Thursday, August 24, 2023

Issue:

Mackay and Whitsunday Life

What does that navigation mark mean?

A system of buoys, piles and lights, known as IALA Buoyage System ‘A’, is used to assist safe navi-gation. These are the equivalent of road signs on highways. Each type of mark has a unique combi-nation of colour, shape, topmark and light. You must be able to recognise these and pass them safely on the correct side. Some of the more common ones are listed below.

When going upstream (away from the sea) keep red (port-hand marks) on the left hand side (to port), and keep green (starboard-hand marks) on the right-hand side (to starboard).

When going downstream (towards the sea) keep red (port-hand marks) on your right-hand side (to starboard) and keep green (starboard-hand marks) on your left-hand side (to port).

Lateral marks

Port and starboard marks are referred to as lateral marks. They indicate the port-hand and star-board-hand sides of navigable waters (channels). When both a port and starboard mark are placed near to each other, travel directly between them. On a pile beacon, look for the shape and colour of the top mark.

Often lateral marks are not placed in pairs. The safe side to pass a lateral mark is generally deter-mined by the direction of travel to or from the sea, or a predetermined local direction of buoyage.

Cardinal marks

A cardinal mark indicates where the deepest and safest water can be found. 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.

NORTH Safe water to the north of the cardinal. Topmarks point ‘up’ toward the north for safest water. At night the frequency of the flashes are an uninterrupted quick flash.

SOUTH Safe water to the south of the cardinal. Topmarks both point ‘down’ towards the south for safe water. The frequency of flashes is 6 quick flashes in a group followed by a long flash.

EAST Safe water to the east of the cardinal. Topmarks are in the shape of an egg, so remember the e of egg is for safe water to the east. The frequency of the flashes is 3 quick flashes in a group.

WEST Safe water to the west of the cardinal. Topmarks make the shape of a wine glass so remem-ber the w of wine glass is for safe water to the west. The frequency of the flashes is 9 quick flashes in a group.

Low Rock Reef off Shute Harbour is one of just 2 places in Australia where all cardinal marks are together.

VMRW membership is cheap insurance at just $80., you can join at https://vmrwhitsundays.com.au/join/

Contributed with thanks to Mal Priday from Whitsunday VMR.

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