Saw that too, and across Europe in December. Found the answer in the sites FAQ: > Why do ships sometimes appear to move across land? > In some cases this is

Saw that too, and across Europe in December. Found the answer in the sites FAQ: > Why do ships sometimes appear to move across land? > In some cases this is because there are ships navigating via canals or rivers that aren’t visible on the map. Generally, though, this effect is an artefact of animating a ship between two recorded positions with missing data between, especially when the positions are separated by a narrow strip of land. We may develop the map to remove this effect in the future.