PURPOSE: To raise the effectiveness of an investment on an icebreaking ship, which carries out its icebreaking operation only in a relatively short period and is usually deficient in open water cruising, which is required to use the ship effectively for other periods, by carrying out the icebreaking operation in the aft part of the ship to ease open water cruising.

CONSTITUTION: An icebreaking ship has a hull 1 including a forward part 2 and an aft part 3. The aft part has the main propulsion equipment including at least one screw arrangement 4 having a rotatable screw 5. The screw arrangement 4 is turnable in a horizontal plane, whereby the screw arrangement serves for steering the ship while the screw arrangement operates by the propulsion thrust of the screw 5. The screw arrangement 4 and the form of the aft part 3 of the hull 1 are dimensioned and designed for allowing the ship to move in the aft direction in heavy ice conditions.