Abstract: A vehicle stabilizing means comprising a cradle (23) supported from a mounting (17) to lie to one side of the mounting, a rotor (19) supported from the cradle between a pair of spaced supports (25) to be rotatably supported by the supports, a drive coupled to the rotor enabling the rotor to rotate at a substantially constant angular velocity, the rotor being rotatable about a first axis, the supports located to the side of the cradle remote from the mounting, the cradle further comprises a base (31) which is rotatably supported from the mounting to be rotatable around a second axis which is perpendicular to the first axis of rotation of the rotor and which intersects the first axis of the rotor, the mounting intended in use to be fixed to the vehicle such that in operation the mean orientation of the first and second axes are substantially perpendicular to the direction of the axis of stabilization.

Abstract: A hydrofoil device is useable as a hydrofoil wing, propeller blade, etc. In a water flow, a relatively lower pressure is generated on a second surface (94) of the device compared with a first surface (96). Near the trailing end of the first surface a protrusion in the form of an adjustable interceptor (98) is provided. The face of this protrusion defines an included angle to the upstream direction of less than or equal to 90° so that water flow thereat is deflected back on itself thereby increasing the local pressure on the first surface. A second protrusion may be provided near the leading edge of the second surface (94) to encourage flow separation thereat. Air may be provided adjacent each protrusion to provide natural ventilation if the pressure of the water flow drops below atmospheric pressure.