Semi-rigid inflatable watercraft

Abstract

A semi-rigid inflatable boat ( 10 ), or “S-RIB”, comprising permanently interconnected inflatable gunwale ( 12 ), a flexible bow hull ( 18 ) portion and a rigid hull ( 18 ) portion located aft of the flexible bow hull portion ( 18 ). The S-RIB may additionally comprise a flexible hull portion ( 18 ) located aft of the rigid hull portion ( 16 ). The flexible hull portions ( 18 ) are suitably inflatable, and in certain embodiments comprise an air cell structure, but in preferred embodiments, comprise a drop-stitch structure, which renders them substantially rigid when inflated.

1 - 33 . (canceled) 
     
     
         34 . A semi-rigid inflatable boat, comprising:
 a hull and   an inflatable gunwale, the hull comprising a rigid hull portion and a flexible bow hull portion, the rigid hull portion being located aft of the flexible bow hull portion, and the inflatable gunwale, rigid hull portion and flexible bow hull portions of the semi-rigid inflatable boat being permanently interconnected.   
     
     
         35 . The semi-rigid inflatable boat of  claim 34 , further comprising a flexible hull portion located aft of the rigid hull portion. 
     
     
         36 . The semi-rigid inflatable boat  claim 35 , wherein the flexible hull portion comprises an inflatable hull portion, comprising an air cell structure. 
     
     
         37 . The semi-rigid inflatable boat of  claim 35 , wherein the flexible hull portion comprises an inflatable hull portion comprising a drop-stitch structure. 
     
     
         38 . The semi-rigid inflatable boat of  claim 37 , wherein the drop-stitch structure comprises a pair of spaced-apart, flexible skins interconnected, at intervals, by space yarns. 
     
     
         39 . The semi-rigid inflatable boat of  claim 38 , comprising a drop-stich construction floor, which when inflated, forms a hard, rigid surface in the bottom of the boat, the floor comprising either: a parallel-sided drop-stich panel comprising a planar upper surface and a planar lower surface, and further comprising a keel interposed between the planar lower surface and a flexible skin extending between lower portions of the inflatable gunwales, whereby the keel defines the profile of the underside of the boat; or a profiled drop-stich panel comprising a planar upper surface and a profiled lower surface defining the profile of the underside of the boat. 
     
     
         40 . The semi-rigid inflatable boat of  claim 39 , wherein floor comprises a plurality of interconnected, coplanar floor panels. 
     
     
         41 . The semi-rigid inflatable boat of  claim 34 , wherein the inflatable gunwale comprises an air-cell structure comprising a closed-ended tube that surrounds the bow and sides of the boat, and optionally the stern of the boat. 
     
     
         42 . The semi-rigid inflatable boat of  claim 41  wherein the inflatable gunwale comprises a number of independently-inflatable gunwale portions. 
     
     
         43 . The semi-rigid inflatable boat of  claim 35 , wherein the flexible hull portion comprises a waterproof sheet spanning a front section of the boat between the gunwales. 
     
     
         44 . The semi-rigid inflatable boat of  claim 43 , wherein the rigid and flexible hull portions seal to an underside portion of the inflatable gunwale. 
     
     
         45 . The semi-rigid inflatable boat of  claim 35 , wherein the flexible hull portion comprises a flange portion adhered to a lower portion of the gunwales using a waterproof adhesive, the flange having a curved profile that matches that of the inflatable gunwale, thereby providing a mating surface for sealingly bonding the rigid hull portion to the gunwale using a waterproof adhesive, and optionally comprises a further portion that overlaps the rigid hull portion and which is bonded to the rigid hull portion by a waterproof adhesive. 
     
     
         46 . The semi-rigid inflatable boat of  claim 34 , wherein the rigid hull portion comprises a modular assembly to which the gunwale and flexible hull portion can be sealingly affixed, the modular assembly comprising a lower rigid hull portion forming a chassis to which is affixed, a propulsion system, a steering system, a fuel tank and controls for the propulsion and steering systems. 
     
     
         47 . The semi-rigid inflatable boat of  claim 34 , wherein the rigid hull portion further comprises an upper rigid hull portion affixed to the lower rigid hull portion forming a cavity therebetween for housing the propulsion system, steering system, fuel tank and controls. 
     
     
         48 . The semi-rigid inflatable boat of  claim 37 , wherein the upper rigid hull portion comprises an integrally formed seat, or driver's console. 
     
     
         49 . The semi-rigid inflatable boat of  claim 34 , wherein the rigid hull portion comprises a propulsion system, being an inboard engine, connected to a screw propeller via propeller shaft and gearbox; or arranged to drive the impeller of a jet propulsion system. 
     
     
         50 . The semi-rigid inflatable boat of  claim 35 , wherein at least a portion of the jet propulsion system is formed integrally with the rigid hull portion. 
     
     
         51 . The semi-rigid inflatable boat of  claim 35 , wherein the inboard engine comprises a closed loop cooling system comprising a heat exchanger forming part of a jet tube or a steering nozzle of the jet propulsion system. 
     
     
         52 . The semi-rigid inflatable boat of  claim 34 , wherein the rigid hull portion is at least partially manufactured from sheet plastics such as vacuum-formed plastics sheet; or glass- or carbon fibre-reinforced plastics. 
     
     
         53 . The semi-rigid inflatable boat of  claim 34 , wherein the rigid hull portion comprises a sandwich structure comprising a polymer foam layer, or a honeycomb layer, interposed between external and internal skins of sheet plastics.