Abstract: A jack comprising a cylinder and a piston, the piston being reciprocal in the cylinder by means of pressure fluid. A piston rod extends out through an end wall of the cylinder. An abutment is fixed to the cylinder or connected to the piston rod. A restricting member, connected to the piston rod or the cylinder, is axially displaceable thereon for engagement with the abutment in any relative position between the piston and the cylinder. A locking device can be connected to the cylinder or the restricting member to lock the latter when engaging the abutment.

Abstract: A method of loading and unloading a vessel with heavy objects whereby an object is vertically lifted, for instance from a vehicle drivable on a quay, by means of a crab, gantry or the like which together with said object is moved horizontally along girders from the lifting position to a position above the hold of the vessel. Said girders are arranged on the quay, extending in a cantilever manner out beyond the edge of the quay substantially up to the adjacent edge of the hold. From said cantilever girders the crab together with the object is moved over to and along horizontal extensions of said girders. These extensions, which are entirely supported by the vessel, bridge the hold. When the crab with the object has reached a suitable position on said extension and above the hold, the object is lowered into the hold. Also described is an equipment intended for carrying out said method into effect.