Select Page

What are the differences between the two IALA buoyage systems, IALA Region A and IALA Region B, and where are they used?

 IALA buoyage map

As recently as the 1970s there were more than 30 buoyage systems in use around the world. This caused confusion and accidents and it was after two fatal incidents in the Dover Straits in 1971 that the IALA (International Association of Marine Aids to Navigation and Lighthouse Authorities) was established.  There followed a worldwide effort to develop a safe, unified maritime buoyage system that could be followed by all vessels at sea.

This resulted in the IALA Maritime Buoyage System and by 1980 there were just 2 systems in use, IALA A and IALA B. Although there is not as yet one unified system for the whole world, this was a major achievement nonetheless and the differences between IALA A and IALA B are only minor. The IALA chose the two systems in order to keep the number of changes to existing systems to a minimum and to avoid major conflict.

IALA REGION A

IALA A is used by countries in Africa, most of Asia, Australia, Europe and India.

IALA REGION B

IALA B is used by countries in North, Central and South America, Japan, Korea and the Philippines.

IALA A buoyage

IALA B buoyage

Take our IALA Buoys & Lights Quiz right now to see how much you know! Just click here.

The differences – lateral marks

The difference between the two systems is the colour and light characteristics used for lateral marks, as follows:

•  IALA REGION A port lateral marks and lights are coloured red.  IALA  A starboard lateral marks and lights are coloured green.

•  IALA REGION B port lateral marks and lights are coloured green.  IALA B starboard lateral marks and lights are coloured red.

Lateral marks indicate the port and starboard sides of navigable channels. These are used in accordance with the direction of buoyage for the region or specific location, as indicated on marine charts. Where a channel divides a modified or “preferred” channel mark may be used to indicate the preferred route to take.  In IALA Region A the lateral marks on the starboard side of the channel are coloured green and should be passed on the starboard side of the vessel. Those on the port side of the channel should be passed on the port side of the vessel.  In IALA Region B the lateral marks on the starboard side of a channel are coloured red and on the port side are coloured green.

The similarities – all other types of buoy

Aside from the different lateral marks, both systems use identical cardinal, isolated danger, safe water and special marks. In 2006 new danger marks were introduced, see details below.

Cardinal Marks

Cardinal marks warn of hazards to be avoided such as shallows or rocks. Their markings and shape indicate which side of a buoy a vessel should pass and are placed either to the north, south, east or west of a hazard. Therefore a vessel should pass to the west of a west cardinal mark, or to the east of a east cardinal mark and so on.  They are painted in combinations of yellow and black and have two distinct cone shapes on top, arranged in different combinations to help identify them.

Isolated Danger Marks

Isolated danger marks are used to indicate a single hazard, such as a wreck, which has navigable water all around it.  Vessels should keep well clear of the mark on all sides. They are coloured black with red bands and have two black balls above each other on the top of the mark.

Safe Water Marks

Safe water marks indicate there is safe water all around the mark. They are used at the start of a buoyed channel when approaching a harbour from the sea. They coloured with red and white vertical stripes.

Special Marks

Special marks are not intended primarily as navigation marks.  They are used to mark the boundaries of areas used for recreation eg water skiing or bathing, as racing marks and also for naval activities such as gunnery ranges.  Special marks are coloured yellow and can be a variety of shapes.

New Danger Marks

New danger marks were introduced in 2006 and are used as emergency marks for recent wrecks or new hazards which do not appear on nautical charts.  They are coloured with blue and yellow vertical stripes.

___________________

Safe Skipper apps have recently updated our Buoys and Lights app, which includes a full illustrated guide and a very useful test yourself section – see here.

Or – take our IALA Buoys & Lights Quiz right now to see how much you know! Just click here.

Essential Knots: Figure of eight

Essential Knots: Figure of eight Use: Stopper knot, prevents a rope from being pulled through a hole e.g. through a block or...

Peer to Peer yacht charter – How can you monetize your boat?

There is a growing trend in peer to peer yacht charter. How does it work? People already rent rooms, cars and bikes from one...

Boating emergency – how to broadcast a MAYDAY emergency call

How to broadcast a MAYDAY emergency call   How to broadcast a MAYDAY emergency call if a vessel or person is in grave...

Antifouling for leisure boats – Part 2

To prepare for antifouling, as soon as your boat has been lifted out and pressure washed, you need to check all the surfaces of the hull below the waterline, remove any remaining barnacles and check for blisters.

Essential Knots: Bowline

Essential Knots: Bowline Use: Making a secure eye or loop in the end of a rope. Bowlines have many uses on a boat, for example to make a...

How to tackle osmosis

Many owners of old GRP boats live in fear of osmosis, but what exactly is osmosis and what can be done about it? Osmosis comes about...

ColRegs Rule 14 – Head-on Situation

  ColRegs Rule 14: Head-on Situation (a) When two power-driven vessels are meeting on reciprocal or nearly reciprocal...

Antifouling for leisure boats – Part 3

Antifouling is one of the least pleasant boat maintenance jobs to do, but it has to be done. The very worst job of all is removing the old antifouling as this can get seriously messy and is very hard work.

Boat electrics and essential checklist

Essential boat electrics Small yachts and power boats have 12-volt DC (direct current) systems, although larger vessels will have...

First Aid Afloat – fish spine injury

First Aid Afloat - Here is what to do if somebody stands on a fish spine: • Check for dangers. Is it safe for you to enter...

An explanation of the IALA maritime buoyage systems – IALA A and IALA B

What are the differences between the two IALA buoyage systems, IALA Region A and IALA Region B, and where are they used?   As recently as the 1970s...

Avoiding collisions at sea – how to stay safe on the water

Boats have many blind spots, including the headsails of sailing boats. Always keep a lookout, stay safe and remember that...

Capsize – understanding the risks

A skipper should know how their boat will cope with rough seas. By working within known limits and understanding the risks,...

Essential Boat Spares for Safety

  Boats Spares Tool kit What you carry in the boats tool kit will be useful for many boat repairs, but you might want...

Essential Knots: Sheet bend

Essential Knots: Sheet bend Use: Joining two ropes together. A sheet bend is particularly useful for joining two ropes of different...

Dag Pike’s Boat Survey

We're really pleased to be working with Dag Pike on some great new apps for iPhone & Android. Here'a a bit more about the first app: Dag Pike's...

Fire prevention on boats

  Fire prevention on boats - common causes of fire: • Smoking below decks • Galley cookers • Build-up of butane or...

Essential Knots: Clove hitch

Essential Knots: Clove hitch Use: Tying a rope to posts, bollards, rings or a guardrail. Step 1. Make a turn around the object and lay...

Boat Handling – anchoring

Anchoring your yacht or motorboat Anchoring is one of the most important boat handling skills. If you can set an anchor...

A simple guide to understanding tides when passage planning

Understanding tides when passage planning When planning a trip in tidal waters, check the tides before going afloat. Use...

Sector lights, directional lights, leading lights – how do they differ?

Sector lights, directional lights and leading lights guide vessels safely through hazardous waters or narrow channels at...

Sailing & Motoring in Fog

Sailing & Motoring in Fog You can only measure the visibility accurately if sailing & motoring in fog when you have...

First Aid Afloat – how to deal with a fracture at sea

First Aid Afloat A closed fracture does not break through the skin. An open fracture is when the bone punctures it. A...

Always have an emergency grab bag to hand when at sea…

  Grab bag: In the event of having to abandon ship, it is recommended to have a designated waterproof bag to carry...

Repairing a leaking hull-to-deck joint

If you suspect a hull-to-deck joint has failed, then being absolutely sure where the actual leak is occurring is of prime...