The operation marks the vessel’s first significant ice-clearing mission since 2017, when the harbor waters last froze over. Harbor officials said breaking the ice is essential to protect docked ships and keep navigation channels open for incoming traffic. The Eisvogel is currently operating in Vienna’s three major port areas, Freudenau, Albern and Lobau, with crews working about every two days to manage ice buildup. The 70-year-old icebreaker was built in 1955 and is specially designed to crush thick ice using its reinforced hull, powerful engines and weight. The 32-meter-long, 80-tonne vessel uses a steel-reinforced bow and its own mass to break ice and push it aside, protecting the hulls of anchored cargo and cruise ships from dangerous ice pressure.