Aalloille Sea

Sea Marks


Sea marks guide for safe boating. Each boater should know how to interpret a sea chart and use a compass for correct directions. Learn to recognise at least the following marks both in nature and on the sea chart.


Cardinal Marks cleverly state on which side to pass them by. That's why boaters need to recognise them and know how to use a compass when boating.

North Mark: Pass on the North side, compass direction 0° (N)

East Mark: Pass on the East side, compass direction 90° (E)

South Mark: Pass on the South side, compass direction 180° (S)

West Mark: Pass on the West side, compass direction 270° (W)


Lateral Marks are the waterway's edge marks. They indicate the waterway's nominal travel direction towards harbours and headwaters. When traveling to the nominal direction the green mark is on the right side of the waterway, and red one on the left side.


Beacons and Line Marks are typically located on islets or shore and they can be seen from afar. They might contain lights, or reflectors.

Sector Lights emit light guiding boaters to stay on the waterway.

Line Marks guide boaters by showing the correct waterway when the further and higher mark is aligned with the nearer and lower mark.