Z-drive
From Wikipedia, the free encyclopedia
The Z-drive is a specialized form of marine propulsion. With a Z drive, a vessel doesn't have conventional propellers at the end of fixed propeller shafts. Instead propellers are mounted on pods that emerge from the bottom of the vessel. The pods can be aimed through a full 360 degrees, allowing for rapid changes in the direction of thrust. Z-drive equipped vessels don't need a conventional rudder.
This form of propulsion is called a Z-drive because, when the propeller is mechanically powered, the rotary motion has to make two right angle turns -- thus looking a bit like the letter "Z". If it is powered by an electric motor in the pod, it is called an azimuth thruster.
The Voith-Schneider marine propulsion system can also quickly change the direction of thrust.
