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A trim tab of resilient material affixed in a cantilever fashion at the stem of a boat and of a regressive flexural stiffness such that when deflected, the undersurface of the trim tab assumes the shape of a progressive curve in the direction of water flow. A trim tab of a progressive curve which ha

A trim tab of resilient material affixed in a cantilever fashion at the stem of a boat and of a regressive flexural stiffness such that when deflected, the undersurface of the trim tab assumes the shape of a progressive curve in the direction of water flow. A trim tab of a progressive curve which has gas or liquid ejection to the undersurface to control the boundary layer. A trim tab located under a surface drive whereby the bite of the propeller is controlled relative to the trim tab and the trim tab is controlled to optimize the boat hull.

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1. An adjustable trim tab for attaching to the stern of a boat, comprising:a resilient plate having a forward end for mounting to the stem of the boat and a rearward end, the plate having a regressive flexural stiffness from the forward end to the rearward end; anda trim adjustment device, coupled t

1. An adjustable trim tab for attaching to the stern of a boat, comprising:a resilient plate having a forward end for mounting to the stem of the boat and a rearward end, the plate having a regressive flexural stiffness from the forward end to the rearward end; anda trim adjustment device, coupled to the rearward end of the plate and for coupling to the stem of the boat, that moves the rearward end of the plate;the plate having an operative bottom surface that is deflected in a progressive curve from the forward end to the rearward end of the plate under operating conditions and with force applied by the trim adjustment device. 2. The adjustable trim tab of claim 1, wherein the progressive curve has the shape of a parabola. 3. The adjustable trim tab of claim 1, wherein the plate includes a plurality of ejection ports to the bottom operative surface and located near the forward end of the plate. 4. The adjustable trim tab of claim 3, wherein each ejection port is angled backwards relative to a line which is perpendicular to the bottom operative surface of the plate. 5. The adjustable trim tab of claim 3, wherein each ejection port has a diffuser with outer extremities that have overlapping streamlines. 6. The adjustable trim tab of claim 5, wherein each diffuser has shallow tapered rearward edges. 7. The adjustable trim tab of claim 5, wherein each diffuser has rearward edges that have an angle of departure that is away from and rearward of a corresponding ejection port. 8. The adjustable trim tab of claim 1, wherein the plate has a generally tapered width. 9. The adjustable trim tab of claim 1, wherein the plate has a generally constant width with generally parallel side edges. 10. The adjustable trim tab of claim 1, further comprising: at least one flood wall, each affixed on an upper surface and near a side edge of the plate, and each projecting upwards. 11. The adjustable trim tab of claim 10, wherein the at least one flood wall comprises a pair of flood walls, each located adjacent a respective one of the side edges of the plate. 12. The adjustable trim tab of claim 1, wherein the plate is skew adjustable. 13. The adjustable trim tab of claim 1, wherein the plate has a generally regressive second moment of inertia from the forward end to the rearward end. 14. The adjustable trim tab of claim 13, wherein the plate includes standing ribs with generally tapered height from the forward end to the rearward end. 15. The adjustable trim tab of claim 14, wherein each standing rib is oriented downward and has a streamlined leading edge. 16. The adjustable trim tab of claim 13, wherein the plate includes generally tapered longitudinal corrugations. 17. The adjustable trim tab of claim 13, wherein the plate is generally tapered height from the forward end to the rearward end. 18. The adjustable trim tab of claim 13, wherein the plate comprises a stack of layered platelets of progressively variable length. 19. The adjustable trim tab of claim 13, wherein the plate includes grooves of generally progressively tapered depth. 20. A surface drive system for a boat, comprising:a surface drive propulsion system including a surfacing propeller affixed to a proreller shaft; anda hull extension having a forward end attached to the stern of the boat and a rearward end positioned under the propeller shaft and in front of the surfacing propeller to reduce variations in propeller blade immersion of the surfacing propeller. 21. The surface drive system of claim 20, wherein the hull extension is rigid. 22. The surface drive system of claim 20, wherein the hull extension comprises:a plate; anda brace coupled to the plate and for coupling to the boat to maintain position of the plate. 23. The surface drive system of claim 20, further comprising:a bite control mechanism, interfaced to the surface drive propulsion system, that adjusts the bite of the surfacing propeller. 24. The surface drive system of claim 23, wherein the bite control mechanism compr ises a jackplate. 25. The surface drive system of claim 23, wherein the bite control mechanism comprises a bite ram with a bite bar. 26. The surface drive system of claim 23, wherein the bite control mechanism comprises an extended bite ram. 27. The surface drive system of claim 23, wherein the bite control mechanism comprises a jackbox. 28. The surface drive system of claim 20, further comprising:a pair of parallel flood walls, each affixed on an upper surface and adjacent an opposite side edge of the hull extension, and each projecting upwards. 29. The surface drive system of claim 20, further comprising:a bite control, interfacing the surface drive propulsion system, that facilitates adjusting the position of the surfacing propeller; anda pair of flood skirts, affixed to the bite control, each projecting vertically downward to limit flooding of the surfacing propeller. 30. The surface drive system of claim 20, further comprising:a pair of flood gates, positioned above the hull extension and hingedly affixed to the boat, that are pivoted down on either side of a surfacing propeller. 31. The surface drive system of claim 20, wherein the hull extension comprises a trim tab. 32. The surface drive system of claim 31, further comprising:the trim tab being hingedly attached to the stern of the boat; anda trim ram attached to adjust position of the trim tab. 33. The surface drive system of claim 31, wherein the trim tab comprises a resilient plate. 34. The surface drive system of claim 33, wherein the trim tab has a regressive flexural stiffness. 35. The surface drive system of claim 33, further comprising:a first adjustment mechanism that interfaces the surface drive propulsion system and the trim tab and for coupling to the boat for adjusting the vertical position of the surfacing propeller and that moves the rearward end of the trim tab. 36. The surface drive system of claim 35, further comprising:a bite control mechanism, coupled to the first adjustment mechanism and interfacing the surface drive propulsion system, that facilitates adjusting the vertical position of the surfacing propeller relative to the boat. 37. The surface drive system of claim 35, further comprising:a second adjustment mechanism, coupled to the first adjustment mechanism and the surface drive propulsion system, that adjusts the vertical position of the surfacing propeller relative to the trim tab. 38. The surface drive system of claim 33, further comprising:a first adjustment mechanism coupled to the surface drive propulsion system and for coupling to the boat for adjusting the vertical position of the surfacing propeller; anda second adjustment mechanism coupled to the trim tab for moving the rearward end of the trim tab. 39. The surface drive system of claim 33, wherein the trim tab comprises a plate with a generally tapered width. 40. The surface drive system of claim 33, wherein the trim tab comprises a plate with a plurality of ejection ports to the bottom operative surface and located near a forward end of the plate. 41. The surface drive system of claim 33, wherein the trim tab comprises a plate having an arcuate rearward edge and wherein the surface drive propulsion system sweeps the surfacing propeller through an arc that is generally parallel to an undersurface of the trim tab and that has a common center as the arcuate rearward edge of the trim tab. 42. The surface drive system of claim 41, further comprising:a bite control, for mounting to the boat and interfacing the surface drive propulsion system, that maintains the depth of the surfacing propeller relative to a rearward edge of an operative surface of the trim tab. 43. The surface drive system of claim 42, wherein the bite control is skew adjustable. 44. The surface drive system of claim 42, wherein the bite control comprises a bite bar. 45. The surface drive system of claim 20, further comprising:the surface drive propulsion system operative to sweep the surfacing propeller through an arc that is generally parallel to an undersurface of the boat;the boat having a longitudinal vertical plane of symmetry running along the centerline of the boat from bow to stern; anda bite control mechanism, mounted to the boat and to the surface drive propulsion system, that moves the surfacing propeller parallel with the longitudinal vertical plane of symmetry. 46. The surface drive system of claim 45, wherein the surface drive propulsion system comprises an outboard motor that is cambered relative to the longitudinal vertical plane of symmetry and wherein the bite control mechanism comprises a jackplate. 47. The surface drive system of claim 45, wherein the surface drive propulsion system comprises an inboard/outboard and wherein the bite control mechanism comprises a jackbox. 48. The surface drive system of claim 45, wherein the surface propulsion system includes propeller shaft carrier and articulating joint and wherein the bite control mechanism comprises an extended bite ram having a lower end attached to the propeller shaft carrier and an upper end mounted with a ball and socket joint to the stern of the boat, wherein the ball and socket is mounted at a location such that a center of rotation of the ball and socket joint is generally collinear with a line formed by a perpendicular projection from the undersurface of the boat through a center point of articulation of the articulating joint. 49. The surface drive system of claim 20, further comprising:the surface drive propulsion system including first and second surface drives and corresponding first and second surfacing propellers;a tie bar coupled between the first and second surface drives; andthe hull extension comprising first and second trim tabs, each having a forward end adapted for attaching to the stem of the boat and a rearward end positioned in line directly in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller under operating conditions. 50. The surface drive system of claim 20, further comprising:the surface drive propulsion system including a single motor that drives first and second surfacing propellers via first and second propeller shaft carriers;the hull extension comprising first and second trim tabs, each having a forward end adapted for attaching to the stem of the boat and a rearward end positioned in line directly in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller under operating conditions; anda steering system coupled to the surface drive propulsion system and the first and second bite controls that control the direction of a boat by changing relative bite of the first and second surfacing propellers. 51. The surface drive system of claim 20, further comprising:the surface drive propulsion system including first and second surfacing propellers via first and second propeller shaft carriers;the hull extension comprising first and second trim tabs, each having a forward end adapted for attaching to the stern of the boat and a rearward end positioned in line directly in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller under operating conditions; anda resilient bridge piece coupled between the first and second trim tabs to generally form a piecewise continuous trim tab with a generally continuous operative bottom surface. 52. A boat, comprising:a chassis including a stem surface;a resilient plate having a forward end and a rearward end, the forward end being mounted a t the stem of the chassis, the plate having a generally regressive flexural stiffness from the forward end to the rearward end; anda trim adjustment device, coupled to the stem of the chassis and to the rearward end of the plate, that applies up and down force generally perpendicular to the rearward end of the plate. 53. The boat of claim 52, wherein the plate includes a plurality of ejection ports to the bottom operative surface located near the forward end of the plate. 54. The boat of claim 53, wherein each ejection port is angled backwards relative to a line which is perpendicular to the operative bottom surface of the trim tab. 55. The boat of claim 52, wherein the plate has a generally tapered width. 56. The boat of claim 52, wherein the plate has a regressive second moment of inertia. 57. The boat of claim 52, wherein the plate has an operative bottom surface that is deflected in a progressive curve from the forward end to the rearward end under operating conditions of the boat and while force is applied by the trim adjustment device. 58. The boat of claim 52, further comprising:the chassis including left and right sides;first and second resilient plates, each having a forward end and a rearward end, the forward end of each plate being mounted at the stem of the chassis on a respective one of the first and second sides; andfirst and second trim adjustment devices, each coupled to the stem of the chassis and to the rearward end of a respective one of the first and second plates, each that applies up and down force to the rearward end of the respective plate. 59. A boat, comprising:a chassis including a stem;a surface drive propulsion system mounted to the chassis and including a surfacing propeller affixed to a propeller shaft; anda trim tab having a forward end and a rearward end, the forward end being mounted to the stem of the chassis, and the rearward end positioned under the propeller shaft and in front of the surfacing propeller to reduce variations in propeller blade immersion of the surfacing propeller. 60. The boat of claim 59, further comprising:a first adjustment mechanism, interfacing the surface drive propulsion system and the trim tab and coupled to the stem of the chassis, that adjusts the vertical position of the surfacing propeller and that moves the rearward end of the trim tab. 61. The boat of claim 60, further comprising:a bite control mechanism, coupled to the first adjustment mechanism and that interfaces the surface drive propulsion system, that facilitates adjusting the vertical position of the surfacing propeller. 62. The boat of claim 60, further comprising:a second adjustment mechanism, coupled to the first adjustment mechanism and the surface drive propulsion system, that adjusts the vertical position of the surfacing propeller relative to the boat. 63. The boat of claim 59, further comprising:a first adjustment mechanism, coupled to the surface drive propulsion system and the stern of the chassis, that adjusts the vertical position of the surfacing propeller; anda second adjustment mechanism coupled to the trim tab for moving the rearward end of the trim tab. 64. The boat of claim 59, wherein the trim tab comprises a plate with a generally regressive flexural stiffness from the forward end to the rearward end. 65. The boat of claim 59, wherein the trim tab comprises a plate with a plurality of ejection ports to the bottom operative surface located near a forward end of the plate. 66. The boat of claim 59, wherein the surface drive propulsion system sweeps the surfacing propeller through an arc generally parallel to the undersurface of the trim tab, and wherein the trim tab comprises a plate having an arcuate rearward edge having a common center as a swept arc of the surfacing propeller. 67. The boat of claim 66, further comprising:a bite control, mounted to the stem of the chassis and that interfaces the surface drive propulsion system, that maintains the depth of the surfacing propeller rela tive to a rearward edge of an operative surface of the trim tab. 68. The boat of claim 67, wherein the bite control is skew adjustable. 69. The boat of claim 67, wherein the bite control comprises a bite bar. 70. The boat of claim 59, further comprising:a people guard, refractively coupled to the surface drive propulsion system, that is positioned above the surfacing propeller to cover the propeller when the boat is not moving or is operating at slow speeds and that is retracted to allow the propeller to ventilate when the boat is operating at high speeds. 71. The boat of claim 70, wherein the people guard is retracted upwards by water spray departing from the surfacing propeller to allow the propeller to ventilate when the boat is operating at high speeds. 72. The boat of claim 70, wherein location of the people guard is controlled by an operator of the boat. 73. The boat of claim 70, wherein the people guard comprises a generally rectangular piece of rigid material. 74. The boat of claim 59, further comprising:at least one bias fin, each coupled to the surface drive propulsion system and positioned on one side of the surfacing propeller, that is immersed in the water during operation. 75. The boat of claim 74, wherein the at least one bias fin comprises a pair of bias fins located on either side of the surfacing propeller. 76. The boat of claim 75, wherein each bias fin has a leading edge that is curved rearward and downward. 77. The boat of claim 75, wherein each bias fin has a side area that is proportional to the swept area of the surfacing propeller. 78. The boat of claim 75 further comprising:the surface drive propulsion system including a propeller shaft carrier; andwherein each bias fin is rotatably adjustable to impose a hydrodynamic side force to the propeller shaft carrier during operation. 79. The boat of claim 59, further comprising:the surface drive propulsion system including first and second surface drives and corresponding first and second surfacing propellers affixed to first and second propeller shafts respectively; andfirst and second trim tabs, each having a forward end mounted to the stern of the chassis and a rearward end positioned under a corresponding one of the first and second propeller shafts and in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller. 80. The boat of claim 59, further comprising:the surface drive propulsion system including a single motor that drives first and second surfacing propellers via first and second propeller shaft carriers;first and second trim tabs, each having a forward end mounted to the stern of the chassis and a rearward end positioned in line directly in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller under operating conditions; anda steering system coupled to the surface drive propulsion system and the first and second trim tabs that steers the boat by changing relative bite of the first and second surfacing propellers. 81. The boat of claim 59, further comprising:the surface drive propulsion system including first and second surface drives driving first and second surfacing propellers;first and second trim tabs, each having a forward end rigidly mounted to the stem of the chassis and a rearward end positioned in line directly in front of a corresponding one of the first and second surfacing propellers, and each positioned sufficiently close to its corresponding surfacing propeller to minimize variations in propeller blade immersion of the corresponding surfacing propeller under operating conditions; anda resilient bridge piece coupled between the first and second trim tabs t o generally form a piecewise continuous trim tab with a generally continuous operative bottom surface. 82. The boat of claim 59, further comprising:the chassis including a transom and a hull extension mounted to the transom;a first adjustment mechanism, coupled to the surface drive propulsion system and the hull extension, that adjusts the vertical position of the surfacing propeller; anda second adjustment mechanism, coupled to the hull extension and the trim tab, that moves the rearward end of the trim tab. 83. The boat of claim 82, wherein the hull extension comprises a swim platform positioned above the surface drive propulsion system and the trim tab. 84. The boat of claim 82, further comprising:a servo valve and servo lever coupled to the first and second adjustment mechanisms to enable synchronized adjustments. 85. The boat of claim 82, wherein:the hull extension includes first and second cantilevers;the first cantilever is mounted above the surface drive propulsion system;the first adjustment mechanism is mounted to the first cantilever;the second cantilever is mounted below the surface drive propulsion system and above the trim tab; andthe second adjustment mechanism is mounted to the second cantilever.