When the temperature drops below ‑10°C, the harbour basin can freeze over in just a few hours. For this reason, MS Eisvogel is used in all three harbours (Albern, Freudenau and Lobau) to break up ice up to a depth of 60 cm (most recently in 1985) to enable vessels to enter and leave the harbour.
The icebreaker is 32 metres long, 6.5 metres wide and weighs 80 tons. The ice is no match for its 520 PS diesel engines and hull protected by 12 mm of steel. To provide even more power, the ship can take on water ballast equivalent to its own weight.
MS Eisvogel has been in service since 1955 and can also be seen on the Danube outside the winter season, for example for tours of the port of Vienna, which can be organised on request.