23,264. Woodward, E. Oct. 21. Screw and like propellers.-Propellers for use in water or air consist of helical blades 3 having their outer edges connected to triangular pieces 4 forming parts of a cylinder and united by a wired edge 9. The pieces 4 may be bent slightly outwards at 6 and the leading edges 7 of the blades may be strengthened by bending them to form a lip. Specification 3045/97 is referred to.