IALA buoyage · Cardinal marks
North cardinal mark
Identical in A and B
Black over yellow with both topmark cones pointing up: safe water lies to the north — pass north of it.
QContinuous quick flashing.Continuous quick flashing.
Pillar buoy; horizontal bands top to bottom: black, yellow; topmark: two black cones, points up. Light: Q.
What it means
Danger lies to the south of this mark; the safe, navigable water is on its north side. Identical in both IALA regions.
What you do
Pass to the north of the mark.
Memory aid
Both cones point up = north (top of the compass), and they point at the black band on top. Light: continuous quick white — think 12 o’clock, the top of the clock face.
Source: IALA Maritime Buoyage System — USCG Navigation Center, U.S. Aids to Navigation System