Rib, rigid-hull inflatable boat
BACKGROUND AND SUMMARY 
     The invention relates to a RIB, rigid-hull inflatable boat, and more particularly to improvements in hull construction and attachment. 
     A rigid-hull inflatable boat includes an inflatable tube having a generally U-shape with a forward end at the bight of the U and trailing sides extending rearwardly therefrom along the legs of the U. A hull is nested to the underside of the tube and attached thereto. The hull has an aft transom for mounting an outboard motor, and has a deck extending forwardly therefrom for supporting the occupants. Prior art hulls are typically made of fiberglass, and are formed as two clamshell halves which are then bonded to each other along a generally horizontal parting line. The assembled hull is then nested to the underside of the tube and attached thereto by tape and/or glue. 
     The present invention provides a simplified, lighter weight, lower cost hull construction. In one aspect of the invention, the fiberglass clamshell halves are eliminated, and instead a unitary rotationally molded hull is provided, preferably of polyethylene. 
     In another aspect of the invention, taping and gluing of the hull to the tube is eliminated, and instead a simple mechanical locking device is provided having a releasable clamp permitting detachment and reattachment of the tube to the hull in a simple, user-friendly manner. 
     In another aspect of the invention, a gutter system is provided for draining water from the interface between the hull and the tube, to minimize squirting of water from such interface back into the boat when the tube is squeezed or otherwise pushed against the hull. 
     In another aspect, the deck of the hull has a forward pocket-configured compartment receiving differing type fuel tanks in nested relation in the bow. In another embodiment, the deck is a substantially flat surface all the way forwardly from the transom to the bow, without a forward pocket-configured compartment. 
     In another aspect of the invention, the transom is provided with anti-compression spacers preventing collapse of the transom under transom bracket clamping pressure. In another embodiment, the top of the transom is open, and a transom board, e.g. plywood, is inserted therein. 
     In another aspect of the invention, integrally formed splash guards extend from the transom forwardly to the hull sides and strengthen the transom. 
     In another aspect, the hull sides extend rearwardly beyond the transom and include aft sections extending upwardly and then inwardly and forwardly to the top of the transom to strengthen the transom. 
     In another aspect of the invention, a drain is provided through the transom by a pair of threaded members thread tightened to each other and providing simplified sealing without gluing the drain to the transom as in the prior art. 
     In another aspect of the invention, the deck of the hull is joined to the upper reach of the concave surface of the outer sidewall by an inner sidewall extending downwardly from the upper reach and curved outwardly and below the tube and the concave surface to provide an undercut in the inner sidewall to provide a wider beam and increased floor space within the boat. 
     In another aspect of the invention, a keel board may be provided between the lower keel and the deck and have mouse holes therethrough permitting flow of material therethrough during rotational molding. 
     In another aspect of the invention, a bunge system is provided to hold the tube to the hull at the transom. 
     In another aspect of the invention, a bow eye attachment is provided by a U-bolt extending through parallel extended surfaces of the gutter drain channel and lower surface of the hull. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a RIB, rigid-hull inflatable boat, constructed in accordance with the invention. 
     FIG. 2 is a perspective view of the hull of FIG. 1. 
     FIG. 3 is a perspective view from the rear of the hull of FIG. 2. 
     FIG. 4 is a top view, partially cut away, of the RIB of FIG. 1. 
     FIG. 5 is a sectional view taken along line 5--5 of FIG. 4. 
     FIG. 6 is a sectional view taken along line 6--6 of FIG. 4. 
     FIG. 7 is a view from the front of a portion of the rear transom of FIG. 1. 
     FIG. 8 is a sectional view taken along line 8--8 of FIG. 7. 
     FIG. 9 is a sectional view taken along line 9--9 of FIG. 7. 
     FIG. 10 is a sectional view taken along line 10--10 of FIG. 7. 
     FIG. 11 is a view taken along line 11--11 of FIG. 10. 
     FIG. 12 is a sectional view taken along line 12--12 of FIG. 4. 
     FIG. 13 is a sectional view taken along line 13--13 of FIG. 4. 
     FIG. 14 is a top view of a portion of the structure of FIG. 2, and additionally shows a fuel tank nested therein. 
     FIG. 15 is a view taken along line 15--15 of FIG. 14. 
     FIG. 16 is a top view of a portion of the structure of FIG. 2, and additionally shows another type of fuel tank nested therein. 
     FIG. 17 is a view taken along line 17--17 of FIG. 16. 
     FIG. 18 is a view taken along a fore-to-aft sectional line of the structure of FIG. 2, and shows a further embodiment. 
     FIG. 19 is a sectional view taken along line 19--19 of FIG. 18. 
     FIG. 20 is a sectional view of a portion of the structure of FIG. 2, and shows an alternate embodiment. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a RIB 22, rigid-hull inflatable boat. An inflatable tube 24 has a general U-shape with a forward end 26 at the bight of the U and trailing sides 28 and 30 extending rearwardly therefrom along the legs of the U. A unitary rotationally molded hull 32, FIGS. 1-5, preferably polyethylene, is nested within the tube and attached thereto, to be described. Rotational molding, or roto-molding, is known in the art, and involves loading resin into a mold, followed by heating and fusion of the resin during biaxial rotation of the mold such that the resin material fills and forms a layer along the outer periphery of the mold inner-cavity, followed by cooling prior to unloading the mold, with the product retaining the shape of the cavity periphery, for which further reference may be had to &#34;Applications For Rotational Molding&#34;, Association of Rotational Molders, ARM-100-589, May 1989. The advantages of rotationally molding hull 32 is the lighter weight unitary construction enabled thereby, as opposed to prior heavier fiberglass assembled clamshell hulls. Rotationally molded hull 32 is a single unitary member of lighter weight than prior hulls, and eliminates the need to assemble and bond clamshell halves together. 
     Hull 32 has right and left sides 34 and 36, FIGS. 2 and 3, extending along the inner surfaces of the tube sides, and a transom 38 extending between the right and left sides 34 and 36. Integrally formed right and left splash guards 40 and 42 extend from transom 38 forwardly to respective sides 34 and 36 and strengthen the transom. Sides 34 and 36 extend rearwardly beyond transom 38 and include aft sections 44 and 45 extending upwardly and then inwardly and forwardly to the top 46 of the transom to further strengthen the transom. 
     In one embodiment, the hull, including the transom, is hollow, and anti-compression spacers 48 and 50, FIGS. 7 and 8, are provided in respective holes 52 and 54 through the transom. The anti-compression spacers prevent collapse of the transom under transom bracket clamping pressure. A stiffener board 56, FIGS. 8 and 9, e.g. plywood, is provided on the aft side of transom 38, and a mounting plate 58 is provided on the front side of the transom. Bolts 60, 62, 64, 66, 68, FIGS. 7 and 9, extend through the transom and secure stiffener board 56 and mounting plate 58 thereto. Each of the mounting bolts may include an anti-compression sleeve 70 there-around further preventing collapse of the transom. 
     In another embodiment, the hull, including the transom, is foam filled, in which embodiment the anti-compression spacers are preferably eliminated because the hardened foam has sufficient rigidity to withstand transom bracket clamping pressure. 
     In another embodiment, the top of the transom is open, FIG. 20, and a transom board 72, e.g. plywood, is inserted therein. 
     In a further embodiment, a keel board 74, FIGS. 18 and 19, extends vertically between deck 76 and lower keel 78 and spans the gap therebetween and maintains the deck and keel in spaced relation. The keel board is in the mold during rotational molding and has a plurality of mouse holes 80 therein, FIG. 19, permitting flow of the resin material therethrough during rotational molding. It is preferred that keel board 74 not be used when the hull is foam filled. 
     Deck 76, FIGS. 2 and 3, extends forwardly from transom 38 between right and left sides 34 and 36. The hull has a forward pocket-configured compartment 82 receiving one or more fuel tanks in nested relation, FIGS. 14-17. Forward compartment 82 is separated from deck 76 by a wall 84, FIGS. 2 and 3, having an opening 86 therein for drainage of water rearwardly therethrough from forward compartment 82. Forward compartment 82 has a first central lower floor 88 spaced between second and third floors 90 and 92 raised thereabove. Floor 88 receives a first type fuel tank 94, FIGS. 14 and 15, nested between floors 90 and 92. In an alternate fuel tank arrangement, floors 90 and 92 receive a second type fuel tank 96, FIGS. 16 and 17, spanning and spaced above floor 88. Floor 90 is spaced rearwardly of floor 92 by floor 88 therebetween. Floor 90 has a rearwardly extending channel 98, FIG. 2, formed therethrough and aligned with opening 86 in wall 84 and funneling water to opening 86, to drain water from floor 88 rearwardly through channel 98 in floor 90 and through opening 86 in dividing wall 84. In another embodiment, the deck is a substantially flat surface all the way forwardly from the transom to the bow, without a forward pocket-configured compartment. 
     A drain 98, FIGS. 10 and 11, extends through a hole 100, FIGS. 2 and 3, in transom 38. Drain 98 includes a pair of threaded members 102 and 104 each having an outer flange 106 and 108, respectively. Threaded members 102 and 104 are thread tightened to each other to urge flange 106 of member 102 toward the forward side of transom 38, and to urge flange 108 of member 104 toward the aft side of transom 38. Sealing O-ring 110 is compressed between flange 106 and the front side of the transom. Sealing O-ring 112 is compressed between flange 108 and the aft side of transom 38. Members 102 and 104 have a central passage 114 therethrough with a one-way valve 116 permitting drainage of water out of the boat, and blocking reverse flow of water into the boat. Valve 116 is an umbrella type flap valve having a flexible rubber disc 118 anchored by central stem 120 to the central hub 122 of a plurality of spokes 124 extending radially outwardly therefrom to the inner sidewall of member 102 and having a plurality of openings 126 therebetween through which water flows leftwardly in FIG. 10 and deflects flap type disc 118 leftwardly to permit discharge of water. A plurality of outer ribs 128 permit gripping and turning of member 102 from inside the boat to facilitate disassembly of the drain if desired. Deck 76 has a recessed floor section 130, FIG. 2, immediately forward of the drain and funneling water thereto. 
     Hull 32 is nested within tube 24 and detachably secured thereto by a mechanical locking device 132, FIG. 6, having a releasable clamp 134 permitting detachment and reattachment of tube 24 to hull 32. Locking device 132 includes a hook 136 bonded to tube 22. Clamp 134 has a first outer portion 138 engaging hook 136, and a second inner portion 140 engaging hull 32 and preferably attached thereto by a threaded bolt 142. Hook 136 is preferably a relatively hard rubber extruded member extending fore to aft along the entire length of the underside of the right side 28 of the tube. Another comparable extruded hard rubber hook member 144, FIG. 5, extends along the underside of the left side 30 of the tube. A third hard rubber extruded hook member 146, FIG. 12, extends along the underside of the front 26 of the tube and mates with the respective right and left extended hook members 136 and 144. Clamps 134, 148 and 150 are preferably plastic members extending along the length of the respective hooks 136, 144 and 146. 
     Hook 136, FIG. 6, has a post 152 extending away from tube 22. Post 152 has an outer side 154 facing outwardly away from hull 32. Side 154 has a knuckle 156 extending therefrom away from hull 32. Post 152 has an inner side 158 facing inwardly toward and engaging the hull. Clamp 134 has a middle portion 160 extending across post 152. Portion 138 of clamp 134 has a finger 162 curled around knuckle 156 and engaging hook 136 at outer side 154 of post 152 between knuckle 156 and tube 22. Hook 136 includes a base pad 164 bonded to the underside of tube 22, preferably by glue. Post 152 extends downwardly and outwardly from base pad 164. Inner side 158 of the post extends downwardly and outwardly away from the hull such that detachment of clamp 134 by unbolting same from the hull enables the hull to slide downwardly away from tube 22 along inner side 158 of post 152. This type of downward direct detachment displacement of the hull from the tube, or upward displacement of the tube from the hull, is simple and user friendly. Hooks 144 and 146 are comparable. A plurality of bolts such as 142 are spaced along the mounting system, and the user merely removes the bolts, and lifts the tube off the hull. This type of mechanical locking device having a releasable clamp permits simple detachment and reattachment of the tube to the hull. There is no gluing or taping of the tube to the hull, but rather a mechanical locking arrangement with simple detachment and reattachment orientation and separation. 
     The hull right side 34 has a concave surface 170, FIGS. 2, 3 and 5, engaging the inner underside of right tube side 28. Left hull side 36 has a concave surface 172 engaging the inner underside of left tube side 30. The front of the hull has a concave surface 174 engaging the inner underside of the front 26 of the tube. Concave surface 170 has an upper surface 176, FIG. 6, engaging the tube, and an upper surface 178 spaced outwardly of surface 176 and engaging base pad 164. The hull has an outer surface 180 extending downwardly and outwardly from surface 178 and engaging inner side 158 of post 152. The hull has a lower surface 182 extending inwardly and downwardly from surface 180 and engaging portion 140 of clamp 134. The clamp has an upper surface 184 along finger 162 engaging base pad 164. The clamp extends downwardly and inwardly from the finger along post 152 and then along surface 182 of the hull. Surfaces 176 and 178 support tube 24 and are spaced by an upper surface 186 recessed below tube 24 and forming a channel 188 therebetween, to be described. The hull has a lower surface 190 extending inwardly from surface 182 and generally parallel to surface 186. Clamp 134 spans hook 136 and has an inner portion 140 engaging the hull and an outer portion 138 engaging the outer surface of the hook 136 such that detachment of clamp 134 enables the hull to slide downwardly away from the tube along inner surface 158 of the hook. The mounting system along concave surfaces 172 and 174 is comparable. 
     The concave surfaces 170, 174, 172 engaging tube 22 extend along the U-shape thereof and have the noted recessed channel 188 extending fore to aft there-along and forming a gutter such that water flowing over the top of tube 24 and then downwardly along the interface between the tube and the hull flows into such gutter. Channel 188 is open at the aft end of the hull such that water in the gutter drains aft. As noted above, the hull is nested to the underside of the tube, and the concave surface has upper and lower sections 176 and 178 spaced by channel 188 therebetween. The hull is detachably secured to the tube by the noted mechanical locking device 132 having a releasable clamp 134 permitting detachment and reattachment of the tube to the hull, and including a hook 136 bonded to the underside of the tube. The clamp clamps the hull to the hook at the noted lower section 178 of the concave surface. The gutter formed by channel 188 extends around the perimeter of the hull in a general U-shape parallel to the U-shape of tube 24. 
     Channel 188 and the lower surface of the hull have parallel extended surfaces 192, 194, FIG. 12, at the front of the boat receiving a U-bolt 196 extending there-through, providing a bow eye attachment. Anti-compression spacers 198 and 200 extend between plates 202 and 204 on surfaces 192 and 194. 
     Concave surface 170, FIGS. 2, 3 and 5, of the outer sidewall of the hull has an upper reach 206 within the boat. Upwardly facing deck 76 of the hull is below upper reach 206 and is joined thereto by an inner side-wall 208, FIG. 5, extending downwardly from upper reach 206 and curved outwardly and below tube 24 and concave surface 170 and toward channel 188 to provide an undercut 210 in the inner sidewall 208 to provide a wider beam and increased floor space within the boat. The left inner sidewall 212 of the hull likewise extends downwardly from upper reach 214 of concave surface 172 and is curved outwardly and below tube 24 and concave surface 172 to provide an undercut 216 in inner sidewall 212. 
     Right and left mechanical clamping devices 218 and 220, FIGS. 4 and 5, releasably hold tube 24 against the right and left sides 34 and 36 of the hull at transom 38. Each clamping device includes a base pad 222, FIG. 13, bonded to tube 24, preferably by gluing, a clasp 224 mounted to the top 46 of transom 38, preferably by rivets 226, 228, and a holding member 230 extending therebetween. In the preferred embodiment, right and left bunge pads 232 and 222 are bonded to tube 24, and each mounts a respective bunge cord 234 and 230. Right and left clasps 236 and 224 are mounted to the transom and receive a respective bunge cord for holding tube 24 against hull sides 34 and 36 at transom 38. Pad 222 pivotally mounts bunge cord 230 at pivot pin 236. The bunge cord is a resilient rubber member having an enlarged end 238 received in clasp 224, which is preferably a split finger member. Bunge cord 230 has a lower knob 240 spaced between enlarged end 238 and pad 222. Knob 240 engages transom 38 and bows the central portion of bunge cord 230 upwardly away from the transom. Clamping device 218 is comparable. 
     The hull is provided with davit lifting eyes 240, 242, 244, 246, FIG. 4, bolted thereto. 
     It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.