| 摘要 |
PURPOSE:To prevent the steerability of a boat having thrust units on both sides of the center line of the tail part thereof from being deteriorated, by providing a main rudder on the center line of the tail part of the boat and auxiliary rudders smaller than the main rudder in the rear of the thrust units, respectively. CONSTITUTION:Thrust units 2 are installed on both sides of a hull, and a main rudder 10 is mounted on the center line of the tail part of the boat laid between the thrust units 2. Further, small type auxiliary rudders 11 which are of the size corresponding to about 1/3 to 1/5 of the size of the main rudder 10, are disposed in the rear of the thrust units 2. The boat is steered by the main rudder 10 alone upon high speed running with the auxiliary rudders being free for directing their stream line in the direction of the main rudder 10, thereby cavitation at the main rudder 10 upon high speed running may be prevented so that the steerability of the boat is prevented from being deteriorated. |
