Patent Publication Number: US-7585197-B1

Title: Crew overboard self rescue device and method for unassisted crew overboard watercraft reentry

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This is a continuation in part of application Ser. No. 11/212,861, Filed 2005 Aug. 26 now abandoned. 

   FEDERALLY SPONSORED RESEARCH 
   Not Applicable 
   SEQUENCE LISTING OR PROGRAM 
   Not Applicable 
   BACKGROUND OF THE INVENTION 
   1. Field of Invention 
   This invention relates to watercraft safety devices, specifically to crew overboard recovery devices which are used to assist reentry of a crew overboard into a watercraft. 
   2. Background of the Invention 
   A serious hazard associated with sailing is that of falling overboard while the boat is under way. Any person who has fallen overboard is referred to as a “crew over board.” Situations which are particularly hazardous include working on deck in heavy seas, being hit unexpectedly by a large wake, being hit by the boom, broaching, or being washed overboard by breaking waves in especially stormy weather. 
   One element of a successful crew overboard rescue is retrieval once the crew overboard has been found. U.S. Pat. No. 6,093,070 to Mannes describes a crane attached to a ship for the lifting of individuals from the water. Unfortunately, the device described in this patent is much too large to be practical on most recreational sailboats. In U.S. Pat. No. 4,599,074, Beckly discloses a more compact boom for crew overboard retrieval. Yet another device employing a detachable boom and sling is described by McDonald in U.S. Pat. No. 4,343,056. A more compact hoisting system is described in U.S. Pat. No. 5,779,511 by Davidson. This system comprises a triangular harness which utilizes two points of attachment to a sailboat and one to a halyard. The harness is placed under the crew overboard and the halyard is hoisted to raise the crew overboard to the level of the deck. A sling with an attachable inflatable buoy and keel is described by Hindle in U.S. Pat. No. 4,747,797. The sling is used as both a flotation aid and device to assist retrieval. Means of hoisting the crew overboard in the sling are not addressed. Yet another example of a crew overboard retrieval device is disclosed by Fryer et al. in U.S. Pat. No. 4,599,073. This retrieval device integrates buoyant material into a lifting sling which is tethered to the boat by a long floating line. A block and tackle attached between the sling and the boom of a sailboat can be used to hoist the crew overboard to a level where he can be swung into the boat. The devices cited above have at least one commonality. They all require at least one person onboard the boat to assist in retrieval of the crew overboard. It is not uncommon for individuals to sail alone without a crew. In such instances, the devices cited above are useless to the single handed sailor in a crew overboard situation. 
   The single handed sailor will often employ a tether attached on one end to a harness worn by the sailor and attached on the other end to a strong point on the boat such as a pad eye. The tether will prevent a sailor from being separated from the boat in the event that he should go overboard. However, a tether will not prevent an individual from going overboard. A tether which is short enough to do so does not provide freedom of movement sufficient to accomplish the tasks necessary to sail the boat. If a tethered single handed sailor does go overboard, he must then reenter the boat without assistance from others. Given the height of the gunwale above the water, this is at best a difficult task. The crew overboard must first find a way to reach above the gunwale to grasp a cleat, stanchion, or other fixture. He must then pull himself up to the point where he can hook his leg over the gunwale. Then he must use both arms and legs to pull himself inside the boat. In addition, these maneuvers must be performed while the boat is under way and the crew overboard is being dragged through the water. Needless to say, better than average strength and fitness are required to reenter the boat unassisted. 
   An example of a commercially available device marketed to the single handed sailor for crew overboard use is a boarding ladder. These are flexible, stowable ladders and require attachment at the level of the gunwale or above. The utility of these devices to the single handed crew overboard is limited since it is unlikely that the crew overboard will be able to reach the level of the gunwale to attach a ladder or that ladders attached to the boat prior to going overboard will be sited appropriately. 
   Trailing line devices are yet another means of assistance targeted at the crew overboard. The simplest manifestation of such a device is a long floating line trailed behind the boat. In theory, the crew overboard swims to the line and then uses it to pull himself to the swim ladder on the back of the boat. To reach the trailing line, the crew overboard must cut his tether, thus separating himself from the boat. In practice, at all but the slowest speeds, the drag on the crew overboard is so great that he will not be able to pull himself up the trailing line. Other examples of trailing line crew overboard assistance are disclosed by Searls in U.S. Pat. No. 4,228,556 and by Brown in U.S. Pat. No. 5,192,238. The system described by Searls employs a trailing line to deploy a life ring and crew overboard pole. Recovery of the crew overboard is not addressed. Brown describes a system which uses a sea anchor and pulley to retract the trailing line and hoist the crew overboard to the level of the gunwale. While overcoming many of the deficiencies of other crew overboard recovery systems, the system described by Brown appears to be complex with the attendant disadvantages of high cost and questionable reliability. 
   From the foregoing discussion, clearly, there is a need for a crew overboard retrieval system which allows the single handed crew overboard to reenter the boat under his own power. 
   OBJECTS AND ADVANTAGES 
   Accordingly, several objects and advantages of my invention are: 
   (a) to provide a boat reentry system which can be utilized by a crew overboard without the assistance of others; 
   (b) to provide a boat reentry system whereby a crew overboard can ascend to the level of the gunwale under his own power; 
   (c) to provide a boat reentry system which is accessible to a crew overboard regardless of the point of egress from the boat; 
   (d) to provide a boat reentry system which does not require the crew overboard to detach his tether; 
   (e) to provide a boat reentry system which does not require additional hardware to be mounted on the boat; and 
   (f) to provide a boat reentry system which allows the crew overboard to overcome the drag on himself resulting from the forward motion of the boat through the water. 
   Further objects and advantages are to provide a boat reentry system which is simple to operate, is light enough to carry on one&#39;s person at all times, and is simple and inexpensive to manufacture. Still further objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description. 
   SUMMARY 
   In accordance with the present invention, a crew overboard recovery system comprises a tether and an ascension device which can be attached to a point on the tether between the ends of the tether. The tether has one or more loops attached to its midsection which serve as attachment points for the ascension device. The ascension device comprises a series of stirrups or steps which are attached to one or more flexible straps or lines. The ascension device has a means of attachment at the end opposite the end to which the lowermost stirrup or step is attached. In normal use, one end of the tether is anchored to the boat and the other end is attached to a harness worn by the user. In a crew overboard situation, the crew overboard attaches the ascension device to the highest loop he or she can reach on the tether. The crew overboard then scales the ascension device by climbing the stirrups or steps using leg extension to elevate himself to a level where he can reenter the boat. 

   
     DRAWINGS 
     Figures 
       FIG. 1  shows the assembled components of the preferred embodiment of the crew overboard self rescue system. 
       FIG. 2  illustrates the use of thread resistant to degradation by ultraviolet light to secure attachment loops to a tether strap. 
       FIG. 3  shows the stitching pattern used to join an attachment device to a tether or an ascension device. 
       FIG. 4  depicts the use of buoyant material in an ascension device causing the ascension device to float. 
       FIG. 5  illustrates the storage of an ascension device in a wearable means of containment. 
       FIG. 6  shows a crew wearing a means of containment for an ascension device. 
       FIG. 7  illustrates use of the crew overboard self rescue system. 
       FIG. 8  illustrates the crew overboard self rescue system with a tether, supplemental tether, and an ascension device. 
       FIG. 9  shows an alternative embodiment of the crew overboard self rescue system in which the length of the ascension device is adjustable. 
       FIG. 10  shows a tether to which a stretched length of elastic material has been attached with the tension in the elastic material relieved. 
       FIG. 11  shows a crew overboard self rescue device in which the ascension device comprises a ladder. 
       FIG. 12  illustrates a crew overboard self rescue device in which both the tether and ascension device comprise cord. 
   

   DRAWINGS 
   Reference Numerals 
   
       
         2  tether 
         4  ascension device 
         6  supplemental tether 
         8  buckle tether 
         10  adjustable ascension device 
         12  ladder 
         20  watercraft attachment device comprising a snap hook 
         22  tether strap 
         24  attachment loop 
         26  attachment loop webbing 
         28  crew attachment device comprising a snap hook 
         30  stitching with thread resistant to degradation by ultraviolet light 
         32  ascension device attachment apparatus comprising a snap hook 
         34  elongate flexible tensile member 
         36  lowermost foothold comprising a stirrup comprising strap 
         38  second foothold comprising a stirrup comprising strap 
         40  third foothold comprising a stirrup comprising strap 
         42  uppermost foothold comprising a stirrup comprising strap 
         44  buoyant material 
         46  stirrup spreader 
         48  harness 
         50  crew 
         52  means for containment of ascension device 
         54  means of attachment to crew for means for containment 
         56  watercraft 
         58  crew center of gravity 
         60  gunwale 
         62  coaming 
         64  water 
         66  waterline 
         68  supplemental watercraft attachment device 
         70  supplemental tether strap 
         72  supplemental attachment loop 
         74  supplemental attachment loop webbing 
         78  upper elongate flexible tensile member 
         80  buckle 
         81  uppermost end of upper elongate flexible tensile member 
         82  lowermost end of upper elongate flexible tensile member 
         84  lower elongate flexible tensile member 
         86  uppermost bitter end 
         88  watercraft attachment device comprising a snap shackle 
         90  crew attachment device comprising a carabiner 
         92  elastic material 
         94  ladder rung 
         96  elongate flexible tensile member of ladder 
         98  cord 
         100  splice 
         102  stirrup comprising cord 
         104  tether comprising cord 
         106  attachment loops comprising cord 
         108  elongate flexible tensile member comprising cord 
     
  
   DETAILED DESCRIPTION 
   FIGS.  1  through  7 —Preferred Embodiment 
   A preferred embodiment of the crew overboard recovery system of the current invention is illustrated in  FIGS. 1 through 7 . 
   Referring to  FIG. 1 , a tether  2  comprises a tether strap  22 , a watercraft attachment device  20 , attachment loop webbing  26  formed into attachment loops  24 , and a crew attachment device  28 . The tether  2  is shown with twists present in the same to reveal pertinent details of construction. The tether strap  22  is preferably high strength webbing approximately 2.5 cm in width. An advantage of webbing is the ease with which loops can be formed and secured by stitching. In the preferred embodiment, attachment loops  24  are formed by gathering a length of attachment loop webbing  26 . As shown in  FIGS. 1 and 2 , the attachment loop webbing  26  is secured to the tether strap  22  with stitching between the attachment loops  24 , preferably with thread resistant to degradation by ultraviolet light  30 . The stitching pattern shown in  FIG. 2  is approximately 5 cm in length and provides stitching between the attachment loops  24  of a sufficient length to support the weight of a crew overboard. Of course, the length of the stitching pattern and the distance between attachment loops  24  can be increased or decreased provided the total length of stitching is sufficient to bear the crew&#39;s weight. As shown in  FIG. 1  and  FIG. 6 , the placement and extent of the attachment loops  24  along the tether strap  22  may be varied to either conserve material and decrease manufacturing costs or to increase versatility. The tether strap  22  is of sufficient length to provide an acceptable range of motion to a user while on a boat. The typical length of tethers commercially available for marine use is approximately 2 meters. The tether of the preferred embodiment is similar in length. As shown in  FIG. 3 , the watercraft attachment device  20  is attached to one end of the tether strap  22  by passing the tether strap  22  through a snap hook  20 , doubling the tether strap  22  back onto itself and securing with stitching, preferably with thread resistant to degradation by ultraviolet light  30 . In the preferred embodiment, the stitching pattern shown in  FIG. 3  is approximately 14 cm in length. Details such as the length and number of passes of stitching may be varied, but the length of the stitching must be sufficient to withstand the shock load imposed by the fall of a sailor being arrested by the tether. The watercraft attachment device  20  is a snap hook which provides a detachable means of attachment of the tether  2  to the watercraft. The crew attachment device  28 , which is also a snap hook, is situated at the other end of the tether strap  22  and is attached to the tether strap  22  in a manner identical to that for the watercraft attachment device  20 . 
   Referring again to  FIG. 1 , an ascension device  4  comprises an ascension device attachment apparatus  32 , an elongate flexible tensile member  34 , and a plurality of footholds  36 ,  38 ,  40 , and  42 . In the preferred embodiment, the ascension device attachment apparatus  32  is a snap hook, the elongate flexible tensile member  34  is a strap made from high strength webbing, and the plurality of footholds  36 ,  38 ,  40 , and  42  are stirrups. For the elongate flexible tensile member  34 , a length of 185 cm and a width of 2.5 cm have been found to be suitable. The plurality of stirrups  36 ,  38 ,  40 ,  42  are attached successively to the elongate flexible tensile member  34  along its length to form a series of steps which the crew overboard may climb. In the preferred embodiment, the stirrups are also made from high strength webbing approximately 2.5 cm in width. The spacing between stirrups is approximately 30 cm and the length of the open loop perimeter of each stirrup is approximately 60 cm. As shown in  FIG. 4 , preferably both the ascension device strap  34  and stirrups  36 ,  38 ,  40 ,  42  are made from a buoyant material  44  such as polypropylene. The purpose behind fabrication of the ascension device from buoyant material is to cause the ascension device  4  to float so that it cannot become entangled in a propeller. Preferably, the stirrups are formed by looping webbing onto itself and stitching the overlapped ends to the ascension device strap  34  with thread resistant to degradation by ultraviolet light  30 . The length of the overlap and the length of the stitching which secures the overlap to the ascension device strap  34  must be sufficient to support the weight of the crew overboard. The stitching pattern shown in  FIG. 3  and having a length of 14 cm has been found to be adequate for this purpose. Stirrup spreaders  46  maintain the stirrups  36 ,  38 ,  40 ,  42  in an open position so that the crew overboard can easily insert his foot into the stirrups  36 ,  38 ,  40 ,  42 . Preferably, the stirrup spreader  46  comprises a short length of tubing approximately 15 cm in length. The stirrup webbing is threaded through the tubing to maintain the stirrup  36 ,  38 ,  40 ,  42  in an open configuration. The ascension device attachment apparatus  32  is attached to the elongate flexible tensile member  34  at the end of the elongate flexible tensile member  34  opposite the lowermost stirrup  36 . Preferably, the elongate flexible tensile member  34  is threaded through the ascension device attachment apparatus  32 , doubled back over onto itself, and secured with stitching of a sufficient length to support the weight of the crew overboard. The stitching pattern shown in  FIG. 3  and having a length of 14 cm has been found to be more than adequate. Preferably, the thread used for stitching is resistant to degradation by ultraviolet light  30 . In a crew overboard situation, the ascension device attachment apparatus  32  is attached to an attachment loop  24 . 
   In situations where use of a tether is desirable, the crew attaches the watercraft attachment device  20  to a hard point on the boat such as a pad eye and the crew attachment device  28  to a harness  48  worn by the crew. In cases where the watercraft attachment device  20  and crew attachment device  28  are identical and the attachment loops  24  are symmetrically disposed with respect to the midpoint of the tether, either attachment device may be attached to the watercraft with the other being attached to the harness. As shown in  FIGS. 5 and 6 , the ascension device  4  is folded and stored in a means for containment  52  attached to the crew  50  by a means of attachment  54 . The means for containment  52  can be a commercially available fanny pack, a pouch secured to the crew&#39;s harness, or other means of wearable containment having a means of attachment  54  to the crew. The means for containment  52  can be made of nylon or any other high durability material. Suitable closure systems for the means for containment are zippers or hook and loop fasteners. In the case of a fanny pack, the means of attachment to the crew  54  might be a webbed belt with adjustable girth and a commercially available closure system such as D-rings, a buckle, a snap closure, or a hook and loop fastener such as Velcro®. For the case of a pouch attachable to a harness  48 , a hook and loop fastening system might be used to join the pouch to the harness. The specific means for containment  52  and means of attachment  54  are of limited significance so long as the means for containment  52  can be worn by the crew in an accessible location. 
   Operation 
   FIG.  7   
   In the event that the crew  50  goes overboard, the crew first retrieves the ascension device  4  from its means for containment  52 . Referring to  FIG. 7 , the crew overboard is suspended from the watercraft  56  in the water  64  by his harness  48  and tether  2 . The crew overboard attaches the ascension device  4  to the highest tether attachment loop  24  he can reach using the ascension device attachment apparatus  32 . Next the crew overboard places one of his feet in the lowermost stirrup  36  or any other convenient stirrup. The crew overboard then climbs the ascension device by extending the leg engaged with the lowermost stirrup  36  thus raising his center of gravity  58  with respect to the waterline  66 . He then places his other foot in the next higher stirrup  38 . The crew overboard continues to climb the ascension device  4  in this manner while stabilizing his upper body by grasping either the ascension device  4  or the tether  2  above the ascension device attachment apparatus  32 . Once the crew has commenced the climbing process, the tether  2  is slack between the ascension device attachment apparatus  32  and the crew attachment device  28 . The range of vertical motion is twice the distance between the ascension device attachment apparatus  32  and the crew attachment device  28 . For an individual having a height of 2 m, the vertical range of motion will be approximately 2 m provided there are sufficient stirrups  36 ,  38 ,  40 ,  42  and that they are properly spaced. Once the crew overboard has elevated his center of gravity  58  to the level of the gunwale  60 , he maneuvers his upper torso over the gunwale  60  or coaming  62 , then swings his legs up over the gunwale  60  and reenters the boat. 
   FIGS.  8 , and  9   
   Additional Embodiments 
   An additional embodiment is shown in  FIG. 8 . In this embodiment, a supplemental tether  6  is attached to the tether  2  of the preferred embodiment. The combination of the supplemental tether  6  and the primary tether  2  is referred to as a double tether. The supplemental tether  6  comprises a supplemental watercraft attachment device  68 , a supplemental tether strap  70 , and supplemental attachment loops  72  formed from a length of supplemental attachment loop webbing  74 . In  FIG. 8 , the supplemental watercraft attachment device  68  is a snap hook. The supplemental tether strap  70  is preferably high strength webbing approximately 2.5 cm in width. The supplemental tether strap  70  is attached to the supplemental watercraft snap hook  68  by passing the supplemental tether strap  70  through the snap hook  68 , doubling the supplemental tether strap  70  back onto itself, and securing with stitching of a sufficient length to withstand the shock load imposed by a crew falling overboard. The stitching pattern shown in  FIG. 3  and having a length of 14 cm is preferred. Preferably, the thread used for stitching is resistant to degradation by ultraviolet light  30 . Supplemental attachment loops  72  are formed by gathering a length of supplemental attachment loop webbing  74  approximately 2.5 cm in width. The supplemental attachment loop webbing  74  preferably is secured to the supplemental tether strap  70  with stitching between the supplemental attachment loops  72 . Preferably, the thread used for stitching is resistant to degradation by ultraviolet light  30 . The stitching between the supplemental attachment loops  72  is of a sufficient length to support the weight of a crew overboard. The stitching pattern shown in  FIG. 2  and having a length of 5 cm is adequate for this purpose. The end of the supplemental tether strap  70  distal to the supplemental watercraft snap hook  68  preferably is attached to the primary tether strap  22  with stitching of sufficient length to withstand the shock load imposed by a crew falling overboard. The thread used for stitching is preferably resistant to degradation by ultraviolet light  30 . The stitching pattern shown in  FIG. 3  and having a length of 14 cm is preferred. The location of the attachment of the supplemental tether strap  70  to the primary tether strap  22  is chosen to provide the crew with a desired mobility as will become apparent in the following description of operation. However, the distance between the crew attachment device  28  and the supplemental watercraft attachment device  68  should not exceed the length of the primary tether  2 . 
   The advantage of the double tether is that it allows a crew to move about the watercraft while remaining attached to the watercraft at all times. To use the double tether, the crew attaches the watercraft attachment device  20  to a hard point on the watercraft such as a pad eye and the crew attachment device  28  to the crew&#39;s harness. To keep the supplemental tether  6  out of the way, the crew may elect to attach the supplemental watercraft attachment device  68  to the pad eye, watercraft attachment device  20 , or attachment loop  24 . To change the location of attachment of the double tether, the crew attaches the supplemental watercraft attachment device  68  to a hard point on the watercraft disposed distal to the point of attachment of the watercraft attachment device  20 , and detaches the watercraft attachment device  20  from its point of attachment. In a crew overboard situation, the ascension device  4  is attached to either the primary tether  2  or the supplemental tether  6  thus supporting the weight of the crew. The ascension device  4  is then utilized as described in the preferred embodiment of the invention. 
   Referring to  FIG. 9 , another embodiment is shown in which the length of the ascension device is adjustable. In this embodiment, the ascension device of the preferred embodiment  4  is replaced by a buckle tether  8  and an adjustable ascension device  10 . The buckle tether comprises an ascension device attachment apparatus  32 , an upper elongate flexible tensile member  78 , and a buckle  80 . In  FIG. 9 , the ascension device attachment apparatus  32  is a snap hook located at the uppermost end of the upper elongate flexible tensile member  81 . The upper elongate flexible tensile member  78  is preferably webbing approximately 2.5 cm in width and of a sufficient strength to support the weight of a crew overboard. The upper elongate flexible tensile member  78  is attached to the ascension device attachment apparatus  32  by looping the upper elongate flexible tensile member  78  through the ascension device attachment apparatus  32 , doubling the upper elongate flexible tensile member  78  back onto itself, and securing with stitching of a sufficient length to support the weight of a crew. Preferably, the thread used for stitching is resistant to degradation by ultraviolet light  30 . A stitching pattern having a length of 14 cm as shown in  FIG. 3  is adequate for this purpose. The lowermost end of the upper elongate flexible tensile member  82  distal to the buckle tether ascension device attachment apparatus  32  is preferably attached to a buckle  80  by looping the upper elongate flexible tensile member  78  through the buckle  80 , doubling the upper elongate flexible tensile member  78  back onto itself, and securing with stitching of a sufficient length to support the weight of a crew. Preferably, the thread used for stitching is resistant to degradation by ultraviolet light  30 . Stitching identical to that used to attach the ascension device attachment apparatus  32  to the upper elongate flexible tensile member  78  is preferred. The length of the buckle tether  8  is minimized so as to maximize elevation of the ascension device stirrups  36 ,  38 ,  40 ,  42  with respect to the tether  2 . The adjustable ascension device  10  is identical to the ascension device  4  of the preferred embodiment except that the ascension device attachment apparatus  32  of the preferred embodiment is eliminated and the length of the lower elongate flexible tensile member  84  determined so that a crew overboard in the water can access both the lowermost stirrup  36  and the ascension device uppermost bitter end  86 . 
   Prior to use of the adjustable ascension device  10 , the ascension device uppermost bitter end  86  is looped through the buckle  80  and the length of the uppermost bitter end  86  adjusted so that a crew can reach both the lowermost stirrup  36  and the ascension device uppermost bitter end  86  while in the water. The adjustable ascension device  10  and buckle tether  8  are then stowed in a storage means  52  attachable to the crew. In a crew overboard situation, the crew retrieves the adjustable ascension device  10  and buckle tether  8  from the storage means  52 , attaches the ascension device attachment apparatus  32  to the highest attachment loop  24  he can reach on the tether  2 , and adjusts the height of the stirrups  36 ,  38 ,  40 ,  42  by pulling on the ascension device uppermost bitter end  86  to provide maximum elevation while maintaining access to the lowermost stirrup  36 . The crew overboard then ascends the adjustable ascension device  10  as he would the ascension device  4  of the preferred embodiment. 
   Alternative Embodiments 
   A variety of alternative embodiments are made possible by substitution of components having the same function as those described in detail above. Additional alternative embodiments become evident when one considers the current state of the art in marine tether design. 
   Numerous existing attachment means can be substituted for the snap hooks  20 ,  28 ,  32 ,  68  terminating the ends of the tether and the ascension device. Two examples shown in  FIG. 10  are the snap shackle  88  and the carabiner  90 . Proprietary snap hooks and safety hooks having various closure systems are also commercially available. Advantages range from quick release to prevention of accidental release. 
   One disadvantage associated with the use of tethers is that they can snag on equipment thus impeding movement. To minimize the snagging of either the tether or ascension device, one alternative embodiment employs elastic to shorten the tether or ascension device. As shown in  FIG. 9 , an extended elastic cord  92  is attached to the tether webbing  22  so that when tension is released from the tether, the effect of the elastic cord is to shorten the tether. Alternatively, the elastic cord may be threaded through the internal cavity of a tether made from tubular webbing and secured at regular intervals with stitching. 
   Another alternative embodiment involves modification of the stirrup. In this case, the tube serving as a stirrup spreader  46  is replaced by a semi-rigid strip of material sewn onto the stirrup. The semi-rigid strip has enough longitudinal stiffness to maintain the stirrup in an open position. 
   Another alternative embodiment entails the use of buoyant material for the stirrup spreaders  46 . 
   Another alternative embodiment is shown in  FIG. 11 . In this embodiment, the ascension device comprises a ladder  12  with an ascension device attachment apparatus  32  at its top. The rungs  94  of the ladder may be constructed of either a rigid or flexible material. Examples of suitable flexible materials include webbing or rope. Rigid materials might include molded plastic, reinforced plastic, or wood. The vertical elongate flexible members of the ladder  96  are made from a flexible material such as rope or webbing so that the ladder may be stored compactly upon one&#39;s person. In  FIG. 11 , a single piece of rope is used. Support of rungs  94  is accomplished by knotting the rope below holes in each end of the rungs  94  through which the rope passes. A vertical spacing between rungs of approximately 30 cm is suitable. Distance between the uppermost rung and the ascension device attachment apparatus  32  is approximately 95 cm. 
   Yet another embodiment is shown in  FIG. 12 . In this embodiment, the tether straps  22 ,  70 , the elongate flexible tensile member  34 , the attachment loops  24 ,  72 , or the stirrups  36 ,  38 ,  40 ,  42  are replaced with rope or line  98  having an essentially circular cross section. In this embodiment, splices  100  are used to create attachment loops  106  and stirrups  102 . Additional splices  100  are then used to join the attachment loops  106  to the tether  104  and the stirrups  102  to the elongate flexible tensile member  108 . The lengths of the tether, the elongate flexible tensile member, stirrup perimeters, and spacing, between stirrups are identical to those specified for the preferred embodiment. By replacing stitching with splices, one need not be concerned with degradation of stitching by ultraviolet light. In yet another embodiment, eye splices are supported by thimbles to minimize chafing of ropes or lines with circular cross section. 
   In an additional embodiment, the tether straps  22 ,  70 , the elongate flexible tensile member  34 , attachment loops  24 ,  72 , or stirrups  36 ,  38 ,  40 ,  42  are replaced with cable. In this case, the required loops in the cable are secured with crimped sleeves or wire rope clamps. 
   The reader will recognize that additional alternative embodiments are possible by varying the distance along the tether straps  22 ,  70  over which the attachment loops  24 ,  72  extend, the spacing between attachment loops  24 ,  72 , the number of attachment loops  24 ,  72 , the size of attachment loops  24 ,  72 , the symmetry of the placement of attachment loops  24 ,  72  along the tether straps  22 ,  70 , or the length of the tether straps  22 ,  70 . Likewise, additional alternative embodiments are possible by varying the distance along the elongate flexible tensile member  34  over which the stirrups  36 ,  38 ,  40 ,  42  extend, the spacing between stirrups  36 ,  38 ,  40 ,  42 , the number of stirrups  36 ,  38 ,  40 ,  42 , the size of stirrups  36 ,  38 ,  40 ,  42 , the symmetry of the placement of stirrups  36 ,  38 ,  40 ,  42  along the elongate flexible tensile member  34 , the length of the elongate flexible tensile member  34 , or the distance between the ascension device attachment apparatus  32 , and the uppermost stirrup  42 . 
   Advantages 
   From the description above, a number of advantages of my crew overboard self recovery device become evident: 
   (a) the crew overboard self recovery system provides the means for a crew overboard to ascend to the level of the gunwale and reenter the boat; 
   (b) the crew overboard does not require assistance from others to reenter the boat; 
   (c) because leg strength is used to power the crew overboard self recovery system, persons of average strength can use the system effectively; 
   (d) because the crew overboard self recovery system also functions as a tether, the crew overboard is attached to the boat at all times; 
   (e) because the crew overboard self recovery system deploys at the location of the crew overboard, there is no need to swim to a remote ladder or trailing line; 
   (f) the crew overboard self recovery system does not require additional hardware to be mounted on the boat; 
   (g) because leg strength is used, the crew overboard can overcome the drag on himself resulting from the forward motion of the boat through the water; 
   (h) all components of the crew overboard self recovery system are worn by the user; 
   (i) the crew overboard recovery system weighs little more than a standard tether with the result that it is likely to be worn; 
   (j) the crew overboard self recovery system is easy and inexpensive to manufacture. 
   CONCLUSION, RAMIFICATIONS, AND SCOPE 
   Accordingly, the reader will see that the crew overboard self recovery system of this invention can be used by a crew overboard to ascend a freeboard in excess of his reach above the water and to reenter a boat unassisted by others. Furthermore, the crew overboard self recovery system has the additional advantages in that
         Because of its construction, a person of average strength can use the system;   The crew overboard is attached to the boat at all times;   There is no need to swim to a remote ladder or trailing line;   No additional hardware need be mounted on the boat;   Because the crew overboard is able to overcome drag induced by the relative motion of his body and the water, drownings resulting from drag are minimized;   All components of the system are close at hand because they are worn by the user;   The light weight of the system makes it no more cumbersome than a standard tether;   Manufacture is simple and inexpensive.       

   Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, webbing can be replaced by rope or cable, rope by webbing or cable, and cable by webbing or rope, etc. 
   Snap hooks can be replaced by snap shackles and snap shackles by carabiners, etc. Cross sectional geometry of tether or ascension device components, attachment means, etc. may be altered to enhance functional characteristics, aid in manufacturability, or because of availability as in the case of off the shelf items. Anti-chafe devices such as thimbles may be added to improve the reliability of the design, etc. 
   Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.