(excerpt from Regulations about way of marking of waterways and aids to navigation)
The cardinal (basic) system mark is used to mark:
- the deepest water in the area is on the named side of the mark
- the safe side on which to pass a danger.
The cardinal (basic) system mark can be also used to mark a more important place in the channel, such as a bend, a junction, a bifurcation or the end of a shoal.
The cardinal (basic) system mark is named after the quadrant to which it refers and indicates that it should be passed from the named side of the mark.
In the cardinal (basic) system, the northern (N), eastern (E), southern (S) and western (W) quadrants are determined, which are bounded by the directions NE, SE, SW, NW taken from the center of danger.
The northern quadrant, bounded by the directions NW and NE is marked by:
- a mark in the shape of a pillar or spar painted in black in the upper half and in yellow in the lower half
- a topmark, 2 black cones, one above the other, points upwards
- a white light with very quick flashing or quick flashing.
The eastern quadrant, bounded by the directions NE and SE is marked by:
- a mark in the shape of a pillar or spar painted in black, with a broad horizontal yellow band in the middle
- a topmark, 2 black cones, one above the other, base to base
- a white light with 3 very quick flashes every 5 seconds or a white light with 3 very quick flashes every 10 seconds.
The southern quadrant, bounded by the directions SE and SW is marked by:
- a mark in the shape of a pillar or spar painted in yellow in the upper half and in black in the lower half
- a topmark, 2 black cones, one above the other, points downwards
- a white light with 6 very quick flashes followed by a flash lasting not less than 2 seconds every 10 seconds or a white light with 6 quick flashes followed by a flash lasting not less than 2 seconds every 15 seconds.
The western quadrant, bounded by the directions SW and NW is marked by:
- a mark in the shape of a pillar or spar painted in yellow, with a broad horizontal black band in the middle
- a topmark, 2 black cones, one above the other, point to point
- a white light with 9 very quick flashes every 10 seconds or a white light with 9 quick flashes every 15 seconds.
A topmark should be of appropriate noticeable size, and the cones should be clearly separated from each other.
Quick flashing is a flashing at a rate of 50 or 60 flashes per minute, and very quick flashing is a flashing at a rate of 100 or 120 flashes per minute.
NAUTICAL CHARACTERISTICS OF CARDINAL MARKS
| Cardinal marks |
N Quadrant |
E Quadrant |
S Quadrant |
W Quadrant |
| Colour |
Black above yellow |
Black with a broad horizontal yellow band |
Yellow above black |
Yellow with a broad horizontal black band |
| Shape |
Pillar or spar |
Pillar or spar |
Pillar or spar |
Pillar or spar |
| Topmark |
2 black cones, one above the other, points upwards |
2 black cones, one above the other, base to base |
2 black cones, one above the other, points downwards |
2 black cones, one above the other, point to point |
| Light (if any) |
White |
White |
White |
White |
| Rhythm |
VQ or Q |
VQ(3) every 5s or Q(3) every 10s |
VQ(6) + LFl every 10s or Q(6) + LFl every 15s
|
VQ(9) every 10s or Q(9) every 15s |