【摘要】 通过对多工况拖船采用不同推进方式的性能比较表明导管螺旋桨优于普通螺旋桨，可调螺距螺旋桨优于导管螺旋桨，二档变转速的导管螺旋桨与可调螺距螺旋桨的推进效果相当。建议在多工况船的螺旋桨设计中采用二档变转速推进方式。更多还原

【Abstract】 The calculation results of propulsive performance for a ultra-shallow draft tug with different propulsion types on both free running condition and bollard condition show that the shrouded propeller is better than the conventional one,the controllable pitch propeller is better than the shrouded one,while the two-step change-speed propeller is analogues to the CPP in respect of the propulsion efficiency. Therefore,it is recommended to adopt the two-step change-speed propeller in the tug design.更多还原