Navigation lights cheat sheet

Power-driven, under 50 m · Rule 23

One masthead light, sidelights and a stern light. A second masthead light aft is optional. A sailing yacht motoring shows these too.

Power-driven, 50 m or more · Rule 23

Two masthead lights, the aft one higher. Their alignment shows which way the ship is heading.

Sailing vessel underway · Rule 25

Sidelights and a stern light, no masthead light. Motor-sailing by day, show a cone point down forward.

Sailing vessel under 20 m, tricolour · Rule 25

Sidelights and stern light combined in one lantern at the masthead. Never use it with the engine running.

Towing, tow under 200 m · Rule 24

Two masthead lights in a vertical line, plus a yellow towing light above the stern light. Over 200 m: three masthead lights, and a diamond by day.

Fishing, trawling · Rule 26

All-round green over white — 'green over white, trawling tonight'. Sidelights and stern light only when making way.

Fishing, not trawling · Rule 26

All-round red over white — 'red over white, fishing at night'. Sidelights and stern light only when making way.

Not under command · Rule 27

Two all-round red lights — 'red over red, the captain is dead'. No masthead light. Sidelights and stern light only when making way.

Restricted in ability to manoeuvre · Rule 27

All-round red, white, red. Masthead, sidelights and stern light when making way. Dredgers, cable layers and survey vessels show this.

Constrained by draught · Rule 28

Three all-round red lights in a vertical line, in addition to normal power-driven lights. Keep out of her way in the channel.

Pilot vessel on duty · Rule 29

All-round white over red — 'white over red, pilot ahead'. Sidelights and stern light when underway. Flies flag H by day.

At anchor, under 50 m · Rule 30

One all-round white light where it can best be seen. One black ball forward by day.