Trim tab systems for adjusting attitude and performing active stabilization of marine vessels

Abstract

A system is provided and includes a trim tab, a hinge assembly, an actuator, and a controller. The trim tab adjusts at least one of pitch, roll or yaw motion of a marine vessel while the trim tab is in a deployed state. The trim tab includes a member, which has first and second ends and curves outward between and forward of the first end and the second end in a direction away from a point rearward of the member. The hinge assembly attaches a rearmost end of the first trim tab to the marine vessel at a location rearward of the member. The member rotates about a portion of the hinge assembly. The actuator actuates the trim tab. The controller controls the actuator to transition the member of the trim tab between a retracted state and the deployed state to adjust an attitude or motion of the marine vessel.

Claims

1. A trim tab system comprising: a first trim tab that adjusts at least one of pitch, roll or yaw motion of a marine vessel while the first trim tab is actuated between a retracted state and a deployed state, wherein the first trim tab comprises a member, wherein the member is a plate and includes a first end and a second end, and wherein a centerline of the member curves outward between and forward of the first end and the second end in a direction away from a point rearward of the member; a hinge assembly that attaches a rearmost end of the first trim tab to the marine vessel at a location rearward of the member, wherein the member rotates about a portion of the hinge assembly; an actuator that actuates the first trim tab; and a controller that controls the actuator to transition the member of the first trim tab between the retracted state and the deployed state to adjust at least one of an attitude or motion of the marine vessel.

2. The trim tab system of claim 1, wherein: the first trim tab while in the deployed state adjusts yaw motion of the marine vessel; and the controller actuates the member of the first trim tab between the retracted state and the deployed state to change the attitude of the marine vessel.

3. The trim tab system of claim 1, wherein the member is convex-shaped.

4. The trim tab system of claim 1, wherein the member is: convex-shaped, such that the member curves outward in a direction of oncoming water; deflects the oncoming water when the member is extended below a surface of the marine vessel; and is connected to the hinge assembly such that the member is moved downward and rearward when being transitioned from the retracted state to the deployed state.

5. The trim tab system of claim 1, wherein the member extends below a hull of the marine vessel when transitioning from the retracted state to the deployed state.

6. The trim tab system of claim 1, wherein: while in the retracted state, a bottom surface of the member is above or in alignment with a bottom surface of a hull of the marine vessel; and while in the deployed state, the member extends partially below the bottom surface of the marine vessel, at least a portion of the member is not below the bottom surface of the marine vessel, and the member extends at least from a first point, adjacent the bottom surface of the marine vessel, to a second point below and rearward of the first point.

7. The trim tab system of claim 1, wherein the first trim tab is mounted forward on the marine vessel.

8. The trim tab system of claim 1, wherein the first trim tab is mounted aft on the marine vessel.

9. The trim tab system of claim 1, wherein the first trim tab is mounted on a transom of the marine vessel.

10. The trim tab system of claim 1, wherein the first trim tab is mounted on the marine vessel forward of a transom of the marine vessel.

11. The trim tab system of claim 1, further comprising at least one additional trim tab, wherein the controller controls actuation of the at least one additional trim tab to control attitude of the marine vessel.

12. A trim tab system comprising: a trim tab that adjusts at least one of pitch, roll or yaw motion of a marine vessel while the trim tab is actuated between a retracted state and a deployed state, wherein the trim tab comprises a member, wherein the member is a plate and includes a first end and a second end, and wherein a centerline of the member curves outward between and forward of the first end and the second end in a direction away from a point rearward of the member; a hinge assembly that attaches a rearmost end of the trim tab to the marine vessel at a location rearward of the member, wherein the member rotates about a portion of the hinge assembly; an actuator that actuates the trim tab; and a controller that controls the actuator to perform active stabilization of the marine vessel including transitioning the member of the trim tab between the retracted state and the deployed state to damp motion in at least one of pitch, roll or yaw axes of the marine vessel.

13. The trim tab system of claim 12, wherein: an attitude of the marine vessel changes at a first angular motion rate; the actuator actuates the trim tab at a second angular motion rate, wherein the second angular motion rate is greater than the first angular motion rate; and the controller, in response to the changes in the attitude of the marine vessel, dampens angular motion of the marine vessel to reduce the first angular motion rate including controlling the actuator to change the second angular motion rate to stabilize the marine vessel.

14. The trim tab system of claim 12, wherein at least one of: the controller controls actuation speed of the trim tab to counter motion rates of the marine vessel; or the actuator transitions the member at speeds to counter motion rates of the marine vessel.

15. The trim tab system of claim 12, wherein: the trim tab while in the deployed state adjusts yaw motion of the marine vessel; and the controller actuates the member of the trim tab between the retracted state and the deployed state to change the attitude of the marine vessel.

16. The trim tab system of claim 12, wherein the trim tab is mounted on the marine vessel forward of a transom of the marine vessel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a partial perspective view of a trim tab assembly for a watercraft having a trim tab in a deployed position;

(2) FIG. 2 is a partial perspective view of a trim tab assembly for a watercraft having a trim tab in a stowed position;

(3) FIG. 3 is a perspective view of an enclosure for a trim tab assembly for a watercraft FIG. 3;

(4) FIG. 4 is a view of an alternate embodiment of a trim tab assembly with a forward facing curved leading edge and its hinge placed aft;

(5) FIG. 5 is a view of a removable plate for attaching to a bottom surface of a trim tab;

(6) FIG. 6 is a view of the trim tab and a hinge assembly;

(7) FIG. 7 is a view of the support structure;

(8) FIG. 8 is a view of the driven member;

(9) FIG. 9 is a view of the trim tab;

(10) FIG. 10 is an alternate embodiment of an enclosure having a pressure relief orifice;

(11) FIG. 11 is a view of a position sensor;

(12) FIG. 12 is an exploded perspective view of the alternate embodiment of FIG. 4;

(13) FIG. 13 is a perspective view of the alternate embodiment of FIG. 12 with the tab in the non-deployed position;

(14) FIG. 14 is a perspective view of the alternate embodiment of FIG. 12 with the tab in an intermediate position;

(15) FIG. 15 is a perspective view of the alternate embodiment of FIG. 12 with the tab in the fully deployed position;

(16) FIG. 16 is a perspective view of the alternate embodiment of FIG. 12 with the enclosure shown;

(17) FIG. 17 is an exploded perspective view of another alternative embodiment of a trim tab assembly;

(18) FIG. 18 is an assembled perspective view of the embodiment of FIG. 17;

(19) FIG. 19 is a partial side sectional view of the trim tab assembly of FIG. 17 installed in a cavity of a watercraft with a trim tab in a retracted position;

(20) FIG. 20 is a partial side sectional view of the trim tab assembly of FIG. 17 with the trim tab in an extended position;

(21) FIG. 21 is a partial side sectional view of the trim tab assembly of FIG. 17 with the trim tab in a retracted position and in an alternate hinge position;

(22) FIG. 22 is a partial side sectional view of the trim tab assembly of FIG. 17 with the trim tab in an extended position and in an alternate hinge position;

(23) FIG. 23 is a perspective view of a trim tab having slits in a curved surface;

(24) FIG. 24 is a perspective view of a trim tab having a diamond surface formed thereon;

(25) FIG. 25 is a perspective view of a trim tab having an eccentric curved surface;

(26) FIG. 26 is a side view of the embodiment of FIG. 25;

(27) FIG. 27 is a perspective view of a trim tab having facets formed thereon;

(28) FIG. 28 is a perspective view of a trim tab having holes formed in a curved surface;

(29) FIG. 29 is a perspective view of a trim tab having horizontal slits formed in a curved surface;

(30) FIG. 30 is a perspective view of a trim tab having multiple curved surfaces to provide an inward protruding inverted plow face;

(31) FIG. 31 is a perspective view of a trim tab having multiple fences formed thereon;

(32) FIG. 32 is a perspective view of a trim tab having triangular holes formed in a curved surface;

(33) FIG. 33 is a perspective view of a trim tab having multiple curved surfaces to provide an outward protruding inverted plow face;

(34) FIG. 34 is a perspective view of a trim tab having a stepped surface;

(35) FIG. 35 is a perspective view of another alternative embodiment of a trim tab assembly having a pivotally moveable trim tab mounting frame and actuator with the trim tab and mounting frame in a non-actuated position;

(36) FIG. 36 is a perspective view of the trim tab assembly of FIG. 35 with the trim tab in a non-actuated position and the mounting frame in an actuated position;

(37) FIG. 37 is a perspective view of the trim tab assembly of FIG. 35 with the trim tab in an actuated position and the mounting frame in a non-actuated position;

(38) FIG. 38 is a perspective view of the trim tab assembly of FIG. 35 with the trim tab in an actuated position and the mounting frame in an actuated position;

(39) FIG. 39 is a side view of the trim tab assembly of FIG. 35 with the trim tab and the mounting frame in a non-actuated position;

(40) FIG. 40 is a side view of the trim tab assembly of FIG. 35 with the trim tab in a non-actuated position and the mounting frame in an actuated position;

(41) FIG. 41 is a side view of the trim tab assembly of FIG. 35 with the trim tab in an actuated position and the mounting frame in a non-actuated position;

(42) FIG. 42 is a side view of the trim tab assembly of FIG. 35 with the trim tab in an actuated position and the mounting frame in an actuated position;

(43) FIG. 43 is a diagram of a control system of the trim tab assembly;

(44) FIG. 44 is a side perspective view of another trim tab with perforated sides and pressure fencing tabs;

(45) FIG. 45 is a perspective view of the trim tab assembly mounted externally to the hull transom;

(46) FIG. 46 is a diagram detailing a force applied to the hinge of the trim tab assembly;

(47) FIG. 47 is a perspective view of the trim tab assembly mounted on a watercraft with a trim tab in a retracted position;

(48) FIG. 48 is a perspective view of the trim tab assembly of FIG. 47 with the trim tab in a partially extended position; and

(49) FIG. 49 is a perspective view of the trim tab assembly of FIG. 47 with the trim tab in an extended position.

DETAILED DESCRIPTION

(50) Differential and differentially are defined within this document as unequal, off center and/or involving differences in: angle, speed, rate, direction, direction of motion, output, force, moment, inertia, mass, balance, application of comparable things, etc.

(51) Dynamic and dynamically may be defined as the immediate action that takes place at the moment they are needed. Immediate, in this application, means that the control action occurs in a manner that is responsive to the extent that it prevents or mitigates vessel motions and attitudes before they would otherwise occur in the uncontrolled situation. Someone skilled in the art understands the relationship between sensed motion parameters and required effector response in terms of the maximum overall delay that can exist while still achieving the control objectives. Dynamic may be used in describing interactive hardware and software systems involving differing forces and may be characterized by continuous change and/or activity. Dynamic may also be used when describing the interaction between a vessel and the environment. As stated above, marine vessels may be subject to various dynamic forces generated by its propulsion system as well as the environment in which it operates.

(52) A vessel attitude may be defined as relative to three rotational axes including pitch attitude or rotation about the Y, transverse or sway axis, roll attitude or rotation about the X, longitudinal or surge axis, and yaw attitude or rotation about the Z, vertical or heave axis

(53) Someone skilled in the art understands that active marine vessel damping is the attenuation of the value of a resonant response, such as the pitch, roll and yaw of the vessel. Someone skilled in the art understands that a marine vessel active stabilization, motion damping and attitude control system is a system selected, sized and integrated, based on a vessel's specific design, to achieve the effector rates required for damping pitch and/or roll and/or yaw.

(54) Someone skilled in the art understands, for motion damping to be achieved, effector angular motion rates may generally be at least 10 times the vessel angular motion rate in the pitch and roll axes. For example, angular motion rates of 4 degrees per second may be typical of conventional high performance planning craft. This means that effector angular motion rates of 40 degrees per second may be used to achieve motion damping for this specific performance class of planing craft.

(55) Someone skilled in the art understands, a hydrofoil, planing device and/or interceptor produces control forces based on a speed-squared relationship and are therefore much more effective at higher speeds than lower speeds. For example, a trim tab produces 4 times the amount of force at 20 knots than it does at 10 knots.

(56) Referring to the figures, there is shown a trim tab assembly 10 for a watercraft. The trim tab assembly 10 may include an enclosure 15 or shell structure, as best shown in FIG. 3. The enclosure 15 may be linked with or joined with a support structure 30, to form a module that may be positioned within a hole formed in a watercraft. Alternatively, the enclosure 15 may be an opening formed within the hull in which the support structure 30 is disposed. Alternatively, the tab assembly 10 may be modular within a self-contained structure that may be attached to a vessel. At least one trim tab 20 is disposed within the enclosure 15. An electric actuator 22 may be linked with the trim tab 20 pivotally moving the trim tab 20 relative to the enclosure 15. The electric actuator 22 may be positioned on a dry side not exposed to water relative to the enclosure 15

(57) Referring to FIG. 3, there is shown one embodiment of an enclosure 15 for use in the trim tab assembly 10. As can be seen in the figure, the enclosure 15 is sized and shaped to accommodate the trim tab assembly 10. The enclosure 15 may include holes 25 formed therein for accommodating various components of the trim tab assembly 10, as will be discussed in more detail below. Additionally, the enclosure 15 may also include a pressure relief orifice 35 formed therein that allows for release of air and water pressure created by movement of the trim tab 20 within the enclosure 15 during actuation

(58) Referring to the figures, the trim tab assembly 10 may include an electric actuator 22 having a driveshaft 40 that is connected to a drive gear 45. At least one bearing 50 supports the driveshaft 40 in the support structure 30. In one aspect, the at least one bearing 50 includes a seal 55 preventing water disposed within the enclosure 15 from exiting the cavity 15. Additionally, the seal 55 isolates the electric actuator 22 that is positioned on a dry side of the enclosure 15 from the water. A position sensor 89 best seen in FIGS. 10, 11 and 12-16 may be attached to the drive shaft 40 to monitor a position of the trim tab 20 relative to the enclosure 15. The position sensor 89 may include a potentiometer or equivalent device used to communicate position data to a central control computer. Alternatively, the electric actuator 22 may include a position sensor integrated with the motor.

(59) Again referring to figures, the trim tab assembly 10 may include a driven member 60 that is attached to the trim tab 20 and is operably linked with the drive gear 45. In one aspect, the driven member 60 may include a flexible gear portion 65 attached to the driven member 60 and is meshed with the drive gear 45. In one aspect, the interface between the drive gear 45 and driven member 60 is a soft interface such that the gear teeth of the flexible gear portion 65 will shear upon application of a predetermined force preventing damage to a gearbox 70 of the electric actuator 22 as well as the driveshaft 40 and enclosure 15. It should be realized that the gear box may be eliminated as a separate component and may be integrated with the electric actuator 22. Additionally, the soft interface provides a joining of the drive gear 45 and driven member 60 without the need for lubrication. Such a dry relationship is advantageous when used in a wet environment within the enclosure 15

(60) Referring to the various figures, in one aspect the trim tab 20 may include a generally planar top 72, bottom surface 74, and side surfaces 76 linked by a curved forward facing (or first) surface 80 defining a wedge-shaped body 82. In one aspect, as best seen in FIG. 9, the trim tab 20 may include an inner support structure 84 surrounded by an outer skin 86. The trim tab 20 may include: a first end 71 having a curved (or first) member 73 with the curved forward facing surface 80; a second end 75; a side (or second) member 77; and a side (or third) member 79. The first member 73 may have a top (or third) end 81 and a bottom (or fourth end) 83 with a bottom surface 91. The trim tab 20 may also include a side (or bottom) surface 87. The curved forward facing surface 80 and the member 73 extend outward from the hinge assembly 100 and upward from the fourth end 83 to the third end 81. In one aspect, the wedge shaped body 82 may include a buoyant material positioned within an interior 88 of the wedge-shaped body 82 providing support for the outer skin 86 as well as decreasing an overall weight of the trim tab 20. Various materials such as closed and open cell foams may be used in conjunction with additional support structure to withstand loads applied to a trim tab 20 during actuation and to provide buoyancy

(61) In another aspect, and as shown in FIG. 5, a removable plate 90 may be attached to a water contacting surface of the trim tab 20. The removable plate 90 may include characteristics for modifying the performance characteristics of the trim tab 20. For example, the removable plate 90 may have various characteristics including concave shapes, convex shapes, and strakes of varying dimension and position, as well as shape surfaces that match the contour of a watercraft hull. In this manner, the removable plate 90 may be tailored to provide various design and performance characteristics that affect the overall performance of a watercraft having a trim tab assembly 10. Additionally, the removable plate 90 can be swapped out with another plate to provide various configurations that may be interchangeable to affect the performance of a watercraft.

(62) Referring to FIGS. 1, 2 and 6, the trim tab assembly 10 may include a hinge assembly 100 that is linked to the enclosure 15 and the trim tab 20 for pivotal movement of the trim tab 20 relative to the enclosure 15. As shown in FIGS. 1 and 2, the hinge assembly 100 may be positioned on a forward edge of the enclosure 15 and linked with a forward portion of the trim tab 20. In one aspect, the hinge assembly 100 may be in two pieces such that one piece is attached to a bottom surface 74 of the trim tab 20 at a forward edge and is mated with a second piece attached to the support structure 30 disposed within the enclosure 15. A hinge pin 115 may be positioned along a center line of the hinge allowing pivotal movement of the trim tab 20 relative to the support structure 30 and enclosure 15.

(63) In one aspect, the trim tab 20 may be positioned within the enclosure 15 in a close tolerance relationship preventing high pressure water created during tab deflection or extension from entering the enclosure 15. In this manner, high pressure water is prevented from contacting a low pressure top surface 72 of the trim tab 20 that is disposed within the enclosure 15. In one aspect, the trim tab 20 remains at least partially within the enclosure 15 when fully deployed to prevent foreign objects from entering the enclosure 15.

(64) In use, the trim tab 20 is pivotally movable within the enclosure 15 to apply deflection forces to the water or obstruction of the water on which a watercraft is traveling to affect the performance of the watercraft. In one aspect, the trim tab 20 is actuated at speeds sufficient to counter motion rates and damp motion in a pitch, roll and yaw axis of the watercraft. In one aspect, the trim tab 20 is actuated to control attitude changes in a pitch, roll and yaw axis of the watercraft.

(65) In one aspect, the watercraft may include at least two trim tab assemblies 10 positioned within the watercraft. The trim tab assemblies 10 may be actuated in series, meaning that the at least two trim tab assemblies 10 actuate in the same manner at a given time, Alternatively, the at least two trim tab assemblies 10 may be actuated differentially wherein actuation of one of the trim tabs 20 is not the same as another to affect various forces on the watercraft to control the attitude, motion and motion damping in the axes, as described above.

(66) Referring to FIGS. 4 and 12-16, there is shown an alternate embodiment of a trim tab assembly 10 including the same components described above except that the curved surface 80 of the trim tab 20 is positioned within the enclosure 15 in a forward facing position relative to the watercraft. The first member 73 is pivoted about a portion 121 and a center (or center point) 111 of the hinge assembly 100 from a fully retracted position to a fully deployed position.

(67) The first member 73 and the trim tab 20 are shown in an example fully extended (or deployed) state 103. The first member 73 is in an upright position during transitioning of the trim tab 20 between the fully retracted state and the fully extended (or deployed) state, because, during the transition, the third end 81 is above the fourth end 83. While being deployed (or in a deployed state), (i) the third end 81 is higher than the fourth end 83. Arrow 105 indicates motion of the marine vessel 107. The marine vessel 107 has a second (or bottom) surface 108. While in the extended (or deployed) state 103, a first portion 113 of the first member 73 is not below the second surface 108, as shown in FIG. 4. A second portion 123 of the first member 73 extends forward of the first portion 113 and away from the second end 75, also as shown in FIG. 4. While in state 103, the first end 71 extends at least from a first point 117, adjacent the bottom surface 108 of the marine vessel 107, to a second point 119 below the bottom surface of the marine vessel 107, also as shown in FIG. 4. Arrows 109 indicate motion of oncoming water relative to the marine vessel 107.

(68) Additionally, the hinge assembly 100, as described above, would be positioned at a rear edge 102 of the bottom surface 74 of the trim tab 20 and a rear 104 of the support structure 30 disposed within the enclosure 15. In this embodiment, the curved surface 80 contacts the water when actuated applying a force to the water and affecting a performance characteristic of a watercraft. In this position, the force needed to actuate the trim tab 20 is decreased in relation to the previously described first embodiment.

(69) As described above and as shown in the figures, the trim tab assembly 10 may include attachment devices. One attachment device (i.e. the actuator 22) is shown in FIG. 1. Another attachment device (i.e. the hinge assembly 100) is shown in FIG. 4. The hinge assembly 100 may include brackets 102 and/or a shaft 104. The member 73, by being convex-shaped and by extending downwardly into and deflecting oncoming water, adjusts motion of the marine vessel 107, such as roll, pitch, and/or yaw motion of the marine vessel 107.

(70) Accordingly, the present disclosure includes a trim tab system with both high-lift and low actuation force performance characteristics. Trim tab assemblies 10, 110 may include curved forward deflection surfaces and aft-hinge designs.

(71) Prior art interceptor tabs are specifically designed to intercept flow within a vessel's boundary layer. In general, interceptor tabs perform best in the high-speed/planing regime. Conversely, their stabilization performance at low to transitional planing speeds, typically below 18 knots, is not especially good. In contrast, the trim tab assemblies 10, 110 perform exceptionally well at high-speed, and have significant control authority below 18 knots. The disclosed curved forward face transitions from interceptor tab-like qualities to trim tab-like qualities as it extends (interceptor tab-like within a vessel's boundary layer and trim tab-like outside a vessel's boundary layer). This design feature provides greater range of lift force production over a vessel's entire speed regime (slow, medium and high). The trim tab assemblies perform like a conventional tab at low-to-medium speeds, and like an interceptor tab at higher speeds.

(72) In general, there is a direct relationship between vessel speed, deflection angle, and the force required to actuate a prior art trim tab. For example increasing vessel speed increases the force required to deflect a trim tab. Prior art trim tabs are hinged forward of the trim tab's deflection surface. As a consequence, prior art trim tab actuators burden substantial forces working against the tab during operation. For example, the forces on prior art trim tabs can be thousands of pounds depending on the tab's surface area, deflection angle and vessel speed. In contrast, the aft hinge designs associated with the disclosed trim tab assemblies receive most of the load; regardless of tab surface area, tab deflection, and vessel speed.

(73) In FIGS. 17-22, another alternative embodiment of the trim tab assembly 110 for a watercraft is shown. The trim tab assembly 110 includes a support structure 115 attached to the watercraft. At least one trim tab 120 is pivotally attached to the support structure 115. An actuator 125 is connected to a trim tab 120 and pivotally moving the trim tab 120 relative to the support structure 115. In one aspect, the at least one trim tab 120 includes a trim tab frame 135 having a curved surface 140 positioned to contact water when the watercraft is in motion.

(74) In one aspect, the actuator 125 may be a linear actuator connected directly to the trim tab frame 135. The connection may include a clevis and joint linking the actuator 125 to the frame 135. Various linear actuators may be utilized including hydraulic, pneumatic, or electric actuators. In one aspect, the actuator 125 may include an actuator mounting assembly 126 that includes the actuator 125. A bearing 116 is removably attached to the actuator 125. A bearing plate 118 having a hole 122 formed therein receives the bearing 116. A bearing mounting plate 124 also including a hole 126 formed therein that receives the bearing 116. First and second bearing inserts 128, 130 are removably disposed about the holes 122, 126 formed in the bearing plate 118 and the bearing mounting plate 124. The bearing mounting plate 124 and bearing plate 118 are coupled together to retain the bearing 116 and bearing inserts 128, 130 between the two components. The actuator 125 is angularly movable about the bearing 116.

(75) Alternatively, the actuator 125 may include rotary type actuators, as described above with the previous embodiments. The rotary actuators may include a drive shaft connected to a drive gear and a driven member attached to the trim tab 120 and operatively linked with the drive gear such that the driven member includes a flexible gear portion meshed with the drive gear. In another aspect, the actuator 125 may include a through hole drive gear that is smaller than a drive shaft diameter to accommodate installation through bearings.

(76) The support structure 115 may include multiple hinge locations 145 pivotally attaching the trim tab 120 to the support the trim tab frame 135 at various locations such that an angle of the trim tab 120 may be adjusted relative to the watercraft and water. As can be seen in the figures, the trim tab 120 may be pivotally attached at either the upper or lower hinge locations 145 on the support structure 115. It should be realized that various numbers of hinge locations 145 may be provided such that the angle of the trim tab 120 relative to the watercraft may be adjusted over a range.

(77) Again referring to FIGS. 17-22, the trim tab frame 135 may include a cylindrical hinge structure 150 that receives a pivot shaft 155 that connects with bearings 160 and is received in journals 165 formed on the support structure 115.

(78) As stated above, the trim tab frame 135 includes a curved surface 140 that is positioned to contact water when the watercraft is in motion. Various trim tab frames 135 may be utilized. In one aspect, the trim tab frame 135 may include a generally planar top 175, bottom 180 and side surfaces 185 linked by the curved surface 140 to define a wedge shaped trim tab body. Several of the top surface 175, bottom surface 180, and side surfaces 185 may include slots formed therein as detailed in the FIGS. 17-22 to lessen a weight of the trim tab assembly 110 and/or to allow relief of pressure applied to the tab assembly 110, and/or to reduce resistance to movement experienced by the tab assembly 110 resulting from its operation in water and/or other fluid.

(79) In FIG. 17 the trim tab assembly 110 is shown having a scraper plate 187. The curved face 140 of the trim tab 120 is adjacent to and is moved relative to the scraper plate 187. The scraper plate 187 is adjacent a member 189 and the curved surface 140. The member 189 and the curved surface 140 moves relative to the scraper plate 187 while transitioning between retracted and extended states. The scraper plate 187 extends parallel to and along the curved face 140 of the member 189. The member 189 and the curved surface 140 have a first portion 191 and a second portion 193. While in an extended state, the first portion 191 does not extend below the scraper plate 187, and the second portion 193 extends below the scraper plate 187. While in a retracted position, the first portion 191 and the second portion 193 of the member 189 and the curved surface 140 do not extend below the scraper plate 187.

(80) The member 189 and the curved surface 140 are shaped and a relationship between the member 189 (and the curved surface 140) and the support structure 115 are such that a distance between the member 189 (and the curved surface 140) and the scraper plate 187 remains unchanged during transitioning of the member 189 (and the curved surface 140) between the retracted and extended states. The scraper plate 187 extends away from a hull of a marine vessel and towards the member 189 (and the curved surface 140). While in the extended state (i) the member 189 (and the curved surface 140) extend partially below the scraper plate 187, (ii) at least a portion of the member 189 (and the curved surface 140) is not below the scraper plate 187, and (iii) the member 189 (and the curved surface 140) extend at least from a first point 195, adjacent the scraper plate 187, to a second point 197 below and rearward of the scraper plate 187. This can be seen best in FIG. 48. The member 189 is a convex-shaped member includes a forward facing surface 201, a first edge 202, and a second edge 203. The convex-shaped member 189 and the forward facing surface 201 curve outward between and forward of the first edge 202 and the second edge 203 in a direction away from an axis of rotation of the trim tab 120 represented by point 204, which is rearward of the convex-shaped member 189. The first edge 202 is higher than the second edge 203. The convex-shaped member 189 pivots about the axis of rotation of the trim tab 120.

(81) In FIG. 23, a trim tab 210 is shown having a curved surface (or face) 212 with slits 214. The slits 214 are spaced away from each other and extend parallel to each other. The slits 214 extend between a top surface 215 and a bottom surface 216 of the trim tab 210. In FIG. 24, a trim tab 220 is shown having a curved face 222. The curved face 222 is a diamond face having triangular-shaped sections 224. Portions of the triangular-shaped sections protrude from the trim tab 220 more than other portions of the triangular-shaped sections.

(82) In FIGS. 25-26, a trim tab 230 is shown having an eccentric curved surface (or face) 232. The trim tab 230 includes a top surface 234 and a bottom surface 236. The top surface 234 and the bottom surface 236 extend from a hinge location 238 to the eccentric curved face 232. The top surface has a first length L.sub.1 between the hinge location 238 and the eccentric curved face 232 that is shorter than a second length L.sub.2 of the bottom surface between the hinge location 238 and the eccentric curved surface 232. The surfaces 234, 236 are not symmetrical for at least the reason that the surfaces 234, 236 have the different lengths L.sub.1, L.sub.2.

(83) In FIG. 27, a trim tab 240 is shown having a curved faceted surface (or face) 242. The curved faceted face 242 has flat rectangular sections 244 that extend laterally between sides 246 of the trim tab 240. The flat rectangular sections extend in parallel to each other. In FIG. 28, a trim tab 250 is shown having a curved face 252. The curved face 252 has holes 254 and thus is perforated. Inclusion of the holes 254 increases surface area of the trim tab 250.

(84) In FIG. 29, a trim tab 260 is shown having a curved surface (or face) 262 with horizontal slits 264. The horizontal slits 264 are spaced away from each other and extend parallel to each other and between sides 265 of the trim tab 260.

(85) In FIG. 30, a trim tab 270 is shown having two curved surfaces (or faces) 272, 274. The curved faces 272, 274 provide an inward protruding inverted plow face. In FIG. 31, a trim tab 276 is shown having a curved surface (or face) 275 with multiple fences 278. The fences extend between a top surface 271 and a bottom surface 273 of the trim tab 270. The fences 278 protrude from the curved face 275. The fences 278 extend parallel to each other. Sides 279 of the trim tab 276 may extend past the curved face 275 to provide two of the fences, as shown. In FIG. 32, a trim tab 280 is shown having a curved surface (or face) 282. The curved face 282 has triangular shaped-holes 284 and thus is perforated. In FIG. 33, a trim tab 286 is shown having two curved faces 288, 289. The curved faces 288, 289 provide an outward protruding inverted plow face.

(86) In FIG. 34, a trim tab 290 is shown having a stepped curved surface (or face) 292. The stepped curved face 292 has rectangular sections 294 that are stepped relative to each other providing side edges 296 that protrude from the trim tab 290. The rectangular sections 294 extend laterally across the stepped curved face 292 between sides 298 of the trim tab 290.

(87) Referring again to FIG. 17, in one aspect, the curved surface 140 may include perforations formed therein or having various shapes and configurations, as shown in FIGS. 23-34. Referring to FIGS. 23-34, various perforations may include small holes of varying shape, slits of varying direction, and other slots or holes to modify the contact surface or curved surface 140 of the trim tab 120. Additionally, the curved surface 140 may include shapes formed thereon including facets, strakes, multiple curved surfaces, steps, curves that may vary, fence structures and mirrored curved surfaces. In this manner, the performance characteristics and contact area of the trim tab 120 may be adjusted for various types of watercraft.

(88) In another aspect as shown in FIG. 44, a trim tab 299 is shown having a curved face 300 and may include strakes or fencing 302 formed as part of sides 304, 306 of the trim tab 299 to contain high-pressure water and prevent lateral migration of water from the curved surface 300. The trim tab 299 may replace the trim tab 120 of FIG. 17. In this manner, lateral stability of the watercraft may be improved. Containing high-pressure water with strakes or fencing may also improve the efficiency of the trim tab 299. The strakes or fencing 302 may extend away from the curved surface 300, as shown, providing a channel 308 external to the trim tab 299 and between the strakes or fencing 302.

(89) As previously stated above, the trim tab 120 of FIG. 17 may be actuated at speeds sufficient to counter motion rates and damp motion in the pitch, roll and yaw axes of a vessel or watercraft. In one aspect, the trim tab 120 may be actuated to control attitude changes in the pitch, roll and yaw axes of the watercraft. The trim tab assembly 110 may be coupled to an active stabilization motion damping and attitude control system 190 linked with the actuator 125 controlling movement of the trim tab 120, as best seen in FIG. 43. The active stabilization motion damping and attitude control system 190 may include a controller 192 that has appropriate hardware and programming to decide on the positioning of the trim tabs 120. The controller 192 is connected with the actuators 125. The controller 192 may also be connected with sensors 194 that detect a position and characteristics of the water craft such as a steering position or a rudder position. The controller 192 may also be coupled with various input and output devices 196 such as a touch screen, buttons, steering controls, throttle, displays, speakers or other types of devices.

(90) Various numbers of the trim tab assembly 110 may be included on the watercraft and in various positions such as forward or aft on a vessel or internal (in a cavity) or external to the hull. In one aspect, at least two of the trim tab assembly assemblies 110 are connected on the watercraft, as shown in FIG. 45, such that the trim tab assemblies are actuated in series or differentially to impart various changes in the pitch, roll and yaw axes of the watercraft. FIG. 46 shows a trim tab assembly 330 attached to a watercraft 332. The trim tab assembly 330 includes a trim tab 334 including a member 336 have a forward facing surface 338. The member 336 (or plate) extends between a first end 340 and a second end 342. The member 336 has a centerline 344 that extends from the first end 340 to the second end 342. The member 336 curves outward between and forward of the first end 340 and the second end 342 in a direction away from a point 346 rearward of the member 336.

(91) In one aspect, the active stabilization, motion damping, and attitude control system 190 may include various protocols for moving the trim tab 120 of the trim tab assembly 110. For example, the control system 190 may include an auto park feature for beaching and trailing such that the trim tab 120 is retracted when the watercraft speed is below a specified level such as 5 knots for example. Such integration may include a throttle position sensor for determining whether the vessel is slowing, stopping and/or reversing. Additionally, the control system 190 may include other features to control the trim tabs 120 as a watercraft or vessel exits the water during high-speed operation. For example, the control system 190 including sensors 196 may detect a change of the vessel attitude or position and retract the trim tab(s) 120 to avoid damage to the trim tab(s) 120, the hinge assembly 100, and actuator assembly 125 due to high load forces that may be incurred as the vessel reenters the water.

(92) The trim tab assembly 110 may be positioned at various locations on a watercraft. In one aspect, the trim tab assembly 110 may be positioned on a transom and is attached to a hull of the watercraft. In another aspect, as shown in FIGS. 19-22, the support structure 115 and trim tab 120 may be positioned within a cavity 200 formed in a watercraft hull. In one aspect, the cavity 200 may include a snorkel opening formed therein for equalizing a pressure within the cavity in response to trim tab actuation.

(93) Referring to FIGS. 35-42, another alternative embodiment of a trim tab assembly 310 for a watercraft is shown. The trim tab assembly 310 may include a support structure 315 attached to the watercraft. A trim tab mounting frame 317 may be pivotally attached to the support structure 315. At least one trim tab 320 is pivotally attached to the trim tab mounting frame 317. A first actuator 325 is connected to the trim tab 320 pivotally moving the trim tab 320 relative to the trim tab mounting frame 317. A second actuator 327 is connected to the trim tab mounting frame 317 pivotally moving the trim tab mounting frame 317, where an angle of deflection of the trim tab 320 relative to ambient water flow is adjusted.

(94) As with the previously described embodiment of FIGS. 17-22, the at least one trim tab 320 includes a trim tab frame 315 having a curved surface 340 positioned to contact water when the watercraft is in motion. Additionally, the actuator 325 may include linear actuators connected directly to the trim tab frame 315 or may include rotary actuators as described above. The trim tab frame 315 may include the hinge structure as described above. Additionally, the trim tab frame 315 may include the top, bottom, and side surfaces linked by the curved surface 340 as described above.

(95) The trim tab assembly of FIGS. 35-42 may also include a control system 190 as described above. In one aspect, the control system 190 may actuate the trim tab 340 and trim tab support frame 317 at speeds sufficient to counter motion rates and damp motion in the pitch, roll and yaw axes of the vessel or watercraft. The control system 190 may actuate the trim tab 320 as well as adjust the angle of the trim tab relative to ambient water by changing the position of the trim tab support frame 317. In this manner, various geometries or positions of a trim tab 320 relative to the watercraft hull and flow of ambient water may be automatically accomplished to optimize the overall watercraft or vessel performance.

(96) While the trim tab assemblies have been described with respect to a watercraft or vessel, it should be realized that the trim tab assemblies 110, 310 may be integrated as a control surface within a wing or similar lifting body for aerospace applications.

(97) FIGS. 47-49 show perspective views of a trim tab assembly 110 mounted on a watercraft 400 with the trim tab 120 in retracted, partially extended, and fully extended positions. The trim tab assembly 110 is shown as including the support structure 115 and the actuator 125.