The present disclosure relates to watercraft, and in particular apparatus and methods for affecting the interaction of wakeboat hulls with their surrounding water.
Watersports involving powered watercraft have enjoyed a long history. Waterskiing's decades-long popularity spawned the creation of specialized watercraft designed specifically for the sport. Such “skiboats” were optimized to minimize the wake in the water behind the watercraft's hull, thereby providing the quietest possible water to the trailing water skier.
More recently, watersports have arisen at the other extreme by actually taking advantage of, and benefiting from, the wake produced by a watercraft. Sports such as wakesurfing, wakeboarding, wakeskating, kneeboarding, and others use the watercraft's wake to allow the participants to perform various maneuvers or “tricks” including becoming airborne.
To address this changing market, skiboats dedicated to a single watersport have yielded to a new type of watercraft known as a “wakeboat”. Wakeboats seek to more completely manage the spectrum of wakes that are produced behind the hull—diminishing it for some activities, while enhancing it for others.
The wake that forms behind the hull of a wakeboat as it moves through water is affected by many factors, including but not limited to the hull's aspect ratio (relationship of length to width), the width of its transom (the rearmost portion of the hull), the velocity of the hull through the water, and the hull's draft (depth in the water).
As mentioned above, modern watersports take advantage of, and benefit from, the wake produced by a wakeboat. For watersports such as wakesurfing, the wake is intentionally made asymmetric: An actual wave is formed behind one side of the hull, thus approximating the unidirectional behavior of a naturally formed ocean wave. A wakesurfing participant can employ a surfboard on the wave behind a wakeboat much as surfboards have historically been used in the ocean, with the wave “breaking left” or “breaking right” depending upon which side of the hull is forming the wave.
An asymmetric wake is formed by the hull having an asymmetrical relationship to the water. One method of introducing asymmetry is to rotate the hull around its longitudinal axis, the axis running lengthwise from the front (bow) to the rear (stern). The result is commonly referred to as “tilt”, “roll”, or the nautical term “list”. A hull that is not level with the water's surface creates an asymmetrical wake as it moves through the water.
One common technique for changing the roll angle of a hull is the use of trim tabs. These comprise plates at or near the transom of the hull, often installed in groups of two or more distributed across the width of the transom, that by angling down into the water below the normal hull profile, cause the moving water to impart a lifting force to the hull. When multiple such trim tabs are deployed in synchronization (e.g. at roughly the same angle), the lifting force is roughly even across the width of the hull and the lifting effect is primarily around the lateral axis—a rotation often referred to as “pitch”.
More usefully for asymmetric wake formation, when multiple such trim tabs are deployed in an unsynchronized fashion some amount of the lifting force contributes to rotation around the longitudinal axis—and thus the hull experiences tilt/roll/list as described above.
For example, a trim tab mounted on the left (port) side of the transom, and deployed into the water, will experience a lifting force from the moving water that will lift the left (port) side of the hull and lower the right (starboard) side of the hull—thus rotating the hull around its longitudinal axis. A trim tab mounted on the opposite side, and deployed into the water, will reverse these directions and lift the right (starboard) side of the hull while lowering the left (port) side.
These asymmetrical lifting forces cause the hull to have an asymmetrical relationship to the water, which in turn causes an asymmetrical wake to form behind the hull.
Trim tabs are a very old and well known technology. For example, U.S. Pat. No. 2,576,744 to Anderson (incorporated herein by reference) describes a pair of independently adjustable trim tabs.
U.S. Pat. No. 2,816,521 No. to Alexander (incorporated herein by reference) goes into even greater detail: “blades 6 may be set to various or different angular positions with respect to each other, to insure the boat operating on an even keel regardless of the location of the load or cargo within the hull” (see Col. 2, Lines 31-34).
U.S. Pat. No. 3,159,131 to Frederick (incorporated herein by reference) reiterates the asymmetric effect of trim tabs: “the upward thrust effected by the flaps may be increased or decreased either simultaneously or individually. By increasing and decreasing the downward inclination of the trim flaps the inclination of the hull may be adjusted about both transverse and longitudinal generally horizontally disposed axes” (see Col. 1, Lines 15-21). Thus the use of trim tabs to impart rotation about the transverse (pitch) and longitudinal (roll) axes has a long history in the art.
While trim tabs have a long history of use for hull control, and are in common use today for asymmetrical wakesports, they suffer from certain restrictions. One such restriction is their limited dynamic range. The effects that trim tabs can impart to a hull are limited in scope; plainly stated, there is only so far that a hull can be safely tilted, and that degree of tilt may not, by itself, achieve the desired asymmetry of wake.
Trim tabs alone being insufficient, the achievement of the desired asymmetry of wake may require one or more supplementary techniques.
A second technique for asymmetric wake formation is based on convergence of the disturbed water coming off the two sides of the rear of the hull. As described in U.S. Pat. No. 3,200,782 to Walden (incorporated herein by reference), in the absence of any convergence controlling element “the slip-streams 76 at the two sides pass close to the sides of the boat at 77 and then converge behind the boat at 78” (see Col. 6, Lines 41-43 and FIGS. 10 through 12).
Walden then describes using vertically oriented trim tab elements to delay the convergence: “As shown in FIG. 12, however, when the vanes are used extending upwardly and curving outwardly from the outboard sides of the elevator plates, the slip-stream 77′ flares outward at 80 in the wake” (see Col. 6, Lines 45-48 and FIG. 12). Walden both describes, and illustrates, delaying the convergence of the wake formed behind a hull using vertically oriented trim tab elements.
While Walden may have originated the concept of delayed convergence, it is not without its disadvantages. One such disadvantage is the fixed nature of its delayed convergence. Walden offers no way to adjust the traditional effect of its trim tabs independently from the convergence delaying effect of its vertically oriented trim tab elements.
The concept of delayed convergence via vertically oriented trim tab elements from U.S. Pat. No. 3,200,782 to Walden is later disclosed by Gasper in a series of US Patents including U.S. Pat. No. 9,260,161 which states: “The neutral position of surf wake system 32 is shown in FIG. 13(a) in which flaps 33 are in their neutral, retracted position. In this position, the flow of water past the transom is unimpeded by the flaps and the water is allowed to converge at it is natural intersection relatively close to the transom. When a surfable starboard side wake is desired, the operator may deploy the port side flap 33p as shown in FIG. 13(b). In this position, the flow of water along the port side past the transom is disrupted such that the flow of water is redirected outwardly and/or rearwardly thereby delaying convergence of the port side flow with starboard side flow to a point further from the transom.” (see Col. 12, Lines 23-38 and FIGS. 13a and 13b.)
As with FIGS. 10 through 12 of U.S. Pat. No. 3,200,782 to Walden, FIGS. 13a and 13b of U.S. Pat. No. 9,260,161 to Gasper show the use of vertically oriented trim tab elements to delay the convergence of wakes behind the hull of a boat.
Gasper describes its vertically oriented trim tabs as a “pair of upright water diverters including a port diverter and a starboard diverter” (see Col. 2, Lines 1-2). Gasper requires that “the pivot angle may be substantially vertical, substantially parallel to the side edge, some other angle therebetween, or some angle slightly inclined with respect to the side edge” (see Col. 6, Lines 16-19). The hinge of Gasper is disclosed as being at or near vertical: “the angle between the pivot axis and the side edge is less than approximately 15 degrees, more preferably less than 10 degrees, and even more preferably less than 5 degrees” (see Col. 6, Lines 19-22).
This at- or near-vertical orientation in the Gasper specification is shown in the figures in which all hinges and flaps are at or near vertical. See flaps 33p and 33s of FIG. 1, hinge 37 and flap 33 of FIG. 2, hinge 37p and flap 33p of FIG. 4A, hinge 37p and flap 33p of FIG. 4B, hinges 37p and 37s and flaps 33p and 33s of FIG. 5A, hinges 37p and 37s and flaps 33p and 33s of FIG. 5B, hinges 37p and 37s and flaps 33p and 33s of FIG. 5C, flap 33 of FIG. 10, flap 33 of FIG. 11, flaps 33 of FIG. 12A, hinges 37 and flaps 33 of FIG. 12B, flaps 33p and 33s of FIG. 13A, flaps 33p and 33s of FIG. 13B, flaps 33p and 33s of FIG. 13C, hinges 37 and flap 33 of FIG. 14A, flap 33 of FIG. 14B, hinges 37 and flap 33 of FIG. 15A, flap 33 of FIG. 15B, flap 33 of FIG. 15C, flaps 33 (also labeled “Surf Gate”) of FIG. 16A, flaps 33 of FIG. 16B, hinges 37p and 37s and flaps 33p and 33s of FIG. 17, and flaps 33p and 33s of FIG. 18.
The disadvantages of the vertically oriented trim tab elements of Walden have already been addressed above. Chief among these is their fixed nature relative to the horizontally oriented trim tabs to which they are attached.
Likewise, the Gasper requirement that the hinges and flaps of its “upright water diverters” be oriented vertically bears its own disadvantages. For example, the sides of the hull often require recesses to permit the hinges and flaps of Gasper to fully retract out of the “flow of water past the transom”. Such recesses complicate hull design and fabrication, and may weaken the structural integrity. They may also compromise aspects of hull design by limiting the freedom of the hull engineer(s) to optimize for hull performance.
More seriously, the Gasper requirement that the hinges and flaps of its “upright water diverters” be oriented vertically may potentially also threaten the safety of nearby persons. When the “upright water diverters” of Gasper are in their deployed positions they extend outboard of the natural curve of the hull and may potentially present an impact and snagging hazard to nearby swimmers or anyone entering the water. Furthermore, the “upright water diverters” of Gasper are articulated by actuators with sufficient power to overcome the extreme water pressure flowing against them—an amount of force sufficient to potentially injure a person or marine animal snagged or entrapped by them. This potential problem of Gasper is compounded by the partial or complete submersion of its “upright water diverters”, potentially rendering them almost invisible to the very people to whom they pose a dangerous threat. For at least these reasons, any benefit from the “upright water diverters” of Gasper is potentially outweighed by downside risks.
A third technique, which is a variation on the “delayed convergence” of Walden and Gasper, is described in U.S. Pat. No. 9,315,235 to Wood. Wood discloses a traditional, full width hinged trim tab with “a second pivot axis forward the first pivot axis. The second pivot axis allows for the device to be installed on boats having different shapes, such as differently sloped transoms” (see Col. 2, Lines 19-22). The second pivot axis of Wood is an installation device, does not play a role in wake creation, and is required to span the entire width of the trim tab.
The first pivot axis of Wood is angled such that “when the water deflectors 216 rotate downwardly, they deflect water in the outboard direction as the boat moves forward, which affects the wake” (see Col. 4, Lines 35-37) and “water deflector 216 deflects the water that released from the stern trailing edge 114 downwardly and in the outboard direction, effectively digging a hole in the water behind the boat 100” (Col. 4, Lines 51-53). In other words, Wood is yet another delayed convergence system.
A fourth technique for asymmetric wake formation is proposed in US Patent Application Publication 2013/0228114 by Gasper. Therein is described the addition of secondary, tertiary, or even more rudders along the keel of a boat hull which are linked by a complex linkage system to operate synchronously. The disadvantages of such a system are numerous, including but not limited to additional complexity of hull manufacture, the displacement of other components otherwise preferentially located within the hull in that volume near the keel, the additional piercings of the hull to accommodate the numerous additional rudder shafts, the necessary additional waterproof fittings on the numerous additional rudder shafts to prevent intrusion of the surrounding water into the hull despite the through-hull rotating mechanisms required below the waterline, and the manufacture and cost and ongoing maintenance of the linkage system to coordinate the numerous additional rudders as described and illustrated in the Publication.
It is clear from the above discussion that individually operated trim tabs and delayed convergence of wakes have been areas of research for decades. However, existing proposals for achieving these ends are fraught with limitations, compromises, and in some cases outright hazards.
There is an ongoing need in the wakeboat industry for a surf wake forming system that delivers desirable asymmetric wakes without adding complexity and cost and, in some cases, without adding a potentially dangerous safety risk.
Various embodiments provide a system that improves the generation of an asymmetric wake, that works with minimal modifications to existing hull designs, enables separate adjustability of its elements, and avoids the creation of hazards in areas likely to be populated with swimmers.
Some embodiments provide means for controllably affecting lift and yaw of one side of the stern of a boat to create an asymmetric wake behind the boat. In some embodiments, the means for controllably affecting lift and yaw comprises a trim tab including a main tab portion pivotably supported from the stern of the boat for rotation about a first axis, and a yaw tab portion pivotably supported from the main tab portion for rotation about a second axis non-parallel with the first axis.
Some embodiments provide a system for forming asymmetric surf wakes behind a wakeboat including a hull having a port side, a starboard side, an inside, an outside, and a stern, the hull being configured to float in water with a waterline on the outside of the hull, the hull when moving forward in the water creating a wake with a left quiet region and a right quiet region, the system comprising a primary left trim tab pivotally supported by the hull proximate the port side of the stern for rotation about a first tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary left actuator mounted between the hull and the primary left trim tab, and configured to rotate the primary left trim tab around the first tab axis of the primary left trim tab from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary left trim tab pivotally supported by the primary left trim tab for rotation about a second tab axis that is non-parallel to the first tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that rotates the stern of the hull in a starboard direction to enlarge the right quiet region; a secondary left actuator mounted between the primary left trim tab and the secondary left trim tab, and configured to rotate the secondary left trim tab to enlarge the right quiet region and create at least one surf right configuration; a primary right trim tab pivotally supported by the hull proximate the starboard side of the stern for rotation about a third tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary right actuator mounted between the hull and the primary right trim tab, and configured to rotate the primary right trim tab around the third tab axis from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary right trim tab pivotally supported by the primary right trim tab for rotation about a fourth tab axis that is non-parallel to the third tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that rotates the stern of the hull in a port direction to enlarge the left quiet region; and a secondary right actuator mounted between the primary right trim tab and the secondary right trim tab, and configured to rotate the secondary right trim tab to enlarge the left quiet region and create at least one surf left configuration.
Other embodiments provide a system for forming asymmetric surf wakes behind a wakeboat including a hull having a port side, a starboard side, an inside, an outside, and a stern, the hull being configured to float in water with a waterline on the outside of the hull, the hull when moving forward in the water creating a wake with a port disturbance and a starboard disturbance, the system comprising a primary left trim tab pivotally attached to the hull proximate the port side of the stern for rotation about a first tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary left actuator connected between the hull and the primary left trim tab, and configured to rotate the primary left trim tab around the first tab axis of the primary left trim tab from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary left trim tab pivotally attached to the primary left trim tab for rotation about a second tab axis that is non-parallel to the first tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that substantially redirects the starboard disturbance to the port side of the wake; a secondary left actuator connected between the primary left trim tab and the secondary left trim tab, and configured to rotate the secondary left trim tab to the position that substantially redirects the starboard disturbance to the port side of the wake to create a surf right configuration; a primary right trim tab pivotally attached to the hull proximate the starboard side of the stern for rotation about a third tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary right actuator connected between the hull and the primary right trim tab, and configured to rotate the primary right trim tab around the third tab axis from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary right trim tab pivotally attached to the primary right trim tab for rotation about a fourth tab axis that is non-parallel to the third tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that substantially redirects the port disturbance to the starboard side of the wake; and a secondary right actuator connected between the primary right trim tab and the secondary right trim tab, and configured to rotate the secondary right trim tab to the position that substantially redirects the port disturbance to the starboard side of the wake to create a surf left configuration.
Still other embodiments provide a system for forming asymmetric surf wakes behind a wakeboat including a hull having a port side, a starboard side, an inside, an outside, and a stern, the hull being configured to float in water with a waterline on the outside of the hull, the hull when moving forward in the water creating a wake with a port disturbance and a starboard disturbance, the disturbances having a convergence at a location in the water behind the stern of the hull, the system comprising a primary left trim tab pivotally secured to the hull proximate the port side of the stern for rotation about a first tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary left actuator supported by the hull and the primary left trim tab, and configured to rotate the primary left trim tab around the first tab axis of the primary left trim tab from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary left trim tab pivotally secured to the primary left trim tab for rotation about a second tab axis that is non-parallel to the first tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that relocates the convergence closer to the stern of the hull; a secondary left actuator supported by the primary left trim tab and the secondary left trim tab, and configured to rotate the secondary left trim tab to the position that relocates the convergence closer to the stern of the hull to create a surf right configuration; a primary right trim tab pivotally secured to the hull proximate the starboard side of the stern for rotation about a third tab axis that is substantially parallel with the waterline when the hull is at rest in the water; a primary right actuator supported by the hull and the primary right trim tab, and configured to rotate the primary right trim tab around the third tab axis from a position having decreased interaction with the water passing beneath the hull to a position having increased interaction with the water passing beneath the hull; a secondary right trim tab pivotally secured to the primary right trim tab for rotation about a fourth tab axis that is non-parallel to the third tab axis, and configured to rotate from a position having decreased interaction with the water passing beneath the hull to a position that relocates the convergence closer to the stern of the hull; and a secondary right actuator supported by the primary right trim tab and the secondary right trim tab, and configured to rotate the secondary right trim tab to the position that relocates the convergence closer to the stern of the hull to create a surf left configuration.
This disclosure is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
Attention is directed towards the following patents, all of which are incorporated herein by reference: U.S. Pat. No. 8,798,825 issued to Hartman on Aug. 5, 2014; U.S. Pat. No. 9,828,075 issued to Hartman on Nov. 28, 2017; and U.S. Pat. No. 9,689,395 issued to Hartman on Jun. 26, 2017, all of which are assigned to Skier's Choice of Maryville Tenn. Attention is also directed towards U.S. Patent Application Publication No. 2007/0036738 to Hartman, Published Feb. 9, 2017, and to U.S. patent application Ser. No. 15/824,787, filed Nov. 28, 2017, both of which are assigned to Skier's Choice of Maryville Tenn., and both of which are incorporated herein by reference. Attention is also directed to commonly assigned U.S. patent application Ser. No. 16/139,847, filed Sep. 24, 2018, naming Hartman et al. as inventors, and incorporated herein by reference.
The assemblies and methods of the present disclosure will be described with reference to
As discussed in the Background section above, a plurality of traditional horizontally oriented trim tabs can impart tilt/roll/list to the hull of a wakeboat via dissimilar angles of deployment. Such rotation causes the hull to have an asymmetric relationship to the water, thus forming an asymmetric wake behind the moving hull.
The present disclosure improves upon a traditional horizontally oriented trim tab by dividing the trim tab into at least two parts, or subtabs. For brevity and ease of understanding this description will refer to a trim tab comprising two subtabs, but it is to be understood that other embodiments can comprise more than two subtabs depending upon the specifics of the application.
In some embodiments of the present disclosure, the primary function of one subtab is to cause the hull to rotate around its roll (also known as the longitudinal, Y, tilt, or list) axis. Meanwhile, the primary function of another subtab is to cause the hull to rotate around its yaw (also known as the vertical or Z) axis—the axis which is oriented primarily vertically, orthogonal to the roll and pitch axes. By imparting yaw rotation to the hull, the hull itself changes the formation of its own wake as it moves forward through the water.
Continuing with
The angle of main tab 210 with respect to hull 100 is adjustable, in operation, via main tab actuator 230. Actuator 230 converts a control signal from controller 130 to a physical force that repositions main tab 210. The control signal may be electrical, mechanical, hydraulic, pneumatic, or another signal type suited to the specifics of the application. The resulting physical force from actuator 230 may be based on electromagnetics, mechanics, hydraulics, pneumatics, or another principle suited to the specifics of the application. In some embodiments actuator 230 is mounted between transom 150 and main tab 210 as shown, but other mounting positions and arrangements may be used as suited to the specifics of the application.
Continuing with
The angle of yaw tab 240 with respect to main tab 210 is adjustable via yaw tab actuator 260, in operation. Actuator 260 converts a control signal from controller 130 to a physical movement that repositions yaw tab 240. The control signal may be electrical, mechanical, hydraulic, pneumatic, or another signal type suited to the specifics of the application. The resulting physical movement from actuator 260 may be based on electromagnetics, mechanics, hydraulics, pneumatics, or another principle suited to the specifics of the application. In some embodiments actuator 260 is mounted on the top surface of main tab 210 as shown, but other mounting positions and arrangements may be used as suited to the specifics of the application. For example, in some embodiments actuator 260 is mounted between the transom and yaw tab 240, with controller 130 selectively coordinating the operation of actuator 230 and actuator 260.
In some embodiments, actuator 260 can be a manual adjustment relying on direct operator input instead of a control signal from controller 130. This manual adjustment may be effected in any applicable manner including but not limited to a threaded shaft in place of actuator 260, a hinge 250 that incorporates a positional lock, a block or wedge that establishes the desired angle between yaw tab 240 and main tab 210, or another manner suited to the specifics of the application.
An example of an electrically powered actuator that could be employed for actuator 230 and actuator 260 is the Lenco 15054-001 (Lenco Marine Inc., 4700 SE Municipal Court, Stuart Fla. 34997). Another example of an electrically powered actuator that could be employed for actuator 230 and 260 is the Bennett BEA2000 (Bennett Marine Inc., 550 Jim Moran Boulevard, Deerfield Beach Fla. 33442). An example of a hydraulically powered actuator that could be employed for actuator 230 and actuator 260 is the Bennett A1101A (Bennett Marine Inc., 550 Jim Moran Boulevard, Deerfield Beach Fla. 33442). For a given embodiment the stroke length, mounting brackets, and other options for the actuator(s) may be selected based on the specifics of that application.
In some embodiments the sizes, shapes, range of deployment angles, and dimensions of main tab 210 and yaw tab 240 may be altered. This may be useful when the absolute, relative, or ratiometric roll axis force and/or yaw axis force are to be adjusted for the specifics of the application, as will be discussed in more detail below.
In some embodiments, such as that illustrated in
Depending upon the specifics of the application, some embodiments may locate yaw tab 240 on the opposite (outboard) side of main tab 210. In such embodiments the relationship of yaw tab side to direction of yaw is reversed, e.g. deployment of an outboard port side yaw tab 240 will impart rotation around the yaw axis of hull 100 toward its port side, instead of the starboard side as shown in earlier examples herein which illustrate an inboard-mounted yaw tab 240. This may be advantageous when, for example, a specific hull design benefits from having an inverse relationship between roll and yaw adjustments from that described above. The non-parallel alignment of hinge 220 and hinge 250 is what allows yaw tab 240 to impart yaw rotation to hull 100; the specific angle of that alignment, and the location of yaw tab 240 in relation to main tab 210, may be changed as suitable for the specifics of hull 100 and its intended application.
In the embodiment of the present disclosure shown in
To impart yaw to the hull, some embodiments deploy the main and trim tabs below the bottom planar surface of the hull.
In contrast, the effect of yaw tab hinge 250 being at an angle relative to main tab hinge 220 (and thus to transom 150 of hull 100) is now evident. As actuator 260 imparts downward movement to yaw tab 240, the axis of yaw tab hinge 250 causes the planar alignment of yaw tab 240 to be non-parallel with respect to transom 150 of hull 100 as it translates through the range of its rotation.
Continuing with
Yaw tab 240 conveys that starboard force through yaw tab hinge 250 to main tab 210. Main tab 210 then conveys the starboard force through main hinge 220 to transom 150. Finally, hull 100 reacts to the starboard force at transom 150 by shifting its transom to starboard (right).
Were this starboard force applied to hull 100 in line with its center of mass, hull 100 would “shift” to the right without rotation. However, since the starboard force is applied at one end of hull 100, that end—the stern, where transom 150 is located and the force is being applied—experiences the majority of the starboard force and the imbalance of force along the length of hull 100 causes it to react unevenly along its length. The result is that hull 100 rotates rather than shifts sideways.
For better understanding of this effect, it is illustrated in
In contrast,
To better visualize this effect in the context of hull 100 in water,
Proceeding with
In short, in this example embodiment, deployment of port yaw tab 240 causes hull 100 to rotate around its yaw axis, with its stern (rear) rotating to starboard and its bow (front) rotating to port.
To enhance clarity and understanding,
As noted earlier, a generally symmetrical hull relationship TO the water yields a generally symmetrical wake behind the hull IN the water. And so it is in
Naturally, a boat hull rotates when changing direction (turning). Therefore it is important to note in
Comparing
This asymmetry is caused by the hull yaw angle. Where in
The effect on the wake behind the hull is clearly visible in
In this embodiment, the opposite yaw rotation (not shown in
Certain embodiments of the present disclosure, including that shown in
Referring again to FIGS. 10 through 12 of U.S. Pat. No. 3,200,782 to Walden, and FIGS. 13a and 13b of U.S. Pat. No. 9,260,161 to Gasper, both of these references illustrate using vertically oriented trim tab elements to widen the “flow of water past the transom”. In the words of Gasper, water from the two sides is “disrupted . . . causing it to converge . . . beyond its natural intersection” (see FIGS. 13A, 13B, and 13C) and “delaying convergence . . . to a point further from the transom” (see Col. 12, Lines 33-34).
By way of differentiation, some embodiments of the present disclosure do not rely upon widening the “flow of water past the transom” nor “delaying convergence to a point further from the transom”. As shown in
The deployment of this embodiment on the port (left) side of the hull causes starboard disturbance 920 to relocate from its traditional location on the starboard (right) side of longitudinal axis 905 in
The same effect occurs on the port (left) side of the wake when this embodiment is deployed on the starboard (right) side of the hull. Returning again to
As the foregoing description and figures explain, various embodiments of the present disclosure can deliver desirable asymmetric wakes using various techniques. This array of options gives the present disclosure increased flexibility, allowing its operation to be implemented in different ways for different hulls depending upon the preference of the boat engineer(s).
Some embodiments of the present disclosure use fixed angles of retraction and employment for the main tab(s) and/or yaw tab(s). Other embodiments employ multiple, discrete angles of deployment. Still others offer a continuum between full retraction and full deployment. A combination of such deployment options may be used, with different options on each of the subtabs in an overall trim tab. As with size, shape, and other physical characteristics noted earlier, the present system has a broad spectrum of applicability and the specifics of each embodiment may be obtained through pure engineering, empirical analysis, or both.
In some embodiments, the main tab 210 and yaw tab 240 of the dimensions shown in
In some embodiments, the main tabs are selected to impart sufficient roll to the hull and the yaw tabs are selected to impart sufficient yaw to the hull. A sufficiently large displacement (e.g. a boat loaded with ballast, passengers, and gear) may achieve the desired wake asymmetry with less reliance on the size and shape of the main and yaw tabs. With less displacement (e.g. the boat is not fully loaded) the positions of the main tabs and yaw tabs may be adjusted to optimize the wake asymmetry.
As the starboard and port main tabs and yaw tabs are deployed down into the water they not only roll or yaw the boat, but they also create lift. Lift acts against the weight, and thus the displacement, of the boat. In some embodiments, operation begins with filling the ballast system to 100% and setting the starboard and port main tabs to 0% deflection. Then, one of the main plates is moved down slowly until sufficient hull roll is achieved to clean up the wake on the desired side.
In some embodiments, operation continues by adjusting the yaw tab until its induced hull yaw creates a surfable wake by optimizing the tradeoff between displacement (of the hull) and lift (from the main and yaw tabs).
In some embodiments, a center trim tab (not shown) is provided between starboard trim tab 120 and port trim tab 110. This center trim tab may be operated independently of, or in synchronization with, starboard trim tab 120 and port trim tab 110 as conditions warrant.
In some embodiments, the yaw tabs are angled to keep edges from shearing water as water passes the side of the hull. In some embodiments, the main tabs are tapered to be longer on their inboard sides. With this tapered shape of the main tab, water flows with reduced turbulence off the main tabs 210 and meets with the water flowing off the middle wake tab.
In some embodiments, when the boat takes off, the starboard and port trim tabs (and middle wake tab, if provided) are all automatically moved down by the controller 130 to create extra lift to improve initial hull acceleration, by reducing the drag of the hull in the water.
In some embodiments, the deflections or sizes of the port trim tab 110 and starboard trim tab 120 are asymmetrical to account for propeller rotation. Propeller rotation affects surf waves. The propeller rotation twists water causing water to flow naturally in one direction. This flow also creates torque and makes it harder to roll the boat one way than the other. The use of asymmetrical port trim tab 110 and starboard trim tab 120 can help alleviate these propeller effects.
Some embodiments provide default deflection percentages that are employed by the controller 130, for example. For example, when it is desired to surf on the port side, the starboard side main tab actuator 230 may be preset to move to 60% deflection, and the yaw tab actuator 260 may be preset to move to 100% deflection. Alternately, when it is desired to surf on the starboard side, the port side main tab actuator 230 may be preset to move to 75% deflection, and the yaw tab actuator may be set to move to 100% deflection. The reason for the different percentages is because of propeller rotation.
In some embodiments, the boat has to be rolled further to one side, or yawed further to one side, to create a similar shaped wave than if there were no propeller effect. Such dissimilar amounts of rotation around the axes of the hull may be stored by some embodiments of controller 130. In certain embodiments, these dissimilar rotation amounts may be automatically integrated by controller 130 such that the operator of the wakeboat need not overtly consider them. In these embodiments controller 130 can be configured with the specifics of the boat in which it is installed and automatically adjust operator-specified rotation magnitudes to provide substantially similar behavior from the same numeric values.
While not always necessary, some embodiments of the present disclosure may benefit from adjustments to the hull which ease the inducement of rotation around the roll and/or yaw axes. For example, longitudinal hull chines—often employed to improve hull tracking—may be revised to allow more freedom of yaw rotation. Likewise, stabilizing chines which resist hull roll may be altered to improve the ability to impart rotation around the roll axis. Those skilled in the art will recognize these and other hull engineering decisions as they integrate various embodiments of the present disclosure into their boat designs. Reference has already been made to U.S. Pat. No. 9,828,075 to Hartman. Therein is described several techniques for measuring the yaw angle of a boat hull. Such yaw measurement techniques can be used in combination with some embodiments of the present disclosure to create a closed loop yaw management system. As noted in '075 to Hartman, “Upon deriving the yaw angle as described above, some embodiments of the present disclosure use the yaw angle value to control the hull of the wakeboat. Referring to FIG. 9, system 154 can selectively control trim plates via connection Trim plate(s) power and sensing 414 to alter the yaw angle of the hull. The trim plates thus controlled may be oriented vertically, horizontally, or any other orientation suitable to the specific embodiment . . . . System 154 can repeatedly measure the yaw angle and apply ongoing adjustments to the hull to compensate for changing conditions” (see Col. 25, Lines 9-25).
The system of
Referring to
In some embodiments, controller 130 includes one or more electrical interfaces which enable it to selectively communicate with other controllers, systems, modules, and devices. These interfaces may comprise one or more of the following: Controller Area Network (CAN) interface, any of the various versions of Ethernet interface, any other wired interfaces whether standard or proprietary, optical interfaces, and wireless interfaces.
In some embodiments, controller 130 is not limited to operating the actuators associated with the present disclosure. The functions and features of controller 130 may be integrated into other controllers, or controller 130 may include functions and features otherwise associated with other controllers.
Certain embodiments use a single actuator to deploy both main tab 210 and yaw tab 240. In these embodiments a mechanical linkage coordinates the motion of main tab 210 and yaw tab 240, as imparted by the single actuator. This may be advantageous in embodiments, including retrofits to existing boat hulls, where space is limited or where connection 160 and/or connection 170 of
Some embodiments are one-sided, e.g. they do not employ the trim tabs of the present disclosure in multiple locations. In some applications a single main tab 210 with yaw tab 240 is sufficient to achieve the desired functionality. For example, a wakeboat dedicated to wakesurfing only on one side may not require multiple trim tabs of the present disclosure, leaving more room available at the transom for other apparatuses. The present disclosure is suitable for use with any number of its trim tabs to achieve the desired behavior of hull 100.
A variety of surf mode operator inputs are employed by some embodiments of the present disclosure.
A further enhancement, provided by some embodiments of the present disclosure, is the ability of controller 130 to store the value represented by Current Performance Indicator 1210 in a configuration memory 105 and later recall it for automated or semi-automated duplication. Some embodiments of the present disclosure may store the value represented by Current Performance Indicator 1210 in configuration memory 105 together with many other configurable aspects of the wakeboat's operation including but not limited to control surface parameters and/or hull speed.
In compliance with the patent laws, the subject matter disclosed herein has been described in language more or less specific as to structural and methodical features. However, the scope of protection sought is to be limited only by the following claims, given their broadest possible interpretations. The claims are not to be limited by the specific features shown and described, as the description above only discloses example embodiments.
This is a continuation of U.S. patent application Ser. No. 16/269,012 filed Jun. 2, 2019, which in turn is a continuation of U.S. patent application Ser. No. 16/140,416 filed Sep. 24, 2018 (now U.S. Pat. No. 10,202,177), which in turn is a continuation of U.S. patent application Ser. No. 16/017,935 filed Jun. 25, 2018 (now U.S. Pat. No. 10,112,688), which in turn is a continuation of U.S. patent application Ser. No. 15/945,711 filed Apr. 4, 2018 (now U.S. Pat. No. 10,040,522), which in turn claims priority to U.S. Provisional Patent Application Ser. No. 62/481,556 filed 4 Apr. 2017, all of which name Hartman et al. as inventors and all of which are incorporated herein by reference.
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Number | Date | Country | |
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62481556 | Apr 2017 | US |
Number | Date | Country | |
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Parent | 16269012 | Feb 2019 | US |
Child | 16450435 | US | |
Parent | 16140416 | Sep 2018 | US |
Child | 16269012 | US | |
Parent | 16017935 | Jun 2018 | US |
Child | 16140416 | US | |
Parent | 15945711 | Apr 2018 | US |
Child | 16017935 | US |