Abstract:
An apparatus for employing and retrieving a seaborne vehicle having a  frable surface includes a muzzle and a cylindrically shaped cocoon. The muzzle is clamped to the vehicle and then pulled by a rope into the cocoon. Bladders within the cocoon are inflated with pressurized air to retain the vehicle. The vehicle can then be safely retrieved by hoisting the cocoon out of the ocean. Vehicle deployment is achieved by placing the vehicle in the cocoon, pressurizing the bladders with air, lowering the cocoon and attendant vehicle into the ocean, exhausting the air from the bladders, and then towing the cocoon so that water passing through apertures in the bow of the cocoon push the vehicle into the open ocean.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. 
    
    
     BACKGROUND OF THE INVENTION 
     The U.S. Navy frequently deploys and retrieves floating vessels that have easily damaged surfaces lacking attachment points. A prime consideration when handling these types of vessels is to ensure that neither the vessel nor its contents are damaged. The conventional method for deploying and retrieving such a vessel utilizes a sling to support the vessel while it is suspended from a ship mounted crane. However, this procedure may subject the vessel to damage from wave action forces generated by rough seas and from passage of the exposed vessel through the interface between the ocean and atmosphere. Damage may also result as the sling responds to rough seas causing the vessel to be slammed against the hull of the ship. Consequently, these activities have been restricted to calm seas. However, the U.S. Navy has a continuing need to launch and retrieve these vessels in rough seas. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes these difficulties. It enables deployment and retrieval of frangible vessels in ocean conditions as severe as sea state three or swells up to eight feet with minimal shock transmission to the vessel and its contents. Deployment is accomplished by placing the vessel in a shock attenuating cocoon, transferring the cocoon from the deployment craft into the ocean, and then releasing the vessel from the cocoon freely into the open sea. Vessel recovery is easily and safely achieved by muzzling the vessel, towing it into the cocoon, and then transferring the cocoon to the retrieval craft. The vessel may then be removed from the cocoon on board a ship. 
     The invention includes a muzzle sized to fit over and grab onto an end of the vessel. A rope attached to the muzzle is threaded through an aperture of a cocoon to recover the vessel in a novel manner. The cocoon is longitudinally split into upper and lower shells having an open end shaped to receive and encapsulate the vessel. Tension applied to the rope by a shipboard winch pulls the muzzle and the attached vessel into the cocoon. Several elongated inflatable bladders mounted parallel to the longitudinal axis of the cocoon against its inside surface are inflated by air pressure to secure the vessel and cushion it. After the vessel has been secured within the cocoon, the cocoon and vessel contained therein can be hoisted on-board the retrieval craft. 
     Vessel deployment from a ship is easily accomplished by placing the vessel in the lower shell, attaching the upper shell to the lower shell, and then pressurizing the inflatable bladders in the cocoon. The cocoon is next lowered into the sea. Pressure in the inflatable bladders is relieved while the cocoon is towed behind the ship. Important features of the cocoon are apertures in the bow through which passing water impinges upon the vessel to push it out into the sea. 
     OBJECTS OF THE INVENTION 
     An object of the invention is to provide an apparatus for shipboard deployment of a vessel. 
     A second object of the invention is to provide an apparatus for shipboard retrieval of a seaborne vessel. 
     A third object of the invention is to provide an apparatus to safely transfer a vessel between the ocean and a ship. 
     These and other objects of the invention will become more readily apparent from the ensuing specification and claims when taken in conjunction with the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation view of the muzzle. 
     FIG. 2 is a view looking into the open end of the muzzle. 
     FIG. 3 is a partially cutaway, elevation view of the cocoon. 
     FIG. 4 is a cross-sectional interior bow view of the cocoon. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, wherein like reference numerals designate like or similar parts throughout the several views, there is illustrated in FIGS. 1 and 2 a novel muzzle 20 for obtaining secure control of an ocean borne floatable vessel 22, illustrated in phantom, having a frangible surface. The muzzle may include a frame 24 configured in the shape of a truncated ellipsoid formed by eight longitudinal tubular spars 26 which converge at nose plate 28. Tow hook 30 is mounted to nose plate 28 by bolts 30a. Air filled lift tube 32 shaped as an irregular annulus is supported by a ring shaped framed 32a which is lashed to frame 24. Lift tube 32 provides buoyancy to muzzle 20. Tow hook 30 extends through a circular opening, not shown, of lift tube 32 and frame 32a. The open end 33 of muzzle 20 opposite nose plate 28 is defined by annular split band 34 which forms a circular opening shaped to receive the vessel. Band 34 has a split opening 36 enabling band 34 to be selectively tightened around vessel 22 by toggle clamp 38 mounted on band 34 that bridges split opening 36. Straps 40 affixed to the exterior of band 34 facilitate manual handling of muzzle 20. Silicone rubber liner 42 is attached as by epoxy cementing it to the inside surface of band 34 to prevent damaging vessel 22 and provides a frictional surface to retain vessel 22 when band 34 is tightened. Sections of silicon rubber hose 44 mounted approximately halfway along the lengths of each tubular spar 26 of frame 24 prevent spars 26 from damaging the surface of vessel 22. Nylon rope 46 is threaded through tow hook 30 via plastic rope thimble 48. Rope end 46a of rope 46 is left free in the ocean to be used as will be discussed herein. 
     A cocoon 50, depicted in FIG. 3 may be configured as a blunt nosed, hollow cylindrical body, longitudinally split into an upper shell 52 and lower shell 54. Cocoon 50 is open to the sea at its stern 56 and substantially closed at its bow 58. A plurality of brackets 60 are welded to the outside surfaces of shells 52 and 54 adjacent to longitudinal split 62 where shells 52 and 54 mate so that each bracket 60 on upper shell 52 aligns with a bracket 60 on lower shell 54 when shells 52 and 54 are fitted together. Threaded fasteners 64 are fitted through aligned brackets 60 and when tightened hold shells 52 and 54 together. Cutout areas 65 formed by slots 65a and 65b in both sides of upper and lower shells, 52 and 54 respectively, provide access while the vessel is encapsulated within the cocoon to equipment which may be mounted on the vessel surface. Pin 66 is pivotally mounted in bow bracket 68 welded to bow 58 of cocoon 50. Nylon rope 70 is threaded through rope thimble 72 pivotally constrained by pin 66 so that cocoon 50 can be towed to and hoisted aboard the retrieval craft. 
     A plurality of apertures 74 in bow 58, as shown in FIG. 4 allow water to pass through bow 58 while cocoon 50 is being towed. The passing water impinges upon vessel 22 and pushes it out of cocoon 50 freely into the open sea. Bow 58 also has an aperture 75 through which the free end 46a of rope 46 is threaded so that muzzle 20 and attached vessel 22 can be towed into cocoon 50. Two flotation tanks 76 mounted by brackets 77 to upper shell 52 provide buoyancy to cocoon 50. 
     Referring to FIGS. 3 and 4, inflatable bladders 79 extending the substantial length of cocoon 50 may be selectively inflated with air pressure to snugly retain and cushion vessel 22 within cocoon 50. When deflated, bladders 79 provide an open area sufficient to enable vessel 22 to pass through stern 56 of cocoon 50. Bladders 79 may be a plurality of elongated, resilient inflatable hoses 79. The end of each hose 79 nearest stern 56 is suspended by compression spring mount 79a mounted in support block 79b. Support blocks 79b are mounted to the interior surfaces of upper shell 52 and lower shell 54. Compression spring mounts 79a accommodate volumetric dimensional changes of hoses 79 when inflated or depressurized. The ends of hoses 79 nearest bow 58 are mounted to the interior surfaces of upper shell 52 and lower shell 54. A plurality of elastic straps 82 fastened to the interior surface of cocoon 50 resiliently hold each inflatable hose 79 against a channel 80 welded to and radially distributed around the interior surface of cocoon 50. Still referring to FIG&#39;s. 3 and 4, a plurality of longitudinal, &#34;C&#34; -shaped rubber bumpers 84 radially mounted about the interior surface of cocoon 50 extend the substantial length of cocoon 50 and act as guides during transfer of vessel 22 to and from cocoon 50. A plurality of lead weights 86 may be mounted within the space formed by surrounding rubber bumpers 84 and distributed the substantial length of cocoon 50. Lead weights 86 establish net buoyancy of cocoon 50 so that the longitudinal center axis of cocoon 50 when deployed coincides with the longitudinal center axis of floating vessel 22. Rubber bumper 88 mounted inside bow 58 of cocoon 50 protects vessel 22 from abrasion damage from bow 58 and cushions muzzle 20 and vessel 22 from docking impact forces while muzzle 20 and vessel 22 are towed into cocoon 50. 
     Returning to FIG. 3, an air supply hose 96 from the ship snaps into a first quick disconnect fitting 98 to provide pressurized air to upper shell pneumatic system 100 which is in gas communication with lower shell pneumatic system 102 via second quick disconnect fitting 104. Gas communication in pneumatic systems 100 and 102 may be accomplished through pneumatic hose or stainless steel tube. Pressurized air is distributed to inflate hoses 79 and exhausted to deflate them through pneumatic systems 100 and 102 by suitable means on board the ship as would be readily understood by one of ordinary skill in this art. 
     Operation of the Invention 
     In the operation of the invention for deployment of a seaborne vessel 22 having a frangible surface from a ship, threaded fasteners 64 are loosened so that upper shell 52 can be separated from lower shell 54. Vessel 22 is then placed onto lower shell 54. Upper shell 52 is fitted and reattached onto lower shell 52 to form cocoon 50 by tightening threaded fasteners 64. Air pressure supplied by suitable means on board ship to cocoon 50 through pneumatic hose 96 to upper shell pneumatic system 100 and lower shell pneumatic system 102 pressurizes inflatable hoses 79 which inflate to snugly engage and cushion vessel 22. 
     After vessel 22 is secured, cocoon 50 is lowered by rope 70 into the sea by suitable means, such as by a crane located on board the ship. Once in the sea, air pressure in inflatable hoses 79 is relieved by suitable means on board the ship as would be readily understood by one skilled in this art. Cocoon 50 is towed by rope 70 at approximately 3 to 5 knots so that water flowing through apertures 74 in bow 58 impinges upon vessel 22 to push it out into the open sea through stern 56 of cocoon 50. Vessel 22 is then free to perform its operational purposes during which time cocoon 50 and muzzle 20 may be brought on board ship. 
     When desired to recover vessel 22, cocoon 50 and muzzle 20 are placed in the ocean in the vicinity of vessel 22 with upper and lower shells 52 and 54, respectively, fastened together. At this stage, air pressure in inflatable hoses 79 is 0 psig so that hoses 79 are not inflated. End 46a of rope 46 is threaded through stern 56 of cocoon 50 and on through aperture 75 in bow 58 of cocoon 50. Divers place muzzle 20 over one end of vessel 22 and frictionally engage it with toggle clamp 38. Rope 46 is pulled by suitable means such as by a winch located on board the ship to draw muzzle 20 and vessel 22 into cocoon 50. Once in cocoon 50, inflatable hoses 9 are pressurized by suitable means located on board ship as would be readily understood by one skilled in the art through pneumatic hose 96 and pneumatic systems 100 and 102 to snugly engage vessel 22. Rope 46 is slackened. Cocoon 50 may then be hoisted by rope 70 on board the ship by suitable means such as by a crane without risk of damaging the vessel or its contents. Then, inflatable hoses 79 are depressurized and upper shell 52 is separated from lower shell 54. Vessel 22 may then be lifted out of lower shell 54 followed by removal of muzzle 20 from vessel 22. 
     Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.