
Red-white-red all-round lights in a vertical line mark a vessel restricted in her ability to manoeuvre, for example while laying cable or servicing a buoy. Making way, she adds masthead, sidelights and sternlight; the green light means you see her starboard side.
Why the other options fall short
Constrained by her draught
A vessel constrained by her draught may show three all-round red lights. The middle light here is white.
Not under command
Not under command is two all-round reds with no white between them, and no masthead light when making way.
Rule 27(b) · Restricted in ability to manoeuvre
A vessel restricted in her ability to manoeuvre shows three all-round lights in a vertical line, red, white, red, and when making way through the water also masthead lights, sidelights and a sternlight.