Abstract: A mechanism is provided by which the wheels of an amphibious vehicle are simultaneously retracted or protracted for switching between a land mode and a marine mode of operation. Each of a transversely spaced pair of wheels is supported by a horizontally arranged spring and damper combination acting on at least one suspension link. Each spring and damper combination is in turn supported by a movable anchor point, the position of which determines the extent of protraction or retraction of the associated wheel. The anchor points for the two wheels may be located at opposite ends of a rotatable rocker member, the rotational orientation of which is determined by an actuator taking the form of for example a hydraulic ram or electric motor.

Abstract: Water craft or amphibious vehicle includes a hull 12 fitted with at least one elongate longitudinal keel; which may be extruded from rubber. The keel has at least one mounting formation, to engage with channel formation. The keel may be mounted directly into hull; alternatively, at least one mounting structure may comprise an extrusion; mounted into a channel in the hull. The keel may be flexible to resist damage if grounded; but is laterally stiff to aid handling on water. The keel may be slid into place longitudinally; and may be finished with a rubber end piece, protected by a further metal end piece. Both end pieces may be detachable. Keel may be foam filled; or may be inflated with fluid to alter its cross section.