Vessel having a non-planing hull provided with an attached foil which is below the surface of the water and spaced from the hull. The foil is attached in proximity to the aft end of the vessel, and is oriented with a downward tilt relative to the horizontal to provide a lifting force with a force co
Vessel having a non-planing hull provided with an attached foil which is below the surface of the water and spaced from the hull. The foil is attached in proximity to the aft end of the vessel, and is oriented with a downward tilt relative to the horizontal to provide a lifting force with a force component in the forward direction. The foil can be located entirely behind the vessel, partly below the aft hull portion of the vessel, or entirely therebelow. In the latter case, the hull is preferably provided with a recess.
대표청구항▼
What is claimed: 1. A vessel for operating on a body of water comprising: a non-planing hull having a waterline and a longitudinal direction with a forward portion, an aft portion, and a central portion, the hull configured to have the aft portion with a smaller water displacement relative to a wat
What is claimed: 1. A vessel for operating on a body of water comprising: a non-planing hull having a waterline and a longitudinal direction with a forward portion, an aft portion, and a central portion, the hull configured to have the aft portion with a smaller water displacement relative to a water displacement at the central portion; and a foil affixed to the aft hull portion, and below the surface of the water, and spaced from the hull, the foil having a chord, and a leading edge and a trailing edge relative to a forward direction, wherein the leading edge of the foil is tilted at a downward angle relative to the horizontal, wherein at least half the chord of the foil is behind a vertical line through the location where the aft portion of the hull leaves the water, wherein the foil has a chord and profile in longitudinal cross section, with a configuration to provide a lifting force, the tilt angle of the chord of the foil being measured with respect to the horizontal, and wherein the foil is oriented to provide a continuous, upward, forwardly directed component of the lifting force. 2. The vessel as in claim 1, having a Froude number less than 0.5. 3. The vessel as in claim 1, wherein the tilt angle is greater than zero and less than or equal to about 22°. 4. The vessel as in claim 1, wherein the spacing between the foil leading edge and the hull is greater than 0.1 times the length of the chord. 5. The vessel as in claim 4, wherein the spacing between the foil leading edge and the hull is in the range of from 0.25 to 0.5 times the length of the chord. 6. The vessel as in claim 1, wherein the chord length is in the range of from 2% to 10% of a longitudinal length of the hull at the waterline. 7. The vessel as in claim 1 further comprising a recess formed in the aft hull portion extending forwardly from the aft end, wherein the location where the aft hull portion leaves the water is located within a vertical projection of the recess, and wherein the foil is positioned at least partially within a vertical projection of the recess. 8. The vessel as in claim 7, wherein the foil is located entirely within the vertical projection of the recess. 9. The vessel as in claim 7, wherein the hull has a sponson located at each side of the hull at the aft portion, each sponson defining at least a side part of the recess and extending vertically beneath the surface of the water, wherein the foil is mounted to, and between, the sponsons beneath the surface of the water. 10. The vessel as in claim 7, wherein the foil is positioned with the leading edge being in the range of from 0.5 times to 0.75 times the chord length behind the location where the aft hull portion leaves the water, in the longitudinal direction. 11. The vessel as in claim 1, wherein a bottom surface of the aft hull portion in a region proximate the aft end is inclined relative to the bottom surface of the aft hull portion distant the aft end, and wherein the angle between the horizontal and the tangent to the hull in the inclined region taken in a vertical plane at the longitudinal position of the foil leading edge is in the range of from 11° to 25°. 12. The vessel as in claim 11, wherein the inclined proximate bottom surface extends between 0.5 and 1.5 times the chord length ahead of the foil leading edge position in the longitudinal direction. 13. The vessel as in claim 7, wherein the recess has a hull portion positioned free of the surface of the water, wherein the vertical spacing of the free hull portion above the surface of the water is in the range of from 0.25 to 0.75 times the chord length. 14. The vessel as in claim 1, wherein a part of the foil including the leading edge extends beneath the aft hull portion forward of the longitudinal location where the aft hull portion leaves the surface of the water, wherein the angle between the horizontal and the tangent to the hull at the location where the aft hull portion leaves the water taken in a vertical plane is in the range of from 8° to 16°, and wherein the tilt angle of the foil is less than or equal to 12°. 15. The vessel as in claim 14, wherein the trailing edge of the foil is positioned at a depth below the waterline in the range of from zero to 0.75 times the chord length. 16. The vessel as in claim 1, wherein no part of the foil extends under the aft hull portion forward of the longitudinal location where the aft hull portion leaves the surface of the water, wherein the angle between the horizontal and the tangent to the hull at the location where the aft hull portion leaves the water taken in a vertical plane is in the range from 8° to 16° and wherein the tilt angle of the foil is less than or equal to 6°. 17. The vessel as in claim 16, wherein the leading edge of the foil is positioned rearwardly from the aft end of the hull a distance of about 1.0 times the chord length, and wherein the trailing edge of the foil is positioned at a depth below the waterline in the range of from zero to 0.5 times the chord length. 18. The vessel as in claim 7, wherein the recess has a bottom surface that is inclined relative to the angle of a bottom surface of the aft hull portion distant the recess, and wherein the angle between the horizontal and a tangent to the hull at the forward-most point of the bottom surface of the recess taken in a vertical plane is in the range from 8° to 16°. 19. The vessel as in claim 1, wherein the tilt angle of the foil is adjustable. 20. The vessel as in claim 1 having a support for mounting the foil to the vessel, wherein the support with the mounted foil is selectively movable with respect to the hull. 21. The vessel in claim 1, wherein the spacing between the foil leading edge and the hull is greater than or equal to 0.25 times the length of the chord. 22. The vessel as in claim 1, wherein the hull is configured for sailing, and wherein the spacing between the foil and the hull is approximately equal to the length of the foil. 23. A vessel for operating on a body of water comprising: a non-planing hull having a waterline and a longitudinal direction with a forward portion, an aft portion, and a central portion, the hull configured to have the aft portion with a smaller water displacement relative to a water displacement of the central portion; and a foil affixed to the aft hull portion, and below the surface of the water and spaced from the hull, the foil having a chord, and a leading edge and a trailing edge relative to a forward direction, wherein the chord of the foil is tilted at a downward angle relative to the horizontal, which downward angle is greater than zero degrees and less than or equal to 22°, wherein at least half the chord of the foil is behind a vertical line through the location where the aft portion of the hull leaves the water, wherein the foil has a profile in longitudinal cross section with a configuration to provide a lifting force, the tilt angle of the foil being measured with respect to the chord, wherein the chord length is in the range of from 2% to 10% of the longitudinal length of the hull at the waterline, and wherein the foil is oriented to provide a continuous, upward, forwardly directed component of the lifting force. 24. The vessel as in claim 23, wherein the spacing between the foil leading edge and the hull is greater than or equal to 0.25 times the length of the chord. 25. The vessel as in claim 24, wherein the spacing between the foil leading edge and the hull is less than or equal to 0.50 times the length of the chord. 26. A vessel for operating on a body of water comprising: a non-planing hull having a waterline and a longitudinal direction with a forward portion, an aft portion, and a central portion, the hull configured to have the aft portion with a smaller water displacement relative to a water displacement at the central portion; and a foil affixed to the aft hull portion, and below the surface of the water, and spaced from the hull, the foil having a chord, and a leading edge and a trailing edge relative to a forward direction, a recess formed in the aft hull portion extending forwardly from the aft end, wherein the location where the aft hull portion leaves the water is located within a vertical projection of the recess, and wherein the foil is positioned at least partially within a vertical projection of the recess; wherein the leading edge of the foil is tilted at a downward angle relative to the horizontal, wherein at least half the chord of the foil is behind a vertical line through the location where the aft portion of the hull leaves the water, wherein the foil has a chord and profile in longitudinal cross section, with a configuration to provide a lifting force, the tilt angle of the chord of the foil being measured with respect to the horizontal, and wherein the foil is oriented to provide a continuous, upward, forwardly directed component of the lifting force.
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이 특허에 인용된 특허 (4)
Danahy Philip J. (12801 Prestwick Drive Oxon Hill MD 20022), Hull foils with hydrodynamic righting forces.
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