These show sailors where they can expect safe water. A north cardinal mark means there is safe water to the north of the buoy (maybe also the east and west, but don’t be certain), an east cardinal mark means there is safe water to the east of the buoy, and so on.
Cardinal marks are black and yellow, and have cones on the top. The cones help you to recognise each mark, because they point to where the black sections will be. The north cardinal has cones pointing up, so the top section will be black and the bottom yellow. The east cardinal has one pointing up, and one down – so will be black top and bottom, with yellow in the middle. The south cardinal marks point down, so the bottom will be black, and the top will be yellow. Finally, the west cardinal has cones pointing towards each other – meaning black in the middle, with yellow top and bottom.
Every cardinal mark will also have a white light. Imagine a clock-face to remember that east is in the three o’clock position, so flashes three times. South is at six o’clock, so flashes six times, then one extra, long flash (this is written as 6+1). West is at nine o’clock, so flashes nine times, and north, at 12 o’clock, flashes continuously. The flashes will be quick or very quick.
Channel markers (lateral marks) are red or green, or both. In IALA A, starboard markers (starboard hand marks – SHM) will be green, and port markers (port hand marks – PHM) will be red. In IALA B, starboard markers will be red, and port markers green. In both systems, the port marker will have a flat “can” shape on top, and the starboard marker will have a cone – pointing up to the stars.
If you are entering a channel, you should leave the starboard markers to starboard, and the port markers to port. If you are leaving a channel, you should leave the starboard markers to port, and the port markers to starboard. It’s not always clear whether you are entering or leaving, so check your chart. The direction of buoyage will be marked with an arrow, like this:
The picture above shows part of the Solent, in the south of England. You can see that, travelling west to east, the direction of buoyage is different from travelling east to west. That’s because whichever direction you approach from, you are going “in” – so green starboard buoys are on the right, and red port buoys are on the left.
Like cardinal marks, channel markers have their own characteristics. A port starboard marker will have a red light (IALA A) or a green light (IALA B). A starboard marker will have a green light (IALA A) or a red light (IALA B). These lights can flash in any sequence EXCEPT for 2+1. Why is that?
It’s because there is one other type of channel marker, which tells you the best way to go if a channel splits, and they all flash 2+1.
In IALA A, you will see a green marker with a red band in the middle if it’s best to follow the split channel to port. So, going into the channel you will leave this preferred channel marker to starboard. It’s light will be green (the same colour as the main body of the buoy), and will flash 2+1. If the preferred channel is to starboard, the marker will be red with a green band (with a red light flashing 2+1), so you should leave it to port.
In IALA B, it’s the other way round. A preferred channel to port will be shown by a red buoy with a green band, flashing red 2+1. A preferred channel to starboard will be indicated by a green buoy with a red band, flashing green 2+1.
If there’s a particular danger in the water, you will see a black and red buoy with two black balls on top – and should give it a wide berth. This buoy will have a white light, flashing twice at night (remember two flashes – “get lost!”).
When you come to safe water, especially near the entrance to a buoyed channel, you might see a safe water mark. This will be red and white, with a red ball on top. The light will be white, and can flash one long flash, occulting, isophase, or morse A (dot dash).
There are also some yellow marker buoys, in various shapes, with a yellow diagonal cross on top. These give information about something specific in the neighbourhood (such as a wave energy station, perhaps, or to indicate low-flying aircraft approaching a coastal runway). The lights on these special marks will be yellow, and can flash in any sequence that is not the same as any white light in the vicinity. Why? Because white and yellow lights look similar at night.
Finally, there’s a buoy that you hope never to use. This is the emergency wreck marker. It is yellow and blue, with a yellow cross on top, and will generally be dropped by a sinking ship to mark the site of the wreck. These marks flash alternately yellow and blue at night, and will remain in place until the wreck has been cleared or properly charted.
Don’t forget that you can watch our animated video about buoyage, in English or in Polish. Click on the image on the left for the English version, and the image on the right for the Polish version. Whichever you choose, it will take you to our YouTube channel and open in a new tab.