PURPOSE: To reduce the size of the whole of constitution by a method wherein, in a device having a deflector for steering mounted to the tip of a nozzle for propulsion, a biparting type bucket to switch forward and reverse by opening and closing a front part in the injection direction of a jet water flow is mounted inside the deflector.

CONSTITUTION: A water drum 12 approximately in a triangle as seem from a side is mounted to the rear end of the bottom part of a ship hull 11, and a water feed port 13 is formed in the bottom part thereof, and a delivery port 14 in the rear thereof. An impeller case 15 is mounted in a manner to cover the delivery port 14 in the rear part of the water drum 12, and a nozzle 16 is mounted to the rear part thereof. An engine 17 is mounted in the ship hull 11, and the rear end part of a driven shaft 18 coupled to the output part of the engine is coupled to an impeller 19 in an impeller case 15. A cylindrical deflector 20 is mounted in a manner to cover the outer periphery of the rear end of the nozzle 16, and a reverse bucket 23 formed with upper and lower buckets 21 and 22 is mounted to the interior of the deflector. Through execution of operation such that the two buckets 21 and 22 are closed, a water flow is deflected to the front side to effect reverse.