The announcement of an ice-breaking operation by the Director of the Maritime Office is associated with additional services provided during ship entry/exit maneuvers in ports. This is a situation that enables safe maneuvering and mooring of ships. It increases port operating costs but allows it to function year-round. The Southern Baltic is formally a non-freezing sea, but in January and February, a situation arises where an ice cover forms in port channels, the outer harbor, and the roadstead, sometimes several nautical miles from the shore. This depends on weather conditions from December onwards. Sustained frost for a period of over 2 weeks and unfavorable wind patterns (for Gdynia, these are easterly winds) can lead to the freezing of the coastal zone. In the winter of 2010/2011, a thaw in January proved favorable. As a result, freezing occurred only in February, and it was necessary to announce an ice-breaking operation for a period of 2 weeks.
The maneuvering capabilities of ships moving in ice cover are limited. For large, fast vessels (e.g., ferries), this situation limits the ability to dock at the quay (due to the piling up of crushed ice floes), and for many other vessels, it may turn out that they are unable to overcome the additional resistance posed by the ice cover.
Advantages of azimuth thrusters
Tugs equipped with ASD (azimuth stern drive) propulsion, i.e., with azimuth drive, have a significant advantage – they can generate significantly greater thrust in lateral directions relative to the ship’s main axis. (…)
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Source: Logistyka Magazine 5/2011