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Buoys, Marks and Beacons

Understanding the Buoyage System

The system of buoys used to assist safe navigation is known as the IALA (International Association of Marine Aids and Lighthouse Authorities) Buoyage System 'A'.

These are the equivalent of road signs on highways. Study a chart as well as the buoys themselves to familiarize yourself with their meanings. Each type of mark has a unique combination of color, shape, top-mark, and light. You must be able to recognize these and pass them safely on the correct side.

Navigation Marks Are Not Enough

There are very few navigation marks in the Whitsundays. If you rely on the navigation marks as your sole source of navigation you will run aground.

Lateral Marks

Port and starboard marks are referred to as lateral marks. They indicate the port and starboard hand sides of navigable waters (channels).

When going upstream (a general northerly direction, or heading into an inlet/river): - Keep red (port hand marks) on the left-hand side (to port) - Keep green (starboard hand marks) on the right-hand side (to starboard)

When going downstream (a general southerly direction, or out of an inlet/river): - Keep red (port hand marks) on your right-hand side (to starboard) - Keep green (starboard hand marks) on your left-hand side (to port)

Local Direction of Buoyage

Where there is doubt, the direction of buoyage is indicated on charts by a symbol showing the conventional direction of buoyage.

Safe Water Marks

Safe water marks indicate that there is navigable water all around the mark – for example, mid-channel.

Characteristics: - Red and white vertical stripes - Spherical top-mark - At night: white light shows a single long flash every 10 seconds

Memory Aid

To remember this, associate a single sphere with a single flash.

Cardinal Marks

A cardinal mark indicates where the deepest and safest water can be found. This is where boats will find safe passage. It may also indicate the safe side on which to pass a danger and to draw attention to a feature in the channel such as a bend or junction.

During daytime, refer to the top-marks and the color/pattern of the marker to determine its meaning. At night, each marker displays a different sequence of light flashes.

North Cardinal

Safe water to the North of the cardinal

  • Top-marks: Both point 'up' towards the NORTH for safest water
  • Color: Black above yellow
  • Light: Uninterrupted quick flash

South Cardinal

Safe water to the South of the cardinal

  • Top-marks: Both point 'down' towards the SOUTH for safe water
  • Color: Yellow above black
  • Light: 6 quick flashes in a group followed by a long flash

East Cardinal

Safe water to the East of the cardinal

  • Top-marks: In the shape of an egg (remember: 'E' of egg is for safe water to the EAST)
  • Color: Black with yellow band
  • Light: 3 quick flashes in a group

West Cardinal

Safe water to the West of the cardinal

  • Top-marks: In the shape of a wine glass (remember: 'W' of wine glass is for safe water to the WEST)
  • Color: Yellow with black band
  • Light: 9 quick flashes in a group

Isolated Danger Marks

Isolated danger marks indicate there is an isolated danger with navigable water all around it – for example, an isolated shoal, rock, or wreck.

Characteristics: - Black with red horizontal band - Two black spheres as top-marks - At night: white flashing light shows groups of two flashes

Memory Aid

The best way to remember this is to associate two flashes with two spheres as the top-marks.

Special Marks

Special marks can be used to mark a specific structure or feature such as a cable or pipeline, or to indicate that a channel divides.

Characteristics: - Yellow color - X-shaped top-mark - The direction to navigate around a special mark is often obvious by looking at a chart for the area

Mark Variations

Variations in the design of buoys will exist in many areas. Always consult your charts and the 100 Magic Miles guide for specific local information.

Many hazards to navigation in the Whitsundays have no special marks. Double-checking your charts and 100 Magic Miles is crucial to safe boating.

Use multiple sources of information: - Marine charts - GPS plotter - Visual observation - 100 Magic Miles guide - Depth awareness (with caution)