GB2208111A - Boat with cavity for a boat propulsion device - Google Patents

Abstract

A boat with a generally vertical transom 13 includes a water planing hull bottom surface 14 shaped to provide a minimum wetted area when on plane and a raised bottom surface 17 above the bottom surface. The raised bottom surface 17 contains a hole 18 therethrough adjacent the transom for mounting a boat propulsion device (11Fig 1 not shown) having a downward and rearward extending propeller drive. The raised bottom surface forms an upward cavity (20) having an open end notched through the transom within the bottom surface of the boat. In a second embodiment (Fig 7 not shown) the boat includes a second raised bottom surface adjacent the upward cavity. <IMAGE>

Description

BOAT WITH CAVITY FOR A BOAT PROPULSION DEVICE The field of tne invention relates to a boat and more particularly concerns a boat with a planing hull having a cavity adjacent the transom with a hole in the top for mounting a boat propulsion device with an encine inside a boat and a steerable ane trimmable drive under a boat anc partly within the cavity.

Prior boat propulsion devices which mount on a boat include the stern orive and the outboard. A boat which uses a stern orive coes not use or reouire a cavity since the stern drive has an encine inside the boat and a drive at the rear of the boat. A boat which uses an outboard also does not use or require a cavity since the outboard mounts outside the boat as an unit assembly.

Other prior propulsion devices such as described in U. S. Patent'2,209,302 issued to L. J. johnson et al provide a cutout through the bottom of the boat and the transom for mounting the device.

Other prior propulsion devices such as descrioeC im u-, S. Patents 2,976,836 ano 3,164,122 issued to L. @. Fageol mount the device through the bottom of the boat.

Other prior propulsion devices such as described in U. S. Patents 2,064,463 and 3,811,3?9 use an upwardly formed portion under the boat hull as an enclosure for the propeller shaft which angles down and from inside the boat.

It is believed that these prior shaped hulls do not improve the structure or operational characteristics of the boat.

In the present invention a boat contains a planing hull and a raised bottom surface in the stern adjacent the transom. Within the raised bottom surface is a generally horizontal hole which provides a simple placement location for a boat propulsion device which mounts through a bottom surface of a boat. The raised hole is ioeally suited for a boat propulsion device which includes a drive under, and extending to the rear of the boat, which steers anc trim/tilWs.

The raised bottom surface extends notched through the transom which permits the drive of the boat propulsion device which is under the boat to swing upward towards the transom within this notched area for trim/tilt. This transom notch also permits the drive of the boat propulsion device to swing from side to side within the transom notch not only for steering but also for steering at trim positions within the trim range. Neither of these needs is specifically considered in known boats and known boat structures with raised bottom surfaces do not provide the convenience and utilities of mounting a drive at a raised bottom surface which permits steering and trim/tilt under the boat.

The raised bottom surface also forms the too of a @rive containing cavity which extends upwardly into the hull with an open end at the transom notch. The cavity includes side walls which are generally vertical. The port and starboard side walls are generally parallel to each other and to the chine surfaces of the boat. In driving a boat with these sidewalls it appears that their edges dig in to the water particularly on turns, which provides a solid feel during turns, resulting in a new sense of driving pleasure.

The cavity forward wall is also an unicue structure wit multiple utilities and advantages. As a vertical wall it en@s a portion of the boat planing surface along the mi@@le of the boat while providing extended planing surface along the cavity which may act as a form of after lane surface. Tis reduces the wetted area of the @oat when on plane and accordingly provides a general increase soeec. The vertical walls as a vertical wall convenient@@ provices an easv-to-use surface for connecting through the boat for ex@aust, c@oling water, @ydraulics etc.

Lastly, it is possible that the cavity vertical sice walls, wnen slightly ta@ere@ to tne rear assist steering.

in a second emoooiment the boat @ncludes a secono raised bottom surface adjacent the cavity which assists in reducing the amount of wetted area auring an on-?lane condition with the general expected advantages from a lesser wetted area achieved.

wnd of course, there is a significant aesthetic futility and advantage achieved from containing the engine of the boat propulsion device aoove the cavity and a cavity @o simply package the drive.

Embodiments of the invention will now be described by way of example only with reference to the accompanying figures in which: Figure 1 is a side elevation view of a boat with a boat propulsion device mounted therein.

Figure 2 is an end elevation view of the boat of Figure l.

Figure 3 is a bottom elevation view of the boat of Figure 1.

Figure 4 is a cross section view on line 4-4 of the boat of Figure 1, appearing with Figure 2.

Figure 5 is a bottom elevation view similar to that of Figure 3 of a second emoodiment of a boat.

Figure 6 is a cross section view on line 6-6 of the boat of Figure 5.

Figure 7 is a cross section view on line 7-7 of the boat of Figure 5.

The @oat 10 with a boat pro@ulsion device :: mounted therein Is sown in Figures I through . he boat 10 which is prefera@ly formed of reinforced fiberglass Incluses a planing hull 12 and a generally vertically; @oright transom 13. The hull 12 includes a bottom planing surface 1 and a pair of bottom chine surfaces 15 and 16.The hull 12 also includes a raised bottom surface 17 adjacent the transom 13. The raised bottom surface 17 includes an o@ening or hole 18 for positioning and mounting the noat propulsion device ::.

The raised bottom surface i7 extends to the transom 13 and is of a width less than the bottom planing surface 14 of the hull 12 adjacent the transom 13 and between the bottom chine surfaces 15 and 16. The width of the raised bottom surface 17 provides a desired steering range.

The raised bottom surface 17 forms the too 19 of a drive containing cavity 20 wnich extends u@wardly into the hull 12. The cavity 20 extends through the transom 13 having an open end which is a notch 21 extending uowardly into the transom 13.

The cavity 20 includes a first portside Wall 22, a second starboard side wall 23 and a third forward wall 24, eacn of the walls connecting between the bottom planing surface 14 and the raised bottom surface 17.

The port side and starboard side walls 22 and 23 of the cavity 20 are generally parallel, but tapering rearward at an angle of taper 25 as shown in Figure 3 of less than 10 degrees. The preferred taper 25 is in the range of 2 to 8 degrees.

The side walls 22 and 23 are also generally centered with respect to the centerline 26 of the boat 10.

The centering of the sidewalls 22 and 23 also centers the cavity 20.

The forward wall 24 is preferably ve-tically upright similar to the transom 13. It is beleveo forming this forward wall 13 upright permits it to be positioned as far rearward as possible against the drive 11. This provides more bottom planing surface. It is also 3elievea that the upright forward wall 24 helps to prevent undesirable water flow through the cavity 20 during on-plane operation of the boat 10.

All the walls, 22, 23, and 24 may have a slight draft of about 1 degree where necessary for removal of the hull 12 from the boat mold.

The size of the cavity may vary with the size of the boat and the size of the boat propulsion device. For a boat of about 20 feet in length and a boat propulsion device of about 125 horsepower, the width of the cavity 20 is about 14 inches at the forward wall 24, the length is about 19 inches and the height is about 12 inches. The heignt varies with different boat propulsion devices 11 and is generally determined by the distance between the mounting member 27 and an anticavitation plate 39. The anticavitation plate 39 preferably is at water level when the boat is on plane.

The hole 18 in the raised bottom surface 17 or top 19 of the cavity 20 is shaped to match the mounting member 27 of the boat propulsion device 11. The top 19 of the cavity includes a builtup fiberglass area which may include plywood reinforcement.

The cavity itself by its shape and placement provides added strength to the boat 10 as well as strength to mount the drive.

The cavity 20 is shown from the inside of the boat 10 in Figure 4 without the engine 28 of the boat propulsion device 11 mounted above the cavity 20. However an engine exhaust corrector 29 (see Figure i) may be conveniently positioned through cutout 30 (Figure 4) in the forward wall 24.

A second embodiment of a boat 31 is shown in Figure 5 through 7. In the second embodiment the same reference numbers refer to parts generally similar to the first emoodimen:. The second emboolment of the boat 31 includes a second raised bottom surface 32 adjacent to the cavity 20 between the chine surfaces 15 and 16. The cavity 33 includes a first portside side wall 34, a second starboard side wall 35, and a third forward side wall 36.

The height of the second raised bottom surface 32 is in the range of 1 to 3 inches with the preferred height being about 1 inch.

The second raised bottom surface 32 extends forward from the forward side wall 36 to a forward edge portion 37 a distance in the range of 1 to 6 inches. The preferred distance is about 2 inches. The height of the forward edge portion 37 is about 1 to 3 inches with a preferred height of about 1 inch. The second raised bottom surface 32 also extends to the inner edges 15 and lóa cf the chine surfaces is and 16.

Figures 6 and 7 show the cross sectional configuration through the-planing hull 12 from forward of tne cavity 33 and through the centerline 38 of the cavity 33. Tnese Figure 6 shows the relationship previously described between the cavity 33 and the second raised bottom surface 32.

Figure 7 shows the relationship of the cavity 33 and the second raised surface 32 between the forward side wall 36 and the forward edge portion 37.

Claims (10)

CLAIMS:

1. A boat having a generally vertical transom, said boat comprising a water planing hull having a bottom surface shaped to provide minimum wetted area when on plane, a raised bottom surface above said bottom surface having a hole therethrough adjacent the transom for mounting a boat propulsion device having a downward and rearward extending drive.

2. The boat defined in claim 1 wherein said raised bottom surface forms an upward cavity within said bottom of the boat, said cavity having an open eno extending notched through the transom.

The boat defined in claim 2 wherein said cavity is of a heignt between said bottom surface and said raised bottom surface to contain a portion of the boat propulsion unit.

4. The boat of claim 3 in which the drive includes an ant icavi tat ion piate wherein the neight of said cavity is determined by the position of an anticavitation plate relative to the boat.

5. The boat of claim 2 wherein said boat includes a second raised bottom surface adjacent said cavity.

6. The boat defined in claim 5 wherein the boat includes chine surfaces and said second raised portion is positioned between said chine surfaces.

7. The boat defined in claim 6 wherein said second raised bottom surface extends across said bottom surface of the boat forward of said cavity.

e. The boat defined in claim 2 wherein said cavity includes generally parallel sidewalls.

9. The boat defined in claim 8 wherein said sidewalls taper towards a forward generally vertical wall, said forward generally vertical wall having a cutout therethrough.

10. A boat substantially as described above with reference to Figures 1 to 4 and Figures 5 to 7 of the accompanying drawings.