GB349450A - Improvements in propellers - Google Patents

Abstract

349,450. Screw propellers. HARVEY, C. J., 47, Elderfield Gardens, Kidderminster, Worcestershire. Feb. 19, 1930, No. 5503. [Class 114.] A screw propeller is mounted on the forward end of a shaft situated at the after end of the ship, this shaft being inclined,to both the horizontal and the vertical and downwardly toward the ship. The propeller is adapted to work semi-immersed and the blades thereof are preferably curved axially and transversely. A propeller shaft 3 is driven through a universal joint from a depending shaft 2 connected with an inboard motor or with an outboard motor. The shaft 3 is inclined downwardly toward the ship and has secured thereto a boss 6 with a number of tangential faces 7 to which the blades 8 are secured. The blades are curved in both directions and are set at an angle of 20‹ to the shaft whereby the lowermost blade is fully immersed to the extent of its width. The blade may have a projection 12 forming a registering means for its attachment to the facet 7 and may also have an extension lug whereby the blade is secured by a rivet to an adjacent blade. In a modification the shaft 3 is driven from a horizontal shaft by bevel wheels 19 and above the installation is a curved deflector plate 18 on a framework 17 also carrying ribs 16 whereby water thrown up by the propeller is deflected and adds to the propelling power. The propeller may be arranged to be swung about a vertical axis so as to provide a steering effect. Two such propellers may be mounted, one on either side of a central rudder.