US3680517A

US3680517A - Hull friction reducing apparatus

Info

Publication number: US3680517A
Application number: US70376A
Authority: US
Inventors: Horace S Morrison
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-09-08
Filing date: 1970-09-08
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01

Abstract

Apparatus for a water vehicle to reduce hull friction including a hollow body for location on a hull submerged beneath the water surface, the external contour of the body producing a surface region of reduced pressure and having an opening communicating through the reduced pressure region to the interior hollow of the body, together with an air conduit for conducting air to the internal hollow of the body for passage through said opening into contact with the hull exterior.

Description

[ 51 Aug. 1, 1972 United States Patent Morrison 2,378,822 6/1945 Barry..........................114/67A 1,824,313 9/1931 Vogler........................l14/67A [54] HULL FRICTION REDUCING APPARATUS [7 2] Inventor:

Primary Examiner-Andrew H. Farrell Attor'ney-Robert K. Youtie 22 Filed:

ABSTRACT Apparatus for a water vehicle to reduce hull friction including a hollow body for location on a hull submerged beneath the water surface, the external contour of the body producing a surface region of reduced pressure and having an opening communicat- A A 7B7 6 6 4%4 161 1 M3 c "urm 1 Mt C d S M U'mF 1]] 2 00 555 ll[ ing through the reduced pressure region to the interior [56] References Cited hollow of the body, together with an air conduit for UNITED STATES PATENTS conducting air to the internal hollow of the body for e h t h .n W t c m w n o r c u .8 m E g m. .m .m w n r W D o 6 d a s m u u w 3 r m0 t m et X We l %u Ph AAA 777 NNM 444 111 111 WWW QMHO S mam o m h TfiA 4009 542 989 111 WWU 47 645 957 6 9 2 l.

; PATENTEDAIJI; 1 I922 INVENTOR. HORACE S. MORRISON ATTORNEY.

BACKGROUND OF THE INVENTION While it is appreciated that there have, in the past, been proposed a wide variety of hull friction reducing devices attempting to interject air between the hull and adjacent water, such devices have not found general acceptance for many reasons. For example, prior devices of this type were often relatively complex in structure, and therefore costly to manufacture, install and maintain, and certain of such prior devices required specifically configured hull under surfaces so as to be usable only in vessels having proper hull shapes, and incapable of employment in existing hulls.

SUMMARY OF THE INVENTION In accordance with the teachings of the present invention it is an object to provide a hull friction reducing apparatus which overcomes the above-mentioned difficulties, is extremely simple in construction for economy of manufacture and durability and reliability throughout a long useful life.

It is another object of the present invention to provide a friction reducing apparatus for a hull having the advantageous characteristics mentioned in the preceding paragraph, which is capable of incorporation in a hull as original equipment, and also adapted for attachment to existing hulls as an accessory therefor.

It is still a further object of the present invention to provide a hull friction reducing apparatus of the type described which incorporates a unique configuration utilizing known principles of physics to draw air into position between the hull and water to effect substantial savings in fuel required by a vessel, and greatly enhance the speed of the vessel, while affording a smoother ride to the vessel, its cargo and passengers.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings, which form a material part of this disclosure.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, which will be exemplified in the construction hereinafter described, and of which the scope will be indicated by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial transverse sectional elevational view showing a water vessel having incorporated therewith a friction reducing device of the present invention.

FIG. 2 is a partial bottom plan view of the hull of FIG. 1, taken generally along the line 22 of FIG. 1.

FIG. 3 is a partial side elevational view taken generally along the line 3-3 of FIG. 1.

FIG. 4 is a partial sectional view taken generally along the line 4-4 of FIG. 1, enlarged for clarity.

FIG. 5 is a partial bottom perspective view illustrating the instant apparatus, enlarged to better show the details.

FIG. 6 is a sectional view similar to FIG. 4, but illustrating a slightly modified embodiment wherein the external conduit of FIGS. l-3 may be eliminated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularly to the drawings, and specifically to FIGS. 1-3 thereof, a vessel or hull of a water vessel is there generally designated 10, and may be generally conventional including a keel 11, bottom frames 12 extending transversely from the keel, and side frames 13 upstanding from opposite ends of the bottom frames, being connected to the latter as by a chine member 14. The hull bottom 16 extends generally laterally from opposite sides of the keel ll, conventionally fastened to the under surfaces of the frames 12, and the hull sides 17 extend upwardly from the chine 14 along the outer edges of the side frames 13. Resting on the upper ends of the side frames 13, extending along the upper edge of the hull side 17, is the side deck 18, provided at its outer edge with a gunwale guard 19. The structure as thus far described may be conventional, and the friction reducing apparatus of the present invention may be applied on many varied hull constructions, the instant hull construction being shown by way of example and without limiting intent.

The friction reducing apparatus proper includes an elongate hollow body generally designated 20 and arranged externally on the hull 10, on the underside of the hull bottom 16. The body 20 is of elongate, internally hollow configuration, and arranged externally on the hull bottom extending generally laterally thereof as between the keel 11 and the outer or chine region of the hull bottom. It is, of course, essential that the body 20 be submerged, or located below the waterline of the hull 10, as will appear presently.

The body 20 includes a generally flat upper wall 21 which may be of an elongate configuration, say of tapering or reducing width in the direction laterally inwardly toward the keel 11, and suitably secured in facing engagement with the under surface of the hull bottom. In addition, the body 20 may include a lower wall 22 of generally congruent external configuration with respect to the upper wall 21, as seen in FIG. 2, so as to be of elongate configuration extending laterally of the boat hull and tapering in the laterally inward direction. The lower wall 22 is specifically contoured so as to combine with the upper wall 21 to define a hollow or space there between, as at 23, which hollow is longitudinally coextensive with the upper and

lower walls

21 and 22, and the overall body 20.

More specifically, the upper wall 21 is generally planar or flat, while the lower wall 22 is generally of dihedral configuration including a generally flat or planar forward portion 24 and a generally flat or planar rearward portion 25. The forward and

rearward portions

24 and 25 are disposed in angular relation with respect to each other and meet along an apex line 26 which extends generally laterally or transversely of the hull 10. More specifically, the forward portion 24 of lower wall 22 merges at its forward edge with the forward edge of the upper wall 21 to define a forward edge portion or margin 27, while the rearward portion 25 of lower wall 22 merges smoothly with the rearward edge region of upper wall 21 to define therewith a rearward margin or edge portion 28. The rearward margin 28 advantageously extends generally normal to the hull center line or keel 11, while the forward margin or edge 27 extends laterally outwardly and obliquely forwardly to define the laterally inwardly tapering configuration of the body 20.

From the forward margin or edge 27, the forward portion 24 of lower wall 22 declines rearwardly and thereby defines .with the upper wall 21 a rearwardly flaring forward portion 30 of hollow 23. The forward lower wall portion 24 is of triangular or trapezoidal outline configuration, tapering in the laterally inwardly direction, while the rearward lower wall portion 25 is of generally rectangular outline configuration.

From the line of intersection or meeting edge 26 of the forward and rearward

lower wall portions

24 and 25, the rear wall portion extends rearwardly and obliquely upwardly to its mergence with the upper plate 21. Thus, the rearward region 31 of internal hollow 23 tapers rearwardly from the forward regions 30. The upper plate 21 may, if desired, be dispensed with or considered an integral part of the hull 10, so that the lower wall 22 then is considered to merge directly into the hull bottom.

By elementary hydraulics it will be appreciated that the body 20, by its rearwardly flaring forward interior portion 30 and its rearwardly tapering interior portion 31 serves to provide a region of reduced external water pressure as the hull moves forwardly, in the direction from right to left as seen in FIGS. 3 and 4. Thus, the rearward lower wall portion 25 is at a reduced pressure. Formed in the rearward lower wall 25 is an opening communicating with the interior hollow 23, which opening may assume the form of a multitude of slits or slots 32 extending in parallelism with' each other generally normal to the rear margin 28. Further, the slots 32 may advantageously each be of triangular configuration, arranged to flare or enlarge in the rearward direction, as best seen in FIG. 5. It will also there be apparent that there are provided strengthening webs or internal walls 33, each extending between the upper body wall 21 and lower body wall 22, spaced between an adjacent pair of slits 32. The walls or webs 33 serve to maintain the rearward, low pressure region of rear lower wall portion 25 stiff and strong despite the removal of considerable material to define the openings 32.

While the body 20, as illustrated and described hereinbefore, has in the past been satisfactorily manufactured from sheet metal and welded, brazed or otherwise suitably secured together, it is appreciated that the body may be otherwise formed, as desired, say of plastic by suitable molding techniques, or other materials and manufacturing procedures, as desired.

It will now be understood that the interior hollow 23 of the body 20 extends laterally inwardly to the keel 11, where it is closed by the keel, and extends laterally outwardly to the chine, where there is provided an air conduit or tube 35 having its lower end in fluid communication with the hollow 23 and extending upwardly therefrom along the hull side wall 17 to a location above the water line and terminating in an air scoop or cowl 36 which may face forwardly or open in the direction of vessel movement. The conduit 35 thus serves to conduct air from the atmosphere into the laterally outer, larger end of interiorly hollow body 20.

Upon vessel movement, leftward in FIG. 4, the relatively low pressure rearward internal region 31 communicates through the conduit 35 for drawing outside air into the hollow of the body 20. From the body hollow 23 air passes rearwardly, outwardly through the slots or openings 32 into position between the hull bottom 16 and the sea water, to effectively reduce skin friction and thereby enhance vessel speed and reduce power and fuel requirements.

In the slightly modified embodiment of FIG. 6, an internally hollow body is there generally designated 20a, and may include a pair of dihedral forward and

rearward wall portions

24a and 25a essentially similar to the

lower wall portions

24 and 25 of the first described embodiment. The forward edge of the forward wall portion 24a is suitably secured to the hull 10a, as by suitable fasteners 40, while the rear margin or edge of the rearward wall portion 25a is also secured to the hull by suitable fasteners 41. Thus, the embodiment of FIG. 6 illustrates the body of the instant invention absent the upper wall of the first described embodiment, for direct securement of the lower wall to the vessell hull.

In addition, the embodiment of FIG. 6 may include the hollow body 20a having its opposite ends closed, and the hull bottom wall 16a provided with a suitable through hull fitting 35a for fluid communication between the interior of body hollow 23a and the interior of the hull 10a. That is, the through hull fitting 35a may include a tube 42 extending through the hull bottom 16a and provided with a flange 43 for securement as by suitable fastener means 44 to the hull. An air inlet duct 45 of any suitable configuration may extend upwardly from the tube 42 to conduct air into the hollow 23a responsive to the lowering of pressure by hull movement relative to the water.

While the embodiments of the instant invention illustrated and described hereinbefore do not require a powered air supply, it is, of course, understood that air may be supplied through the conduit means 35 and 35a by blower means, or the like, if desired.

The underside of the body 20a may be substantially identical to that of the first described embodiment, as seen in FIG. 5, so that operation of the alternative embodiment is understood to be essentially the same as that described in connection with the preferred embodiment.

From the foregoing it will now be appreciated that the instant invention provides a friction reducing apparatus for a water vessel hull which is extremely simple in construction and operation, capable of being built into a hull as original equipment or applied thereto as an accessory, and which otherwise fully accomplishes its intended objects.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be made within the spirit of the invention.

What is claimed is:

1. Friction reducing apparatus for the hull of a water vessel, said apparatus comprising an elongate internally hollow body for location on a hull below the waterline extending transversely of relative water movement, an externally contoured formation on said body producing a region of reduced water pressure on said body upon said movement, there being an opening communicating through said body region between the internal hollow region being located in said rearward body portion.

2. Friction reducing apparatus according to claim 1, said opening being located in said rearward body portion.

3. Friction reducing apparatus according to claim 2, said opening being defined by a plurality of slits extending generally longitudinally of said relative water movement and opening rearwardly from said body.

Claims

1. Friction reducing apparatus for the hull of a water vessel, said apparatus comprising an elongate internally hollow body for location on a hull below the waterline extending transversely of relative water movement, an externally contoured formation on said body producing a region of reduced water pressure on said body upon said movement, there being an opening communicating through said body region between the internal hollow and exterior of said body, and an air conduit connected in fluid communication between an air source and said internal hollow to conduct air to the latter for passage through said opening into contact with the exterior of said hull, said formation being defined by a forward body portion flaring rearwardly from a smooth mergence with the hull to a maximum protuberance from the hull, and a rearward body portion tapering rearwardly to a smooth mergence with the hull, said body region being located in said rearward body portion.