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Buoyage quick sheet

Lateral, cardinal, danger, safe-water, and special marks.

Region matters only for lateral colours. Cardinal, isolated-danger, safe-water, special, and emergency-wreck marks keep the same meaning in Regions A and B. Always read the charted channel direction and the mark’s topmark, colour pattern, and light rhythm together.

Port-hand lateral mark

IALA Region A

Fl R 4s

IALA Region B

Fl G 4s

Marks the port (left) edge of the channel when travelling with the direction of buoyage — a red can in Region A, a green can in Region B.

Region A: “Is there any red port left?” — red = port = left, and port wine comes in a can-shaped bottle. Region B flips the colours (green can to port) but the can shape still says port.

Starboard-hand lateral mark

IALA Region A

Fl G 4s

IALA Region B

Fl R 4s

Marks the starboard (right) edge of the channel when travelling with the direction of buoyage — a green cone in Region A, a red cone (nun) in Region B.

The cone points up like a mountain you steer right around. Region B (the Americas): “red right returning” — red nun on your right when returning from sea.

Preferred channel to starboard

IALA Region A

Fl(2+1) R 10s

IALA Region B

Fl(2+1) G 10s

A banded junction mark: the channel splits and the preferred channel lies to starboard — so treat the mark like a port-hand mark.

Read the top band and the shape — they win. Composite light Fl(2+1): “two-plus-one, the channel splits, pick one.”

Preferred channel to port

IALA Region A

Fl(2+1) G 10s

IALA Region B

Fl(2+1) R 10s

A banded junction mark: the channel splits and the preferred channel lies to port — so treat the mark like a starboard-hand mark.

Same trick: top band + shape read like an ordinary lateral. The stripe just warns you there is a second channel on the other side.

North cardinal mark

All IALA regions

Q

Black over yellow with both topmark cones pointing up: safe water lies to the north — pass north of it.

Both cones point up = north (top of the compass), and they point at the black band on top. Light: continuous quick white — think 12 o’clock, the top of the clock face.

East cardinal mark

All IALA regions

Q(3) 10s

Black with a yellow band, cones base-to-base: safe water lies to the east — pass east of it. White light Q(3) 10s.

Cones point apart like an Easter Egg — East. The points aim at the black: top and bottom. Light: 3 flashes = 3 o’clock = east on the clock face.

South cardinal mark

All IALA regions

Q(6)+LFl 15s

Yellow over black with both cones pointing down: safe water lies to the south — pass south of it. White light Q(6)+LFl 15s.

Both cones point down = south (bottom of the compass), at the black band below. Light: 6 flashes = 6 o’clock, plus one long flash so you can’t miscount it as 9 or 3.

West cardinal mark

All IALA regions

Q(9) 15s

Yellow with a black band, cones point-to-point: safe water lies to the west — pass west of it. White light Q(9) 15s.

Points together make a Wineglass — a Wasp-waisted W for West. The points aim at the black band in the middle. Light: 9 flashes = 9 o’clock = west.

Isolated danger mark

All IALA regions

Fl(2) 5s

Black with red bands and two black spheres: a small danger with navigable water all around it. White light Fl(2).

Two spheres, two flashes — double trouble sitting right underneath.

Safe-water mark

All IALA regions

LFl 10s

Red-and-white vertical stripes with a single red sphere topmark: navigable water all around — the mid-channel or landfall mark.

Red-and-white candy stripes = all clear. Its white light is gentle, never quick: Iso, Oc, one long flash every 10 s, or Morse “A” (short–long, “Alfa — I’m arriving”).

Special mark

All IALA regions

Fl Y 4s

All yellow with a yellow ✕ topmark: marks a special area or feature — check the chart for what and which side to pass.

Yellow with a yellow ✕: “X marks the special spot — go check the chart.” Its light is always yellow, in any rhythm not used by white lights.

Emergency wreck-marking buoy

All IALA regions

Al Bu/Y 3s

Blue-and-yellow vertical stripes with an upright yellow cross, light alternating blue/yellow: a new wreck not yet on your chart.

Blue and yellow = brand new. Nothing else afloat shows an alternating blue/yellow light — one second blue, one second yellow.

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

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A learning aid — not for navigation. Rule text is reproduced from the public-domain USCG Navigation Rules. Chart symbols follow NOAA U.S. Chart No. 1. All diagrams and questions are our own. Not affiliated with or endorsed by the RYA, ASA, NASBLA, IMO, or any licensing authority.

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Core content reviewed: July 15, 2026