PURPOSE: To equalize the attack angle of a propeller blade as well as the generation of propulsion force, by securing a ring attached guide blade to the stern and installing a ring attached propeller rotatably at will through minute space behind the guide blade.

CONSTITUTION: A ring attached guide blade 10 is composed of plural guide blades 11 and a ring 12 which comes as one body in close contact with the outer boundary of the guide blade 11 and secured to the stern 1. On the other hand, a ring attached propeller 20 is composed of plural propeller blades 21 and a ring 20 which comes as one body in close contact with the outer boundary of the propeller blades 21 and turned round by a main engine of the ship to generate the propulsion required. An interval between the ring 12 of the guide blade 10 and the ring 22 of the propeller blade 21 is very close together, making a very small clearance so that a whirl-pool becomes prevented from occurring owing to this clearance G.