Ships for navigating in icy waters having improved propulsion performance

A ship for navigating in icy waters, provided in a bow area with a bulb adapted to generate a bow wave in phase opposition with respect to that generated by a ship hull in such a way that the size of a resulting wave is reduced, thus reducing the ship's resistance, said bulb being connected to the ship hull by a connecting portion which defines a groove inclined downwards towards a stern to convey water under the hull, wherein the ship comprises a rib which frontally protrudes from the bulb on a vertical centreline plane of the bulb and extends from a front end of the bulb to said connecting portion, said rib having at least one front portion arranged below a waterline (WL) of the ship so that, in the case of forward movement in icy waters, the rib engages with such a front portion the ice from below and due to the forward motion of the ship progressively lifts it upwards above the bulb while simultaneously causing the breakage of the ice by bending, the front portion of the rib extending below the waterline (WL) to a depth (H1) predefined according to the maximum thickness of crushable ice, said rib being connected to the connecting portion at the bow of the groove without joining with a stem so as to leave a passage channel free between one side and the other of the bulb at said groove, the rib guiding the ice crushed thereby up to the passage channel in such a way that it is sucked into the groove itself and conveyed under the hull.