WATER-BORNE VESSEL AND METHOD OF MOVING VESSEL THROUGH WATER

Abstract: A water-borne vessel has a duct (12) through which water flows from the bow to the stern past the main part of the hull. At the stern end of the duct, the water impinges on a propeller (16) which extracts kinetic energy from the water.

Description: Title: "Water-borne vess el and method of moving vessel through water" Description of Invention From one aspect, the present invention relates to a method of moving a vessel through water. The vessel may be a ship, barge or boat and may be self-propelled or intended to be towed or pushed. The invention also relates to a vessel for use in the method. When a vessel moves through a body of water in one direction, flow of water in the opposite direction occurs in the vicinity of the vessel. To enable the vessel to move through the water, it is necessary to impart kinetic energy to water adjacent to the vessel. According to a first aspect of the invention, there is provided a method of moving a vessel through water wherein kinetic energy possessed by that part of the water which flows past the vessel is used to assist forward motion of the vessel. The reference to water flowing past the vessel includes a case where water flows through a duct defined by the vessel. In performance of the method, there will be frictional and other losses of energy. Accordingly, it is necessary for the vessel to be pulled or propelled if a selected speed through the water is to be maintained. The vessel may be propelled by sails and/or an engine on board the vessel or by another vessel. By using kinetic energy of the water which flows past the vessel to assist forward motion of the vessel, the loss of kinetic energy to the water is reduced and the power input needed to maintain a selected speed of the vessel is reduced - accordingly. In performance of the method of the invention, it is not necessary that the water which flows past the vessel shall give up all kinetic energy imparted to that water. According to a further aspect of the invention, there is provided a water-borne vessel having a water- driven device for transferring kinetic energy to the vessel from water which flows past the vessel when the vessel moves forwards. The device may comprise a propeller or the like, by which is meant herein a member which, when rotated in contact with water, tends to cause displacement of the water relative to the member. A paddle wheel and a turbine are considered to be like a propeller. Examples of vessels embodying the invention for use in the method of the invention will now be described, with reference to the accompanying drawings, wherein:- FIGURE 1 shows diagrammatically a side elevation of a boat? FIGURE 2 shows diagrammatically a plan view of the boat of Figure 1; FIGURE 3 shows diagrammatically a side elevation of a further boat; FIGURE 4 shows diagrammatically a plan view of the boat of Figure 3ϊ FIGURE 5 shows diagrammatically a plan view of a third example of boatj FIGURES 6 to 9 illustrate alternative rotating elements which may be provided in the boat of Figures 3 and 4; FIGURE 10 illustrates diagrammatically the arrange¬ ment of rotating elements provided in the boat of Figures 1 and 2 and in the boat of Figure 5; and FIGURE 11 illustrates an alternative form of rotating element which may be used in the boat of Figures 1 and 2 or in the boat of Figure 5. The boat of Figure 1 comprises a hull 10 which floats in water having a surface 11. Below the surface 11, there are provided on the hull 10 two elongated ducts, 12 and 13, one at each side of a longitudinal centreline of the hull. The ducts are substantially identical and therefore the duct 12 only will be described in detail. The duct 12 has open ends 14 and 15 disposed adjacent to the bow and stern of the hull respectively. The open end 14 is spaced somewhat from the stem of the boat towards the stern and the duct may converge from the open end 14 over a part of its length towards the end 15. The open end 15 is disposed adjacent to the stern of the boat, at a position where the beam and draught of the hull decrease considerably. Immediately adjacent to the open end 15, the duct is formed as a venturi. The duct is substantially rectilinear and is arranged with its length parallel to the centreline of the hull and at least approximately horizontal when the boat is in use. When the boat moves forwards through water, water which initially lies at a position in front of the hull 10 is displaced as the hull advances and flows past the hull through the ducts 12 and 13 towards the stern of the hull so that, as the hull advances, water moves into the space previously occupied by the stern of the hull. eans is provided for extracting from water flowing through the ducts 12 and 13 kinetic energy and applying that kinetic energy to the hull 10, to assist forward motion of the hull. This means comprises two rotatable elements in the form of propellers, each of which is mounted outside and immediately adjacent to the open end 15 of a corresponding one of the ducts. The propeller 16 associated with the duct 14 is mounted for rotation about an axis which coincides with the longitudinal axis of the duct 12 on a shaft rigidly secured to the hull 10. The other propeller is mounted in a corresponding manner. OMPI As water leaves the duct 12 through the open end 15 thereof, it impinges on the propeller 16 and causes the propeller to turn in a direction such that the propeller exerts forward thrust on its supporting shaft. This thrust is transmitted to the hull 10. ' The water which leaves the propeller is depleted of kinetic energy and occupies the position out of which the hull moves. As shown in Figure 10, the propellers associated with the ducts 12 and 13 rotate in opposite directions when the boat moves forwards. In place of the propellers, there may be provided adjacent to the stern ends of the ducts 12 and 13 respective turbines as illustrated in Figure 11. These turbines also would rotate in opposite directions when the boat moves forwards. In either case, each rotatable element, either propeller or turbine, may be arranged to drive the associated shaft, instead of rotating freely on the shaft. The shaft, in turn, would then be used to drive means for propelling the boat through the water. The boat illustrated in Figures 1 and 2 may be provided with primary means for propelling the boat through the water, for example sails or an internal combustion engine which drives a further propeller. The boat illustrated in Figures 3 and 4 is provided with two ducts on each side of the centreline of the hull of the boat. On each side, there is a lower duct 17 which lies generally below the hull and extends from a position near to a bow of the hull to a position near to the stern of the hull. There is also a side duct 18 having an inlet adjacent to the bow of the hull and at one side of the hull " . The side duct extends from this inlet beside the hull and upwardly to a position near to the stern, where the duct turns inboard and extends over a rotatable element 19 mounted adjacent to the stern end of the corresponding lower duct 17. The side duct is arranged to direct water which flows through the side duct down¬ wards onto the element 19 in a manner to assist turning of that element by water which flows through the lower duct. A corresponding arrangement of two ducts and one rotatable element is provided at the other side of the centreline of the hull. The rotatable elements may have the form shown in any one of Figures 6 to 9 and are arranged with their axes of rotation transverse to the length of the hull and generally horizontal when the boat is in use. Immediately upstream of the rotatable element 19, the lower duct 17 may be formed as a venturi. The aggregate cross-sectional area of the ducts in a plane transverse to the length of the hull is similar to the cross-sectional area of the remainder of the hull in a plane transverse to the length of the hull -where the maximum draught of the hull occurs. Each of the rotatable elements shown in Figures 6 to 9 is freely rotatably mounted on a supporting shaft secured to the hull. The element shown in Figure 6 has a number of solid vanes 20 projecting radially from the shaft and parallel to the length of the shaft. The element shown in Figure 7 has vanes arranged in a similar manner on a shaft but apertures 21 are defined between the vanes 22 and the shaft 23. The element illustrated in Figure 8 has helical vanes mounted on a shaft. Figure 9 illustrates the two rotatable elements of a boat having helical vanes of opposite hand. Figure 5 illustrates a modification of the boat shown in Figures 1 and 2, wherein each duct is provided with means for causing water flowing through the duct to rotate about a longitudinal axis of the duct and thus to follow a substantially spiral path. This means may be in the form of rifling on walls of the duct or vanes provided in the duct. In each embodiment of the invention, filters may be provided to prevent debris entering the ducts and outer walls of the ducts may be removable to facilitate maintenance. For controlling the flow of water through OMPI the ducts and thereby enhancing manoeuvreability of the vessel, there may be provided mechanically or electric¬ ally operated gates incorporated in the ducts. In larger vessels, there may be provided a number of ducts greater than that illustrated, these ducts being spaced apart longitudinally and/or transversely of the hull. The boat of Figures 1 and 2 and the boat of Figure 5 may be so modified that each duct extends downwardly in a direction from the bow towards the stern. With this arrangement, the propeller axis may be parallel to a longitudinal centreline of the duct or may be sub¬ stantially horizontal and therefore inclined to the longitudinal centreline of the duct. The ducts of the boat of Figures 1 and 2 and of the boat of Figure 5 may be defined by tubular members mounted on the outside of the hull or may extend within the main hull of the boat. Also, the bow end of each duct may be flared. OMPI

Claims: CLAI S : 1. A method of moving a vessel through water wherein kinetic energy possessed by that part of the water which flows past the vessel is used to assist forward motion of the vessel. 2. A method according to Claim 1 wherein kinetic energy is given up by water to the vessel in the vicinity of a stern of the vessel. 3. A method according to Claim 1 or Claim 2 wherein water flows past the vessel through a duct defined by the vessel and kinetic energy is given up by the water as it leaves the duct. 4. A method according to any preceding claim wherein water which flows past the vessel gives up kinetic energy by impinging on and rotating a propeller or the like. 5. A method according to Claim 4 wherein the propeller or the like is arranged to propel the vessel forwards relative to water surrounding the vessel when the propeller or like is rotated by the action of water flowing past the vessel in a direction from bow to stern. 6. A method according to Claim 3 or according to either of Claims 4 and 5 as appendant to Claim 3 wherein water flows through a venturi in the duct immediately upstream of the position where the water gives up kinetic energy. 7. A water-borne vessel having a water-driven device for transferring kinetic energy to the vessel from water which flows past the vessel when the vessel moves forwards. 8. A vessel according to Claim 7 wherein said device comprises a propeller or the like on which water flowing past the vessel impinges. 9. A vessel according to Claim 8 which has a duct through which water flows to the propeller or the like. 10. A vessel according to Claim 9 wherein the duct has the form of a venturi at a position immediately upstream of the propeller or the like. 11. A method of moving a vessel through water substantially as herein described with reference to and as illustrated in the accompanying drawings. 12. A vessel substantially as herein described with reference to and as illustrated in Figures 1 and 2 or Figures 3 and 4 or Figure 5 of the accompanying drawings. 13. Any novel feature or novel combination of features disclosed herein or in the accompanying drawings.

Inventors: SEE BRIAN
Applicants: SEE BRIAN
Application year: 1982
Main classification: B63J3
IPC codes: B63B1, B63J3