A HYDROFOIL VESSEL

Abstract

The invention involves a hydrofoil vessel (1) comprising a hydrofoil assembly (4), and a hull assembly (2) presenting, when the vessel is floating at rest, a vertical symmetry plane (SP), wherein the hydrofoil assembly (4) comprises two struts (401) extending from the hull assembly (2) on opposite transverse sides of the symmetry plane (SP), mainly downwards when the vessel is floating at rest, or mainly partly away from the symmetry plane and partly downwards when the vessel is floating at rest, wherein the hydrofoil assembly (4) comprises two main foil portions (411) each extending from a respective one of the struts (401), at least partly towards the symmetry plane (SP), wherein each strut (401) comprises a strut foil (402) with a non-symmetrical cross-section, and with a pressure side (402P) facing at least partly towards the symmetry plane, and a suction side (402S) facing at least partly away from the symmetry plane (SP).

Claims

1. A hydrofoil vessel comprising a hydrofoil assembly, and a hull assembly presenting, when the vessel is floating at rest, a vertical symmetry plane, wherein the hydrofoil assembly comprises two struts extending from the hull assembly on opposite transverse sides of the symmetry plane (SP), mainly downwards when the vessel is floating at rest, mainly partly away from the symmetry plane and partly downwards when the vessel is floating at rest, or mainly partly towards the symmetry plane and partly downwards when the vessel is floating at rest, wherein the hydrofoil assembly comprises two main foil portions each extending from a respective one of the struts, at least partly towards the symmetry plane (SP), wherein each strut comprises a strut foil with a non-symmetrical cross-section, and with a pressure side facing at least partly towards the symmetry plane, and a suction side facing at least partly away from the symmetry plane (SP).

2. A hydrofoil vessel according to claim 1, wherein each strut comprises a major portion and a transition portion, the transition portion forming a transition from the major portion to the respective main foil portion, wherein the length of the transition portion is no more than 30% of the length of the respective strut.

3. A hydrofoil vessel according to claim 1, wherein each main foil portion extends to the other of the main foil portions.

4. A hydrofoil vessel according to claim 1, wherein the hull assembly presents, when the vessel is floating at rest, a horizontal plane (HP) coinciding with a waterline of the hull assembly, wherein the main foil portions extend substantially in parallel with the horizontal plane (HP).

5. A hydrofoil vessel according to claim 1, wherein the hull assembly presents, when the vessel is floating at rest, a horizontal plane (HP) coinciding with a waterline of the hull assembly, wherein the main foil portions each extend partly towards the symmetry plane and partly towards the horizontal plane (HP).

6. A hydrofoil vessel according to claim 1, wherein the hull assembly presents, when the vessel is floating at rest, a horizontal plane (HP) coinciding with a waterline of the hull assembly, wherein each main foil portion has a non-symmetrical cross-section, and a pressure side facing at least partly away from the horizontal plane (HP), and a suction side-facing at least partly towards the horizontal plane (HP).

7. A hydrofoil vessel according to claim 1, wherein the strut foils each extend substantially within a respective plane which is parallel to the symmetry plane (SP).

8. A hydrofoil vessel according to claim 1, wherein the strut foils and the main foil portions are fixed in relation to the hull assembly.

9. A hydrofoil vessel according to claim 1, wherein the strut foils and the main foil portions are surface piercing.

10. A hydrofoil vessel according to claim 1, wherein the vessel comprises, in addition to the hydrofoil assembly-, an adjustable hydrofoil having an adjustable pitch orientation so as to change the angle of attack of the adjustable hydrofoil.

11. A hydrofoil vessel according to claim 10, wherein the hull assembly presents, when the vessel is floating at rest, a horizontal plane (HP) coinciding with a waterline of the hull assembly, wherein the adjustable hydrofoil-is, compared to the hydrofoil assembly, further away from the horizontal plane (HP).

12. A hydrofoil vessel according to claim 10, wherein the adjustable hydrofoil is connected to the hull assembly independently of the hydrofoil assembly, by means of one or more foil holding members.

13. A hydrofoil vessel according to claim 1, wherein the vessel is not adapted to be driven by wind power.

14. A hydrofoil set for a hydrofoil vessel-comprising a hull assembly presenting, when the vessel is floating at rest, a vertical symmetry plane (SP), the hydrofoil set comprising a hydrofoil assembly comprising two struts adapted to extend from the hull assembly on opposite transverse sides of the symmetry plane (SP), mainly downwards when the vessel is floating at rest, mainly partly away from the symmetry plane and partly downwards when the vessel is floating at rest, or mainly partly towards the symmetry plane and partly downwards when the vessel is floating at rest, wherein the hydrofoil assembly comprises two main foil portions each adapted to extend from a respective one of the struts, at least partly towards the symmetry plane (SP), wherein each strut comprises a strut foil with a non-symmetrical cross-section, and with a pressure side adapted to face at least partly towards the symmetry plane, and a suction side-adapted to face at least partly away from the symmetry plane (SP).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Below, embodiments of the invention will be described with reference to the drawings, in which:

[0045] FIG. 1 shows a perspective view a hydrofoil vessel according to an embodiment of the invention,

[0046] FIG. 2 shows a side view of the vessel in FIG. 1,

[0047] FIG. 3 shows a view of the vessel in FIG. 1 from in front of the vessel,

[0048] FIG. 4 shows a cross-sectional view with the section oriented as indicated by the arrows IV in FIG. 2,

[0049] FIG. 5 shows a detail in FIG. 3,

[0050] FIG. 6 shows the view of FIG. 3, when the vessel is heeling over,

[0051] FIG. 7 shows a hydrofoil vessel according to an alternative embodiment of the invention, in a view corresponding to the view in FIG. 3,

[0052] FIG. 8 shows a hydrofoil vessel according to a further alternative embodiment of the invention, in a view corresponding to the view in FIG. 3,

[0053] FIG. 9 shows a hydrofoil vessel according to another embodiment of the invention, in a view corresponding to the view in FIG. 3,

[0054] FIG. 10 shows a hydrofoil vessel according to a further embodiment of the invention, in a view corresponding to the view in FIG. 3,

[0055] FIG. 11 shows a hydrofoil vessel according to a yet another embodiment of the invention, in a view corresponding to the view in FIG. 3, and

[0056] FIG. 12 shows a hydrofoil vessel according to a further embodiment of the invention, in a view corresponding to the view in FIG. 3.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0057] FIG. 1 and FIG. 2 show a hydrofoil vessel 1. The vessel comprises a hull assembly 2 comprising a single hull.

[0058] Reference is made also to FIG. 3. The hull assembly 2 presents, when the vessel is floating at rest, an imaginary vertical symmetry plane SP, and an imaginary horizontal plane HP coinciding with a waterline of the hull assembly 2.

[0059] The vessel comprises an adjustable hydrofoil 301 having an adjustable pitch orientation so as to change the angle of attack of the adjustable hydrofoil. The adjustable hydrofoil 301 is connected to the hull assembly by means of two foil holding members 302. The adjustable hydrofoil 301 may be, as exemplified in FIG. 2, in the direction of travel of the vessel 1, located substantially at a center of gravity CG of the vessel.

[0060] The vessel also comprises a propulsion arrangement. The propulsion arrangement comprises a propeller 501. The propulsion arrangement is provided at a stern of the hull. In this example, the propulsion arrangement comprises an electric motor in a pod 502. The motor is arranged to drive the propeller, which is mounted on the pod. The pod is mounted to the hull assembly via a pod carrying element 503. The motor is arranged to be powered by a power source such as a battery pack 504. The propulsion arrangement may be controlled so as to steer the vessel.

[0061] The vessel could be provided with any suitable alternative propulsion arrangement, e.g. comprising an outboard or an inboard engine.

[0062] The vessel further comprises an aft foil 601. The aft foil is arranged to support, in a hydrofoil driving mode, an aft part of the hull assembly. The aft foil is mounted to the hull assembly via an aft foil carrying element 503. In this embodiment, the aft foil carrying element is also the pod carrying element.

[0063] The vessel further comprises a hydrofoil assembly 4. As exemplified in FIG. 3, the adjustable hydrofoil 301 is, compared to the hydrofoil assembly, further away from the horizontal plane HP. As exemplified in FIG. 2, the hydrofoil assembly 4 may be, in the direction of forward travel of the vessel 1, located further forward than the adjustable hydrofoil 301. Alternatively, the hydrofoil assembly 4 may be located behind the adjustable hydrofoil 301. As a further alternative, the hydrofoil assembly 4 and the adjustable hydrofoil 301 may be in substantially the same position in the direction of travel of the vessel 1.

[0064] The hydrofoil assembly 4 comprises two struts 401 extending from the hull assembly 2 on opposite transverse sides of the symmetry plane SP, mainly within a respective plane which is parallel to the symmetry plane. Each strut 401 comprises a strut foil 402.

[0065] As exemplified in FIG. 4, each strut foil 402 has a non-symmetrical cross-section, and with a suction side 402S facing away from the symmetry plane SP, and a pressure side 402P facing towards the symmetry plane.

[0066] The hydrofoil assembly 4 comprises two main foil portions 411 each extending from a respective of the struts 401, towards the symmetry plane SP and substantially in parallel with the horizontal plane HP. Each main foil portion 411 extends to the other of the main foil portions 411. The main foil portions 411 form together a single main foil.

[0067] Each main foil portion 411 has a non-symmetrical cross-section, and a pressure side 411P facing downwards when the vessel is floating at rest, and a suction side 411S facing upwards when the vessel is floating at rest.

[0068] The strut foils 402 and the main foil portions 411 are fixed in relation to the hull assembly 2. The strut foils 402 and the main foil portions 411 are surface piercing. In some embodiments, the strut foils 402 and/or the main foil portions 411 may be adjustable and/or retractable.

[0069] Reference is made also to FIG. 5. Each strut 401 further comprises a major portion 403 and a transition portion 404. The transition portion forms a transition from the major portion to the respective main foil portion 411. The transition portion 404 is provided as a bend from the major portion 403 to the main foil portion 411. The transition portion forms a smooth transition from the major portion to the main foil portion. The length Ltp of the transition portion 404 is preferably no more than 30% of the length Ls of the respective strut. In the example in FIG. 1 - FIG. 5, the length Ltp of each transition portion 404 is about 10% of the length Ls of the respective strut. A trailing edge TE of the hydrofoil assembly is indicated with a broken line in FIG. 5. The length Ltp of the transition portion may be defined by the length of a trailing edge thereof. The length Ls of the strut may be defined by the length of a trailing edge thereof.

[0070] The adjustable hydrofoil 301 is in the embodiment in FIG. 1 - FIG. 4 connected to the hull assembly, independently of the hydrofoil assembly 4, by means of the two foil holding members 302. In alternative embodiments, the adjustable hydrofoil 301 may be mounted to the hydrofoil assembly 4, by means of the one, or more than two, foil holding members 302.

[0071] Reference is made also to FIG. 6. When the vessel is not heeling over, the strut foils 402 may be, depending on the speed of the vessel, above the water, or partly submerged in the water. When the vessel heels over, one of the strut foils 402 becomes lower than the other of the strut foils. Thereby, the lower strut foil may be further submerged in water than the higher strut foil. The lower strut foil may be partly or fully submerged in the water while the higher strut foil may be less submerged than the lower strut foil, or above the water. Thereby, the hydrodynamic force will be larger on the lower strut foil than on the higher strut foil.

[0072] The orientation of the lower of the strut foils serves to provide a smallest angle AS 1 between a resultant hydrodynamic force F1 acting on the lower strut foil, and a vector V1 from the center of gravity CG of the vessel to a center of pressure of the hydrodynamic force F1, which is at least 10 degrees, in this example 29 degrees. Thereby, the force F1 will counteract the heeling of the vessel.

[0073] Further, when the vessel heels over, one of the main foil portions 411 becomes lower than the other of the main foil portions. Thereby, the lower main foil portion may be further submerged in water than the higher main foil portion. The lower main foil portion may the partly or fully submerged in the water while the higher main foil portion may be less submerged than the lower main foil portion, or above the water. Thereby, the hydrodynamic force will be larger on the lower main foil portion than on the higher main foil portion.

[0074] The orientation of the lower of the main foils portion serves to provide a smallest angle AS2 between a resultant hydrodynamic force F2 acting on the lower main foil portion, and a vector V2 from the center of gravity CG of the vessel to a center of pressure of the hydrodynamic force F2, which is at least 10 degrees, in this example 32 degrees. Thereby, the force F2 will also counteract the heeling of the vessel.

[0075] FIG. 7 shows an alternative embodiment, which is similar to the embodiment shown in FIG. 1 - FIG. 6, except for the following features: Outer parts of the main foil portions 411 each extend from a respective one of the struts 401, towards the symmetry plane and partly upwards when the vessel is floating at rest. Inner parts of the main foil portions 411 each extend towards the symmetry plane SP and substantially in parallel with the horizontal plane HP. The outer parts of each main foil portion 411 has a pressure side 411P facing partly downwards when the vessel is floating at rest, and a suction side 411S facing partly upwards when the vessel is floating at rest. The inner parts of each main foil portion 411 has a pressure side 411P facing downwards when the vessel is floating at rest, and a suction side 411S facing upwards when the vessel is floating at rest.

[0076] FIG. 8 shows a further alternative embodiment, which is similar to the embodiment shown in FIG. 1 - FIG. 6, except for the following features: The main foil portions 411 each extend from a respective one of the struts 401, towards the symmetry plane and partly upwards when the vessel is floating at rest. Each main foil portion 411 extends to the hull assembly 2. Thereby, the main foil portions may be mounted to the hull assembly. Each main foil portion 411 has a pressure side 411P facing partly downwards when the vessel is floating at rest, and a suction side 411S facing partly upwards when the vessel is floating at rest.

[0077] FIG. 9 shows a further alternative embodiment, which is similar to the embodiment shown in FIG. 1 - FIG. 6, except for the following features: The struts 401 extend from the hull assembly 2 on opposite transverse sides of the symmetry plane SP, mainly partly away from the symmetry plane and partly downwards when the vessel is floating at rest. Thereby, the strut foil pressure sides 402P face partly towards the symmetry plane SP, and the strut foil suction sides 402S face partly away from the symmetry plane SP.

[0078] FIG. 10 shows another embodiment, which is similar to the embodiment shown in FIG. 1 -FIG. 6, except for the following: The vessel does not comprise an adjustable hydrofoil. The vessel comprises a surface piercing hydrofoil assembly.

[0079] FIG. 11 shows yet another embodiment. The vessel comprises a hydrofoil assembly comprising two struts 401 extending from the hull assembly on opposite transverse sides of the symmetry plane SP, mainly within a respective plane which is parallel to the symmetry plane. Each strut 401 comprises a strut foil 402. Each strut foil 402 has a non-symmetrical cross-section, and with a suction side 402S facing away from the symmetry plane SP, and a pressure side 402P facing towards the symmetry plane.

[0080] The hydrofoil assembly 4 comprises two main foil portions 411 each extending from a respective of the struts 401, towards the symmetry plane SP and substantially in parallel with the horizontal plane HP. Each main foil portion 411 extends to the other of the main foil portions 411.

[0081] Cantilevered foil portions 412 each extend from a respective of the struts 401, away from the symmetry plane SP. The cantilevered foil portions 412 extend substantially in parallel with the horizontal plane HP. The main foil portions 411 and the cantilevered foil portions 412 form together a single main foil. The main foil has a non-symmetrical cross-section, and a pressure side facing downwards when the vessel is floating at rest, and a suction side 411S facing upwards when the vessel is floating at rest. The main foil has an adjustable pitch orientation so as to change the angle of attack of the adjustable hydrofoil. The main foil is an immersed hydrofoil.

[0082] FIG. 12 shows a further alternative embodiment, which is similar to the embodiment shown in FIG. 1 - FIG. 6, except for the following features: The struts 401 extend from the hull assembly 2 on opposite transverse sides of the symmetry plane SP, mainly partly towards the symmetry plane and partly downwards when the vessel is floating at rest. Thereby, the strut foil pressure sides 402P face partly towards the symmetry plane SP, and the strut foil suction sides 402S face partly away from the symmetry plane SP. Further, the main foil portions 411 each extend partly towards the symmetry plane and partly away from the horizontal plane HP.

[0083] It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.