14 August 2013
Cardinal markers indicate where deeper water can be found and signify the best route for boaters to take when passing through a shallow or dangerous passage in the water.
They indentify tricky parts of a channel, such as a bend or junction, and help avoid dangers such as rocks, wrecks and sandbars.
However, they will only guide you if you understand what they mean.
Each mark has top marks for daytime use and lights that can be seen at night. The marks and type of light show which side is safe.
The top marks are made up of two black cones and, together with the black part of the marker post, indicate the safe direction.
The posts are also painted in a way to indicate what they are if the top mark is missing. There is part black and part yellow, the black section follows the direction the cones are pointing.
north – Top mark points up, black band above yellow band.
east – Top mark points outward, black bands above and below yellow band
south – Top mark points down, black band below yellow band.
west – Top mark points inward, black band between yellow bands.
The lights symbolise a clock face: three flashes for east, six flashes plus a long flash for south and nine flashes for west and continuous flashes for north.
Cardinal marks page on sa.gov.au