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Lights & shapes quick sheet

High-yield vessel configurations, rules, and memory aids.

Read the whole pattern. First identify the vertical all-round-light stack, then add sidelights, masthead, stern, or towing light to decide activity and aspect. A single view can hide lights outside their sectors.

Power-driven vessel under 50 m

Rule 23
Light profile seen from dead ahead: white — Masthead light, red — Port sidelight, green — Starboard sidelight

Masthead light, sidelights, and sternlight — the baseline pattern every other vessel modifies.

One masthead light = under 50 m. From ahead you see white over red+green; from astern only white.

Sailing vessel underway

Rule 25
Light profile seen from dead ahead: red — Port sidelight, green — Starboard sidelight

Sidelights and a sternlight only — no white masthead light, which is exactly how you tell sail from power at night.

Sail runs dark up top: sidelights + sternlight, and NO white masthead light.

Under sail and power (motorsailing)

Rule 25
Light profile seen from dead ahead: white — Masthead light, red — Port sidelight, green — Starboard sidelight

Sails up but engine engaged: she is a power-driven vessel — full Rule 23 lights at night and a cone, point down, by day.

Day shape: One conical shape, apex downwards, forward where it can best be seen — sails set but engine driving.

Engine on = power boat, no matter the sails. Cone point down says 'motoring' by day.

Vessel engaged in trawling

Rule 26
Light profile seen from dead ahead: green — All-round green (upper), white — All-round white (lower)

Green over white all-round lights; ≥50 m trawlers also carry a masthead light abaft and higher than the green. Sidelights and a sternlight appear only when making way.

Day shape: Two cones with their apexes together in a vertical line — the day mark of every vessel engaged in fishing.

Green over white — trawling tonight.

Vessel fishing (other than trawling)

Rule 26
Light profile seen from dead ahead: red — All-round red (upper), white — All-round white (lower)

Red over white all-round lights; sidelights and sternlight only when making way — and never a masthead light.

Day shape: Two cones with their apexes together in a vertical line.

Red over white — fishing tonight.

Vessel not under command (NUC)

Rule 27
Light profile seen from the starboard side: red — All-round red (upper), red — All-round red (lower)

Two all-round red lights in a vertical line (two balls by day); sidelights and sternlight appear only when she is making way.

Day shape: Two balls in a vertical line where they can best be seen.

Red over red — the captain is dead (nobody is in control).

Vessel restricted in ability to manoeuvre (RAM)

Rule 27
Light profile seen from the starboard side: red — All-round red (top), white — All-round white (middle), red — All-round red (bottom)

Red-white-red all-round lights in a vertical line and ball-diamond-ball by day; making way adds masthead lights, sidelights and sternlight.

Day shape: Ball, diamond, ball in a vertical line where they can best be seen.

Red, white, red — restricted ahead.

Vessel towing astern (tow 200 m or less)

Rule 24
Light profile seen from the starboard side: white — Masthead light (upper of two = tow ≤ 200 m), white — Masthead light (lower of two), green — Starboard sidelight

Two masthead lights in a vertical line, sidelights, sternlight — and a yellow towing light above the sternlight.

Two whites up the mast + yellow over white at the stern = short tow astern (200 m or less).

Pilot vessel on duty

Rule 29
Light profile seen from dead ahead: white — All-round white (upper), red — All-round red (lower), red — Port sidelight, green — Starboard sidelight

White over red all-round lights at the masthead; sidelights and sternlight when underway, anchor lights when at anchor.

White over red — pilot ahead.

Vessel at anchor (under 50 m)

Rule 30
Light profile seen from the starboard side: white — All-round white anchor light

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

Day shape: One ball in the fore part where it can best be seen.

Asleep on the hook: one white ball of light by night, one black ball by day.

Vessel aground

Rule 30
Light profile seen from the starboard side: red — All-round red (upper), red — All-round red (lower), white — Anchor light (forward)

Anchor lights plus two all-round red lights in a vertical line — and three balls by day.

Day shape: Three balls in a vertical line where they can best be seen.

Anchor light PLUS red over red = she is on the bottom, not just stopped. Three balls by day.

Learning aid only — not for navigation. Confirm current rules and local requirements with the relevant authority.