| 摘要 |
PURPOSE:To improve the propeller efficiency by fixing a speed increase propeller and a reverse rotation propeller above/below a propulsion propeller while coupling said propellers through a transmission thereby preventing the cavitation. CONSTITUTION:A speed increase propeller 5 and a reverse rotation propeller 6 are provided above/below a propulsion propeller 3 where the shafts 5', 6' of said propellers 5, 6 are coupled with a transmission 7. Consequently the reverse rotation propeller 6 will rotate by the relative water flow produced due to the advance of the vessel thus to drive the speed increase propeller 5. As a result the reverse rotation propeller 6 will lower the flow speed in the vicinity while the speed increase propeller 5 will increase the flow speed in the vicinity thereby the flow speed on the disc of the propulsion propeller 3 is uniformed thus to improve the propeller efficiency. |
