A cardinal mark is a sea mark (a buoy or other floating or fixed structure) commonly used in maritime pilotage to indicate the position of a hazard and the direction of safe water.
Cardinal marks indicate the direction of safety as a cardinal ( compass) direction ( north, east, south or west) relative to the mark. This makes them meaningful regardless of the direction or position of the approaching vessel, in contrast to the (perhaps better-known) lateral mark system.
The characteristics and meanings of cardinal marks are as defined by the International Association of Lighthouse Authorities.
A cardinal mark indicates one of the four compass directions by:
Characteristic | North | South | East | West |
---|---|---|---|---|
Topmark | ▲ ▲ Both cones point upwards |
▼ ▼ Both cones point downwards |
▲ ▼ Cones point away from each other |
▼ ▲ cones point towards each other |
Colour | Black above yellow | Yellow above black | Yellow horizontal band on a black body | Black horizontal band on a yellow body |
Light (if fitted) | Continuous flashes | 6 quick flashes + 1 long flash | 3 flashes | 9 flashes |
Either a quick or a very quick sequence of light flashes may be used; the choice allows for two similar nearby marks to be uniquely identified by their lights.
A cardinal mark may be used to accomplish the following:
Other uses:
The north and south topmarks are self-explanatory (both cones pointing up, or both pointing down). Remembering the east and west marks can be more of a problem.
The colours can be remembered this way: The two conical top-marks always point to black.
A cardinal mark is a sea mark (a buoy or other floating or fixed structure) commonly used in maritime pilotage to indicate the position of a hazard and the direction of safe water.
Cardinal marks indicate the direction of safety as a cardinal ( compass) direction ( north, east, south or west) relative to the mark. This makes them meaningful regardless of the direction or position of the approaching vessel, in contrast to the (perhaps better-known) lateral mark system.
The characteristics and meanings of cardinal marks are as defined by the International Association of Lighthouse Authorities.
A cardinal mark indicates one of the four compass directions by:
Characteristic | North | South | East | West |
---|---|---|---|---|
Topmark | ▲ ▲ Both cones point upwards |
▼ ▼ Both cones point downwards |
▲ ▼ Cones point away from each other |
▼ ▲ cones point towards each other |
Colour | Black above yellow | Yellow above black | Yellow horizontal band on a black body | Black horizontal band on a yellow body |
Light (if fitted) | Continuous flashes | 6 quick flashes + 1 long flash | 3 flashes | 9 flashes |
Either a quick or a very quick sequence of light flashes may be used; the choice allows for two similar nearby marks to be uniquely identified by their lights.
A cardinal mark may be used to accomplish the following:
Other uses:
The north and south topmarks are self-explanatory (both cones pointing up, or both pointing down). Remembering the east and west marks can be more of a problem.
The colours can be remembered this way: The two conical top-marks always point to black.