The International Association of Marine Aids and Lighthouse Authorities (IALA) established a worldwide buoyage system to standardize aids to navigation after several accidents occurred in the Dover Strait in 1971 due to different buoyage systems causing confusion. The IALA system divides the world into two regions - Region A and Region B - and established six types of marks: lateral marks, cardinal marks, isolated danger marks, safe water marks, special marks, and emergency wreck marking buoys. Lateral marks indicate which side of the channel to follow while cardinal marks use compass directions to indicate navigable waters and dangers. The document provides details on the colors, shapes, lights and meanings of each type of mark.

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B.Sc SEM V UG21T4106 Topic :3
IALA System of Buoyage
INTRODUCTION
IALA (International Association of Marine Aids and Lighthouse Authorities)is a
non-profitorganization, established in 1957. Its Headquarters is at Paris, France.
It has over 85member countries around the world.
IALA encourages its members to work together to harmonise aids to navigation
worldwide and to ensure the movements of vessels are safe, expeditious and
cost effective whilst simultaneously protecting the environment.
IALA achieves this is by establishing technical committees to bring together
experts from member countries around the world. These committees are
constituted to develop recommendations on technologies and practices for safe
navigation and protection of the environment.
IALA is known for its buoyage system. As early as 1976, there were more than
30 buoyage systems in use throughout the world which were totally dissimilar.
These different systems caused confusion rather than help navigators in safe
navigation. In order to a scenario of safe navigation to mariners of different
regions, IALA has created a worldwide buoyage system which is common to
most of the sea areas.
HISTORY OF IALA BUOYAGE SYSTEM
Series of following accidents in the Dover Straits might have culminated in what
is today IALA BUOYAGE System.
On 11 January 1971, the tanker M.T. Texaco Caribbean was on a voyage from
the Netherlands to Trinidad when she was struck by M.V. Paracas in thick fog in
the DoverStraits. The latter ignored the shipping lanes of Dover Straits and took
the shorter course along the English coast. The Texaco Caribbean exploded upon
collision, split in two and sank, releasing around 600 MTs of fuel oil and ballast.
8 crew members lost their lives in the accident and 22 were rescued by other
crafts around. M.V. Paracas was also seriously damaged in the accident. Salvage
tugs towed her to port of Hamburg.
Immediately, British coastal authorities marked the wreck with 3 vertical green
lights on green buoy on site to warn other ships. However, the following day
M.V. Brandenburg hit the Texaco Caribbean and sank. M.V. Brandenburg did not
understand the importance of the buoys and the lights erected. Out of 32 crew

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members only 11 were rescued by local fishing boats. 14 crew members
remained missing while the bodies of 7 were found.
A light ship and 5 light buoys were added on site to warn other ships. But on
27th February the same year, M.V Nikki, sailing from Dunkirk to Alexandria, did
not understanding the importance of the above warnings and collided with the
submerged wrecks. M.V. Nikki went down with her entire crew before rescue
ships crafts could come.
All 3 wrecks posed a serious danger to all ships transiting this stretch of Dover
Strait. British coastal authorities positioned another lightship and about 10 more
buoys. In the next 2 months, British authorities reported over 15 ships for
having ignored the lightships and buoys. Luckily,no further causalities were
reported in this area.
To prevent this such disasters various countries improvised their buoyage
systems. So, there were almost 30 well established buoyage system around the
world but they were not uniform hence most of the time they created confusion
rather assist the mariners. IALA got into the act and started working on
establishing an uniform system of buoyage. It several years to come to a
consensus.
In 1980, at a conference convened with the assistance of the Inter-
Governmental Maritime Consultative Organisation (IMCO), now known as the
IMO and the International Hydrographic Organisation (IHO), the Lighthouse
Authorities from fifty countries and the representatives of nine International
Organisations concerned with aids to navigation agreed to adopt the rules of the
new combined system, and reached decisions on the buoyage regions.
The system has now been implemented throughout much of the world,
however, in some parts conversion to the new system is still incomplete.
REGION A & REGION B
To minimise the number of changes to existing systems and to meet conflicting
requirements IALA decided to create a system divided into two regions. The
region followed is dependent on geographical location:
Region A:Europe, Australia, New Zealand, Africa, the Gulf and some Asian
countries
Region B:North, Central & South America, Japan, North & South Korea and the
Philippines

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TYPES OF MARKS
IALA buoyage system provides six types of marks:
1. Lateral marks
2. Cardinal marks
3. Isolated danger Marks
4. Safe Water Marks
5. Special Marks
6. Emergency Wreck Marking Buoy
1. LATERAL MARKS: The lateral marks help to indicate which side of the
waterway is to be followed. The port marks should be kept to the vessel’s port
side and starboard marks to its starboard. The general direction of the lateral
buoys is marked on the chart.The general direction taken by the mariner when
approaching a harbor, river, estuary, or other waterway from seaward, or the
direction determined by the proper authority. In general, it follows a clockwise
direction around land masses.
However, when a vessel sails downstream, the meaning of the buoys will
change accordingly, i.e. port marks to be kept on starboard side while starboard
marks on the port. When a channel divides to form more than one way, a
modified lateral mark is then used to indicate the “preferred channel”. A
preferred channel is indicated by red and green horizontal bands on the lateral

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mark. If the buoys are numbered, it indicates that the sequence of numbering
follows the conventional direction of buoyage.
Every buoy is identified by their colour, shape, top marks, light and the rhythm
of light.
The table below will give a better illustration of the buoys found in the respective
regions.
LATERAL MARKSin Region A:Europe, Australia, New Zealand, Africa, the Gulf
and some Asian countries.
LATERAL MARKSin Region B:North, Central & South America, Japan, North &
South Korea and the Philippines

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2. CARDINAL MARKS :
Cardinal marks are used in conjunction with the compass to indicate where the
mariner may find the safenavigable water. The Cardinal marks are named by the
quadrant in which they are placed with respect to the point of interest. Their
colours and shapes are shape irrespective of the regions A and B. There are 4
cardinal marks named after the four cardinal points of the compass: NORTH,
SOUTH, EAST AND WEST.
Cardinal marks can be used to show the following:
- The deepest water on an area on the named side of the mark
- The safe side on which to pass a danger
- Draw attention to a feature
Cardinal marks have distinctive black and yellow markingsand top marks.The
rhythm of light can be related to the face of a clock. All cardinal mark exhibit
white light.

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The table below describes the light rhythm for each cardinal mark.

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Note that Quick flashing light (Q) has a flash frequency of 50 to 60 flashes every
minute and a Very Quick flashing light (VQ) has a flash frequency of at least 100
to 120 flashes every minute.
3. SAFE WATERMARKS:
Unlike other marks that use horizontal stripes, this is the only mark to use
vertical stripes. Safe watermark specifies that safe navigable water is all around
the mark. It does not point to any danger. It indicates the beginning of a marked
channel. When a navigator sees a safe watermarking buoy, he should soon
realize that he is approaching a channel. It is the demarcation between open sea
waters and confined waters. Sighting this buoy indicates the entrance to any
port. It also points out the best point of passage under a fixed bridge. Safe
watermark uses a red ball as a top mark. Safe watermarks can be used in a line
to mark navigable safe water route through shallow areas.
4. ISOLATED DANGER MARKS:
These buoys are used to mark dangers to shipping. They bring to the attention
of navigators any hazards or dangers to safe navigation. These marks are
erected or moored above the danger to alert navigators of any hazard ahead.

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These marks can be distinguished from other by their top marks, which consist
of 2 black spheres one above the other and by their colour – black with one or
more red horizontal bands. The rhythm of light, group flashing 2 can easily be
retained in memory by correlating to its top mark -2 black spheres.
5. SPECIAL MARK:
Special marks are used to denote navigator’s areas with special features. They
point out areas of certain interests to mariners. The nature of such areas and
associated activities are indicated in the charts or Sailing Directions. Special
marks may indicate spoil grounds, military exercise areas, recreational zones,
boundaries of anchorage areas, cables and pipelines, mooring areas, protected
areas, marine farms or aquaculture, oil wells, ODAS(Ocean Data Acquisition
System). These marks can easily be differentiated from other buoys by their
yellow colour and topmark which is a cross.
6. EMERGENCY WRECK MARKING BUOY:
These buoys have come into existence much later compared to the other 5 types
of marks. The sinking of the MV Tricolour in the Dover Strait in 2002 introduced
the emergency wreck marking buoy in the IALA buoyage system. The wreck was
struck further by 2 other ships causing havoc damage to shipping and loss of

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life. Post this incident, it was immediately necessary to mark such new dangers
so that it is readily recognized by ships as a new hazard and further collisions
are prevented from occurring. Emergency wreck marking buoys mark newly
discovered unsurveyed dangers which are yet to be announced and declared in
nautical publications and charts. This buoy is placed as close as possible to the
wreck and unlike other buoys, is designed to provide a highly conspicuous visual
and radio aid to navigation.It shall display light flashes alternate yellowand blue
for one second each with half second gap between.

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