Buoyage, Marks and Aids to Navigation
Hong Kong is an IALA Region A area - red to port, green to starboard when proceeding in the direction of buoyage - and Part A tests whether you can identify a mark from its shape, colour, topmark and light rhythm, and say on which side to pass it.
Lateral marks
- Port hand: red, can-shaped, red light, any rhythm except those reserved for cardinal and safe-water marks.
- Starboard hand: green, conical, green light.
- The direction of buoyage is shown by arrows on the chart; where no direction is indicated, it is the direction taken when entering from seaward.
Cardinal marks
- North: two cones point up, black above yellow; light quick or very quick.
- East: two cones base to base, black-yellow-black; VQ(3) 5s.
- South: two cones point down, yellow above black; VQ(6) plus long flash every 10s.
- West: two cones point to point, yellow-black-yellow; VQ(9) 10s.
- The number of flashes tells you the clock position: three flashes, three o'clock, east; six, south; nine, west.
Other marks
- Safe water: red and white vertical stripes, single red sphere, isophase or occulting white light or Morse A.
- Isolated danger: black with a red band, two black spheres.
- Special: yellow, yellow cross topmark.
- Emergency wreck marking buoy: blue and yellow vertical stripes, alternating blue and yellow flashes.
Worked example
At night you see a mark showing VQ(3) 5s. In daylight it has two black cones base-to-base and black-yellow-black bands. Identify it and the passing side.
Reasoning: three flashes mean three o'clock, east. The cones base-to-base and the black-yellow-black paint confirm an East cardinal. You pass to the east of the mark, keeping it between you and the danger, and hold the rhythm in view until clear.
Traps
- Using Region B logic, where red is to starboard.
- Naming a cardinal mark from paint colour alone and ignoring the rhythm.
- Passing a North cardinal to the south of the mark.
- Confusing a safe-water mark with a special mark.