TRANSOM STERN HULL FORM AND APPENDAGES FOR IMPROVED HYDRODYNAMICS

• US 20100000455A1
• Filed: 07/02/2008
• Published: 01/07/2010
• Est. Priority Date: 07/02/2008
• Status: Active Grant

• Current Assignee: Justin Harper
• Original Assignee: Justin Harper
• Inventors: Harper, Justin Alexander
• Granted Patent: US 8,122,840 B2
• Time in Patent Office: Days
• US Class Current: 114/61.29
• CPC Class Codes: B63B 1/08 Shape of aft part
• CPC Class Codes: B63B 1/40 by diminishing wave resistance
• CPC Class Codes: B63B 2001/325 Interceptors, i.e. elongate blade-like members projecting from a surface into the fluid flow substantially perpendicular to the flow direction, and by a small amount compared to its own length
• CPC Class Codes: Y02T 70/10 Measures concerning design or construction of watercraft hulls

Abstract

An improved displacement hull form for ships and boats, in one of many possible embodiments includes a transom stern hull form (100F) having a hull underside (120A) that is substantially horizontal in transverse orientation along the aft-most portion of said hull form (100F), a pair of endplates (300D) having a substantially vertical orientation along the aft half of said hull form (100F) waterline length, a pair of cambered rudders (502J) located near the stern of said hull form (100F) with said cambered rudders (502J) having pressure faces oriented towards said hull form longitudinal centerplane (110A), and stern buttock-line shaping defined by a supercavitating hydrofoil (700M) shape. The hydrodynamics of said hull form (100F) are improved in terms of reduced resistance, reduced trim and draft aft, and reduced ship wave train. Other embodiments are described and shown.

Claims

1. An apparatus, comprising:

a transom stern displacement hull to operate at a speed-to-length ratio of from about 0.80 to about 3.00, the hull bisected along its length by a vertical centerplane, the hull including a hull underside along an aft portion of the hull, the hull underside having a deadrise angle along the hull underside of from approximately −

12 degrees to approximately 10 degrees, with the hull underside bounded on a right lateral side of the hull by a right hull side and on a left lateral side of the hull by a left hull side, the right and left hull sides each extending from the hull underside to a waterline;

a right endplate coupled to the hull proximal the right hull side; and

a left endplate coupled to the hull proximal the left hull side and generally opposite the right endplate, the right and left endplates each having a fixed height from approximately 0.2 percent of a displacement hull form beam measured adjacent the waterline to approximately 10 percent of the displacement hull beam measured adjacent the waterline,

wherein the right and left endplates extend along a hull length from approximately the aft end of the hull toward a bow of the hull from about 1 to about 40 percent of hull waterline length, with the right and left endplates each generally aligned within approximately 20 degrees of the vertical plane.

2. The apparatus of claim 1, further comprising a pair of fins having a substantially vertical span orientation, the pair of fins fixed to the hull underside on opposite sides of the vertical plane.

3. The apparatus of claim 1, further comprising a pair of rudders having a span orientation that is substantially perpendicular to a plane defined by the waterline, the pair of rudders coupled to the hull underside on opposite sides of the longitudinal center plane.

4. The apparatus of claim 3, wherein the rudders are moveable.

5. The apparatus of claim 3, wherein the span orientation of each of the pair of rudders is approximately parallel.

6. The apparatus of claim 3, wherein each of the pair of rudders have a quarter chord line located less than approximately 25 percent of the waterline length of the hull from the aft end of the hull.

7. The apparatus of claim 3, wherein a right rudder is disposed proximal the right hull side, and a left rudder is disposed proximal the left hull side.

8. The apparatus of claim 3, wherein a right rudder of the pair has a right rudder cross section profile when sectioned along a plane that is substantially parallel to a plane defined by the waterline, and a left rudder of the pair has a left rudder cross section profile that substantially mirrors the right rudder cross section profile, wherein the left and right cross sections profiles each include a streamlined cambered hydrofoil such that a respective pressure side of each rudder faces the vertical centerplane of said hull form, said camber having a lift coefficient of between 0.01 and 1.0.

9. An apparatus, comprising

a transom stern displacement hull to operate at a speed-to-length ratio of from about 0.80 to about 3.00, the hull including a hull underside along an aft portion of the hull, the hull underside having a deadrise angle along the hull underside of from approximately −

12 degrees to approximately 10 degrees, with the hull underside bounded on a right lateral side of the hull by a right hull side and on a left lateral side of the hull by a left hull side, the right and left hull sides each extending from the hull underside to a waterline; and

a pair of rudders coupled to the hull underside on opposite sides of a vertical centerplane that bisects the hull along its length, the rudders each having a span orientation that is substantially perpendicular to the underside, the rudders each having a chord orientation that is substantially parallel to the vertical centerplane of the hull, the rudders each having a cross-sectional shape along a plane substantially parallel to the plane defined by the waterline, the shape defining a streamlined cambered hydrofoil, with respective pressure sides of the rudders each facing the vertical plane, the rudders to produce lift coefficients of between 0.01 and 1.0, with each of the rudders having a respective rudder quarter chord line located a distance from the aft end of the hull, the distance being between 0 and approximately 25 percent of the hull waterline length.

10. The apparatus of claim 9, wherein the rudders are moveable.

11. The apparatus of claim 9, wherein the hull defines a right and left chine, with the right rudder disposed along the underside proximal the right chine, and the left rudder disposed along the underside proximal the left chine.

12. The apparatus of claim 9, wherein the hull underside defines a cambered surface including a supercavitating hydrofoil and

wherein the cambered surface has a longitudinal extent along the hull underside, the extent extending from the aft portion of the hull underside toward a bow from about 10 percent to about 50 percent of the waterline length of the hull, the cambered surface having a transverse extent spanning the underside, wherein the cambered surface has a two-dimensional section design lift coefficient between 0.01 and 0.12.

13. The apparatus of claim 9, further comprising means for moving the rudders independently in a first mode and in alignment in a second mode.

14. The apparatus of claim 13, further comprising means for adjusting alignment of the rudders with respect to each other based on varying displacement hull speed and based on resistance reduction and rudder cavitation.

21. The apparatus of claim 12, wherein the supercavitating hydrofoil includes one of the group including a Johnson 3-term shape and a Johnson 5-term shape.

15. An apparatus, comprising:

a transom stern displacement hull to operate at a speed-to-length ratio of from about 0.80 to about 3.00, the hull including a hull underside along an aft portion of the hull, the hull underside having a deadrise angle along the hull underside of from approximately −

12 degrees to approximately 10 degrees, with the hull underside bounded on a right lateral side of the hull by a right hull side and on a left lateral side of the hull by a left hull side, the right and left hull sides each extending from the hull underside to a waterline,

wherein the hull underside defines a cambered surface that includes a supercavitating hydrofoil, the cambered surface having a two-dimensional section design lift coefficient of between 0.01 and 0.12, with a longitudinal extent spanning from the aft portion of the hull toward a bow from about 10 to about 50 percent of the waterline length of the hull, said cambered surface having a transverse extent spanning the underside.

16. The apparatus of claim 15, further comprising:

a right endplate coupled proximal the right hull side; and

a left endplate coupled proximal the right hull side and generally opposite the right endplate,

wherein the endplates each have a fixed height of about 0.2 to about 10 percent of a displacement hull beam measured adjacent a waterline.

17. The apparatus of claim 15, further comprising:

a right endplate coupled proximal the right hull side and extending generally along a length of the hull; and

a left endplate coupled proximal the right hull side and generally opposite the right endplate and extending generally along the length of the hull,

wherein the right and left endplates extend along a hull length from the aft portion and toward a bow from about 1 to about 40 percent the waterline length of the hull, with the right and left endplates each generally aligned within approximately 20 degrees of being parallel to a vertical centerplane of the hull.

18. The apparatus of claim 17, wherein the right and left endplates are generally perpendicular to a plane defined by the waterline, and wherein the right and left endplates each extend along respective outboard portions of the hull underside, the right and left endplates being proximal respective right and left hull sides.

19. The apparatus of claim 15, further comprising a pair of rudders coupled to the hull underside on opposite sides of a vertical centerplane that bisects the hull along its length, the rudders each having a span orientation that is substantially perpendicular to the underside, the rudders each having a chord orientation that is substantially parallel to the longitudinal centerplane of the hull, the rudders each having a cross-sectional shape along a plane substantially parallel to the plane defined by the waterline, the shape defining a streamlined cambered hydrofoil, with respective pressure sides of the rudders each facing the longitudinal vertical centerplane, the rudders to produce lift coefficients of between 0.01 and 1.0, the pair of rudders oriented substantially perpendicular to a plane defined by the waterline, the pair of rudders disposed along the underside joined at a substantially vertical orientation to said hull underside, the rudders having a quarter chord line located less than approximately 25 percent of the waterline length of the hull from the aft end of the hull, with a right rudder disposed proximal the right hull side and with a left rudder disposed proximal the left hull side, wherein the hull defines a right and left chine, with the right rudder disposed along the underside proximal the right chine, and the left rudder disposed along the underside proximal the left chine.

20. The apparatus of claim 19, wherein the rudders are moveable.

22. The apparatus of claim 15, wherein the supercavitating hydrofoil surface includes one of the group including a Johnson 3-term shape and a Johnson 5-term shape.