Patent Publication Number: US-7721671-B2

Title: Bracing for collapsible boat

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to collapsible boats, such as those formed by panels hinged together. More particularly, the invention relates to a method for bracing such boats when in an erected configuration to provide stiffness and rigidity. 
   It is known to provide collapsible boat hulls, comprising a pair of hingedly interconnected bottom panels and a pair of side panels hinged to the bottom panels. Such boats can be collapsed and folded along the hinging edges of the panels into a substantially flat configuration for ease of transport and storage, and then erected into a suitable hull shape for use on water. Typically, collapsible boat hulls are also provided with a stern member functioning as a transom, a bow member, and seats which are mounted onto the boat hull when the boat hull is in an erected configuration. It is important that the junction between the boat hull and the bow member, and the boat hull and the stern member, are leak-proof. Provision is generally also made to mount an outboard motor on the stern member. Some collapsible boat hulls are provided with rigid stern members, while others are provided with diaphragms that can accommodate rigid panels, which rigidify and stabilise the diaphragm when an outboard motor is mounted thereon. The stress exerted on the boat hull by the outboard motor mounted on the stern members, however, has meant that it has not generally been possible to use outboard motors whose power exceeds about 4 horsepower. 
   In a traditional boat design, rigidity and stiffness including torsional stiffness are largely achieved by the provision of ribs extending laterally across the hull of the boat. These provide lateral support, complementing the longitudinal support provided by stringers, the hull panels and strakes in the hull and thus strengthening the hull in two dimensions. As a result, stiffness and rigidity of the hull is established, particularly in response to torsional forces. 
   In a collapsible boat, it has not proved possible to include ribs in the same way, although attempts have been made. As a result, many collapsible boats have a limited capacity to resist twisting as a result of torsional forces. 
   One method employed to provide bracing in collapsible boats is to use seats of the boat for this purpose. Such bracing is largely ineffectual, as the seat is spaced from the boat hull, and has no direct connection to panels at the base of the boat or to the transom. 
   A degree of torsional stiffness can be gained near a boat&#39;s transom by coupling of the transom to each of the panels. Typically, the transom of a collapsible boat is a removable member. A suitable coupling arrangement can be complex, and make assembly of the boat more difficult. 
   The present invention seeks to provide a means for bracing a collapsible boat which overcomes, at least in part, some of the above mentioned disadvantages. 
   SUMMARY OF THE INVENTION 
   In accordance with a first aspect of the present invention there is provided a collapsible boat hull comprising: a pair of bottom panels, each bottom panel having a first continuous hinge along an inner edge thereof and a second continuous hinge along an outer edge thereof; a pair of side panels, each side panel being connected to an adjacent bottom panel along a respective second continuous hinge; a stern member; and a seat, the seat providing a brace between the stern member and the side panels. 
   Preferably, the seat is V-shaped. 
   Advantageously, this permits force and vibration from an outboard motor mounted on the stern member to be transmitted to the side panels. 
   In accordance with a second aspect of the present invention there is provided a means for bracing a collapsible boat, the boat having two sides and at least one bottom panel, the means for bracing including a first member which extends between one side of the boat and the other, and at least one second member, the at least one second member extending between a bottom panel and the first member, wherein the at least one second member restricts the movement of its associated bottom panel in at least one direction. Advantageously, this assists in restricting twisting of the boat hull when subjected to torsional forces. 
   Typically a collapsible boat will have two bottom panels. In this case, it is preferred to have two second members, one extending from each panel. 
   The first member may include protrusions extending towards the bow or stern of the boat, with the second members attaching to the protrusions. The protrusions may mount over the bow or stern of the boat, for instance over the boat&#39;s transom. 
   The first member and the bottom panel may each have receiving means for the second member. One of the receiving means, preferably on the bottom panel, may allow for the second member to be connected to the receiving means so as to be rotatable about the receiving means. The second member may be able to hook about the other receiving means, which may be a protrusion extending from the first member. 
   The second member may be rigid. It may also be of adjustable length, and able to be brought into tension when connected between the respective receiving means. 
   The first member may be a seat. In a preferred embodiment of bracing at the stern of the boat, the first member is a rear seat extending between the two sides of the boat, the seat having protrusions extending rearwardly and mounting over the boat&#39;s transom. This allows a motor to be mounted on the transom in such a way that force and vibration are transmitted through the protrusions to the seat and thence to the boat sides. The second members are connected to the bottom panels so as to be able to rotate about their connection means, and then hook over the projections. This allows the stern of the boat to be locked together in a rigid fashion. 
   Alternatively, the second members may be flexible, for instance being ropes or cables. Flexible second members may be coupled to the protrusions, and be arranged to attach to the receiving means on the bottom panel by a hook-and-loop arrangement. 
   The second member may be a composite unit, for instance composed of first cables extending downwardly from the first member and second cables extending upwardly from the bottom panels, the first and second cables being connected by a joining means. The joining means may be adjustable, and able to provide tension to the first and second cables. 
   The second cables may extend from the joining means, through the receiving means, to another at least one anchoring position. The anchoring position may be at the bow of the boat. 
   In a preferred embodiment of bracing at the bow of the boat, the anchoring position is located on a collapsible two-piece nose cone. The nose cone includes two resilient arms which, when in an assembled configuration, form a curved prow of the boat. This allows the assembled boat to be easily manipulated from the front, and also acts to minimise damage to other boats in the event of a low-speed collision. The resilient arms may have a gap between their outer ends in the assembled configuration to allow for the passing of a rope or chain between the arms. 
   The nose cone has two inwardly depending portions, which when brought together provide the anchoring position. The act of bringing the second cable into tension acts on the two parts of the nose cone, bringing them together into an erected configuration. The anchoring position may be a hook over which the second cable can be looped. 
   The first member may be a cross bar near the bow of the boat. The first cables may connect to the first member, and also to a removable bow cover to maintain the bow cover in position. The first may alternatively be the nose cone. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     It will be convenient to further describe the invention with reference to the accompanying drawings which illustrate preferred embodiments of the bracing of the present invention. Other embodiments are possible, and consequently, the particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention. In the drawings: 
       FIG. 1  is an upper perspective view of a collapsible boat hull in accordance with a first embodiment of the present invention, shown in an erected configuration; 
       FIG. 2  is a side view of the collapsible boat hull of  FIG. 1 , shown in a collapsed and folded configuration; 
       FIG. 3  is a top plan view of the collapsible boat hull of  FIG. 1 ; 
       FIG. 4  is a side elevation view of the collapsible boat hull of  FIG. 1 ; 
       FIG. 5  is a front elevation view of the collapsible boat hull of  FIG. 1 ; 
       FIG. 6  is a rear elevation view of the collapsible boat of  FIG. 1 ; 
       FIG. 7  is an exploded diagrammatic view of a side panel and a bottom panel of the collapsible boat hull of  FIG. 1 . 
       FIG. 8  is a plan view of a boat having bracing in accordance with a second embodiment of the present invention; 
       FIG. 9   a  is a partially cut away view of a boat having bracing in accordance with a third embodiment of the invention; 
       FIG. 9   b  is an enlarged cut away view of the stern of the boat of  FIG. 9   a;    
       FIG. 10   a  is a partially cut away view of a portion of a boat having bracing in accordance with a fourth embodiment of the invention; 
       FIG. 10   b  is an alternative cut away view of a portion of the boat of  FIG. 10   a;    
       FIG. 11  is a cross sectional view of the bow of the boat of  FIG. 8 , showing bracing in accordance with a fifth embodiment of the invention; 
       FIG. 12  is a cut away view of the bow of the boat of  FIG. 11 ; 
       FIG. 13  is an enlarged cut away view of a portion of the bow of the boat of  FIG. 11 ; 
       FIG. 14   a  is a perspective of a two-piece nose cone from the bow of the boat of  FIG. 8  shown in an assembled configuration; and 
       FIG. 14   b  is a perspective of the nose cone of  FIG. 14   a  shown during collapsing. 
   

   DESCRIPTION OF PREFERRED EMBODIMENT(S) 
   Referring to  FIGS. 1 to 7 , there is shown a collapsible boat hull  10  comprising a pair of side panels  12 , a pair of bottom panels  14 , a stern member  16 , and a bow member  18 . Each bottom panel  14  has a first continuous hinge  20  along an inner edge thereof, and a second continuous hinge  22  along an outer edge thereof. In the embodiment of the drawings, each of the first continuous hinges  20  is connected to respective first and second sides of a centrally disposed keel member  24 . In an alternative keel-less embodiment of the invention, the two bottom panels  14  are connected along a single common first continuous hinge  20 . 
   Each bottom panel  14  is connected to a corresponding side panel  12  along its second continuous hinge member  22 . Spines of each of the first and second continuous hinge members  20 , 22  have resilient flexibility along respective longitudinal and transverse planes thereof, thereby facilitating the bottom and side panels  14 ,  12  to be collapsed and folded from a first position wherein the boat hull  10  is in an erected configuration shown in  FIG. 1  to a second position wherein the boat hull  10  is in a collapsed and folded state as shown in  FIG. 2 . 
   The side and bottom panels  12 ,  14  are made from stiff, lightweight materials that have high tensile strength and resist abrasion. Typically, the side and bottom panels  12 ,  14  are made from a composite fibreglass material. Alternatively, the side and bottom panels  12 ,  14  may be made from a marine grade aluminium honeycomb closed cell composite panel of approximately 10 mm width, such as a 5052 HR A1 composite panel, or a heavy duty alternative such as kevlar and polypropylene. These may be a combination of composite or honeycomb structures. 
   Preferably, the rigidity of the material is such that when the boat hull  10  is in the erected configuration, the boat hull  10  is almost rigid and rides very well in the water. 
   Further, the side and bottom panels  12 ,  14  could also be made from a rigid and/or composite aluminium, plywood or plastics materials, with high tensile strength and abrasion resistivity. 
   The keel member  24  is substantially flat and elongate. It is arranged to be longitudinally aligned along the keel line of the boat hull  10 . The keel member  24  may be made from any suitable rigid or semi-rigid material including metal, plastics or wood having sufficient flexibility from a mid-ship line  1  (see  FIG. 7 ) forward to the aft of the boat hull  10  to form a compound curve toward the bow increasing its curvature and tension to partly form a unique bow shape while the boat hull  10  is being erected. 
   Each side panel  12 , shown in isolation in  FIG. 7 , is substantially flat and elongate having an inner surface  26 , an outer surface  28 , a gunwale edge  30 , an inner edge  32 , an aft edge  34 , and a fore edge  36 . The gunwale edge  30  of the side panel  12  is shaped to define a first continuous convex curve  38  descending from the aft edge  34  to the fore edge  36 , as shown in  FIG. 7 . A descent of the first continuous convex curve  38  becomes steeper from about the mid-ship line  1  towards the fore edge  36 . 
   The inner edge  32  of the side panel  12  is shaped to define a second continuous convex curve  40  descending from the aft edge  34  to the fore edge  36 , as shown in  FIG. 7 . A descent of the second continuous convex curve  40  becomes steeper from about the mid-ship line  1  towards the fore edge  36 . The descent of the second continuous convex curve  40  is greater than the descent of the first continuous convex curve  38  such that the side panel  12  is asymmetrically disposed about a central longitudinal plane A-A of the side panel  12 . Accordingly, the fore edge  36  is shorter in length than the aft edge  34 , and the fore edge  36  is disposed asymmetrically about the central longitudinal plane A-A towards to the gunwale edge  30 . 
   Typically the aft edge  34  is disposed at substantially right angles to the gunwale edge  30  and the inner edge  32 . However, the angle may vary by as much as ±20°. The aft edge  34  is substantially symmetrically disposed about the central longitudinal plane A-A of the side panel  12 . 
   The depth of the side panel  12  may be varied from the gunwale edge  30 . 
   Each bottom panel  14 , shown in isolation in  FIG. 7 , is substantially flat and elongate having an inner surface  42 , an outer surface  44 , an inner edge  46 , an outer edge  48 , an aft edge  50 , and a fore edge  52 . 
   The inner edge  46  of the bottom panel  14  is shaped to define a substantially straight longitudinally disposed portion  54  between the aft edge  50  and about the mid-ship line  1 , and a third continuous convex curve  56  descending from about the mid-ship line  1  to the fore edge  52 , as shown in  FIG. 7 . The outer edge  48  of the bottom panel  14  is shaped to define a fourth continuous convex curve  58  which flares outwardly from the aft edge  50 , reaching its maximum outward extent at a point rearwardly disposed of the mid-ship line  1 , then descends from about the mid-ship line  1  to the fore edge  52 , as shown in  FIG. 7 . The difference in shapes of the inner edge  46  and outer edge  48  mean that the bottom panel  14  is asymmetrically disposed about a central longitudinal plane B-B of the bottom panel  14 . 
   Accordingly, the fore edge  52  is shorter in length than the aft edge  50 . Typically the fore edge  52  is rearwardly inclined from the outer edge  48  by about 20°, although this may vary by ±20°. 
   Typically the aft edge  50  is disposed at substantially right angles to the inner edge  46  and the outer edge  48 . The aft edge  50  is substantially symmetrically disposed about the central longitudinal plane B-B of the bottom panel  14 . 
   The width of the bottom panel  14  may be varied from the inner edge  46 . 
   It is envisaged that the length of the collapsible boat hull  10  of the present invention could vary from about 2 m to 8 m in length. The shape of the side and bottom panels  12 ,  14  are adapted such that when the collapsible boat hull  10  is in the erected configuration, the side panels  12  bend inwardly and the bottom panels  14  bend upwardly such that the stern of the boat hull  10  is raised above the stern of the boat hull  10 , as in a conventional small boat hull. Accordingly, the collapsible boat hull  10  handles very well in the water when it is in the erected configuration. 
   The side and bottom panels  12 ,  14  are shaped such that as the boat hull  10  is opened from its folded configuration, each side panel  12  provides a tensile force to its corresponding bottom panel  14  and vice versa. This tensile force causes portions of the bottom panels  14  from about the mid-ship line  1  to the aft edges  46  thereof to be directed upwardly in a continuous curve, as shown in  FIG. 4 , and respective portions of the side panels  12  from about the mid-ship line  1  to the aft edge  34  thereof to form a concave curvature to define the sides of the boat hull  10 . In this way, the boat hull  10  is afforded a conventional shape, rather than the flat-bottomed hull or variations of cathedral designs and gull wing designs generally available in prior art collapsible boat hulls. 
   The bottom panels  14  are interconnected to the opposing sides of the keel member  24  along the whole length of the bottom panels&#39;  14  inner edges  42  by the pair of first continuous hinges  20 . The wings of the first continuous hinges  20  are fastened to the outer surface  44  of the bottom panels  14  and the opposing sides of the keel member  24  by suitable fastening means such as rivets or screws, together with an adhesive/sealant. The outer edge  48  of each bottom panel  14  is interconnected along its whole length to the inner edge  32  of a corresponding side panel  12  by a second continuous hinge  22 . The wings of each second continuous hinge  22  are fastened to respective outer surfaces  44 , of corresponding bottom and side panels  14 ,  12  with suitable fastening means such as rivets or screws, together with an adhesive/sealant. The first and second continuous hinges  20 ,  22  are made from a plastics material, the spines thereof being typically a plasticised membrane of a co-polymer material and the wings thereof being typically a PVC material which provide a water-tight seal along the length of each of the first and second continuous hinges  20 ,  22 . 
   The bow member  18  is shaped to substantially cap a space defined by the fore edges  36 ,  52  of the side and bottom panels  12 ,  14  and the keel member  24  when the boat hull  10  is in the erected configuration. The bow member  18  is generally rigid and can be formed as an integral member from a moldable material such as fibreglass or suitable plastics material. Alternatively, it can be formed as a frame covered with waterproof fabric membranes, such as canvas, sailcloth, or vinyl fabrics such as RipStop™. 
   The bow member  18  can be provided with a sealing means to provide a waterproof seal between the bow member  18  and the fore edges  36 ,  52  of the side and bottom panels  12 ,  14  and the keel member  24  when the bow member  18  is capped therearound. 
   Generally, the bow member  18  is releasably fastened to the boat hull  10  by means of resilient tensioning straps  60  or clips secured to receiving means  62  provided on an outer surface  28  of the side panels  12 . 
   The stern member  16  is shaped to substantially fit a space defined by the aft edges  34 ,  50  of the side and bottom panels  12 ,  14  and the keel member  24  when the boat hull  10  is in the erected configuration. In a preferred embodiment of the invention, the stern member  16  comprises a membrane  64  which provides a waterproof seal across the aft edges  34 ,  50  of the side and bottom panels  12 ,  14 , and a removable, rigid transom member  66  which locates outside the membrane  64  when the boat hull  10  is in the erected configuration. 
   The membrane  64  is preferably constructed of strong, flexible or semi rigid materials such as vinyl or suitable plastics such as polypropylene. 
   The transom member  66  may be shaped and adapted for mounting of short or long shaft outboard motors thereon in accordance with well known principles. 
   The stern member  16  further includes a removable supporting member  68  located internally of the membrane  64 . Each of the side panels  12  includes a guide  70  located adjacent the aft edge  34 . The supporting member is held, in use, between the guides  70  and the membrane  64  and provides additional rigidity and protection to the membrane  64 . 
   The boat hull  10  is provided with a detachable rigid V-shaped seat  72  disposed adjacent to the stern member  16  when the boat hull  10  is in the erected configuration, with an apex  74  of the V-shaped seat  72  is rearwardly disposed relative to respective free ends  76  of the V-shaped seat  72 . The free ends  76  of the V-shaped seat member  72  are engaged, in use, by locking members  78  located on the inner surfaces  26  of the side panels  12 . 
   Preferably, the locking members  78  are spring loaded, and cooperate with catches adjacent the free ends  76  of the V-shaped seat  72  when the V-shaped seat  72  is in a desired location. 
   The angle of the apex  74  is preferably about 120°, although may range from an acute angle through to a straight seat (ie an angle of 180°). Accordingly, the length of the V-shaped seat  72  will vary according to the angle of the apex such that the free ends  76  of the V-shaped seat  72  can be engaged to respective side panels  12  of the boat hull  10 . The apex  74  of the V-shaped seat  72  can be spaced as much as 30% of the length of the boat hull  10  from the stern member  16 . Alternatively, the apex  74  can be integral with the stern member  16 . Typically, the apex  74  is provided with a rearwardly extending longitudinal strut  80  provided with suitable fastening means to facilitate interconnecting the stern member  16  and the apex  74  of the V-shaped seat  72 . 
   Accordingly, the V-shaped seat  72  acts as a brace to readily transfer the force and vibration of an outboard motor, when the outboard motor is mounted on the stern member  16 , to the side panels  12  of the boat hull  10 . In this way, an outboard motor of greater than 4 horsepower can be readily mounted on the stern member  16  and used to its full capacity without destabilising the transom member  66 , affecting the integrity of the boat hull  10 , or substantially diminishing the quality of handling of the boat hull  10  in the water. 
   The V-shaped seat  72  is typically mounted midway up the side panels  12 , but may be positioned anywhere between a location within about 20% of the inner edge  32  and a location adjacent a gunwale line of the boat hull  10 . 
   Advantageously, the V-shaped seat  72  has an ergonomic design that affords more efficient use of available space in the boat hull  10 . 
   The boat hull  10  is also provided with a detachable second seat  82  comprising an elongate member transversely disposed between the side panels  12  when the boat hull  10  is in the erected configuration. The second seat  82  is generally positioned substantially on a mid-ship line of the boat hull  10 , but it may be positioned at a location at or between about 20% of the length of the boat hull  10  fore or aft of the mid-ship line. 
   The second seat  82  is typically mounted midway up the side panels  12 , but may be positioned anywhere between a location within about 20% of the inner edge  32  and a location adjacent a gunwale line of the boat hull  10 . 
   Outer ends of the second seat  82  are engaged, in use, by locking members  84  located on the inner surfaces  26  of the side panels  12 . Preferably, the locking members  84  are spring loaded, and cooperate with catches adjacent the outer ends of the second seat  82  when the second seat  82  is in a desired location. 
   Typically the transom member  66 , the V-shaped seat  72  and the second seat  82  can be made from a rigid lightweight material including, but not limited to, composite materials, fibre glass, aluminium, plywood, rigid PVC, and rigid plastics materials. 
   Although in this embodiment of the invention the V-shaped seat  72  and the second seat  82  are engaged by locking members  78 ,  84   s , the invention envisages other fastening means which may be used. Suitable fastening means include, but are not limited to, latches and barrel bolts, stainless steel or metallic alloy male/female receptors, self latching/locking devices, and known locking devices that can be manually or automatically operated. 
   The collapsible boat hull  10  further includes a V-shaped forward bar  86  which fastens at opposed ends thereof to gunwale edges  30  between the fore edges  52  and the second seat  82 . The forward bar  86  can support a flexible spray deck if desired. 
   The collapsible boat hull  10  may optionally be provided with detachable clamp-on rollicks disposed on the gunwale line, and/or a detachable fore deck formed from flexible materials, such as mesh, vinyl, sail cloth or plastics materials to conveniently hold life jackets, safety equipment, fishing equipment, and the like. 
   Alternatively, the collapsible boat hull may have a rigid foredeck, constructed of material such as fibreglass, alloy, plywood or plastics. The rigid foredeck may be removable, and is preferably foldable for easing stowing. 
   In the collapsed and folded state, the bottom and side panels  14 ,  12  are substantially disposed contiguously upon one another as shown in  FIG. 2 . In the collapsed and folded state, the bottom and side panels  14 ,  12  may be readily inserted into a carrier bag shaped to accommodate the collapsed and folded boat hull  10 , and transported on or in a marine or land vehicle. 
   In use, from the collapsed and folded state, the bottom and side panels  14 ,  12  and the keel member  24  can be readily opened and assembled to the open configuration. In order to assist with this operation, a separating member  90  may be employed. 
   The separating member  90  comprised two elongate members  92  hingedly connected, with pins  94  extending laterally from outer ends thereof. The pins  94  are sized to located within corresponding apertures  96  in the gunwale edges  30 . A downward force applied to one of the elongate members  92  causes the pins  94  to move apart, thus forcing the side panels  12  into their erected configuration. 
   The bow member  18  is then capped around the space defined by the fore edges  36 ,  52  of the side and bottom panels  12 ,  14  and the keel member  24 , and secured therearound by securing tensioning straps  60  from the bow member  18  around receiving means  62 , or alternately by the use of latches. 
   The transom member  66  is also fitted into the space defined by the aft edges  34 ,  50  of the side and bottom panels  12 ,  14  and the keel member  24 , outside the membrane  64 . The membrane  64  may be looped over the transom member  66  and secured by releasable means such as hook and loop fasteners  88 . 
   Guide means may be used to facilitate attachment of the second seat  82  and the V-shaped seat  72  to the side panels  12  and the transom member  66  respectively by engaging the fastening means provided for that purpose. 
   Once these members, together with the forward bar  86 , are in place the separating member  90  may be removed. 
   Optionally, once the boat hull  10  is erected the outboard motor may also be mounted on the stern member  16 . Advantageously, the ready erection of the boat hull  10  in its erected configuration can be achieved in most locations, including shallow water. 
   Referring to  FIGS. 8 to 14 , there is shown a collapsible boat  110  having a bow  112  and a stern  114 . The collapsible boat  110  is formed according to the method described above. The boat  110  has two side panels: a port panel  116  and a starboard panel  118 ; and two bottom panels  120 . 
   The boat  110  has bracing means at both the bow  112  and the stern  114 . The bracing means of the stern  114  is in accordance with one embodiment of the present invention, and will be described first. 
   The stern  114  includes a first member in the form of a rear seat  122 . The rear seat  122  extends between the port panel  116  and the starboard panel  118 , and is rigidly attached to each of the side panels  116 ,  118  using a releasable connection means. 
   The rear seat  122  has two protrusions in the form of longitudinal rods  124  extending away from the seat  122  towards the stern  114 . The rods  124  mount over a transom  126  of the boat  110 . The arrangement is such that, in use, force and vibration from an outboard motor mounted on the transom  126  can be transmitted through the rods  124  and seat  122  to the side panels  116 ,  118 . This is in contrast to previous collapsible boats where the force and vibration is transferred to the boat hull through the transom  126 . 
   Second members in the form of rigid bracing rods  128  extend, in use, between each of the bottom panels  120  and a respective longitudinal rod  124 . A bracing rod  128  can be seen clearly in  FIGS. 9   a  and  9   b.    
   Each bracing rod  128  has a first connection means  130  for connection to the bottom panel  120  and a second connection means  132  for connection to the longitudinal rod  124 . 
   The first connection means  130  is substantially in the form of a hook, and is arranged to engage with a first receiving means  134  located on the bottom panel  120 . The first receiving means  134  is formed by a longitudinally extending bar above the panel  120 . When the hook  130  is engaged around the bar  134 , the bracing rod  128  is able to rotate about the bar  134  in a substantially transversely aligned, substantially vertical plane. 
   The second connection means  132  includes a hinged locking portion  136 . The hinged locking portion  136  is moveable between an open configuration and a closed configuration. When the locking portion  136  is in the open configuration, the bracing rod  128  can be freely rotated about the first receiving means  134 , from a position of being prone on the bottom panel  120  to a position where an upper end of the bracing rod  128  is resting against the longitudinal rod  124 . The hinged locking portion  136  can then be hooked over the longitudinal rod  124  and secured in position, preventing relative movement of the bracing rod  128  and the longitudinal rod  124 . It will be appreciated that the longitudinal rod  124  is acting as a second receiving means, for receiving the second connection means  132 . 
   The bracing rod  128  may also include tensioning means  138 . The tensioning means may be operable when the locking portion  136  is secured over the longitudinal rod  124 , in order to slightly reduce the length of the bracing rod  128  in order to bring it into tension. It will be appreciated that, once the bracing rod  128  is hooked onto the first receiving means  134 , locked onto the longitudinal rod  124 , and brought into tension, the bottom panel will be restricted from movement relative to the seat  122 , at least from movement away from the seat  122 . It will also be appreciated that the tension in the bracing rods  128  will be transmitted through the longitudinal rods  124  and the bottom panels  120  to provide a compressive force on the transom  126 . This acts to lock or clamp the transom in position, and prevents relative movement of the transom particularly in a vertical direction. 
   The bracing rod  128  may also be adjustable in length, for instance using an internal screw thread arrangement. 
   When both bracing rods  128  are connected and in tension, a ‘box’ force distribution is achieved at the stern  114  of the boat  110 . The stern is thus rigidly locked together. Any torsional force applied to the stern  114  of the boat  110  will act to twist the hull. Any twisting of the hull would cause lengthening of at least one of the bracing rods  128 . The tension of the bracing rods  128  thus acts to prestress them, allowing them to resist the applied forces and restrict twisting of the hull. This in turn increases the rigidity and stiffness of the boat  110  overall. 
     FIGS. 10   a  and  10   b  show bracing means at the stern  114  in accordance with a further embodiment of the invention. In this embodiment, the second members are in the form of flexible cables  228 . Each cable  228  is connected to a longitudinal rod  124  by a second connection means in the form of a sleeve coupling  232 . The cables  228  are connected to the bottom panels  120  by a hook-and-loop arrangement with the first connection means  130 . 
   Preferably, the cables  228  include provision for tensioning during use. 
   The bracing means at the bow  112  is in accordance with a further embodiment of the invention, and can be seen in  FIGS. 11 to 13   
   The bow  112  includes a first member in the form of a cross bar  142 . The cross bar  142  extends between the port panel  116  and the starboard panel  118 , and is rigidly attached to each of the side panels  116 ,  118  using a releasable connection means. The bow also includes a composite second member comprising first cables  144 , second cables  146  and a joining means  148 . 
   In the embodiment of the drawings there are three first cables  144 . Two first cables  144   a  extend downwardly from the cross bar  142  to the joining means  148 . In practice the two first cables  144   a  are two halves of a single length of cable. The third first cable  144   b  extends from a removable bow cover  150  to the joining means  148 . 
   Each of the two first cables  144   a  is connected to the cross bar  142  by a suitable receiving means. This may be releasable, or may represent a permanent connection. 
   In the embodiment of the drawings there is a single second cable  146 . The second cable  146  forms a loop through an anchoring position  152 , first brackets  154  on each bottom panel  120 , and second brackets  156  on each bottom panel  120 , and upwardly to the joining means  148 . 
   As for the first cables  144   a , the second cables  146  may be two separate lengths of rope or cable, one for each bottom panel  120 . 
   The second bracket  156  acts as a receiving means on the bottom panel  120  for the second member. 
   The anchoring positions  152  are located at the bow  112 . The collapsible boat  112  of the drawings has a collapsible, two piece nose cone  158  at the bow  112  which will be further described below. The anchoring positions  152  are located such that a tensile force applied to the positions  152 —such as by a second cable  146  in tension—acts to pull the two pieces of the nose cone  158  together. This is best seen in  FIG. 13 . The nose cone  158  may be part of the bow cover  150 . 
   The anchoring positions  152  cooperate to form a channel  153 . The second cables  146  extend from a bracket  155  at their outer end, the bracket  155  being shaped to slot within the channel  153 . 
   The joining means  148  of the embodiments of the drawings is a strap having a loop  160  at an upper end through which the first cables  144  can be secured and a hook  162  at a lower end which can accommodate the second cables  146 . The strap includes a buckle  164  for adjustment and tightening. 
   In the embodiment of the drawings, the first cables  144  are relatively rigid, with the second cables  146  being flexible ropes. When the boat is assembled, tightening of the joining means  148  by use of the buckle  164  brings the first and second cables  144 ,  146  into tension. This has the effect of locking the nose cone  158  and bow cover  150  into position. It also has the effect of restraining movement of the bottom panels  120 , in a similar fashion to the bracing of the stern  114  described above. 
   The efficacy of this arrangement in restraining movement of the bottom panels  120  is dependent to an extent on the geometry of the second cables  146 . In some configurations, where the second cable  146  is a single loop as shown in the drawings it may be desirable to include means to restrict the sliding of the rope through the brackets  154 ,  156 . The second brackets  156  and/or the first brackets  154  may also be moved away from the centre of the boat  110  towards the side panels  116 ,  118  in order to change the angle through which the tension on the cable  146  acts. 
   The two piece nose cone  158  can be best seen in  FIGS. 14   a  and  14   b . The nose cone  158  is arranged to fit over the bow  112  of the boat  110  and to provide a splash-proof seal at the bow. 
   The nose cone  158  has a prow  170  formed by two resilient arms  172 . The arms  172  are curved towards each other, to create a curved profile at the bow  112 . The curved arms  172  can thus be used as a handle for the boat  110 . Further, the resilient nature of the arms  172  means that they can serve as a ‘bumper’ for the boat  110 , preventing damage to other boats during low-speed collision. 
   Outer ends of the arms  172  are slightly spaced from each other in an erected configuration. This gap can be used for running a rope or a chain, for instance connected to a sea anchor. 
   Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.