Cardinal marks say where the safe, navigable water lies: north, east, south or west of the mark. They are always black and yellow, carry a topmark of two black cones, and show a white light. They are identical in Region A and B.
The cones point to the black: North cones up, black on top; South cones down, black below; East bases together (an egg shape) with black top and bottom; West points together (a wineglass, W for wineglass). Lights: E = 3, S = 6, W = 9 flashes (a clock face), N = continuous.
North cardinal mark (N)
Colour
horizontal bands: black, yellow
Buoy shape
pillar or spar
Topmark
two cones, one above the other, points up
Light
VQ or QWhite, continuous very quick (VQ) or quick (Q) flashing, without a pause.
What it means
Safe, navigable water lies to the north of the mark. Pass it on its north side.
East cardinal mark (E)
Colour
horizontal bands: black, yellow, black
Buoy shape
pillar or spar
Topmark
two cones, base to base
Light
VQ(3) every 5 s or Q(3) every 10 sThree quick flashes (3 o’clock on the clock face), then a pause.
What it means
Safe water lies to the east of the mark. Pass it on its east side.
South cardinal mark (S)
Colour
horizontal bands: yellow, black
Buoy shape
pillar or spar
Topmark
two cones, one above the other, points down
Light
VQ(6)+LFl every 10 s or Q(6)+LFl every 15 sSix quick flashes (6 o’clock), followed by one long flash.
What it means
Safe water lies to the south of the mark. Pass it on its south side.
West cardinal mark (W)
Colour
horizontal bands: yellow, black, yellow
Buoy shape
pillar or spar
Topmark
two cones, point to point
Light
VQ(9) every 10 s or Q(9) every 15 sNine quick flashes (9 o’clock), then a pause.
What it means
Safe water lies to the west of the mark. Pass it on its west side.
Facts per the IALA Maritime Buoyage System (MBS ed. 2.0). The drawings are our own vectors. The light rhythm and colour in the drawing are illustrative: check the real characteristics of a specific buoy on the chart and in the list of lights.