Skip to content
RulesAtSea

Free boating rules practice

IALA buoyage quiz: Region A and B navigation marks

Identify a mark from its shape, colours and topmarks, or watch its light rhythm. Choose Region A, Region B or both for practice. Establish the conventional direction of buoyage before deciding how to pass a lateral mark; cardinal marks use compass direction.

Try the quizRead the buoys and navigation marks guide

14 concepts · explained answers · no account needed

Practice scope: Free, original supplementary practice using International COLREGs / IRPCS and separately labeled IALA Regions A and B. These are authored learning questions, not official examination questions or a qualification. Use the full applicable rules, current charts and local requirements on the water. IALA A and B practice using fictional approaches. Choose the labeled region for each exercise; local publications provide the actual direction and mark details.

Try a short practice set

Check your understanding

Choose a set, inspect each cue, then check your answer. Every question includes an explanation, a rule reference and linked simulator practice.

Set up your practice

No account or WebGL needed. Scores last for this page visit. Original teaching graphics and synthesized signals support the questions; the simulator adds movement and replay.

Review before or after a quiz

Question topics and explained answers

The quiz draws from these 14 concepts. Recognition questions may change the viewing aspect, whistle or day/night cue. Open a topic to review its explanation and governing reference.

Port-hand mark · Region ARegion A

Which mark is shown, and what does it tell you?

IALA Region A. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Port-hand mark · Region A Red can-shaped lateral mark. In the conventional direction of buoyage, leave it to port. In the opposite direction, leave it to starboard. Read the charted buoyage direction rather than assuming every passage is inward.

Lateral marks · Region A · IALA Recommendation R1001 · Maritime Buoyage System
Starboard-hand mark · Region ARegion A

Which mark is shown, and what does it tell you?

IALA Region A. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Starboard-hand mark · Region A Green conical lateral mark. In the conventional direction of buoyage, leave it to starboard; travelling against that direction reverses the side of your vessel on which you leave it.

Lateral marks · Region A · IALA Recommendation R1001 · Maritime Buoyage System
Preferred channel to starboard · Region ARegion A

Which mark is shown, and what does it tell you?

IALA Region A. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Preferred channel to starboard · Region A A red port-hand form with a broad green band identifies a junction. Following buoyage, leave it to port for the preferred branch to starboard. The chart still determines whether either branch suits your vessel.

Modified lateral marks · Region A · IALA Recommendation R1001 · Maritime Buoyage System
North cardinal

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

North cardinal Black above yellow, with two cones pointing up. White continuous quick or very quick flashes. The named northern side is the indicated side for passage; check the chart for the danger and clearance.

Cardinal marks · IALA Recommendation R1001 · Maritime Buoyage System
East cardinal

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

East cardinal Black–yellow–black, with two cones pointing apart. White light in groups of three quick or very quick flashes. Pass on the eastern side and establish clearance from the chart.

Cardinal marks · IALA Recommendation R1001 · Maritime Buoyage System
South cardinal

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

South cardinal Yellow above black, with both cones pointing down. Six quick or very quick white flashes followed by a long flash. The long flash distinguishes six from nine. Pass south.

Cardinal marks · IALA Recommendation R1001 · Maritime Buoyage System
West cardinal

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

West cardinal Yellow–black–yellow, with cone points together. Groups of nine quick or very quick white flashes. Pass west of the mark, using the chart to determine the danger extent.

Cardinal marks · IALA Recommendation R1001 · Maritime Buoyage System
Isolated danger

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

Isolated danger Black with broad red horizontal bands and two black spheres. A white group-flashing (2) light. A danger of limited extent has navigable water around it; the mark does not specify a safe distance from the danger.

Isolated danger marks · IALA Recommendation R1001 · Maritime Buoyage System
Safe-water mark

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

Safe-water mark Red and white vertical stripes with a red sphere. White isophase, occulting, long-flashing every ten seconds, or Morse A. Indicates navigable water around the mark, commonly at a fairway or landfall.

Safe water marks · IALA Recommendation R1001 · Maritime Buoyage System
Special mark

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

Special mark Yellow with a yellow X topmark when fitted. Indicates an area or feature described on the chart. Its yellow light avoids characters reserved for cardinal, isolated-danger and safe-water marks; colour alone does not tell you which side to pass.

Special marks · IALA Recommendation R1001 · Maritime Buoyage System
Emergency wreck-marking buoy

Which mark is shown, and what does it tell you?

The same mark family applies in both IALA regions. Use charted dangers and local navigational information to plan your passage.

Emergency wreck-marking buoy Blue/yellow vertical stripes and an upright yellow cross. The three-second cycle is blue for one second, darkness for half a second, yellow for one second, then darkness for half a second. Consult current information and keep clear of the new hazard.

Emergency wreck marking · IALA Recommendation R1001 · Maritime Buoyage System
Port-hand mark · Region BRegion B

Which mark is shown, and what does it tell you?

IALA Region B. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Port-hand mark · Region B Green can-shaped lateral mark. Following the conventional direction of buoyage, leave it to port. Region B reverses the lateral colours while retaining the port-hand can shape.

Lateral marks · Region B · IALA Recommendation R1001 · Maritime Buoyage System
Starboard-hand mark · Region BRegion B

Which mark is shown, and what does it tell you?

IALA Region B. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Starboard-hand mark · Region B Red conical lateral mark. Following the conventional direction of buoyage, leave it to starboard. The region does not determine which collision-rule jurisdiction applies.

Lateral marks · Region B · IALA Recommendation R1001 · Maritime Buoyage System
Preferred channel to starboard · Region BRegion B

Which mark is shown, and what does it tell you?

IALA Region B. Interpret lateral marks in the conventional direction of buoyage, which can differ from your heading.

Preferred channel to starboard · Region B A green port-hand form with a broad red band marks a junction. Following buoyage, leave it to port for the preferred branch to starboard. Identify the dominant colour and shape together.

Modified lateral marks · Region B · IALA Recommendation R1001 · Maritime Buoyage System

Keep practising

Choose another topic