When you drive in a car there is a clear road to follow. When you are out at sea, it is not possible to see a safe passage because some of the dangers are hidden below the water. Buoys act like road signs. They are important markers and if you do not fully understand them you might run aground.
Lateral marks are used to mark out a channel like a roadway in the water. Port cans are red can-shaped buoys and starboard cones are green cone-shaped buoys.
When you are entering a harbour the port can should be on your left and the starboard cone should be on your right. When you leave the harbour this is reversed.
Learn how to navigate buoys into a harbour
Cardinal buoys show areas of danger and are based on the points of a compass. The arrows on top of the buoys show which side is the safe passage. So, the west cardinal buoy tells you to sail on the westerly side of the buoy as there is danger to the east.
This buoy marks isolated danger and is nick-named 'Dennis the Menace' because of its black and red stripes.
This red and white stripy buoy indicates that there is navigable water all round the buoy. It is used to mark the centre line of a channel or to indicate a landfall.