In my latest blog post I showed you an intensity plot and a movie of the large commercial ships sailing in and out of the Baltic Sea through Fehmarnbelt.
But when building a tunnel across Fehmarnbelt it is also important to have knowledge about the intensity of movements with smaller local ships, such as pleasure boats, local fishing ships and the like.
The safety of these ships is equally important. Persons in a pleasure boat are vulnerable in collisions with construction vessels or large commercial ships and therefore a pleasure boat crossing Fehmarnbelt will draw much attention from construction vessels and the large commercial ships. When we know the intensity and sailing
pattern of the smaller local ships, we can plan how to handle this issue and introduce the necessary risk reducing measures for all vessels in Fehmarnbelt.
How to get that information?
So, how do we get the information we need? Luckily a radar is there is installed at the top of a silo in Rødbyhavn (Rødby Habour), and by using those data we were able to get an overview of the smaller local ships.
First we had to seek out and remove all the tracks from the larger commercial ships (also seen in AIS data – a GPS based system for tracking of ships).
We did that by creating an algorithm to match the tracks in radar with the tracks seen in AIS. As you see in the picture, the problem with matching data from the two data sets was that they were registered at almost the same spot at almost the same time.
Well, we solved the problem and were able to remove the international commercial traffic from the radar data and were left with illustrations of movements from smaller local ships, such as pleasure boats, local fishing ships and the like.
As you can see, the local traffic with smaller ships has quite another pattern than the international commercial traffic that I showed in my last blog post, and a significant seasonal variation: on top you see around 400 tracks in January, on the buttom you see around 1800 tracks in July.