Apparatus to launch and recover a boat

Abstract

Launch and recovery apparatus ( 220 ) for launching a boat ( 230 ) into water from a supporting structure ( 210 ) such as a ship comprises a cradle ( 211 ) shaped to receive and support a boat and having a cradle axis, the cradle being moveable relative to the supporting structure between a first stowed position to a second ramp position at which the boat is typically in the water, and wherein the attitude of the axis of the cradle with respect to the water is steeper that when the boat is in the stowed positions. A movement mechanism is configured to move the cradle between the first stowed position and the second ramp position, typically having a linkage mechanism guiding the movement of the cradle into the water, which can be provided in a collapsing parallelogram arrangement which controls the change in attitude of the axis of the cradle as the cradle moves between the stowed and ramp positions.

1 . An apparatus for connection to a supporting structure, for launching a boat into water from the supporting structure, and/or for recovering a boat from water to the supporting structure, the apparatus comprising:
 a cradle shaped to receive and support a boat and having a cradle axis;   the cradle being moveable relative to the supporting structure between a first stowed position to a second ramp position, wherein an attitude of the cradle axis with respect to the water changes as the cradle moves between the first stowed position and the second ramp position; and   a movement mechanism configured to move the cradle between the first stowed position and the second ramp position.   
     
     
         2 . The apparatus as claimed in  claim 1 , mounted on a vessel. 
     
     
         3 . The apparatus as claimed in  claim 1 , wherein when the cradle is in the first stowed position, the cradle axis is substantially parallel to a surface of the water. 
     
     
         4 . The apparatus as claimed in  claim 1 , wherein the cradle is movable between at least two ramp positions comprising a launch position and a recovery position, and wherein an angle of the cradle with respect to a surface of the water is greater when the cradle is in the launch position than when in the recovery position. 
     
     
         5 . The apparatus as claimed in  claim 1 , wherein the cradle is pivotally connected to the supporting structure. 
     
     
         6 . The apparatus as claimed in  claim 1 , wherein the cradle is pivotally connected to the supporting structure by a linkage mechanism comprising at least one link member pivotally connected to the cradle at one end and pivotally connected to the supporting structure at a second other end. 
     
     
         7 . The apparatus as claimed in  claim 1 , having at least two link members connected between the supporting structure and the cradle arranged in a collapsing parallelogram arrangement which controls a change in attitude of the cradle axis as the cradle moves between the first stowed position and the second ramp position. 
     
     
         8 . The apparatus as claimed in  claim 7 , wherein the parallelogram is asymmetrical and wherein the linkage mechanism raises the cradle into a substantially horizontal configuration relative to the water in the first stowed position, and lowers it into a non-horizontal configuration relative to the water in the second ramp position. 
     
     
         9 . The apparatus as claimed in  claim 1 , wherein an angle of the cradle axis with respect to the water is larger when the cradle is in the second ramp position than when the cradle is in the first stowed position. 
     
     
         10 . The apparatus as claimed in  claim 1 , wherein the cradle comprises a buoyancy element such that it is at least partially buoyant when placed in water. 
     
     
         11 . The apparatus as claimed in  claim 10 , having more than one buoyancy element in the cradle. 
     
     
         12 . The apparatus as claimed in  claim 10 , wherein the buoyancy is adjustable. 
     
     
         13 . The apparatus as claimed in  claim 1 , in which the cradle is less buoyant in the water when in the launch position than in the recovery position. 
     
     
         14 . The apparatus as claimed in  claim 1 , having a chamber adapted to be flooded during launch so that upon entering the water, the cradle falls away from the boat, which remains more buoyant in the water than the cradle. 
     
     
         15 . The apparatus as claimed in  claim 1 , wherein the buoyancy in the cradle is increased during recovery of the boat. 
     
     
         16 . The apparatus as claimed in  claim 1 , having a latch device to restrain the boat on the cradle. 
     
     
         17 . The apparatus as claimed in  claim 1 , wherein a connection between the supporting structure and the cradle allows the cradle to move passively in the water relative to the supporting structure in response to wave action in the water. 
     
     
         18 . The apparatus as claimed in  claim 1 , wherein the movement mechanism comprises a winch mechanism having a winch line connected between the cradle and the supporting structure. 
     
     
         19 . The apparatus according to  claim 18 , wherein the winch line is attached to the cradle, and wherein the movement mechanism on an inboard end of the cradle guides pivoting movement of the cradle as the winch supplies the power to lift the boat. 
     
     
         20 . The apparatus as claimed in  claim 18 , wherein the winch line is attached to the cradle at a location between the ends of the cradle. 
     
     
         21 . The apparatus as claimed in  claim 18 , wherein the winch mechanism comprises a primary winch device and a secondary winch device, each with a respective winch line, and wherein the winch lines from the primary and secondary winch devices are attached at different spaced apart locations on the cradle, at least one of the winch lines being spaced away from the inboard end of the cradle, at or near to the centre of gravity of the boat when located on the cradle. 
     
     
         22 . The apparatus as claimed in  claim 18 , wherein at least one winch line from the winch mechanism is supported from above the cradle, and extends to the cradle from a support beam located above the cradle. 
     
     
         23 . The apparatus as claimed in  claim 1 , having at least one rolling element on the cradle to reduce friction between the boat and the cradle during relative movement of the two. 
     
     
         24 . The apparatus as claimed in  claim 1 , wherein the cradle is convex and has a recess configured to receive the boat and to support a hull of the boat out of the water. 
     
     
         25 . The apparatus as claimed in  claim 1 , wherein the cradle is concave and has a protrusion configured to be received within a recess of a hull of the boat, and configured to support the hull of the boat out of the water. 
     
     
         26 . A vessel incorporating the apparatus as claimed in  claim 1 . 
     
     
         27 . A method of launching a boat into water from a supporting structure, or recovering the boat from the water to the supporting structure, the method comprising:
 supporting the boat on a cradle that is movably connected to the supporting structure via a movement mechanism; and   moving the cradle and the boat supported thereon relative to the supporting structure between a stowed position, in which the boat is out of the water, and a ramp position, in which the boat is in the water.   
     
     
         28 . The method as claimed in  claim 27 , comprising mounting the cradle on a vessel and launching and recovering the boat from and to the vessel. 
     
     
         29 . The method as claimed in  claim 27 , comprising moving the cradle between at least two ramp positions comprising a launch position and a recovery position, and wherein an angle of the cradle with respect to a surface of the water is greater when the cradle is in the launch position than when in the recovery position. 
     
     
         30 . The method as claimed in  claim 27 , comprising pivotally moving the cradle relative to the supporting structure. 
     
     
         31 . The method as claimed in  claim 27 , wherein the cradle is pivotally connected to the supporting structure by a linkage mechanism comprising at least two link members pivotally connected to the cradle at one end and pivotally connected to the supporting structure at a second end, and wherein the link members control the change in orientation of an axis of the cradle as the cradle moves between the stowed and ramp positions. 
     
     
         32 . The method as claimed in  claim 27 , comprising raising the cradle into a substantially horizontal configuration relative to the water in the stowed position, and lowering the cradle into a non-horizontal configuration relative to the water in the ramp position. 
     
     
         33 . The method as claimed in  claim 27 , comprising adjusting the buoyancy of the cradle in the water between the stowed and the ramp positions. 
     
     
         34 . The method as claimed in  claim 33 , comprising reducing a buoyancy of the cradle when the cradle is in the launch position as compared to the amount of buoyancy in the cradle when the cradle is in the recovery position. 
     
     
         35 . The method as claimed in  claim 33 , comprising flooding a chamber in the cradle during launch so that upon entering the water, the cradle falls away from the boat, which remains more buoyant in the water than the cradle. 
     
     
         36 . The method as claimed in  claim 33 , comprising increasing the buoyancy in the cradle during recovery of the boat. 
     
     
         37 . The method as claimed in  claim 27 , comprising latching the boat to the cradle in the stowed position. 
     
     
         38 . The method as claimed in  claim 27 , comprising allowing the cradle to move passively in the water relative to the supporting structure in response to wave action in the water, when the cradle is in the ramp position. 
     
     
         39 . An apparatus to launch a boat, the apparatus comprising:
 a cradle shaped to receive a boat thereon,   the cradle comprising a connecting mechanism to connect the boat with the cradle, and which may be released to release the boat from the cradle.