Twin propellers turn inward (when going ahead)

双螺旋桨(向前推进时)内旋。

Twin propeller turn outward (when going ahead)

双螺旋桨(向外推进时)外旋。

71.do twin propellers turn inward or outward when going ahead?

双螺旋桨在向前推进时向内旋还是外旋？

In addition, the most important feature of the ships is that they have two low-power engines, twin propellers, and waste heat recovery systems.

此外，该船最重要的特点是拥有两台低功率发动机、双螺旋桨和废热回收系统。