The present invention relates to vessels. More particularly, the present invention relates to a vessel having a variable draft, such that the vessel may be configured to operate in shallow waters and in deep waters.
Vessel hulls have traditionally been designed for specific uses, such as for use in shallow waters or in deep waters. Different hull designs provide for optimal operating characteristics for different uses. Shallow-draft vessels, for example, often have hulls that are relatively “flat” to maximize displacement and minimize draft, whereas deep-draft vessels often have v-shaped hulls that provide deep draft for desired seakeeping (e.g., good seakeeping providing low undesired motion, such as vertical motion or rocking).
More specifically, shallow-draft vessels are often designed with flat bottom hulls to provide the ability to navigate in relatively shallow waters, such as in shallow-water harbors, along rivers, along shorelines and in other bodies of shallow water. Shallow-draft vessels are also designed to maximize payload carrying capacity and to provide for simplified on-loading and off-loading of cargo. Examples of shallow-draft vessels include landing craft mechanized (LCM) and landing craft utility (LCU) that are often used by amphibious military forces to transport equipment and troops from sea to beachheads and/or to piers.
Shallow-draft vessels typically have relatively high water resistance due in part to large beam to length ratios, large wetted surfaces, and blunt water contact. Such characteristics provide for the generation of large amounts of resistance, such as turbulence and/or Kelvin wake, and high power requirements. Accordingly, shallow-draft vessels typically have poor seakeeping, poor ride, and poor handling characteristics. Due to these and other operational characteristics, shallow-draft vessels typically are not suited for use in deep water.
Alternatively, deep-draft vessels are often designed with v-hulls having relatively low beam to length ratios to provide the ability to navigate the vessels in deep waters, such as in the oceans and seas. Deep-draft vessels are often designed to provide desired seakeeping (e.g., good seakeeping providing low undesired motion, such as vertical motion or rocking) in high sea states. Deep-draft vessels, however, are typically not available for shallow-water use, such as docking in shallow harbors, river use, and navigation adjacent to shorelines, as the vessels may run-a-ground in these waterways.
A variety of operations require the use of vessels in both shallow and deep waters. As traditionally designed vessels typically have features that provide for optimized use in either shallow water or deep water, but not both, traditionally designed vessels do not provide optimal operating characteristics for both shallow and deep-water use.
Therefore, there is a need for vessels that may be operated in both shallow and deep waters, that provide for desired seakeeping and high speed operation in high sea states, and that provide high cargo carrying capacity with effective shallow-water operability.
The present invention provides a vessel. More particularly, the present invention provides a vessel having a variable draft, such that the vessel may be configured to operate in shallow waters and in deep waters.
According to one embodiment of the present invention, a variable-draft vessel is provided that includes a center hull; a first side hull coupled to a first side of the center hull; a second side hull coupled to a second side of the center hull; and at least one cross support coupling the first and second side hulls, wherein the center hull is configured to be vertically translated with respect to the first and second side hulls. According to a specific embodiment, the vessel further includes lifting mechanism configured to vertically translate the center hull with respect to the first and second side hulls. The lifting mechanism may include a plurality of hydraulic actuators coupled between the center hull and the first and second side hulls.
According to another embodiment of the present invention, a variable-draft vessel is provided that includes a center hull that includes a first plurality of ballast tanks; a first side hull coupled to a first side of the center hull, the first side hull including a second plurality of ballast tanks; a second side hull coupled to a second side of the center hull, the second side hull including a third plurality of ballast tanks; and at least one cross support configured to couple the first and second side hulls, wherein the center hull is configured to be vertically translated with respect to the first and second side hulls by selectively transferring ballast water into or out of one or more of the ballast tanks.
According to another embodiment of the present invention, a variable-draft vessel is provided that includes a central hull; a plurality of struts coupled to the central hull, the struts extending downward with respect to the central hull; a plurality of pods coupled to the struts; and a plurality of floatation devices slidably coupled to the struts, wherein a draft of the pods is configured to be increased or decreased by vertically translating the floatation devices.
Numerous benefits may be achieved using the present invention over conventional vessels. For example, embodiments of the invention provide a vessel having a variable hull form and variable draft for operation in shallow and deep waters. Various hull forms provide for various operations modes and include two of three hulls having water contact (e.g., a deep-draft-transit mode), a center deck matched to a pier height (e.g., a deep-draft-pier-docking mode), three hulls having water contact (e.g., a shallow-draft mode), and a center hull relatively deep or submerged (e.g., a recovery mode). The above forms provide for variable seakeeping and fuel efficiency and may be selected for deep-water operation or shallow-water operation. The vessel may be transitioned from deep-water use to shallow-water use so that the vessel may be operated with a desired seakeeping (e.g., good seakeeping providing low undesired motion, such as vertical motion or rocking) in deep waters and high sea states and transitioned for use in shallow harbors, such as for pier docking, for landing on a beach, and for recovery of cargo and people afloat, for example, in the oceans or in seas. Depending upon the specific embodiment, there can be one or more of these benefits. These and other benefits can be found throughout the present specification and more particularly below.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
The present invention provides a vessel. More particularly, the present invention provides a vessel having a variable draft, such that the vessel may be configured to operate in shallow waters and in deep waters.
One or more of the three hulls may be in the water or lifted out of the water to change the configuration and operational characteristics of the vessel. To change the number of hulls in the water and the draft of the hulls, center hull 25 is configured to be vertically translated (i.e., elevated or lowered) relative to first and second side hulls 15 and 20. The center hull may be translated through a continuum of vertical positions or a set number of vertical positions.
According to one embodiment, center hull 25 is vertically translated by a lifting mechanisms 50 as shown in FIG. 6A. Lifting mechanisms 50 may include: screw jacks, chain jacks, wire rope and linear winches, rack and pinions, hydraulic actuators or the like. According to the specific embodiment of the lifting mechanism shown in
According to one embodiment, the side hulls and struts of a vessel are disposed relatively parallel to each other and may be disposed vertically with respect to the water surface or canted. Canting the struts may provide improved seakeeping and may provide a low radar profile as may be desired for various applications, such as military applications. Additionally, the side hulls, struts, and/or hulls may have slender-elongated shapes to reduce water resistance. Moreover, the side hulls may include a number of compartments, which may provide for fuel storage, include living quarters, house propulsion systems, and the like. Side hulls so configured may be wing walls. Wing walls may further include ballast tanks or the like. Wings walls may be barge structures.
According to one embodiment, the three hulls of a vessel are configured relatively symmetric from end to end so that the vessel may be operated forward and backward in a similar manner. Hull symmetry provides that vessel operations may be executed in both backward and forward traveling directions without the need to turn the vessel around. For example, symmetric hull configurations provide for low and high speed operations in both forward and backward directions.
As briefly described above, a vessel according to embodiments of the present invention may adapt a variety of characteristics associated with the variety of configuration the vessel may adopt. A number of characteristics and associated uses of the vessel are presently described. It should be understood that the characteristics and uses described are for exemplary purposes only. Those of skill in the art will recognize other characteristics and uses for vessels described herein. As shown in
In deep-draft-transit mode, the height of the center hull may be adjusted such that a top deck of the center hull approximately matches, for example, the height of a pier or the like. For convenience, a vessel's configuration in which the height of the center hull's top deck is matched to a pier height is referred to as the deep-draft-pier-docking mode. Deep-draft-pier-docking mode provides for simplified loading and offloading of cargo and passengers. For example, in the deep-draft-pier-docking mode, a ramp at one end of the vessel may be unfolded as shown in FIG. 3 and matched to a pier height so that vehicles may be driven onto and off the vessel. According to a further embodiment, another ramp disposed at the other end of the vessel may be used for off loading vehicles, so that the vehicles may be driven in a forward direction from the vessel.
In deep-draft-transit mode, the center hull may be lifted to a height to provide for simplified cleaning and/or repair of the underside of the center hull without the need to dry dock the vessel. Similarly, with the side hulls lifted above the water (referred to as the recovery mode, see
As shown in
As briefly discussed above, the vessel may be operated in a recovery mode in which the center hull may be partially or totally submerged (see FIG. 5). The recovery mode may be used to recover floating items, such as cargo that has fallen in the water or may be used for rescue work to remove people from the water. For example, passengers from aviation accidents, boating accidents, or soldiers executing military operations may be recovered relatively simply by lowering one or more of the ramps to scoop the passengers from the water. The recovery mode also provides for simplified launching of watercraft that may be stowed on a top deck of the center hull. As briefly described above, the center hull may be vertically translated to such depths that the side hulls are lifted from the water, therefore, providing for maintenance (e.g., cleaning) without the need for dry-docking.
According to one embodiment, ballast water is transferred to and from the three hulls to transition a vessel from one configuration to another configuration.
According to one embodiment, a vessel may be variously ballasted at one end or one side, for example, to tilt or level a vessel. One end of a vessel may be heavily ballasted to tilt the vessel into the water, for example, to provide simplified loading and offloading of cargo in shallow-draft mode or recovery mode. Alternatively, one side of a vessel may be ballasted to level a vessel. A vessel may be leveled, for example, if a ballast tank one side of a vessel is flooded and cannot be drained.
According to another embodiment, a vessel may be transitioned between various configurations to provide various operational characteristics for a single mission. For example, cargo may be loaded from a pier in deep-draft-pier-docking mode, transported with the center hull raised to a relatively high position in deep-draft-transit mode, and then the center hull may be lowered to shallow-draft mode for delivery of the cargo at a beach or the like. It should be understood that the foregoing vessel uses are described for exemplary purposes only and are not intended to be limiting on the invention. Those of skill in the art will readily recognize other uses for vessels described herein.
It is to be understood that the examples and embodiments described above are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. Therefore, the above description should not be taken as limiting the scope of the invention as defined by the claims.
This application claims the benefit of U.S. Provisional Patent Application No. 60/426,070, filed Nov. 12, 2002, titled Multi-Mission-Type Ship and Related Concepts, of Terrence W. Schmidt et al.; and claims the benefit of U.S. Provisional Patent Application No. 60/502,625, filed Sep. 15, 2003, titled Variable Depth/Variable Draft Catamaran (VDD CAT), of Terrance W. Schmidt et al., and are incorporated by reference herein in their entirety including all appendices thereto for all purposes.
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Number | Date | Country | |
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20040134402 A1 | Jul 2004 | US |
Number | Date | Country | |
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60502625 | Sep 2003 | US | |
60426070 | Nov 2002 | US |