Ships – Displacement-type hull – Multiple hulls
Reexamination Certificate
1999-01-04
2001-04-03
Basinger, Sherman (Department: 3617)
Ships
Displacement-type hull
Multiple hulls
C114S06700A, C114S283000
Reexamination Certificate
active
06209470
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of marine vehicles that are at least partially supported by one or more artificially pressurized air cushions. The air cushion provides a supporting layer of air between the marine vehicle and the water thereby reducing wetted area friction and hence making for a more efficient marine vehicle. This greater efficiency is particularly evident at high speed.
BACKGROUND OF THE INVENTION
There have been numerous Air Cushion Vehicle (ACV) designs with the majority using either fill or partial periphery flexible fabric air seals. The full periphery flexible seal craft are normally known as Ground Effect Machines (GEMs) and are amphibious. The second common type generally use fixed structure catamaran side keels with flexible seals fore and aft to thereby define a single rectangular air cushion that supports a craft limited to the marine environment. These latter craft are generally referred to as Air Cushion Vehicles (ACV's) or Surface Effect Ships (SESs). The term SES is most descriptive since these vehicles run mostly in surface effect over a water surface no matter the exact design.
Some simple and yet vastly improved SES variations have been proposed by the Inventor such as can be seen in Burg, U.S. Pat. No. 5,176,095 and 5,415,120. All of these utilize multi-hull designs that have a simple hull structure recess built into one or more of the multi-hulls. There are no air cushions between the multiple hulls and there are no flexible seals. Quite simply, these inventions avoid the problems associated with flexible seal SESs including high flexible seal initial and maintenance costs, a rough bumpy ride related to the flexible bow seal of the generic flexible seal SES allowing waves to disturb the large air cushion that is in reality a large gas spring, and poor ride qualities in rough seas that is largely due to the wide barn door shape of the SES's flexible bow seal.
The instant invention presents improvements to the ideas presented in Inventor's previously listed patents in that it provides an exceptionally smooth ride in rough seas when at rest or traveling at low speeds. This is done without sacrificing the high speed efficiency of the Inventor's previous inventions. The ability to have a very efficient high speed vessel combined with exceptional stability when at rest or low speeds offers unique advantage. Some applications for this new technology include military craft, offshore oil field support vessels, fishing vessels, offshore gaming vessels, and other craft. It is primarily applicable to any marine craft that must be able to get to a station location quickly at high speed and then stay on station for long periods with a minimum of passenger and crew discomfort.
A very stable relatively low speed vessel has been available for a number of years in the form of the Small Waterplane Twin Hull (SWATH). The SWATH concept generally uses twin submerged torpedo or submarine shaped hulls disposed in catamaran configuration below a main hull that is above the waterline. Each submerged torpedo hull is connected to the main hull by one or more struts. While very stable, SWATH has a high drag coefficient at higher speeds. For example, a 100 foot SWATH would generally be considered to require very high propulsive power at over 20 knots. This is due to the very large amount of wetted surface area of the twin submerged sidehulls. Further, since the SWATH's sidehulls are submerged its overall draft requirements are considered excessive for all but deep water ports and cruising areas.
The instant invention, in its preferred embodiment, offers three distinct modes of operation: 1) High speed as a minimum draft Surface Effect Ship wherein blower pressurized air cushions built into at least one of the multiple hulls support a majority of displacement, 2) Intermediate speed where the blower system is turned off and the hulls function primarily in a planing and/or displacement mode, and 3) Low speed maximum stability configuration wherein the sidehulls are at least semi-submerged, generally with the assistance of water ballast, such that there is a minimum strut waterplane area which results in minimum craft motions in a seaway.
The instant invention offers advancements over applicant's earlier inventions as well as over the prior art. These advancements are discussed in some detail in the following sections.
SUMMARY OF THE INVENTION
The object of the instant invention is to offer the advantages of the great high speed efficiencies of an air cushion supported vessel such as the Surface Effect Ship (SES) coupled with tremendous stability while at rest or at low speeds that is accomplished by having small water surface intersection(s) or, as they are most commonly known, small waterplane area(s).
A related object of the invention is that one or more secondary supporting hull(s) are used for supporting a main hull that are disposed below the main hull and connected to the main hull by struts.
It is a further related object of the invention that the struts will be, at least in part, airfoil shaped.
Yet another related object of the invention is that at least one of the connecting struts will include a gas passageway that serves to pass pressurized gas from a blower to a pressurized gas cushion disposed in a recess in a secondary supporting hull.
A further related optional object of the invention is that the gas pressurized blower be disposed distal from a secondary supporting hull that it is supplying pressurized gas to.
A directly related object of the invention is that the gas pressurizing blower can be, at least partially, disposed in the main hull.
A further object of the invention is that a gas cushion recess be built into the structure of a secondary hull.
Another object of the invention is that a bow of a secondary hull can have a pointed or fine entry shape for improved ride qualities in rough seas.
Yet another object of the invention is that sidekeels disposed either side of a gas cushion recess in a secondary hull diverge going aft from said secondary hull's bow.
It is still another object of the invention that, in order to provide best rough sea ride qualities, total secondary hull sidekeel divergence angle does not exceed 26 degrees.
A further object of the invention is that a secondary supporting hull's sidekeels diverge for at least one quarter of the waterline length of the secondary supporting hull going aft from said secondary supporting hull's bow and then become more parallel.
Yet another object of the invention is that a gas cushion recess shall include an aft seal to reduce gas leakage.
A directly related object of the invention is that a gas cushion aft seal shall be, as seen in a vertical transverse plane of the secondary supporting hull, angled over a majority of its width.
Another object of the invention is that separate gas cushions in separate secondary supporting hulls be connected by a duct.
A directly related object of the invention is that a duct connecting gas cushions in separate supporting hulls at least in part can pass through struts.
Yet another object of the invention is that a hydrofoil connect secondary supporting hulls.
It is a directly related object of the invention that the hydrofoil can add stability to the vessel.
It another related object of the invention that the hydrofoil can add to the weight carrying capabilities of the vessel.
A related object of the invention is that the hydrofoil can contain a duct that, at least in part, connects separate gas cushions in separate secondary supporting hulls.
REFERENCES:
patent: 1307135 (1919-06-01), Lake
patent: 3279407 (1966-10-01), Stenger
patent: 4802428 (1989-02-01), Lang
patent: 5176095 (1993-01-01), Burg
patent: 5860380 (1999-01-01), Burg
Basinger Sherman
Van Der Wall Robert J.
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