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.

Repairing chips and dings in gelcoat

The gelcoat topsides of a GRP boat can be pampered and restored to their former glory relatively easily when it is ashore. Gelcoat is only a very thin outer layer of the hull, often less than 1mm thick, so you should avoid cleaning it with highly abrasive cleaners, or an-ything that could potentially damage its surface.

Getting a tow for your sail or power boat at sea or on inland waterways

FREE tips from the Safe Skipper App for iPhone/iPad/Android: Getting a tow for your sail or power boat Plan how to secure a...

Learn ColRegs: Traffic Separation Schemes

Learn ColRegs Rule 10: Traffic Separation Schemes. (c) A vessel shall, so far as practicable, avoid crossing traffic lanes...

Medical Emergency at Sea

How to deal with a medical emergency afloat   If you are planning a boating trip, it is important to have at least one...

Leaking decks

Leaking decks are perceived as a nuisance by some boat owners, but if leaks are ignored a much more serious situation may well be developing, especially in the case of boats with balsa or plywood deck cores. So deck leaks do need to be investigated and dealt with.

Antifouling for leisure boats – Part 1

Boats that are kept afloat can very quickly become a home for small marine organisms such as barnacles, weed and slime. Applying an antifouling paint to your hull is necessary to protect it from these micro-organisms, as a fouled hull can cause problems and will slow down a boat’s maximum speed considerably if left unchecked.

How diesel engines work

The basic principle of a diesel engine is less complex than that of a petrol engine. No spark plug or ignition system is needed, making the basic diesel engine a comparatively straightforward system that results in fewer faults and has lower maintenance costs than a petrol engine.

Top 5 Reasons Why an Inflatable SUP Should Be Your Next Yacht Accessory

In this article, inflatable paddle board expert Jason Paul gives the top 5 reasons why an inflatable SUP should be your next...

Rudders and steering systems – Part 1

Rudders and steering systems. A rudder is one of the most critical parts of a boat. Rudder failure is a common occurrence on neglected or overworked boats and a very unpleasant and potentially dangerous thing to happen when you are out at sea.

Rewiring a boat – overcoming the challenges involved

Skippers need to have a basic knowledge of boat electrics, to avoid potential problems and to be able to solve them when they happen.

ColRegs – avoiding collisions at sea

ColRegs - avoiding collisions at sea ColRegs Rule 8: Action to avoid collision (a) Any action taken to avoid collision shall...

Boat surveys

A full boat survey assesses the condition of the hull, mechanical gear and means of propulsion. The survey is carried out with the boat...

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...

Stress cracks on GRP boats

It is quite common to find cracks in the gelcoat when inspecting the deck and superstructure of a GRP boat. It is important to differentiate between a gelcoat crack and a scratch.

Sailing Boat Rig Care

The rig of a sailing boat is put under huge stresses and strains so it is important for inspections of a yacht’s spars and rigging to be carried out at regular intervals.

Top Ten Tips For Learning The ColRegs Boating Rules Of The Road

Colregs Boating Rules Of The Road Skippers struggle to learn and remember the ColRegs Yachtmaster and Day Skipper course...

Steel and Aluminium Hulls

The two metals used for hull construction are steel and aluminium. These are both very strong materials and will last a long time as long as they are cared for, which primarily means protecting steel boats from rust and aluminium boats from electrolytic action.

Competent crew skills: mooring lines

Mooring lines are used when arriving or leaving a berth. One of the most important competent crew skills is to know how to...

Boat engine fuel system

If engines are installed and serviced correctly then most marine engines are very reliable, but one of the most important parts of the engine to check and service is the fuel system.

Essential Yachting + Power Boat Safety Briefing

Yachting Safety Briefing   Down below Lifejackets and harnesses - fitting, when to wear, clipping on Gas - risks,...

Keel design – options to consider when choosing a yacht

Keel design is constantly evolving and nowhere is this more apparent than in modern racing yachts such as the Imoca Open 60...

Steel hull maintenance

A steel boat owner’s biggest enemy is corrosion. You don’t have to worry about osmosis or rotting timbers, instead rust is the number one issue that will keep you awake at night.

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...

Cutless bearing replacement

Cutless bearings can last for many years but if the propeller shaft is out of alignment they will wear through more quickly. If you have noticed a clunking sound when motoring then it could be a worn cutless bearing that is causing the problem.

Points of Sailing

The course on which a boat is sailing can be described by its angle to the wind, not to be confused with its compass...