Patent Application
20060060128
The present invention relates to a shoreline interface for transferring passengers, troops, vehicles, and the like between a ship and a shore facility.
There are a variety of situations in which passengers, troops, or vehicles must be transferred from a ship to a shoreline or vice versa. Examples of vessels that engage in this operation include roll-on/roll-off vehicle ferries and naval logistics support vessels.
The transfer requires a device that holds the ship near the shoreline and some way for passengers, vehicles, etc. to offload or onload. Offloading and onloading is typically performed using a ramp. The ramp and the holding/stabilizing device are collectively referred to as an “interface.” Usually, some portion of the interface is carried by the ship (“the shipside interface”) and some portion is located on the shore (“the shoreside interface”).
The interface must maintain vessel position and yaw angle during offloading and onloading operations. And it must permit the vessel to resist wave, current and wind forces while accommodating pitch and heave due to tides and the transfer of vehicles.
The conventional approach to the ship-to-shore interface has been to provide a simple vehicle ramp on the shipside and to construct elaborate shoreside facilities to guide, position, and hold the vessel to the shore. But this approach has several drawbacks.
In particular, having an elaborate shoreside facility equates to high harbor infrastructure costs. Furthermore, extensive shoreside interface facilities can have a deleterious impact on the surrounding environs. For military applications, landing forces are often required to rapidly offload on unimproved or semi-improved beachheads. For such applications, an elaborate shoreside facility is not possible.
As a consequence, there is a need for an interface that is capable of creating a temporary connection between a ship and a shoreline that:
The illustrative embodiment of the present invention is a ship-to-shore interface that avoids some of the drawbacks of the prior art.
In accordance with the illustrative embodiment, the ship-to-shore interface comprises a shipside ramp and a shoreside ramp. The shoreside ramp is securely fixed to the shoreline. The shoreside ramp has one or more physical adaptations that enable it to passively engage the shipside ramp. In the illustrative embodiment, the physical adaptation is a plurality of recesses that receive a lug that depends from the shoreside end of the shipside ramp.
Most prior art ship-to-shore interfaces are necessarily expensive and complex because the include mechanisms, usually disposed on the shoreside, that are intended to guide, position, hold and interface a ship to the shoreline. The illustrative embodiment of the present invention is based on the inventors' recognition that the shipside ramp itself is an excellent mechanism for controlling a ship at the shoreline if an attachment can be made so that it can interface with the shore. In particular, by virtue of its structure, a ramp can geometrically constrain movement of the ship, as caused by wave, current, wind and tidal forces, using nothing more than the ship's thrust or ballasting subsystems.
Thus, in a ship-to-shore interface in accordance with the illustrative embodiment, a relatively more robust shipside ramp is used, in conjunction with the ship's thrust or ballasting subsystems, to position, hold and interface a ship to the shore. As a consequence, the shoreside facility is substantially simplified compared to prior-art ship-to-shore interfaces.
A ship-to-shore interface in accordance with the illustrative embodiment of the present invention provides the following benefits:
A ship-to-shore interface in accordance with the illustrative embodiment of the present invention comprises a passive shoreside ramp having a first feature; an active shipside ramp having a second feature, wherein the second feature is disposed at a shoreside end of the shipside ramp; and wherein the second feature reversibly couples to the first feature to physically restrain the vessel from moving away from the shoreside ramp.
Ship-to-shore interface 108 includes shoreside ramp 110 and shipside ramp 112, which detachably couple to one another. In the illustrative embodiment, shipside ramp 112 is “active.”
As used herein to describe a ramp, the term “active” means that the ramp is movable to create the coupling between shoreside elements of the ship-to-shore interface and the shipside elements of the ship-to-shore interface. In the embodiment depicted in
On the other hand, in the illustrative embodiment, shoreside ramp 110 is “passive.” As used herein to describe a ramp, the term “passive” means that the ramp is not moved to create the coupling between shoreside elements of the ship-to-shore interface and the shipside elements of the ship-to-shore interface. As described further below, in the illustrative embodiment, shoreside ramp 110 includes one or more physical adaptations that enables it to passively receive and reversibly couple to shipside ramp 112.
Shoreside ramp 110 is disposed on shoreline 102. In the illustrative embodiment, shoreside ramp 110 includes a plurality of recesses 220. The recesses are disposed along the side edges of the ramp.
Recesses 220 in shoreside ramp 110 passively receive lugs 218 to create a reversible coupling between shipside ramp 112 and shoreside ramp 110. In the illustrative embodiment, two lugs 218 (only one lug is visible in the side view shown in
The position and yaw angle of the ship must be maintained substantially constant during offloading and onloading operations. The ship must resist wave, current and wind forces while accommodating some pitch and heave adjustment due to tides and the movement of vehicles across shipside ramp 112.
Since the interface between shoreside ramp 110 and shipside ramp 112 is passive, the surge, sway, roll and pitch of ship 104 is controlled via a combination of the angle of shipside ramp 112 (relative to shoreline 102), the ship's thrust subsystem, or the ship's ballasting subsystem, all of which will geometrically constrain lugs 218 within recess 220. When the transfer of vehicles, personnel, etc., is complete, the ramp angle, thrust, or ballast is suitably varied to relax the coupling interface constraint, thereby enabling lugs 218 to decouple from recesses 220. For example, to relax the constraint, the ballast can be adjusted to cause ship 104 to float lower in water 100. Alternatively, assuming that a small amount of thrust is being applied to constrain lug 218 to recess 220, thrust can be cut.
Shipside ramp 112 is typically implemented as a metal grating, although other materials and structural arrangements can suitably be used. Lugs 218 are advantageously formed from a corrosion-resistant material. In some embodiments, lugs 218 are formed from or otherwise covered by a resilient material (e.g., a hard rubber, etc.).
In some embodiments, the shoreside ramp is formed by pouring a slab of concrete at the shoreline and then inserting, on both side edges of the slab, metal performs having wave-like crests and troughs (i.e., recesses). In some alternative embodiments, shoreside ramp 110 is two separate beams that have receptacles for receiving lugs 218. The beams are fixed to shoreline 102 in a spaced, parallel relationship to one another such that they present substantially the same “face” to lugs 218 as do recesses 220 of shoreline ramp 110 of
Shoreside ramp 110 can be a part of the permanently-installed infrastructure of a shoreside installation, or, as might be required for military operations, can be installed at the time of landing. In either case, shoreside ramp 110 is secured to the ground. In the case of a permanent installation, shoreside ramp 110 can be cemented to the shoreline. Alternatively, shoreside ramp 110 can be spiked to shoreline 102, which is suitable for both permanent and temporary installations. Other suitable alternatives for forming and securing shoreside ramp 110, as will occur to those skilled in the art, can suitably be used.
It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. For example, in this Specification, numerous specific details are provided in order to provide a thorough description and understanding of the illustrative embodiments of the present invention. Those skilled in the art will recognize, however, that the invention can be practiced without one or more of those details, or with other methods, materials, components, etc.
Furthermore, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the illustrative embodiments. It is understood that the various embodiments shown in the Figures are illustrative, and are not necessarily drawn to scale. Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that a particular feature, structure, material, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the present invention, but not necessarily all embodiments. Consequently, the appearances of the phrase “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout the Specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.
