Collapsible kayak

Abstract

A flexible skin 3 is fitted over a framework 20 that includes a plurality of longitudinal stringers 50 - 58 running the length of the bottom and sides of the kayak. Each stringer 50 - 58 is assembled from several elongate segments 80 - 85 held together by an internal shock cord. Transverse formers 10 - 13 separate the stringers to define the hull outline and are releasably fixable to the stringers. Bow and stem formers 10, 13 are fixed in a manner allowing them to slide longitudinally, thereby laterally spreading and tensioning the stringers 51 - 58. Flexible tension members 73, 74 provide longitudinal bending strength and assist in shortening the framework 20 for assembly. A block 21 inserted in a joint 30′ between adjacent segments of a stringer provides a means for locking the segments in a telescopically extended position, for expanding the framework longitudinally.

What I claim is:  
     
         1 . A collapsible kayak having an internal framework and a hull, the hull comprising a water impermeable flexible skin, the framework comprising: 
 bow and stern members;    a plurality of stringers connected between the bow and stern members and running the length of the bottom and sides of the kayak, each stringer being assembled from a plurality of elongate segments;    a plurality of transverse formers approximately conforming to the transverse outline of the hull, each former being releasably connectable with each stringer;    at least one of said formers being an end former slidably connected with each stringer for laterally spreading the stringers; and    fixing means for fixing each end former longitudinally with respect to the stringers.    
     
     
         2 . A collapsible kayak as claimed in  claim 1  wherein each end former is positioned near a longitudinal end of the framework and said fixing means comprises an adjustable tension device connected between each end former and a respective bow or stern member.  
     
     
         3 . A collapsible kayak as claimed in  claim 1  wherein each joint between adjacent segments of a stringer includes: 
 a hollow axial spigot fixed at the end of a first segment;  
 an axial recess at the end of a second segment for telescopically receiving the spigot, and  
 a resilient member extending through the first and second segments for retaining the segments together.  
 
     
     
         4 . A collapsible kayak as claimed in  claim 3  further including locking means for engagement at the joint between adjacent first and second segments to lock the first and second segments in a telescopically extended position.  
     
     
         5 . A collapsible kayak as claimed in  claim 4  wherein a block is provided for insertion between annular faces on the first and second segments respectively to lock the first and second segments in a telescopically extended position, the block comprising an elongate cylindrical face for engagement with the outer surface of the spigot and longitudinally opposing ends for abutting each of the annular faces.  
     
     
         6 . A collapsible kayak as claimed in  claim 3  wherein the resilient member extends through each said joint and opposing ends of the resilient member are fixed to respective terminal segments of the stringer.  
     
     
         7 . A collapsible kayak as claimed in  claim 1  wherein each former is slidably connected with the stringers allowing the longitudinal position thereof to be varied.  
     
     
         8 . A collapsible kayak as claimed in  claim 1  wherein the formers include segment-shaped connectors for connection with the stringers, each connector having a cylindrical inner surface for engagement with a corresponding outer surface of the stringers, whereby the opening at the mouth of the connector is less than the diameter of the stringer allowing the stringer to be entered thereinto in the radial direction and retained by a snap-fit.  
     
     
         9 . A collapsible kayak as claimed in  claim 1  wherein single piece resilient bow and stem members are releasably connectable with the stringers.  
     
     
         10 . A collapsible kayak as claimed in  claim 1  wherein the framework further includes at least one forward deck stringer and at least one aft deck stringer supporting a deck of the kayak.  
     
     
         11 . A collapsible kayak as claimed in  claim 10  wherein said forward deck stringer is connected to the bow member and terminates proximate a forward end of a cockpit opening and said aft deck stringer is connected to the stem member and terminates proximate an aft end of the cockpit opening.  
     
     
         12 . A collapsible kayak as claimed in  claim 1  wherein the cockpit opening has a coaming formed from the material of the skin, a rim of the coaming comprising a sleeve for receiving a removable coaming-reinforcing rod.  
     
     
         13 . A collapsible kayak as claimed in  claim 1  wherein the framework includes two pairs of identical formers spaced in the longitudinal direction, the first pair comprising slidably fixed bow and stem end formers, the second pair comprising cockpit formers fixed either side of a cockpit opening.  
     
     
         14 . A collapsible kayak as claimed in  claim 13  wherein the cockpit formers define the maximum lateral dimensions of the framework and in the disassembled state a bow or stern end former can be nested inside each cockpit former.  
     
     
         15 . A collapsible kayak as claimed in  claim 1  further including at least one flexible longitudinal tension member connected between the bow and stem members for taking tensile loads induced by bending about an axis perpendicular to a longitudinal axis of the kayak.  
     
     
         16 . A collapsible kayak as claimed in  claim 15  including two longitudinal tension members, each being symmetrically held in locating fixtures in the formers on either side of the longitudinal axis.  
     
     
         17 . A collapsible kayak as claimed in  claim 13  wherein the skin includes longitudinally extending closures extending between the forward end of the skin and the cockpit opening, and the aft end of the skin and the cockpit opening respectively.  
     
     
         18 . A collapsible kayak as claimed in  claim 13  wherein straps fixed to at least the cockpit formers are provided for laterally tensioning the skin.  
     
     
         19 . A collapsible kayak as claimed in  claim 15  further including at least one block for insertion in the joint between adjacent first and second segments to fix the first and second segments in a telescopically extended position.  
     
     
         20 . A collapsible kayak as claimed in  claim 1  wherein the kayak may be collapsed into a bundle of a pre-determined size adapted to be readily carried in a backpack.  
     
     
         21 . A collapsible kayak as claimed in  claim 20  wherein the maximum linear dimension of the bundle is less than 1 metre and the weight of the bundle is less than ten kilograms.  
     
     
         22 . A collapsible kayak having an internal framework and a hull, the hull comprising a water impermeable flexible skin, the framework comprising: 
 bow and stem members;    a plurality of stringers connected between the bow and stem members and running the length of the bottom and sides of the kayak, each stringer being assembled from a plurality of elongate segments, each joint between adjacent segments of a stringer including: a hollow axial spigot fixed at the end of a first segment; an axial recess at the end of a second segment for telescopically receiving the spigot; a resilient member extending through the first and second segments for retaining the segments together, and locking means for locking the first and second segments in a telescopically extended position;    a plurality of transverse formers approximately conforming to the transverse outline of the hull, each former being releasably connectable with each stringer;    at least one of said formers being an end former slidably connected with each stringer for laterally spreading the stringers;    fixing means for fixing each end former longitudinally with respect to the stringers, and    at least one flexible longitudinal tension member connected between said bow and stem members for taking tensile loads induced by bending about an axis perpendicular to a longitudinal axis of the kayak.