Abstract: Panels constructed from a light weight core bonded to specially shaped perimeter members such that the vertical members overlap and interlock with similar members on adjacent panels whereby transverse motion of adjacent panels toward the common center line serves to urge adjoining panels into close abutment, top and bottom runners with an elastomerically biased member mating with the horizontal perimeter members such as to grip the panels inserted between them while providing a centering force which serves to both align the panels and abut them to form a continuous batten free wall without the use of any other mechanical fastenings. Provision is made for locking the biased member in order to inhibit the removal of panels.Such demountable partition walls may be erected and dismantled without the use of tools or skills or interference with the building structure or furnishings.

Abstract: A propeller nozzle provided with duct means whereby fluid may be circulated from the area of higher pressure adjacent the lowermost propeller blade position to an area of lower pressure adjacent the uppermost blade positon in order to equalise the pressure differential across the vertical diameter of a propeller disc resulting from the different depth of submergence. This reduces the amplitude of cyclic stress acting upon the roots of the propeller blades.

Abstract: A propeller nozzle or duct in which the walls thereof terminate in two or more planes inclined symmetrically about an axis normal to the nozzle or duct centerline with one or more deflecter rudders pivotedly mounted across the opening so formed such that by swinging the rudder(s) one half of the exit area may be closed and the propeller race diverted through the remaining open area under the guidance of the rudder(s) upon which the race reacts to develop a steering force. The turning capabilities of a fixed nozzle or duct are thereby improved whilst wetted area may be reduced and propulsive efficiency increased by recovery of rotational energy otherwise lost to the wake. When used in conjunction with a pivoted steering nozzle a reverse thrust may be developed.