Yellow below, black above
North cardinal mark. Foundation level, about 3 min. IALA cardinal marks.
The situation
You are heading east along the coast. Ahead lies a pillar buoy, black over yellow, with two black cones on top, both pointing up. Your present heading would take you just south of it.
On which side do you pass the mark?
- Alter to port and pass north of the mark: Keep the mark on your starboard side.
- Alter to starboard and pass south of the mark: Keep the mark on your port side.
- Hold your heading: You will clear the buoy itself.
Lookout: A cardinal mark is named for the side on which you pass it. Both cones point up for north: “north points north”.
The sound answer
Alter to port and pass north of the mark
A north cardinal mark is placed so that the safest water lies to its north; the danger lies to the south. Passing north of it, then resuming your heading, keeps you clear.
Why the other options fall short
Alter to starboard and pass south of the mark
South of a north cardinal mark is the side of the danger. Here that is where the rocks are.
Hold your heading
Clearing the buoy is not the point. A cardinal mark tells you where the danger lies; passing on the wrong side, even close to the mark, takes you toward it.
Cardinal marks
A cardinal mark lies in one of four quadrants (north, east, south, west) from the point of interest and is named after that quadrant. You pass it on its named side. North: black over yellow, two cones pointing up, light quick or very quick continuous.