...to ship owners about controllable-pitch propellers. Nationwide, hundreds of seagoing vessels have controllable-pitch propulsion systems, which allow the angle of the propeller blades to be adjusted to improve efficiency and directional...

...of 47 crewmen died, is expected in about six months. Nationwide, hundreds of seagoing vessels have controllable-pitch propulsion systems, which allow the angle of the propeller blades to be adjusted to improve efficiency and directional...