Patent Publication Number: US-2016221644-A1

Title: Floating cage launch and retrieval system and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/876,813, filed Sep. 12, 2013. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosure generally relates to the launch and retrieval of a vessel from a larger structure in water. More specifically, the disclosure relates the launch and retrieval of a is vessel from a larger offshore structure, such as an offshore platform or ship. 
     2. Description of the Related Art 
     Larger structures in water, such as offshore platforms, FPSOs, and ships, often deploy and retrieve smaller vessels for reconnaissance, transport, and when needed, evacuation. Typically, the smaller vessels are launched by being lowered using hoists and rope to the surface of the water and released, and then later retrieved by the same manner. For lifeboats, the launch may be a quick release for the vessel into the water. 
     The launch of the smaller vessel from the larger structure can be somewhat straightforward. The smaller vessel can be deployed generally by being suspended from the larger structure by ropes or cables attached to the bow and stern of the smaller vessel, and the ropes or cables are released after the smaller vessel is lowered and floating on the water. However, the retrieval can be more complicated. The different heave motion of the larger structure compared to the smaller vessel can cause difficulties in reattaching the ropes or cables to hoist the smaller vessel up to a storage position with the larger structure. 
     One system shown in GB  2 , 150 , 903  and entitled, “Method and Assembly for Launching or Retrieving a Lifeboat,” describes in the Abstract: an assembly for launching or retrieving a lifeboat, pick-up boat or the like from a ship or a stationary installation includes a boat dock having float bodies. Control wires extending down to the sea from the ship or the stationary installation cooperate with guide means on the boat dock to control the dock during lowering and hoisting. In this manner, the boat dock can float in the sea and follow the wave movements, while at the same time it is stabilized due to the control of the wires. There is a coupling means on the boat dock, which engages with a coupling means on the boat when the boat is in the dock. The system shows a boat with a ball on the end of a smaller diameter rod located on top of the boat that engages and disengages the coupling means (sized to fit the ball with the rod so that the ball does not slip through the coupling means) for launch and retrieval from the larger structure. For launch, the suspended dock with the boat is lowered to the water and the ball with the rod on the boat are released. For retrieval, the boat can approach the dock and as the boat passes under the dock horizontal bar, the ball and rod on the top of the boat can engage the horizontal bar to couple the boat with the dock, so that the dock and boat can be raised to a storage position. Variations of this system include lowering the boat on a separate line from the dock. However, the concentrated load from the tensile stresses with the ball and rod of the boat structure generally would require extra structural support that adds weight and may interfere with other desirable design features in the boat. 
     Another system, shown in U.S. Pat. No. 6,152,065 and entitled “Apparatus for Launching and Recovery of Boats”, describes in the Abstract without the numbered elements: “A dock, for launching and recovery of a lifeboat, rescue boat or like small boat on a vessel, a floating platform or a fixed installation. The boat is normally stored on the dock. The dock is provided with buoyant elements fixed to a frame. The boat is supported in a cradle within the frame. On launching and recovery of the boat, the dock is lowered to a floating position on the surface of the water. In order to fix the boat to the dock, a locking device is provided. By modifying the configuration and size of the buoyant elements, the dock is given rolling and pitching periods which coincide as closely as possible with those of the boat. The dock and the boat will thereby behave in approximately the same manner in the water, which makes it relatively simple to run the boat into the dock even in a very heavy sea. When the boat has been introduced into the dock, it is in contact with the dock at least two points, and the boat and the dock are then fixed to one another by a locking device to form a cohesive unit.” In general, the system provides a frame suspended by lines with floats fixed in elevation relative to the frame. The boat enters the frame and the frame is raised to a storage position with the boat supported by the frame. However, the floats do not adjust in elevation relative to the frame, because of their fixed positions, as stated in the specification. At stages of the launch as the vessel begins to float, it is possible that the vessel might become dislodged and trapped under the floats. Similarly, during retrieval, the vessel might become dislodged and incorrectly supported in the frame. 
     Despite these systems, there remains then a need to provide an improved launch and retrieval system for such smaller vessels. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure provides a vessel launch and retrieval system and method with a cage that can at least partially surround a vessel and a variable elevation float movably coupled with the cage that allows the cage to change elevations relative to the float in the water. The variable elevation float allows the vessel in the cage to be guided throughout the process of launch and retrieval, because the float and vessel can remain in a floating elevation while the cage changes elevation to launch and release the vessel within a range of available movement independent of the float elevation. On launch, the cage with the vessel that is at least partially surrounded by the cage members can be lowered into the water until the vessel is floating above certain cage members sufficiently to allow the vessel to exit the cage. The variable elevation float guides the vessel as the vessel enters the water and continues to guide as the vessel begins to float and then clear the surrounding members. On retrieval after the vessel has entered the cage, the cage can be raised relative to the float that is floating in the water at the float elevation, so that the floating vessel continues to be guided in the cage by the float until the vessel support of the cage engages the bottom of the vessel. Then, the cage, vessel, and float can be raised from the water surface. 
     The disclosure provides a system for launch and retrieval of a vessel in water comprising: a cage comprising a plurality of structural members configurable to at least partially surround the vessel; an opening in at least one portion of the cage configurable to allow the vessel to enter and exit the cage; and at least one float movably coupled to an upright structural member of the cage and configured to be allow movement of the cage between a first elevation and a second elevation relative to the float. 
     The disclosure also provides a method of launching or retrieving a vessel in water with a cage comprising a plurality of structural members; an opening in at least one portion of the cage; and at least one float movably coupled to an upright structural member of the cage, the method comprising: lowering the cage and float into the water with the vessel resting on the cage, so that the float is adjacent the vessel and the cage is at a first elevation relative to the float; further lowering the cage into the water to a second elevation relative to the cage that is different from the first elevation with the float continuing to be adjacent the vessel; and allowing the vessel to exit the cage. 
     The disclosure also provides a method of launching or retrieving a vessel in water with a cage comprising a plurality of structural members; an opening in at least one portion of the cage; and at least one float movably coupled to an upright structural member of the cage, the method, comprising: establishing the cage in the water at an initial elevation to allow the vessel floating in water to enter the cage through the opening while guiding the vessel in the opening with the at least one float; raising the cage in the water while guiding the vessel with the float at different elevations relative to the cage; and further raising the cage in the water and allowing the vessel to rest on the cage while the at least one float is adjacent the vessel at a final elevation relative to the cage that is different than the initial elevation. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective front schematic view of an exemplary vessel launch and retrieval system having a cage with a float that moves in variable elevations relative to the cage, according to the invention. 
         FIG. 2  is a side view of the exemplary system. 
         FIG. 3  is a top view of the exemplary system. 
         FIG. 4  is a side view of the exemplary system placed in water with a vessel partially in the cage with the variable elevation float floating at an elevation relative to the vessel support of the cage that allows the vessel to enter the cage. 
         FIG. 5  is a top view of  FIG. 4 . 
         FIG. 6  is a side view of the exemplary system shown in  FIG. 4  with the vessel resting on the cage and at least partially surrounded by the cage with the variable elevation float floating at a lower elevation relative to the cage and therefore the cage being at a higher elevation in the water compared to  FIG. 4 . 
         FIG. 7  is a top view of  FIG. 6 . 
         FIG. 8  is an alternative exemplary system. 
     
    
    
     DETAILED DESCRIPTION 
     The Figures described above and the written description of specific structures and functions below are not presented to limit the scope of what Applicant has invented or the scope of the appended claims. Rather, the Figures and written description are provided to teach any person skilled in the art to make and use the inventions for which patent protection is sought. Those skilled in the art will appreciate that not all features of a commercial embodiment of the inventions are described or shown for the sake of clarity and understanding. Persons of skill in this art will also appreciate that the development of an actual commercial embodiment incorporating aspects of the present disclosure will require numerous implementation-specific decisions to achieve the developer&#39;s ultimate goal for the commercial embodiment. Such implementation-specific decisions may include, and likely are not limited to, compliance with system-related, business-related, government-related and other constraints, which may vary by specific implementation, location and from time to time. While a developer&#39;s efforts might be complex and time-consuming in an absolute sense, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in this art having benefit of this disclosure. It must be understood that the inventions disclosed and taught herein are susceptible to numerous and various modifications and alternative forms. The use of a singular term, such as, but not limited to, “a,” is not intended as limiting of the number of items. Also, the use of relational terms, such as, but not limited to, “top,” “bottom,” “left,” “right,” “upper,” “lower,” “down,” “up,” “side,” and the like are used in the written description for clarity in specific reference to the Figures and are not intended to limit the scope of the invention or the appended claims. Where appropriate, one or more elements may have been labeled with an “A” or “B” to designate various members of a given class of an element. When referring generally to such elements, the number without the letter is used. Further, such designations do not limit the number of members that can be used for that function. 
     The present disclosure provides a vessel launch and retrieval system and method with a cage that can at least partially surround a vessel and a variable elevation float that moves relative to the cage. The variable elevation float allows the vessel in the cage to be guided throughout the process of launch and retrieval, because the float moves relative to the cage and floats in correspondence with the vessel independent of the cage depth within a range of available movement. On launch, the cage with the vessel that is at least partially surrounded by the cage members can be lowered into the water until the vessel is floating above the surrounding members of the cage sufficiently to allow the vessel to exit the cage. The variable elevation float guides the vessel as the vessel enters the water and continues to guide as the vessel begins to float and then clears the surrounding members. On retrieval after the vessel has entered the cage, the cage can be raised by moving relative to the float that is floating in the water, so that the floating vessel is guided in the cage by the float until the vessel support of the cage engages the bottom of the vessel. Then, the cage, float, and vessel can be raised from the water surface. 
       FIG. 1  is a perspective front schematic view of an exemplary vessel launch and retrieval system having a cage with a float that moves in variable elevations relative to the cage, according to the invention.  FIG. 2  is a side view of the exemplary system.  FIG. 3  is a top view of the exemplary system. The system  2  generally includes a cage  4  having a series of structural members and at least one float movably coupled with a structural column on the cage. Without limitation, the cage includes a plurality of longitudinal members  8  that are coupled to a plurality of lateral members  10 . A plurality of columns  6  are coupled to longitudinal members and/or lateral members to form a height of the cage  4 . The term “column” is used broadly herein to indicate a generally upright structural member. Various bracing and other structural members are not detailed, but would be known to those with ordinary skill in the art as are appropriate for the particular cage and the vessel supported in the cage. The cage can be configured to allow at least one opening  12  into the cage. The cage can include sufficient clearance as may be appropriate for a particularly sized vessel and any protrusions arising from the vessel. 
     In at least one embodiment, the cage  4  can include a bow stop  14 . The bow stop  14  can be disposed on an end of the cage, where the bow stop might be encountered by a bow of a vessel after it enters the cage  4  through the opening  12 . The bow stop  14  can include a first lateral member  14 A at an upper elevation, a second lateral member  14 B at a lower elevation, and an upright member  14 C disposed between the lateral members  14 A,  14 B. 
     In some embodiments, the lateral members can be curved as might better comport with a typical curve of the bow of a vessel. Further, in some embodiments, a stern stop  16  can also be included across a lower elevation of the opening  12 . The stern stop  16  can be an elevation that corresponds to the bow stop lateral member  14 B or other elevations that are generally higher than a bottom of the vessel when the vessel is resting on the cage. 
     A vessel support  18  is formed in the cage  4  generally at lower elevations of the cage, such as at the bottom of the cage. The vessel support  18  can be angled to correspond generally to an angularly formed hull of a vessel. The vessel support  18  can be split across the width to allow a keel of the vessel to be disposed in the vessel support. The vessel support  18  can be supported by cage members  19  around the cage at various positions. 
     One or more floats  20 A,  20 B are movably coupled with the columns  6 . In at least one embodiment, the floats  20 A,  20 B are aligned longitudinally with the cage  4  to assist in guiding the vessel along the starboard side  40  and the port side  42 , shown in  FIG. 5 . A guide surface  32 A,  32 B can be formed on the floats  20 A,  20 B to assist in an initial approach of the vessel into the opening  12  alongside the floats  20 A,  20 B. 
     The float  20  moves along the height of the column  6  within a range of elevations relative to the cage  4 , as the cage is lowered and raised in the water. The float  20  floats on the surface of the water while the cage is raised or lowered into or out of the water and thus the relative elevations between the cage and float change and are not fixed. The float  20  maintains a constant guide, such as in a lateral direction across the cage, at the surface of the water for a vessel entering or exiting the opening  12  of the cage  4  independently of the depth of the cage in the water. A maximum height of the float (and therefore minimum is elevation of the vessel support  18  relative to the float) is limited by the upper float stops  22 A,  22 B. The upper float stop  22  restricts the highest distance that the float  20  can proceed up the column  6  and therefore limits the depth of the stern stop  16  and the vessel support  18  in the water when the cage is supported in the water by the float. The minimum height of the float  20  relative to the cage (and therefore maximum elevation of the vessel support  18  of the cage relative to the float) is limited by the lower float stops  24 A,  24 B. Thus, the upper and lower float stops determine the range of elevations in which the cage and its structural members can move relative to the float. 
     For raising, the cage can be supported by structural members on top of the cage. A raising member  26 , such as a structural frame support, can articulate about a joint  28  as it is folded down against the cage and as it is raised into a raising position. The upward maximum articulation of the raising member  26  is restricted by the length of one of more linkages  30  that are attached to a portion of the frame distally from the articulating joint  28 . The linkages can be lines, such as cables, ropes, chains, and others flexible members, or rigid members such as bars and tubing. A hook  46  can be coupled to the raising member  26 , so that a line  36  can be coupled to the frame  4 . The line  36  can be used to raise and lower the cage with the vessel, when the vessel is supported by the cage. 
       FIG. 4  is a side view of the exemplary system placed in water with a vessel partially in the cage with the variable elevation float floating at an elevation relative to the vessel support of the cage that allows the vessel to enter the cage.  FIG. 5  is a top view of  FIG. 4 . For retrieval, the vessel  38  can approach the cage  4  and enter the cage through the opening  12 . The stern stop  16  and the vessel support  18  can be at an elevation sufficiently below the water surface  34  to provide clearance for the draft of the vessel over the stern stop  16 . The float  20  can guide the vessel  38  on the starboard side  40  and port side  42 , or at other locations as is appropriate for the particular approach of the vessel, as the vessel enters the opening  12  at an initial elevation relative to the vessel support  18 . The starboard side  40  of the vessel  38  can be guided into the opening  12  with the float  20 B and the guide surface  32 B. Likewise, the portside  42  can be guided into the opening  12  by the float  20 A and the guide surface  32 A. The vessel  38  can stop entering the cage when it reaches the bow stop  14 . 
       FIG. 6  is a side view of the exemplary system shown in  FIG. 4  with the vessel resting on the cage and at least partially surrounded by the cage with the variable elevation float floating at a lower elevation relative to the cage and therefore the cage being at a higher elevation in the water compared to  FIG. 4 .  FIG. 7  is a top view of  FIG. 6 . The is vessel  38  can continue entering the opening  12  until it is stopped by the bow stop  14  and at least partially surrounded by the cage  4 . The line  36  can be used to raise the cage  4  upward in the water. Because the float  20  can move downward along the column  6  as the cage is being raised, the float  20  can continue to float in the water near or at the water surface  34  and continue to guide the vessel  38  within the opening  12 . As the cage continues being raised, the vessel support  18  can be raised to engage the hull  44  of the vessel  38 . If the stern stop  16  is present in a particular embodiment, the vessel  38  can be surrounded by the bow stop  14 , stern stop  16 , and any longitudinal members between the stops, including the floats  20 A,  20 B. 
     As the cage  4  is further raised, the lower float stop  24  contacts the float  20  at the minimum elevation of the cage relative to the float. Then, as the cage  4  continues to be raised, the float  20  is raised above the water surface  34  along with the cage and the vessel  38 , which is supported on the cage by the vessel support  18 . The system  2 , having the cage  4  with the float  20 , and vessel  38  can be raised to a storage position on another structure, such as a platform or another vessel. 
       FIG. 8  is an alternative exemplary system. In this alternative embodiment, the floats  20 A,  20 B can be of a cylindrical shape with a conical nose to form the guide surfaces  32 A,  32 B. This embodiment functions in a similar matter as had been described above. 
     For launch, the process is generally reversed. The system  2  with the vessel  38  at least partially enclosed on the cage is lowered from a storage position into the water. After the cage  4  contacts the water surface  34  and continues being lowered, the variable elevation float  20  begins to float and the cage continues being lowered while moving relative, such as sliding through, the variable elevation float. As the cage  4  continues being lowered and the vessel  38  begins to float, the float  20  continues to float and self-adjust its elevation relative to the cage to help guide the vessel at different elevations relative to the cage. When the cage  4  has been lowered sufficiently for the vessel  38  to clear the cage surrounding members, including the stern stop  16 , the vessel can exit the cage  4  while being guided by the variable elevation float  20 . 
     Further, the various methods and embodiments of the system can be included in combination with each other to produce variations of the disclosed methods and embodiments. Discussion of singular elements can include plural elements and vice-versa. References to at least one item followed by a reference to the item may include one or more items. Also, various aspects of the embodiments could be used in conjunction with each other to accomplish the understood goals of the disclosure. Unless the context is requires otherwise, the word “comprise” or variations such as “comprises” or “comprising,” should be understood to imply the inclusion of at least the stated element or step or group of elements or steps or equivalents thereof, and not the exclusion of a greater numerical quantity or any other element or step or group of elements or steps or equivalents thereof. The device or system may be used in a number of directions and orientations. The term “coupled,” “coupling,” “coupler,” and like terms are used broadly herein and may include any method or device for securing, binding, bonding, fastening, attaching, joining, inserting therein, forming thereon or therein, communicating, or otherwise associating, for example, mechanically, magnetically, electrically, chemically, operably, directly or indirectly with intermediate elements, one or more pieces of members together and may further include without limitation integrally forming one functional member with another in a unity fashion. The coupling may occur in any direction, including rotationally. 
     The order of steps can occur in a variety of sequences unless otherwise specifically limited. The various steps described herein can be combined with other steps, interlineated with the stated steps, and/or split into multiple steps. Similarly, elements have been described functionally and can be embodied as separate components or can be combined into components having multiple functions. 
     The invention has been described in the context of preferred and other embodiments and not every embodiment of the invention has been described. Obvious modifications and alterations to the described embodiments are available to those of ordinary skill in the art. The disclosed and undisclosed embodiments are not intended to limit or restrict the scope or applicability of the invention conceived of by the Applicant, but rather, in conformity with the patent laws, Applicant intends to protect fully all such modifications and improvements that come within the scope or range of equivalent of the following claims.