ICE-BREAKER

To improve the manoeuvrability of ships when sailing in ice-covered water both when sailing ahead and astern, the hull of an ice-breaking ship is provided with ice-breaking parts, such as reamers (30) or cutting edges, which are arranged on and project laterally from the ship's sides (21, 22) and preferably form the widest point of the underwater hull, in which arrangement the width of the underwater hull in the area of the ice-breaking parts of the ship, such as reamers (30) or cutting edges, can be removed entirely or partially during the operation of the ship by displacing or swinging the reamers (30) or cutting edges or parts of them out of the underwater area, as a result of which the underwater hull is designed in such a way that it can be reduced to a smaller width during the operation of the ship, preferably to the width of the part of the ship which adjoins the part of the ship carrying the reamers (30) or cutting edges.