US 3893405 A
Jet drive for watercraft. A device is provided applicable for mounting in the hull of a boat by which a jet stream can be created and directed in any desired direction for movement of the boat accordingly. There is provided an elbow having a substantially vertical intake portion and substantially horizontal discharge opening. The elbow is rotatable on an axis coincident with its intake portion and contains a suitable motor driven impeller. A motor driven device is provided for rotating the elbow around the axis of its intake opening for effecting discharge in an operator determined direction. A device is usually provided defining a downwardly sloping substantially annular discharge opening into which said discharge end of said elbow discharges by which the jet emerges from the hull of the boat in a generally horizontal downwardly sloping direction. The device is particularly adaptable for shallow draft vessels.
Claims available in
Description (OCR text may contain errors)
United States Patent Lais et a1.
Schottel-Werft Josef Becker KG, Spay, Rhein, Germany Filed: Feb. 22, 1974 Appl. No.1 444,912
 Foreign Application Priority Data Mar. 28, 1973 Germany 2315447 U.S.Cl 115/12 R; 115/16 Int. Cl B63h 11/04 Field of Search 115/12 R, l4, 16
References Cited UNITED STATES PATENTS 3,098,464 7/1963 Holland I. 115/16 FOREIGN PATENTS OR APPLICATIONS 1,195,626 9/1964 Germany 115/16 July 8, 1975  ABSTRACT .let drive for watercraft. A device is provided applicable for mounting in the hull of a boat by which a jet stream can be created and directed in any desired direction for movement of the boat accordingly. There is provided an elbow having a substantially vertical intake portion and substantially horizontal discharge opening. The elbow is rotatable on an axis coincident with its intake portion and contains a suitable motor driven impeller. A motor driven device is provided for rotating the elbow around the axis of its intake opening for effecting discharge in an operator determined direction. A device is usually provided defining a downwardly sloping substantially annular discharge opening into which said discharge end of said elbow discharges by which the jet emerges from the hull of the boat in a generally horizontal downwardly sloping direction. The device is particularly adaptable for shallow draft vessels.
5 Claims, 6 Drawing Figures Fig. 4
PNEHTFHJUL 8 m5 SHEET Fig. 5
I HYDRO-JET PROPULSION DEVICE FOR DRIVING AND CONTROLLING OF WATERCRAFT FIELD OF THE INVENTION The invention relates to a hydro-jet propulsion de' vice for the driving and controlling of watercraft, same having a thrust producing device, such as a drivable propeller pump arranged within the body of the ship on a substantially vertical shaft, which device draws in the stream of water in a substantially vertical direction and discharges same at a considerable angle in an operator selected direction.
BACKGROUND OF THE INVENTION One objective of the invention is to provide a hydrojet propulsion device for floating apparatus, as watercraft, with a universal control, which is suitable for vessels of extremely low draught and will assure a good efficiency for the drive unit. Such good efficiency requires among other things that as little as possible of air is drawn into the unit. The device is so constructed that it can be mounted on the bottom of the watercraft.
The basic purpose of the invention is attained by a drive mechanism which has a motor driven propeller pump arranged in the hull of the watercraft and drivable through suitable drive mechanism. Said pump is arranged directly above the bottom of the watercraft and is located on a vertical shaft which in turn is positioned within an elbow whose lower end does not extend beyond the bottom surface of the watercraft. The elbow is constructed approximately as an inverted L- shape and is arranged for drivable pivoting about a ver tical axis in the stem of the L, whereby the water stream can be drawn thereinto by the propeller pump in a vertical direction, and is discharged from the elbow in an operatorselected substantially horizontal direction. The elbow is surrounded by suitable stream guiding means to cause the water to be discharged from the bottom of the watercraft in a generally horizontal. but usually downwardly inclined direction. Thus the control desired is adequately obtained with only a relatively small mechanical part requiring rotary move ment and the mounting therefor. The elbow is constructed advantageously in the form ofa nozzle to assist the desired flow. The propeller pump or the other thrust-producing device is so arranged in the elbow according to the invention that only a small suction height is required. The elbow or the nozzle is preferably provided with suitable guide blades. Inasmuch as the water stream is, according to the invention, directed inclinedly downwardly, the drive mechanism can as a practical matter be arranged at any desired point of the watercraft. The invention is not limited to a discharge in a downwardly inclined direction but the water stream can also be discharged wholly or partially horizontally. depending on the position or size of the drive mechanism of the watercraft and further upon the size and shape of the watercraft.
The jet propulsion device of the invention is suitable for mounting in the bottom of the watercraft. For this reason the jet pump of the invention is further provided with a shield-or bell-shaped housing to direct the jet in the desired downwardly inclined direction. The bellshaped housing cooperates with an internally positioned cone having walls generally parallel with those of said housing and connected thereto by any desired support means. However, if desired, the perpendicular spacing of the cone and housing may be narrowed slightly from the center toward the outlet thereof for improving its efficiency.
The motor for driving the propeller pump can'be installed in the hull of the watercraft separate from the housing of the drive mechanism. It can be arranged on the housing and can be mounted, for example, integrally therewith. The same is true for the elbow control drive.
Further advantages and characteristics of the invention will be apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWING The invention will be described in connection with the exemplary embodiments which are illustrated in FIGS. I to 6.
In the drawings:
FIG. 1 schematically illustrates a cross-sectional view of a hydro-jet propulsion device according to the in vention.
FIG. 2 illustrates a cross-sectional view of the hydrojet propulsion device on a plane perpendicular to FIG. 1.
FIG. 3 illustrates a top view of the hydro-jet propulsion device according to FIGS. 1 or 2.
FIG. 4 illustrates a modified exemplary embodiment of the invention.
FIG. 5 illustrates a cross-sectional view directed perpendicularly to FIG. 4.
FIG. 6 illustrates a top view of the exemplary embodiment according to FIGS. 4 or 5.
DETAILED DESCRIPTION FIG. 1 illustrates the stern ofa watercraft l which has a very small draught from the water level 2 to its bottom or keel line 3, so that this watercraft cannot be driven by a normal propeller. Also a vertically adjustable steerable propeller can be used only with a minimum depth of water to be navigated. The drive mechanism of the invention is provided in order that it is also possible to travel on very shallow waters. Same consists substantially of a nozzle-shaped elbow 4 in which there is supported a thrust-producing mechanism, such as a propeller pump 5 having a vertical axis.
The elbow deflects the water which is drawn in by the propeller pump in a vertical direction into a substantially horizontal direction. In order that the suction lift of the propeller pump is low, the propeller or the lowermost one of several propellers is arranged closely above the inlet opening of the elbow. The lower end of the elbow lies approximately flush with the bottom of the watercraft. One or more guide blades 6 are provided to increase the efficiency of the elbow. In order that the watercraft can be both driven and also controlled by the propeller pump arranged in the elbow, the elbow is supported pivotably about a vertical axis which preferably coincides with the axis of the propeller pump. The elbow then exerts a thrust onto the watercraft in a direction which is opposite the discharge opening of the elbow.
The propeller pump is driven by a motor 7 for example through a coupling 8, a transfer shaft 9 and an angular drive 10. If required, it is possible to provide in this power transmitting device a change-speed gear and/or a reversing gear. The angular drive may for example be a worm gearing or a bevel gearing, the driven member of which is arranged on the drive shaft of the propeller pump. If required, the transfer shaft may be constructed as a propeller shaft or as a cardan shaft. For effecting the swivel movement, there is provided a motor, which may for example be an electric or hydraulic motor, which acts through an angular drive 12 (for ex' ample a worm gearing or a bevel gearing) to drive the shaft I3 of the elbow. The elbow is supported in a base plate 14 which is secured in a suitable manner in the watercraft. Said base plate lies above the elbow. It is possible, if desired, to provide for the elbow and the propeller pump further but not illustrated support means which may be located approximately at the level of the bottom of the watercraft.
A bell-shaped shield 15 is connected to the base plate I4 and a bell-or shieldlike cone 16 is mounted and spaced therefrom by baffle plates 17. The spacing of the shield 15 from the cone 16 is in this embodiment at a vertical distance approximately equal to the diameter of the discharge opening of the elbow. However, this spacing, including the radial spacing therebetween at the outlet therefrom, may be chosen as desired in accordance with known liquid flow principles to effect proper control of the jet with minimal frictional interference therewith. Further, in this embodiment the opposed surfaces of the shield 15 and cone 16 appear as parallel with each other but they may also diverge or converge from the entry point therebetween, likewise according to known design principles, to secure the control characteristics desired. The shield and the cone form an annular outlet opening 18 at the bottom 3 of the watercraft. The annular outlet opening is dimensioned corresponding with the exiting stream of water. The housing which is formed of shield, cone and baffle plates is so constructed that the stream of water which is discharged in an approximately horizontal direction by the outlet opening is directed inclinedly downwardly, as illustrated by the arrows 19.
If the watercraft has a horizontal bottom 3, as illustrated in FIG. 2, then the described housing forms also a substantially horizontal bottom surface having an annular outlet opening. The housing which surrounds the elbow and contains the guide mechanism can also be so constructed that the stream of water is discharged horizontally if the watercraft, or other floating apparatus, has a shape which is suitable therefor.
In the example of FIGS. 1 to 3 the motor 7 for the propeller pump is supported in the watercraft and the motor 11 for the elbow swivelling is supported on the base plate. Other suitable arrangements may also be made. Thus it is for example possible to support the motor for the propeller pump also on the base plate or axially equally with the propeller or the propellers.
FIGS. 4 to 6 illustrate an exemplary embodiment of the invention in which the drive mechanism is installed into a watercraft 21, the bottom 22 of which extends inclinedly downwardly to form a keel. The water level 23 again is positioned very close above the keel line 24 of the watercraft, namely it has a very small draught. The elbow with the propeller pump and the drive mechanisms required herefor are substantially arranged in the same manner as described in connection with FIGS. 1 to 3. Like in the aforedescribed exemplary embodiment, again a bell-shaped shield 25 is provided which is paired with a shieldlike cone 26. In contrast, however, to the aforedescribed exemplary embodiment, the shieldlike cone here has a larger radial extension so that the out-flowing water is guided further away from the outlet of the elbow by which means penetration of air into the propeller zone is positively prevented. The shield and the cone are spaced apart by a guide mechanism 27 which is formed of baffle plates, guide blades or the like. Spacer tubes 28 are provided for the radial support of both parts. Since the housing comprising the shield and cone is circular in the basic concept, and the watercraft to form a keel is tapered to a point downwardly, the outlet opening 29 of the housing is an oval ring, the area of which is dimensioned to correspond to the volume of water being discharged.
One or more drive mechanisms of the invention can be provided in the watercraft. Such a design of the drive mechanism is further advantageous in that it can be manufactured, supported and mounted in the watercraft as an independent structural unit.
The swivel angle of the elbow will usually be at least 360. If special reasons exist, such swivelling can be through a lesser range without altering the principle of the invention.
One particular advantage of the present invention will be noted in that the parts required to be rotated are relatively small, being only the elbow and shaft associated therewith with the guide means 15 and I6 being fixed with respect to the hull of the watercraft. Hence, the mounting and driving means for same can be substantially smaller and lighter than in certain prior art devices, such as that shown in US. Pat. No. 3,098,464 to Holland.
The description of the guide mechanism is only an example in the shield-or bell-like housing and it may be modified to meet different requirements. For a particular example, it may be extended to the outlet opening. Although particular preferred embodiments of the invention have been disclosed above for illustrative purposes, it will be understood that variations or modifications thereof which lie within the scope of the appended claims are fully contemplated.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
l. A hydro-jet propulsion device for driving and controlling shallow draught watercraft, comprising:
hull means; means defining a conically shaped downwardly opening recess in a bottom surface of said hull means, the apex of said conically shaped recess being located above said bottom surface of said watercraft;
stationary annular ring means having means defining an opening therethrough mounted in said conically shaped recess, the axis of said annular ring means and said opening being coaxial with the axis of said conically shaped recess;
surface means facing inwardly of said conically shaped recess on said annular ring means being spaced from and extending generally parallel to the outwardly facing conical surface of said conically shaped recess whereby said spaced and parallel outwardly facing conical surface and said inwardly facing conical surface define a downwardly extending annular conically shaped passageway therebetween;
elbow means consisting of first and second hollow sections generally perpendicular to each other ro tatably mounted in said conically shaped recess, said first hollow section being mounted coaxially with said conically shaped recess. said annular ring means and said opening through said annular ring means, said hollow second section communicating with the upper end of said annular conically shaped passageway; and
propeller pump means and drive means therefor, said propeller pump means being mounted in said elbow means for drawing in water through said opening in said annular ring means and into said first hollow section and ejecting water from said second section into said downwardly extending annular conically shaped passageway.
2. Hydro-jet propulsion device according to claim I, wherein said outwardly facing conical surface and said inwardly facing conical surface are spaced apart by spacer means, the spacing at the upper end of said annular conically shaped passageway being in a vertical direction substantially equal to the diameter of said second hollow section of said elbow means and the radial distance is dimensioned at the outlet of said second section so that the water jet therefrom can exit substantially unhindered.
3. Hydro-jet propulsion device according to claim 2, wherein the space between said outwardly facing conical surface and said inwardly facing conical surface is reduced as the radial distance increases from the axis of said conically shaped recess.
4. Hydro-jet propulsion device according to claim 3, wherein said conically shaped recess is defined by a base plate and a downwardly extending conically shaped shield secured at its upper end to said base plate.
5. Hydro-jet propulsion device according to claim 4, wherein said drive means for said propeller pump means is mounted on said base plate and has an output shaft coaxial with said axis of said conically shaped recess; and
wherein said propeller pump means is mounted in said first hollow section.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 893 405 Dated July 8 1975 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 6, line 8; change "claim 3" to -claim l.
Signed and Scaled this seventh Day of October1975 [SEAL] AHESI.
RUTH C. M AnSON C. MARSHALL DANN Arresting Officer (ummissz'uner of Parents and Trademarks