Patent Application
20140113514
1. Field of the Invention
The invention relates generally to devices and methods for providing a watercraft transom having an adjustable height feature allowing optimal matching with the drive shaft of the watercraft's motor.
2. Description of the Related Art
Outboard watercraft motors are generally available in either a short, long or extra long drive shaft version as further described herein.
As used herein, a short drive shaft outboard may be approximately 15 inches in length. These short drive shafts may be found in use in, e.g. small boats, sailboats with movable brackets, small sailboats, inflatable boats and canoes. These short drive shafts may comprise the primary motor or be used as a trolling motor or other non-primary motor. Generally, the watercraft making use of the short drive shaft outboard motors comprise an aft transom that is approximately 15 to 17 inches in height.
Long drive shafts, as that term is used herein, for available outboard motors may comprise a drive shaft that is approximately 20 inches in length. Such long drive shaft outboard motors may be found in use with, without limitation, sailboats, and pontoons. The watercraft using the 20-inch long drive shaft outboard motors generally comprise an aft transom that is approximately 18 to 21 inches in height.
Finally, extra long drive shafts for available outdoor motors may comprise a drive shaft that is approximately 25 inches in length. Outboard motors comprising the long drive snail may be found in use with pontoons, catamarans, sailboats, large barges and other watercraft having a relatively high transom, i.e., wherein the transom is between 21 to 27 inches in height.
When a watercraft owner selects an outboard motor to match with the watercraft for optimal performance, it is critical to measure the watercraft's transom as well as the motor, specifically the drive shaft length, to make sure the motor will fit the watercraft's transom. With outboard motors, the most important measurement is the drive shaft length. Mismatching the outboard motor drive shaft length with the transom height can result in poor performance. For example, an outboard with a shaft length that is too short for the watercraft will cause the propeller to lift out of the water when the watercraft is on plane, compromising performance.
Outboard motor drive shafts are thus optimally individually fitted to a watercraft according to the boat's aft transom height. When a watercraft lifts under power and skims across the water, it performs and handles most efficiently when the propeller is the only engine part remaining in the water. For this reason, the shaft length must match the height of a watercraft's aft transom. This general and known concept is illustrated in
Table 1 below illustrates some available combinations of transom height and the closest available outboard motor drive shaft length:
Table 1 illustrates the basic problem: for many current applications, the transom height vs. drive shaft length is mismatched, resulting in sub-optimal watercraft performance.
To illustrate in terms of the state of the art, we refer now to the typical construction strategy on, e.g., a pontoon watercraft that is designed for use with an extra long drive shaft outboard motor, i.e., the drive shaft length is approximately 25 inches. This exemplary pontoon would optimally comprise an aft transom that is fixed at approximately 25 inches to provide optimal matching between drive shaft length and transom height. If, on the other hand, the exemplary pontoon watercraft is being designed for use with a long drive shaft outboard motor with a drive shaft, length of 20 inches, the fixed transom height will be designed to compensate with a height of approximately 20 inches to optimally match the drive shaft length and transom height. Thus, in both of these cases, S≈T as illustrated in exemplary
In these known cases, the transom height is always fixed, i.e., not adjustable in height, and is manufactured to fit an outboard motor comprising a known and specified drive shaft length that is also always fixed. At times, the watercraft user may subsequently wish to switch from a short drive shaft outboard motor to a long drive shaft outboard motor, from a long to an extra long drive shaft, etc. In this event, the fixed, non-adjustable transom height is no longer optimal with adverse impact on the watercrafts performance. Currently, correction of this mismatching between the transom height T and new drive shaft length S requires modifying the transom height T to re-optimize its match with the length S of the new outboard motor's drive shaft. Modification of the transom height T requires cutting and fabrication of components to make the conversion and adjustment. Such conversion is difficult and expensive.
The present invention addresses these problems.
The invention provides devices and methods for providing a watercraft transom having an adjustable transom height feature allowing optimal matching with the drive shaft of the watercraft's motor in one embodiment, the adjustable transom height feature comprises two transom height settings to accommodate long or extra long drive shafts or, alternatively short or long or, still more alternatively, short or extra long drive shafts. In another embodiment, the adjustable transom height feature comprises more than two transom height settings, preferably to include matching transom height to known and available outboard motor drive shafts in order to accommodate and virtually optimize any drive shaft length.
The figures and the detailed description which follow more particularly exemplify these and other embodiments of the invention.
The Invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, which are as follows.
Left and right hollow inner center channels 120, 122 comprise a lower height HL while outer vertical support members 124, 126 comprise an upper height HU. A lower mount ledge 128 is therefore provided disposed between the outer vertical support members 124, 126 and with height matching that of the left and right hollow inner center channels 120, 122, i.e., HL. Left and right hollow inner center channels 120, 122 may further comprise a series of through holes in matched pairs H, aligned horizontally and vertically for securement of an upper member to lower member 100 at varying heights as will be discussed further below.
The difference D between HL and HU comprises in certain embodiments, the difference in outboard motor drive shaft lengths. For example, in various embodiments, HU−HL may comprise one of the following exemplary configurations:
Thus, in each of these exemplary configurations shown in Table 2, the Upper Height HU matches the longer of the two exemplary drive shafts, while the Lower Height HL matches the shorter of the two exemplary drive shafts. The difference D, i.e., HU−HL, is therefore equal to the difference between the lengths of the two exemplary drive shafts in an optimal configuration where, as in
Turning now to
Vertical stakes 250, 252 are configured so that left vertical stake 250 slidingly fits within left hollow inner center channel 120 of lower member 100. Similarly, right vertical stake 262 is configured to slidingly fit within the right hollow inner center channel 122 of lower member 100. As illustrated, the geometrical shape and profile of right and left hollow inner center channel 120, 122 are complementary with right and left vertical stakes 250, 252, respectively.
Further, in the illustrated embodiment, right and left vertical guide channels 224, 226 slidingly receive at least part of the right and left outer vertical support members 126, 124, respectively.
With continued reference to
Further, the throughholes on right and ten vertical stakes 260, 252 are aligned with the througholes on the right and left hollow inner center channels 120, 122 when the right and left vertical stakes 250, 252 are fully engaged within inner center channels 120, 122. This full engagement results in the bottom side 240 of upper transom place 210 engaging the upper side of lower member 100. As discussed above, this embodiment of the present invention may comprise a fixed transom height T, i.e., height that is customized to fit a particular drive shaft length for the proposed watercrafts outboard motor. In this case, the fixed transom height T is equal to the Upper Height HU that is discussed supra, wherein the outboard motor rests on the top side 230 of upper member 200.
Alternatively, as in
In this embodiment, the invention comprises two possible, but still fixed and otherwise non-adjustable transom height positions: a longer transom height T corresponding to HU and a shorter transom height T′ corresponding to HL.
Thus, one embodiment of the present invention comprises an adjustable height transom with at least two positions: a first position with the upper member 200 fully engaging and received within the lower member 100, and a second position without the upper member 200 engaging the lower member 100. The first position, with lower and upper members 100, 200 in engagement, thus comprises a transom height that is higher than that of the second position, i.e., without the upper member 200. The upper and tower heights for this embodiment of the present invention may comprise the transom heights illustrated above in Table 2 in order to capture the most common drive shaft lengths S and provide optimal performance.
As a result, the following optimal transom height combination pairs may be realized:
An upper transom height of 25 inches and a lower transom height of 15 inches;
An upper transom height of 25 inches and a lower transom height of 20 inches; and
An upper transom height of 20 inches and a lower transom height of 15 inches.
Additional transom height pairings are certainly possible and well within the scope of the present invention. The illustrated transom height pairing combinations are provided to match with the most commonly available outboard drive shaft lengths S as illustrated in Table 2.
Referring back to Table 1 which illustrates various combinations of outboard motor drive shaft length S and transom height T. In order to provide maximum, flexibility in matching the transom height H with the drive shaft length S, an additional embodiment of the present invention comprises multiple fixed transom height positions. Another embodiment of the present invention may provide selectably adjustable transom heights. We now describe this embodiment, with continued reference to
In the selectably adjustable embodiment, upper member 200 is at least partially engaged with, and received by, lower member 100 in the manner described above. The difference between the currently illustrated embodiment and the above-described embodiments is that there are more than two, and preferably a plurality, of transom heights that may be obtained with the current embodiment, dependent upon the outboard motor's drive shaft length S in order to provide optimal watercraft performance. This adjustability is achieved by the plurality of througholes pairs H′ on right and left stakes 252 and 250 of upper member 200, at least one of such pairs H′ successively match with at least one of the throughholes H of right and left inner channels 122, 120. As the stakes 252, 250 of upper member 100 are slidingly received within right and left inner channels 122, 120, the upper member throughhole pairs H′ will begin to match with at least one throughole pair H of the lower member 200. Each such successive matching of H′ and H pairs corresponds with a variable transom height, as measured from the lower transom plate 110 to the top side 230 of upper member 200 as shown in
The skilled artisan will now readily recognize that the upper member 200 may be lowered to a variety of positions slidingly engaged within the lower member 100 in order to achieve a selectable transom height that most closely matches the outboard motors drive shaft length S. Sliding the upper member 200 further into the inner channels 120, 122 of lower member 100 to the next successive matching of throughhole pairs H′ and H results in a correspondingly lowered transom height.
Consequently, this embodiment of the present invention may comprise a selectably variable transom height in the range of 15 inches to 25 inches in order to cover the most commonly available outboard motor drive shaft lengths of 15 inches, 20 inches and 25 inches, as well as selectable heights between 15 inches and 20 inches and between 20 inches and 25 inches. Further, the selectable variable transom height may be within a range of 14 inches to 27 inches, in order to cover not only the most common drive shaft lengths of 15, 20 and 25 inches, but also some older drive shaft lengths that may be utilized.
Further, in all embodiments, the skilled artisan will recognize that the upper member may be an optional element in the case where the drive shaft length is equal to that of the lower height in this case, the lower member is all that is required to optimize current performance. However, should the watercraft owner want to change outboard motors from, e.g., a 15 inch short shaft to a 20 inch or 25 inch, or other length, drive shaft, the upper member will be employed to provide a selectably variable upper height to accommodate the longer drive shaft length(s).
While the invention is amenable to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and described in detail herein, it should be understood, however, that the intention is not to limit the Invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives failing within the spirit and scope of the Invention.
