Abstract:
A system is provided for rigidly attaching a supply ship to a receiving ship to facilitate efficient transport of materials there-between even when the vessels are subject to heavy seas and weather. A telescoping truss assembly is provided on the first ship, and has a distal end configured to mate with a receptacle assembly on the second ship. Cables are disposed within the truss and are used to draw the truss and receptacle assemblies into engagement with each other. Once the assemblies are engaged, a hydraulic system is used to draw the two ships together, rigidifying the truss assembly and fixing the two ships in a “catamaran” arrangement. Subsequent transfers of materials between the ships can be carried out without the need to compensate for the relative dynamic vertical and horizontal displacements between the ships due to wind and waves.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of the priority date of Provisional Application No. 60/708,624, filed Aug. 16, 2005. 

   FIELD OF THE INVENTION 
   The present invention relates to the field of coupling systems between ships to allow replenishment while underway. 
   BACKGROUND 
   Underway Replenishment is the method by which supplies are transferred from one ship to another at sea to enable a ship to remain at sea for prolonged periods of time. One current method of underway replenishment involves rigging a cable between the supply ship and the receiving ship and sending supplies over a wire using a trolley system. 
   An ideal scenario for transfer would be what is referred to as “skin-to-skin” replenishment, which is conducted by transferring material from two ships located directly next to each other. Currently this is possible only when the involved ships are at anchor or are moving at slow speeds in calm seas, due to the forces of water acting between the vessels, and the danger of the vessels colliding even while not making way. This method would be ideal for transfers at higher sea states because it would allow the transfer of supplies in 20 foot containers using standard crane systems. While skin-to-skin replenishment is not possible under all conditions and with all situations, increased capabilities for situations with higher sea states are desired. 
   One alternative is to develop a crane system that is capable of compensating for the relative movement between ships. However, such systems are highly complex and still may not be safe for transferring containers at higher sea states. 
   Alternatively, if the supplying and receiving ships can be rigidly attached, materials can be transferred from one ship to the other much more efficiently than previous systems, since complex crane systems would not be required. Larger, heavier loads could be transferred at relatively higher rates from hull to hull if a “catamaran” configuration were achieved between the ships. Further, it is expected that material transfers could be made at sea states of up to 4 or higher. 
   Accordingly, there is a need for a device which can securely and safely connect two large cargo ships at sea, in conditions of up to sea state  4  or higher, so that transfer of standard 20-foot containers ship-to-ship by crane can be performed. 
   SUMMARY OF THE INVENTION 
   A system for connecting first and second floating bodies is disclosed. The structure can comprise a truss assembly attached to the first floating structure; and a receptacle assembly attached to the second floating structure. The truss assembly may comprise first and second truss portions and a longitudinal axis, and the first truss portion may be slidably connected to the second truss portion along the longitudinal axis. The first truss portion further may have a coupling disposed at a distal end thereof for engagement with the receptacle assembly. The second truss portion may be connected at a proximal end thereof to the first floating structure via an adjustment assembly, the adjustment assembly being configured to allow the truss assembly to rotate about three mutually perpendicular axes with respect to the first floating body. 
   A system for connecting first and second floating bodies is disclosed, comprising a truss portion connected to the first floating body via a first adjustable assembly, and a receptacle portion connected to the second body via a second adjustable assembly. The truss portion can comprise first and second truss members. The first truss member can have a first end slidably engaged with the second truss member and a second end having a coupling element for engaging a corresponding recess in the receptacle portion. The first and second adjustable assemblies may each be configured to allow movement about three mutually perpendicular axes. 
   A method of connecting first and second floating bodies is disclosed. The method may include the steps of: providing a first ship with a truss assembly comprising first and second telescopically interrelated truss members, the truss assembly having an extended position and a retracted position; providing a second ship with a receptacle assembly comprising a recess for engaging the truss assembly; configuring the truss assembly to the extended position; engaging the truss assembly with the receptacle assembly; locking the truss assembly to the receptacle assembly; and configuring the truss assembly to the retracted position, thereby locking the first and second floating bodies together in a first direction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by, the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
       FIG. 1  is a side view of a pair of truss members of the coupling system of the present invention; 
       FIG. 2  is a side view of the truss members of  FIG. 1 , further including a cabling and gimbal arrangement of the coupling system of the present invention; 
       FIG. 3  is a partial side view of the pair of truss members and cabling arrangement of  FIG. 2 , and further showing preliminary engagement with receptacle arrangement; 
       FIG. 4  is a partial side view of the pair of truss members fully engaged with the receptacle arrangement of  FIG. 3 ; 
       FIG. 5  is a side view of the truss members of  FIG. 1  fully engaged with the receptacle arrangement of  FIG. 3 , the truss members being in a partially retracted position; 
       FIG. 6  is a side view of the truss members of  FIG. 1  fully engaged with the receptacle arrangement of  FIG. 3 , the truss members being in a fully retracted and locked position; 
       FIGS. 7   a ,  7   b  and  7   c  are side, top and end views, respectively, of an articulation mechanism for use with the truss members of  FIG. 1 ; 
       FIGS. 8   a ,  8   b  and  8   c  are side, top and end views, respectively, of a second articulation mechanism for use with the truss members of  FIG. 1 . 
   

   DETAILED DESCRIPTION 
   In the accompanying drawings, like items are indicated by like reference numerals. 
   This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. 
   The present invention comprises a system of telescoping trusses, winches and receptacles that can be used to couple ships in a temporary catamaran configuration in order to allow cargo to be transferred therebetween. The term “catamaran” in the context of this application shall mean at least two hulls connected together by at least one spacing member. The ships involved in the operation can sail alongside each other in close formation (e.g. within 50-75 feet). One ship can be provided with an extendable telescoping truss assembly  100 , while the other ship can have a cooperating receptacle assembly  300 . The telescoping truss assembly  100  can be attached to one of the ships (e.g. the supplying ship), while the corresponding receptacle assembly  300  can be attached to the other ship (e.g. the receiving ship). Further, one or both assemblies can be adjustably mounted to its respective ship using, for example, an adjustment assembly  200  ( FIGS. 2 ,  7   a - c ) that may allow the truss assembly to move with respect to both ships during the initial engagement phase between the truss and receptacle assemblies  100 ,  300  (i.e. before the ships are “locked” together). This adjustability may facilitate a smooth and orderly connection process between the ships  1000 ,  2000 . 
   Additionally, cables  500  can be disposed within the truss assembly  100  and can be passed from one ship to the other using known techniques. The cables  500  can be permanently stowed within the truss assembly  100  (for example, they may be retractably positioned within one or more of the longitudinal structural elements  104   a , and then dispensed through the center of the associated coupling members  109  at the appropriate time). Once the cables  500  are attached to the receptacles, load sensing winches located on one of the ships can draw the truss assembly  100  into engagement with the receptacle assembly. A hydraulic ram system can then be used to draw the telescoping sections of the truss assembly together to form a stronger, axially compact configuration that will maintain nearly skin-to-skin positioning of the two vessels. It is expected that for large ships, maintaining this skin-to-skin positioning may require the use of a plurality of truss/receptacle assembly pairs  100 ,  300 , with at least one pair located near the bow and at least one pair located near the stem of each ship. In one embodiment, a control system utilizing a laser and target system can be provided to steer the truss assembly  100  into initial engagement with the receptacle assembly  300 . 
   Referring to  FIG. 1 , truss assembly  100  may comprise first and second truss members  102 ,  104  connected in telescopic relation. The truss assembly  100  may also have an effective total length “L” and an extension axis A-A along which at least one of the members  102 ,  104  is movable. The first truss member  102  may have a first end  103  configured to engage an adjustment assembly  200  ( FIG. 2 ) associated with a first ship  1000  ( FIG. 2 ). The adjustment assembly  200  may be capable of allowing rotation of the truss assembly  100  about three mutually perpendicular axes (x, y, z—see  FIGS. 7   a - c ) with respect to the ship  1000 . An opposite second end  106  may be provided with at least one coupling member  107  for engaging a corresponding receptacle element  302  ( FIG. 3 ) associated with a second ship  2000  ( FIG. 3 ). The second truss member  104  may have a first end  105  disposed adjacent to the adjustment assembly  200  of the first ship  1000  and a second end  108  provided with at least one coupling member  109  for engaging a corresponding receptacle element  304  associated with the second ship  2000  ( FIG. 3 ). The receptacle elements  302 ,  304  may be connected to a receptacle assembly  300  associated with the second ship  2000 . In the illustrated embodiment, the receptacle assembly  300  is fixed to the hull of the second ship  2000 . As will be explained in greater detail later with regard to  FIGS. 8   a - c , receptacle assembly  300  alternatively may be mounted to an adjustment assembly  400  capable of allowing rotation of the receptacles  302 ,  304  about three mutually perpendicular axes (x, y, z—see  FIGS. 8   a - c ) with respect to the second ship  2000 . 
   In the illustrated embodiment, the coupling members  107 ,  109  are conical elements configured to couple with corresponding conically shaped receptacle elements  302 ,  304 . The coupling members  107 ,  109  are also spaced apart appropriately so that they will register with the complementary receptacle elements  302 ,  304 . It is noted that although the coupling members and receptacle elements are shown as being conical, they could assume other appropriate geometric shapes, and/or configurations as desired. 
   In the illustrated embodiment, the truss members  102 ,  104  each comprise at least a pair of longitudinal structural elements  102   a ,  104   a  connected and reinforced by a plurality of perpendicularly oriented brace elements  102   b ,  104   b  and diagonal brace elements  102   c ,  104   c . Although shown in two dimensions in the figures, the truss members  102  can also be positioned with respect to each other so that the truss assembly  100  itself has an overall triangular, square (see, e.g.,  FIGS. 7   a - c ,  8   a - c ), or other geometric shape in cross-section. Such three-dimensional configurations may increase the tensile, torsional and/or shear strength of the assembly  100 . Additionally, such three-dimensional truss members  102 ,  104  could be made large enough and spaced far enough apart from one another that personnel could walk from ship-to-ship through the opening defined by the truss members. Likewise, materials transfers could also be made through the truss members. The top surfaces of the truss members  102 ,  104  also might be utilized for material movement or for support of liquid transfer devices such as hoses or pipes. 
   It is further noted that although only a single truss assembly  100  is shown, it is contemplated that more than one assembly may be used to rigidly connect the first and second ships  1000 ,  2000 . Thus, in one embodiment, one truss assembly may be located near the bow of the ship  1000  and one near the stem. Likewise, a pair of receptacle assemblies  300  may be located in corresponding locations on the second ship  2000 . For connecting larger ships, three or more truss assemblies  100  may be required. 
   A plurality of cables  500  may be provided within the truss assembly  100  for drawing the assembly into mating alignment with the receptacle elements  302 ,  304 . In the illustrated embodiment, cables  500  are disposed within the longitudinal structural elements  104   a  of the second truss member  104  so that one end of each cable extends distally from the coupling member  109  associated with each element  104   a . The cables can be transferred from the first ship to the second ship using known techniques, such as using a gun to propel a rope from one ship to the other (the cable being connected to the rope). The cable can then be connected to the respective receptacles  304  or to appropriate structure located adjacent the receptacles. One or more winches  600  ( FIGS. 3-4 ) located on the first ship  1000  (the supplying ship) may then be used to tighten the cables  500  to draw the coupling members  109  into provisional engagement with the receptacles  304  ( FIGS. 3-4 ). The winches  600  could be mounted either in the distal end of the truss assembly  100 , or within the first ship  1000  (the supplying ship), with the cables  500  exiting into the truss assembly  100  through a suitable fairlead. During this provisional engagement phase, shown in  FIG. 4 , the adjustment assembly  200  may angulate to allow the ships to continue to move with respect to each other while maintaining the engagement between the truss assembly  100  and the receptacle assembly  300 . 
   Referring to  FIGS. 7   a ,  7   b  and  7   c , an exemplary adjustment assembly  200  is illustrated for connecting the truss assembly  100  to the first ship  1000 . As previously noted, the adjustment assembly  200  may allow the truss assembly  100  to move, with three mutually perpendicular degrees of freedom, with respect to the ship  1000  to thereby allow for a smooth engagement between ships  1000 ,  2000 . The adjustment assembly  200  further may be lockable so that when the desired tight engagement between ships is effected, the two will be fixed rigidly together in a catamaran configuration. Thus, the adjustment assembly  200  may comprise a series of interlinking elements which are engaged and movable with respect to each other to achieve the degrees of articulation desired. As such, the adjustment assembly  200  may comprise a roller bearing  204 , a horizontally extending member  208 , and an intermediate plate member  212  interlinked in series to provide the desired articulation. The roller bearing  204  may have a first portion that is rigidly attached to the hull of the ship  1000  and a second portion that is connected to the horizontally extending member  208 . The roller bearing  204  may have an axis of rotation “y” oriented parallel to the ship&#39;s pitch axis, thus allowing the horizontally extending member  208  to rotate with respect to the ship about the “y” axis. The horizontally extending member  208  may further be rotatably connected to the intermediate plate member  212  via a pinned connection. The pinned connection may comprise a vertically oriented pin  209  which is received within a correspondingly shaped bores  210 ,  211  formed in the horizontally extending member  208  and the plate member  212 . The vertically oriented pin  209  may have an axis of rotation “z” that is oriented substantially parallel to the ship&#39;s yaw axis to allow the horizontally extending member  208  and the intermediate plate member  212  to rotate with respect to each other about the “z” axis. The intermediate plate member  212  may itself be linked to the first ends  103  of the truss member via a pair of laterally extending pins  213 , each of the pins being oriented to provide an axis of rotation “x” that is oriented substantially parallel to the ship&#39;s roll axis. One end of each laterally extending pin  213  may further be disposed within a correspondingly shaped bore  215  formed in the first ends  103  of the truss member  102 , and a second end of each laterally extending pin  213  may be disposed within a corresponding slot  216  formed in a pair of vertically-oriented portions  218  of the plate member  212 . The slots  216  may each have an axis SA-SA that is oriented substantially parallel to the extension axis A-A of the truss assembly  100 , thus allowing the pins  213  and the associated truss member  102  to: (a) rotate about the “x” axis with respect to the intermediate plate member  212 , and (b) slide along the extension axis A-A with respect to the intermediate plate member  212 . Thus arranged, the truss assembly is capable of rotating with respect to the ship about the pitch, roll and yaw axes. In addition, the truss assembly  100  is slidable along the extension axis A-A with respect to the ship  1000 . 
   As previously noted, and in order to provide an added measure of adjustability, the receptacle assembly  300  may also be adjustably mounted to its respective ship  2000  using an adjustment assembly  400 . Referring to  FIGS. 8   a ,  8   b  and  8   c , adjustment assembly  400  is illustrated for use in adjustably mounting the receptacle assembly  300  to ship  2000 . As can be seen, the adjustment assembly  400  may have substantially the same construction as adjustment assembly  200 , with the principal exception being that the horizontally extending member  408  and the intermediate plate member  412  may be freely releasable from each other to allow the truss assembly  100  to be engaged with, and disengaged from, the receptacle assembly  300  as desired. 
   For purposes of clarity, the second truss member  104  has not been shown in  FIGS. 8   a - c , although it will be appreciated that it remains part of the system.  FIG. 8   a  shows a disengaged configuration of the assemblies, in which the roller bearing  404 , the intermediate plate member  412  and the vertically oriented pin  409  are connected to the second ship  2000 , while the horizontally extending member  408  is separately engaged with the truss member  102 . To deploy the system, the truss assembly  100  may lower using cable  700  until the bore of the horizontally extending member  408  receives the pin  409  of the intermediate plate member  412 . Once the pieces are engaged, the adjustment assembly  400  enables articulation of the truss assembly  100  with respect to the ship  2000  in the same manner as previously described in relation to adjustment assembly  200  and ship  1000 . 
   For the embodiment in which only one adjustment assembly ( 200 ) is provided, once the coupling members  109  of the second truss member  104  are provisionally engaged with their respective receptacles  304 , the winches  600  can be used to gradually draw the coupling members  107  of the first truss member  102  into the associated receptacles  302 . Again, at this point, the adjustment assembly  200  still allows the truss assembly  100  to angulate with respect to the ships. Once the coupling members  107 ,  109 ;  302 ,  304  of the truss and receptacle assemblies are fully engaged, a hydraulic ram system  602  located on the supplying ship  1000  (i.e., the ship to which the truss assembly  100  is permanently attached) may be used to compress the truss assembly, gradually telescoping the second truss member  104  into the first truss member  102 , thereby reducing the total effective length “L” of the truss assembly  100  and drawing the ships  1000 ,  2000  into closer relation. In addition to forcing the coupling members  107 ,  109 ;  302 ,  304  together, this telescoping process also forces the first ends  103  of the first truss members  102  to slide within the slots  216  of the adjustment assembly  200  until the conic ends  103   a  are received in correspondingly shaped recesses  1103  associated with the ships hull. Thus, when the truss assembly assumes the configuration shown in  FIG. 6 , it is in its most compact form (i.e. it can not be shortened any further). The tight contact between the coupling members  107 ,  109 ;  302 ,  304  of the truss and receptacle assemblies  100 ,  300  (for ship  2000 ) and between the conic ends  103   a  and the recesses  1103  of the ship hull (for ship  1000 ) also causes the adjustment assembly  200  to “freeze” or lock in place, thus preventing any further articulation. Cargo or other transfers can then be undertaken between the ships. 
   For the embodiment of  FIGS. 8   a - c , in which a pair of adjustment assemblies  200 ,  400  are provided, the truss assembly must first be coupled to the adjustment assembly  400 . This may be done by lowering the distal end of the truss assembly  100  down onto the intermediate plate member  412  so that the vertically extending pin  409  engages the bore  410  in the horizontally extending member  408 . The cables  500  and/or hydraulic ram  602  may then be used to gradually telescope the second truss member  104  into the first truss member until the two can not be telescoped further. Thereafter, the hydraulic ram  602  may be used to draw together the associated coupling members (as well as the conic ends  103   a  and recesses  1103 ) of the truss and receptacle assemblies ( 107 ,  109 ;  203 ,  304 ;  103   a ,  1103 ) to “freeze” or lock the adjustment assemblies  200 ,  400  in placed, thus preventing any further articulation. 
   Regardless of the number of adjustment assemblies used, the ultimate compact form of the truss assembly  100  provides the strength necessary to fix the ships together in a substantially rigid manner to form the catamaran previously described. In one embodiment, the total effective length “L” will be about 20 feet when the truss assembly  100  is in its fully retracted (i.e. compact) configuration. In this configuration, the ships will be fixed relative to each other, so that waves and sea surges will move both ships together rather than independently. As a result, cranes operating on either ship  1000 ,  2000  can transfer cargo between the ships without needing to compensate for dynamic changes in relative height and other positional differences between the decks of the two ships that would exist were the ships free to move with respect to each other. 
   The invention will find application in a variety of sea-based applications where it is desirable to transfer cargo between ships, and between ships and platforms, including U.S. Merchant Marine cargo and container ships. 
   It is expected that the first ship  1000  will be the supplying ship, and will have the truss assembly  100  attached thereto, along with winch or winches  600 , truss guidance control equipment (e.g. laser guiding system  604 ), and hydraulic ram equipment  602 . The truss assembly  100  preferably will be positioned in a recessed or “swung-away” configuration. The second ship  2000  will appropriately be the receiving ship, and will thus have the receptacle assembly  300 , primarily because it will require less space on board the ship and would also be cheaper to provide to a large number of ships throughout a fleet. 
   To deploy the system, the truss assembly  100  can be unstowed and extended into the position of  FIG. 2 , by lowering or swinging the assembly  100  using of one or more cables  700  attached to an appropriate portion of the truss assembly (in the illustrated case the cable  700  is attached to the first truss member adjacent coupling members  107 ). The second ship  2000  could then come along side the first ship so that the receptacle assembly  300  is roughly positioned opposite the coupling member  109  of the truss assembly  100 . An initial standoff distance of about 50-75 feet between the two assemblies is expected. The cables  500  can then be dispensed from the ends of the coupling members  109 . As previously noted, the cables can be attached to ropes which can be propelled from ship to ship using a known technique. The cables  500  would be received by operators located on the first or second ship  1000 ,  2000 , who would engage them with the associated receptacles  304  and at least one winch  600 . Preferably, the winches  600  will be located on the first ship  1000 , which is the supplying ship. The winch  600  would then be operated to retract the cables  500 , causing the coupling members  109  to be drawn into engagement with the receptacles  304 . The remainder of the engagement procedure would proceed as previously described, the details of which may depend on whether one or two adjustment assemblies are provided. 
   As will be appreciated, a combination of winches  600  and hydraulic rams  602  may be used to achieve the desired telescoping (retraction) of truss members  102 ,  104 , as well as the coupling and locking of the truss assembly  100  between the ships  1000 ,  2000 . In one embodiment, the total effective length “L” of the truss assembly will be about 20 feet when the first truss member  102  is fully retracted with respect to the second truss member  104 . Where more than one truss assembly is provided, the above method would be performed simultaneously for all assemblies. 
   As an alternative to the cable and winch system described above for initiating engagement between the truss and receptacle assemblies  100 ,  300 , a laser guidance system  604  could be used to position the coupling members  109  of the truss assembly within the corresponding receptacles  304 . Thus, a laser scanner can be mounted on the first ship  1000  or on the truss assembly  100  with a clear view of the receptacles  304  on the second ship  2000 , to which a plurality of targets can be mounted. The targets can comprise reflective tape, cylinders or plates. The scanner can measure the distance and angle to each target and provide the coordinates to a control program. The control program, in turn, can adjust the position of the truss assembly to place the coupling members  109  into engagement with the receptacles  304 . 
   Alternatively, a manual control system could be used to position the truss. For example, a joystick controlled system could be used, and visual adjustments made by the operator or with the assistance of other personnel using binoculars or other viewing equipment. 
   Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.