United States Patent 3796177

A watercraft is disclosed having an upwardly and aftwardly sloping central hull with a plurality of longitudinally-spaced drives located on parallel, distinct, longitudinally-extending axes to provide an efficient propeller arrangement with reduced drag from water turbulence. A pair of pontoons flank the central hull to compensate for the aftwardly-progressive reduction in the central hull displacement due to the upwardly-sloped hull and to provide efficient planing surfaces.

Application Number:
Publication Date:
Filing Date:
Primary Class:
International Classes:
B63B1/20; (IPC1-7): B63B1/00
Field of Search:
115/37 114
View Patent Images:
US Patent References:
3677212SUBMERSIBLE WATERCRAFT1972-07-18Gregoire
3566822AIR CUSHION VEHICLES1971-03-02Crewe
2619929High-speed propeller train ship attachment1952-12-02Hoke
1777258Propulsion of ships1930-09-30Meo

Primary Examiner:
Blix, Trygve M.
Assistant Examiner:
Goldstein, Stuart M.
Parent Case Data:


This application is a continuation-in-part of my copending application Ser. No. 150,419, filed June 7, 1971, for "Watercraft" which issued into U.S. Pat. No. 3,702,598. All of the disclosure of this related application is intended to be incorporated by reference in the present disclosure.
I claim

1. A craft which is at least partially water borne when forwardly propelled along the longitudinal axis of the craft including in combination:

2. A craft according to claim 1 wherein said upwardly and aftwardly sloping surfaces are such as to establish an aftwardly-progressive decrease in buoyant displacement of said central portion when propelled forwardly, said pair of side portions being so configured as to correspondingly compensate for said aftwardly-progressive decrease in buoyancy in said central portion so that said watercraft has a substantially horizontal attitude when water borne.

3. A craft according to claim 2 wherein said hull side portions each further include a generally horizontally extending planing surface for providing an upwardly-directed lifting force when said craft attains planing speeds.

4. A craft according to claim 3 wherein said side portions are pontoons which are adapted for removal from each side of said central portion for replacement thereof.

5. A craft according to claim 1 wherein said plurality of drive means includes pairs of drives with each pair being disposed at substantially the same longitudinal locations and each drive of each pair being laterally separated so as to be on opposite sides of the longitudinal center of said central portion.

6. A craft according to claim 1 wherein each of said drive means includes a propeller and each of said propellers circumscribes a mutually extensive area out of any substantial interference with each other.

7. A craft according to claim 6 wherein said plurality of drive means includes pairs of said drives having propellers with each pair being disposed at substantially the same longitudinal location and each propeller of each drive pair being laterally spaced the same distance from the longitudinal centerline of the hull.

8. A craft according to claim 7 wherein said pairs are vertically offset.

9. A craft according to claim 8 wherein said drives of sequential pairs are laterally spaced to a different amount so that the combination of said vertical offset and said different amount of lateral spacing is sufficient so that said propellers circumscribe mutually exclusive areas in a vertical projected plane.

10. A craft according to claim 1 wherein said side portions are pontoons which are releasably secured beneath the side edges of the hull.

11. A craft according to claim 10 wherein said side pontoons are hollow and are filled with styrofoam.

12. A craft according to claim 10 wherein said side portions have runners on the inner edge providing directional stability to the hull.

13. A portion according to claim 10 wherein an outer upwardly extending portions on the pontoons provide protection to the sides of the hull.


The present invention relates to a watercraft having longitudinally-spaced drives on a central hull portion which slopes upwardly and aftwardly so that the drives are located on parllel, longitudinally-extending axes which are offset one from the other to provide efficient propulsion of the watercraft and to reduce drag from water turbulence caused by the drives. The drives may be conventional propellers, water-jets or other known means. When propellers are used as the drive means, the axes thereof are sufficiently separated so that the areas inscribed by the propellers occupy discrete locations when viewed from the stern of the watercraft, i.e. in a projected, vertical plane. Laterally-spaced, longitudinally-extending side pontoons or sponsons are affixed to and flank the central hull adjacent the upwardly sloped portion to compensate for the afterwardly-progressive reduction in displacement of the central hull as it slopes upwardly so that the watercraft has a horizontal attitude at rest. Each pontoon has a substantial horizontally-extending surface for planing of the watercraft upon attainment of a sufficient speed. Importantly, the pontoons provide both directional and roll stability so as to improve the ride motion of the watercraft. Preferably, the pontoons extend laterally outwardly from the watercraft so as to protect it and are replaceable in the event of severe damage. The pontoons may be filled with styrofoam or other flotation material to enhance the flotation capability of the watercraft in the event that it is severely damaged.

The watercraft is preferably provided with fore and aft rudders to provide simultaneous bow and stern control. The rudders are controllable independently so as to facilitate docking maneuvers.


FIG. 1 is a side view of a watercraft according to the present invention having an upwardly and aftwardly sloping central hull portion with a plura ity of longitudinally-spaced drives.

FIG. 2 is a stern view of the watercraft of FIG. 1.

FIG. 3 is a side cross-sectional view of the watercraft of FIG. 1; and

FIG. 4 is a view illustrating one manner in which the watercraft of FIG. 1 may be constructed.


In FIG. 1 a watercraft 100 of considerable size is illustrated which may be used to carry a substantial number of passengers and/or a substantial tonnage of cargo. The watercraft 100 has pairs of drives 102, 104, 106, and 108, from fore to aft, respectively. As best seen in FIG. 2, the pairs of drives 102-108 are located on an aftwardly and upwardly sloping central hull portion 110 so that the pairs of drives are conveniently provided with vertically offset longitudinally-extending axes. The central hull 110 may smoothly and continuously slope upwardly and rearwardly or may be created of discontinuous substantially planar surfaces 112, 114, 116 and 118 as illustrated. Preferably, the drives 102-108 are laterally and/or vertically offset a sufficient degree so that each drive means, e.g. a conventional propeller, circumscribes mutually exclusive areas in projected vertical plane. In this regard, the first and last pairs 102 and 108, respectively, are not laterally offset since the vertical offset is sufficient to provide complete separation of the circles circumscribed by their propellers while the remaining pairs of drives 104 and 106 are laterally as well as vertically offset. It can be seen that the lateral and vertical spacing of the drive means 102, 108, and specifically, the mutual exclusivity of the areas inscribed by each, provides a very efficient drive scheme whereby the turbulence created by the forward drives are less apt to undesirably affect the operation of the aftwardly-located drives. Furthermore, the interaction between the discharge currents of the drive means 102, 108 and the hull surface is minimized because of the upward slope of the hull to further contribute to the efficiency of the drive means of this invention.

The central hull portion 110 is also provided with a fore rudder 120 and an aft rudder 122 which may or may not be directly associated with one of the drive means 102, 108 as by positioning directly behind the drive means in the discharge path thereof. The fore and aft rudders 120, 122, respectively, are preferably independently operable to provide independent and simultaneous bow and stern control to provide a high degree of manueverability. Also, preferably, the rudders may be interlocked when desired so as to operate in unison when desired.

The central hull portion 110 is flanked by laterally-spaced side pontoons or sponsons 124 and 126 which longitudinally extend for a substantial portion of the overall length of the watercraft 100 and provide added buoyant displacement which is related to the upward and rearward slope of the central hull portion 110 so that the longitudinal axis of the watercraft 100 is substantially horizontally oriented when the watercraft 100 is at rest (or at displacing speeds). More specifically, it wi l be noted that the upward and rearward slope of the central hull portion 110 would cause the stern of the watercraft 100 to squat or to rest at an aftwardly downwardly angle if it were not for the buoyancy provided by the pontoons 124 and 126. Consequently, it will be appreciated that the sponsons 124 and 126 coact with the upwardly and rearwardly sloping central hull portion 110 so as to maintain the longitudinal axis of the watercraft 100 substantially horizontally aligned when the watercraft 100 is at rest or at displacing speeds.

The pontoons 124 and 126 are provided with generally horizontally-extending, substantially planar surfaces 128 and 130 which provide an upward acting force when the watercraft 100 attains planing speeds. The pontoons 124, 126 may be further supplied with skegs or runners 132 and 134 which contribute to the directional stability of the watercraft 100.

The pontoons 124 and 126 are also preferably provided with bulbous, laterally-outwardly projecting side portions 136 and 138 which serve to fend the watercraft 100 off docks and the like to protect the watercraft 100 as best illustrated in FIGS. 2 and 3. The sponsons 124 and 126 provide a high degree of lateral stability both when the watercraft is in motion, as by providing laterally-outwardly disposed planing surfaces as well as when the watercraft is at rest by providing laterally-outwardly disposed buoyant chambers thereby further contributing to the overall efficiency and safety of the design of the watercraft 100.

It should be noted that the leading edges of the pontoons are aft of the leading edge of the central hull a sufficient distance so that the wake produced by the central hull substantially avoids the pontoons by generally passing forwardly of their leading edges. In this manner, turbulence caused by the wake of the central hull is reduced so as to contribute to the efficient operation of the craft.

In FIG. 3, a cross-sectional view of the watercraft 100 is shown which illustrates a typical efficient arrangement of the passenger and cargo areas. In FIG. 3, the engine compartment is indicated generally at 140 and is seen to contain propulsion units 142 and 144 which may be any suitable unit such as a diesel engine, steam turbine, etc. Also illustrated as a readily accessible cargo area 146 of convenient configuration for the on-loading, off-loading and storage of cargo, and a spacious passenger compartment 148 with ports 150. A bridge or command 151 is situated on the upper level. The bridge 151 is flanked by decks 152. Enclosed lifeboats 154 are disposed immediately adjacent the sides of the watercraft 100.

In FIG. 4, the manner in which the sponsons 124 and 126 may be attached to the watercraft 110 in order to be readily removable for replacement is illustrated. As also illustrated in FIG. 4, the passenger and cargo section 156 is removable for replacement or substitution with an upper craft structure of differing function or design.

In view of the above-detailed description of the watercraft 100, it will be appreciated that an improved highly-efficient drive system is provided in combination with a hull of enhanced stability. Consequently, the watercraft 100 is believed to constitute an improvement in water-borne craft which will rise to the challenge provided by other competitive types of passenger and cargo transportation.

While it will be apparent that the teachings herein are well calculated to teach one skilled in the art the method of making preferred embodiments of this invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope of meaning of the subjoined claims.