AU612656B2

AU612656B2 - Boat with cavity for a boat propulsion device

Info

Publication number: AU612656B2
Application number: AU17665/88A
Authority: AU
Inventors: David T. Livingston
Original assignee: US Marine Corp; U S Marine Corp
Current assignee: Brunswick Corp
Priority date: 1987-06-15
Filing date: 1988-06-14
Publication date: 1991-07-18
Anticipated expiration: 2008-06-14
Also published as: JPH0194097A; CA1318817C; GB8814213D0; AU1766588A; GB2208111A; GB2208111B

Description

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a~58 Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE SApplication Number: Lodged: Class Int. Class Complete Specification-Lodged: Accepted: Published: Priority: Related Art; Name of Applicant: Address of Applicant: Actual Inventor: TO BE COMPLETED BY APPLICANT U.S. MARINE CORPORATION 105 Marine Drive, Hartford, Wisconsin 53027, United States of America DAVID T. LIVINGSTON Address for Service: SANDERCOCK, SMITH BEADLE 207 Riversdale Road, Box 41) Hawthorn, Victoria, 3122 Complete Specification for the invention entitled: BOAT WITH CAVITY FOR A BOAT PROPULSION DEVICE The following statement is a full description of this invention, including the best method of performing it known to me:- ~9 i

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The field of the invention relates to a boat and 5 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 engine inside a boat and a steerable and trimmable drive under a boat and partly within the cavity.

10 Prior boat propulsion devices which mount on a boat include the stern drive and the outboard. A boat which uses a stern drive does not use or require a cavity since the stern drive has an engine-i'-side 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.

2 Other prior propulsion devices such as described in U.S. Patents 2,976,836 and 3,164,122 issued to L.J. Fageol mount the device through the bottom of the boat.

Other prior propulsion eivices such as described in U.S. Patents 2,064,463 and 3,811,399 use an upwardly formed portion under the boat hull as an enclosure for the propeller shaft which angles down and from inside the boat.

SIt is believed that these prior shaped hulls do not improve the structure or operational characteristics of the a 3 'boat.

I* I The present invention provides a boat having a hull j| with a bottom planing surface and a transom extending upwardly from the bottom planing surface, said boat further comprising a raised bottom surface adjacent the transom, said raised bottom surfacce providing a cavity within the t .hull, which cavity is open at the bottom and open rearwards i through the transom but is bounded by spaced side walls, by an upwardly extending front wall extending across the Scavity between said side walls, and by said raised bottom surface which forms a top of the cavity, said raised bottom surface having a mounting hole located in the hull above the cavity so as to permit mounting of a boat propulsion device on said raised bottom surface with an engine above the raised bottom surface and a connected steering and trim/tilt drive in said cavity below the raised bottom surface.

The raised bottom surface may extend notched through the transom which permits the drive of the boat S propulsion device which is under the boat to swing upward bc/9/us1047 1('91 4 26 i OFtowards 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 B under the boat.

9 s C bc/9/us1047 1991 4 26 1986/4 The raised bottom surface also forms the top of a drive 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 unique structure with multiple utilities and advantages. As a vertical wall it ends a portion of the boat planing surface along the middle of the boat while providing extended planing surface along the cavity which may act as a form of 9 afterplane surface. This reduces the wetted area of the boat when on plane and accordingly provides a general increase in speed. The vertical walls as a vertical wall conveniently provides an easy-to-use surface for connecting through the boat for exhaust, cooling water, hydraulics etc.

L;istly, it is possible that the cavity vertical side wal's, when slightly tapered to the rear assist steering.

In a second embodiment the boat includes a second raised bottom surface adjacent the cavity which assists in reducing the amount of wetted area during an on-plane condition with the general expected advantages from a lesser wetted area achieved.

And of course, there is a significant aesthetic utility and advantage achieved from containing the engine of the boat propulsion device above the cavity and a cavity to simply package the drive.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevation view of a boat-with a -3-

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c 1986/4 boat propulsion device mounted therein.

Figure 2 is an end elevation view of the boat of Figure 1.

Figure 3 is a bottom elevation view of the boat of S Figure 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 embodiment of a boat.

Figure 6 is a cross section view on line 6-6 of the boa' of Figure Figure 7 is a cross section view on line 7-7 of the boat of Figure DESCRIPTION OF THE PREFERRED EMBODIMENT The boat 10 with a boat propulsion device 11 r mounted therein is shown in Figures 1 through 3. The boat 10 which is preferably formed of reinforced fiberglass includes a planing hull 12 and a generally vertically; upright transom 13. The hull 12 includes a bottom planing surface :4 a pair of bottom chine surfaces 15 and 16. The hull 12 also includes a raised bottom surface 17 adjacent the transom 13.

raised bottom surface 17 includes an opening or hole 18 for positioning and mounting the boat propulsion device 11, The raised bottom surface 17 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 top 19 of a drive containing cavity 20 whichextends upwardly into the hull 12. The cavity 20 extends through the transom 13 having an-open end which is a notch 21 extending upwardly a n:J 7 h E, i 1986/4 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, each 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 LO 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 The centerino of the sidewalls 22 and 23 also centers the 9@ 9

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.9 cavity The forward wall 24 is preferably vertically upright similar to the transom 13. It is believed forming this forward wall 13 upright permits it to be positioned as S far rearward as possible against the drive 11. This provides more bottom planing surface. It is also believed that the upright forward wall 24 helps to prevent undesirable water flow through the cavity 20 during on-plane operation of the boat 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 thr 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 height varies with different boat propulsion devices 11 and is generally determined by the distance between the mounting

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_1 6member of the propulsion device and an anticavitation plate 39. Therefore the height of the cavity is dependent on the position of the anticavitation plate relative to the boat.

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 built-up fibreglass area which may include plywood reinforcement. The cavity itself by its shape and placement provides added strength to the boat as well as strength to mount the drive.

The cavity 20 is shown from the inside of the boat 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 1) 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 embodiment. The second embodiment of the boat 31 includes a second raised bottom surface 32 adjacent to the cavity 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 S to 3 inches with the preferred height being about 1 inch.

V AThe second raised bottom surface 32 extends forward bc/9/us1047 1991 4 26 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 15a and 16a of the chine surfaces 15 and 16.

Figures 6 and 7 show the cross-sectionale e48 9

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1986/4 configuration through the planing hull 12 from forward of the cavity 33 and through the centerline 38 of the cavity 33. These 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.

While embodiments and application of the invention have been shown and described, it would be apparent to those skilled 1JO in the art that modifications are possible without departing from 0 the inventive concepts herein. Therefore, the invention is not S to be restricted other than by the scope and equivalency of the Sfollowing claims.

The claims form part of the disclosure of this specification.

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Claims

1. A boat having a hull with a bottom planing surface and a transom extending upwardly from the bottom planing surface, said boat further comprising a raised bottom surface adjacent the transom, said raised bottom surface providing a cavity within the hull, which cavity is open at the bottom and open rearwards through the transom but is bounded by spaced side walls, by an upwardly extending front wall extending across the cavity between It) said side walls, and by said raised bottom surface which forms a top of the cavity, said raised bottom surface having a mounting hole located in the hull above the cavity so as to permit mounting of a boat propulsion device on said raised bottom surface with an engine above the raised bottom surface and a connected steering and trim/tilt drive. in said cavity below the raised bottom surface.

2. The boat defined in claim 1 wherein the rear opening of said cavity extends notched through the transom.

3. The boat defined in claim 1 or claim 2 together with a boat propulsion unit mounted on said .ed bottom surface with an engine above the surface and a drive unit below said surface, the drive unit providing steering and trim/tilt movements for a propeller projecting below the boat through the open bottom of the cavity.

4. The boat of claim 3 in which the drive includes an anticavitation plate wherein the height of said cavity is determined by the position of an anticavitation plate relative to the boat. /y

5. The boat of any one of claims 1 to 4 wherein bc/9/us1047 1991 4 26 -9 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 raised bottom surface is positioned between said chine surfaces.

7. The boat defined in claim 5 or claim 6 wherein said second raised bottom surface extends across said bottom surface of the boat forward of said cavity.

8. The boat defined in any one of the preceding r* claims wherein said cavity includes generally parallel sidewalls. 5e

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 5 reference to Figures 1 to 4 and Figures 5 to 7 of the accompanying drawings. DATED this 26 April, 1991 20 SMITH SHELSTON BEADLE .5 Fellows Institute of Patent Attorneys of Australia Patent Attorneys for the Applicant: U.S. MARINE CORPORATION bc/9/us1047 1991 4 26