To provide a motorboat having good high-speed operational stability and a small turning radius function and an off-road motorbarrow.

A motorboat equipped with wings is constructed in such a manner that wings 9a and 9b having auxiliary wings 7a and 7b and hoist rudders 8a and 8b and a boat main body 5 having a rudder 10 and rear float 11a and 11b are supported in cantilever on the shaft of a front 4 having an internal combustion engine 1 and a screw 2 arranged by buffer devices 6a and 6b so as to be freely rotated and the boat main body 5 is floated with the shaft of the front float 4 as a fulcrum and direction-changed freely by the operation of an operation stick 12. A motorbarrow equipped with a wings is constructed in such a manner that a barrow main body having wings 9a and 9b of the same structure as those of the motorboat equipped with the wings and an auxiliary wheel is supported in cantilever on a barrow having an internal combustion engine and a driving force transmission arranged in front of an axle with the axle as a fulcrum by a buffer device.