327,075. Davies, J. W., and MacLaren, G. July 6, 1929. Driving-arrangements for screw propellers.-In manually-operated boat-propelling mechanism a pair of slide members are reciprocated on fore and aft guides and through bevel gearing actuates a crank shaft which is geared to the propeller. Two slide members 19 are mounted in guides 21 and are connected by rods 18 with pairs of cranks at 90‹ on a crank shaft 15. The shaft is supported on pillars 16 and carries a crown wheel 14 which gears with a. smaller bevel 13 on the propeller shaft 11. This shaft also carries a fly wheel 26. For the purpose of reversing the propeller a pawl arrangement is mounted in conjunction with the crown wheel 14.