Abstract: Icebreaker (10) for a vessel (12), where the icebreaker (10) is connected to a bow (12a) of a vessel (12) for breaking up solid ice (40) floating on a water surface, the icebreaker (10) comprises a central part (14) sliding on a first side of the ice (40) and two or more side parts (16) sliding on an opposite part of the ice (40). The centre part (14) and the side parts (16) extend in parallel forward and works against each other when breaking the ice (40) to prevent the ice (40) from lifting, wherein a lower edge of the side parts (16), being in contact with the ice (40), is narrow and sharp to initiate breaking lines (50) in the ice (40), and the centre part (14) comprises a forward protruding cam structure (14a) to break the ice (40) between the side parts (16).

Abstract: This relates to vessels in general, but in particular to displacement vessels designed to be exposed from low to medium to high waves. Both for comfort of persons, animals or fragile goods, steady sailing is preferred, without causing the waves slamming in on the vessel hull or excessive pitching of the vessel. This is also the case for service and supply vessels performing operations in relation to offshore or subsea installations. To obtain a solution to the aforementioned issues the present invention provides a vessel, wherein a stern of the vessel extend below a design waterline (Tdwl), and wherein opposite side surfaces of the stern, when seen in an opposite direction of the vessels primary sailing direction, form an acute angle under and above the design waterline (Tdwl) to decrease the vessels displacement in the rear end and are adjoined along at a line of symmetry forming a stern centerline.

Abstract: Ships for navigating in icy waters having improved propulsion performance in open water and at the same time good maneuverability forward in icy waters are provided. Such ships include those having a bow area with a bulb adapted to generate a bow wave in phase opposition with respect to that generated by the ship's hull.

Abstract: A technique for protecting a structure from an impact with ice involves providing a horizontal spall initiator extending from the wall a distance of 1 to 10 cm, the horizontal spall initiator being resilient to the ice impact, and formed by blade segments having a blade width less than ½ a thickness of an expected hard zone of the ice; and situating the horizontal spell initiator at an elevation of the expected hard zone. Situating the horizontal spall initiator at an elevation of the hard zone may involve providing an elevation control mechanism (e.g. buoyancy, mechanical, or hydrodynamic), or may involve a panel with a plurality of horizontal spell initiators at respective elevations. The horizontal spell initiator may be driven.

Abstract: A method of providing a watercraft, especially an icebreaker or a cargo ship, tanker or similar transport vessel, with improved ice penetration characteristics and a watercraft manufactured according to the method, which watercraft has a hull (1) with a first end (2) and a second end (3) and which is equipped at said second end with a propulsion arrangement, which provides the main propulsive thrust of the watercraft, while the watercraft moves with either end ahead, and the steering of the watercraft, whereby said second end (3) of the watercraft is shaped and designed so that it, as such, has efficient ice penetration characteristics.

Abstract: Ice is broken with a motor-driven watercraft with three hulls, i.e. a trimaran (4), having a middle hull (3), a propulsion device (9), a right (1) and a left (2) side hull and a deck (5). The three hulls are attached. Ice is broken with the middle hull (3) of the trimaran. The propulsion device (9) is arranged in the middle hull (3) and a keel (7) in the longitudinal direction of the middle hull is arranged in the bow (3a) of the bottom of the middle hull for breaking ice.

Abstract: A vessel hull that does not create bow, stern, or transverse waves when moving through the water having an exterior surface that has a substantially constant cross-section along the length of the hull, and an interior surface that substantially encloses a flow channel for the length of the hull, the interior surface forming a converging-diverging diffuser. One standing half wave is contained within the hull, and no waves are generated outside the hull. The hull operates most efficiently at higher speeds, and has broad applications, including icebreaker, hybrid displacement and waveless hull, and other hull types.

Abstract: A jet propulsion unit for a small watercraft includes a reverse thrust arrangement. The reverse thrust arrangement includes a water diverter bucket assembly moveable between an open position and a closed position with respect to a steering nozzle of the jet propulsion unit. An idle speed of the watercraft's engine can be manually and/or automatically adjusted between a low engine idle speed and a high engine idle speed. The lower engine idle speed allows comfortable shifting maneuvers. The higher engine idle speed provides for tighter turning when the throttle is released. The engine cannot be started unless the reverse trust arrangement is in a partially open position.

Abstract: A relatively wide vessel is assisted through an ice field by an icebreaker having a relatively narrow hull. The icebreaker includes two steerable propulsion mechanisms at the opposite ends respectively of the hull, and the propulsion mechanisms are used to propel the icebreaker through the ice field in a direction at a substantial angle to its keel line, thereby opening in one pass of the icebreaker a passage having a width substantially greater than the waterline width of the icebreaker.

Abstract: The present invention pertains to sloped-faced, ice control elements that are each spaced apart across a riverbed adjacent to a floodplain region. The elements arrest a breakup ice run. The size and spacing of the ice-resisting elements can vary with river size and average ice piece size diameter. The ice-resisting elements, for example, can comprise three or four quarried granite blocks buried in the riverbed in a relatively narrow river of 100 feet or less. This arrangement allows gaps between each ice-resisting element for easy canoe and fish passage. These gaps prevent the ice pieces of the ice jam from passing through during breakup ice runs. The ice-resisting elements may be formed from various materials such as quarried rock, poured concrete, rock-filled cribs, etc. After the ice-resisting elements have retained and stabilized the ice jam, water levels recede and warming water temperatures melt the ice in place behind the ice-resisting elements.

Abstract: A hull for improved seakeeping characteristics of an icebreaking ship so that the breadth of the ship's hull will be decreased on the aft side of a wide foreship in the vicinity of the waterline. It can be implemented with solid hull form or so that on the side of the hull there is a section removable with respect to the solid hull, location or position of which will be changed with respect to the hull. In the solid structure on the side of the hull there will be formed a recess and above it a reamer, rising towards the stern and formed by a sloping surface. The recess forms a pass between the bilge keel and the reamer becoming wider towards the stern and joining the hull's narrower part of the aft body of the ship.

Abstract: An ice-breaking vessel having a spoon-shaped bow portion and an obliquely downwardly/rearwardly extending reamer at each longitudinal side is provided with second reamers located above the water line, above the rear portion of the adjacent first reamer and extending further outward than the same. A plow-shaped extension projects downwards from the plane bottom of the vessel, and has a breadth less than the breadth thereof. The rearmost part of the deck of the aft portion of the vessel has a reduced breath, so two corners are formed at each side of the deck. The bilges at the bottom plating extend to the forward of these corners, while the bilges at the plow-formed extension extend to the rearward corners.

Abstract: A semi-submersible oil platform comprising two pontoons (1), columns (2) extending up from the pontoons and supporting a deck structure (3), and stays (4) extending transversally of the pontoons between the columns (2), is provided with a plough-like protecting device (8) for diverting drifting objects, e.g. ice bodies which are not sufficiently large to be detected by radar, but which, nevertheless, could cause considerable damage to the horizontal stays (4) of the platform and the drill string.

Abstract: The stern apron is constructed as a volume body tapering to a sharp end in streamlined manner towards the stern of the ship and which at its lower outer edges is in each case wider than in the overlying region, so that the ship's resistance and the necessary propulsive power when travelling in open water is reduced and, particularly when moving astern, the propulsion and control members are protected against contact with the ice.

Abstract: A mooring and liquid transfer column which is fixed to the floor of an offshore body of water for securing a marine vessel. The column is resiliently retained and cable supported to permit its being deflected in response to ice forces acting thereagainst. The column upper end includes a narrow tower which extends beyond the water's surface and encloses fluid carrying conduits. A plurality of support cables depend from the column to transmit ice resisting forces into one or more remote anchors to which the support cables are attached.

Abstract: The prow of the ship with a lower power requirement in open and ice-covered water has a front surface which is forwardly inclined at the top over the entire beam of the ship with marginal cutting edges, preferably on rod-like profiles. The front surface passes into an underwater prow part with frames which are V-shaped at the bottom. The cutting edges above the waterline can forwardly pass into two catamaran-like stems, the front surface being curved in the longitudinal direction. The front surface is carried by thwartships frames, which are horizontal at the bottom in the central part of its longitudinal extension, below the construction waterline and approximately forms a plane there. In the midships longitudinal direction an ice-cutting central skid is provided on the prow. Even in the case of widely varying ice characteristics, favorable conditions are provided for breaking out one-part ice floes.

Abstract: In an ice-breaking ship, having sufficient power and being generally designed for efficient ice-breaking, the breaking of the ice is made more effective by changing the zone of ice crushing and shearing which occurs at the stem during normal ice-breaking of level ice, to a zone where the breaking occurs due to bending. This is obtained by forming the front portion of the ship so that at least within the area where the stem contacts and breaks level ice, the basically wedge-formed stem is truncated to form a relatively broad runner-like portion being inclined forwards in a relatively small angle to the water line plane of the ship. The width of the runner-like portion is determined in conformity with the general ice-breaking ability of the ship, whereby the driving power (P) of the ship, in kW, and the maximum beam (B) of the ship at its design water line, in meters, forms the basis for calculating, in meters, the width (W) of the runner-like portion by means of the formula:W=(0.02 to 0.08)(P/B).sup.0.63.

Abstract: A mobile monopod operations platform for use in ice covered seas and adapted for carrying out two modes of ice disaggregation, either or both such modes being selectively useable during either transit or relatively stationary operations. An ice breaker bow is employed in conjunction with simulated pitching and heaving brought about by the programmed use of a plurality of fully vectorable thrusters on a submersible hull. At the stern of the monopod structure, counter-rotating cutting drums are utilized for ice disaggregation in a mode particularly useful when the ice is thick. Topside of the bow and cutter area, an enclosed, generally circular, superstructure is provided for carrying out the requisite operations while mitigating the adverse effects of high winds.

Abstract: An icebreaker vessel having a forecastle of a pontoon-shaped configuration and of a greater width than the width of the ship's hull wherein an upper portion of the lower surface of the forecastle is substantially planar and inclined upwardly, and a lower portion gradually merges into a wedge-shaped portion with a central keel. The forecastle may be equipped with heat generating and/or heat transfer devices, with ice cutting devices and/or with water discharge orifices. The icebreaker vessel may include a trimming apparatus.

Abstract: With ships fitted with more than one propeller, it has been found that a remarkable increase in a ratio speed/power can be obtained especially in full-form ships, if the under-water portion of the ship's afterbody, at a level corresponding to the top clearance of the propellers, is divided into an upper, full body portion and a lower, narrow body part, with the transient part between said body portions being designed to form a substantially horizontal hull surface at each hull side.