In an azimuth thruster the propeller rotates 360° around the vertical axis so the unit provides propulsion, steering and positioning thrust for superior manoeuvrability. Designs have been developed for propulsion and dynamic positioning in response to market requirements. As a result there is a azimuth design available to suit virtually any application. Simple and robust construction provides high operational reliability together with simple maintenance for low through life costs. Units can be supplied for diesel or electric drive together with a remote control system.
- Mechanical transmission, which connects a motor inside the ship to the
outboard unit by gearing. The motor may be diesel or diesel-electric. Depending on the shaft arrangement, mechanical azimuth thrusters are divided into L-drive and Z-drive. An L-drive thruster has a vertical input shaft and a horizontal output shaft with one right-angle gear. A Z-drive thruster has a horizontal input shaft, a vertical shaft in the rotating column and a horizontal output shaft, with two right-angle gears.
- Electrical transmission, more commonly called pods, where an electric motor is fitted in the pod itself, connected directly to the propeller without gears. The electricity is produced by an onboard engine, usually diesel or gas turbine. Invented in 1955 by Friedrich W. Pleuger and Friedrich Busmann (Pleuger Unterwasserpumpen GmbH), ABB Group’s Azipod was the first product using this technology.
- Primary advantages are maneuverability, electrical efficiency, better use of ship space, and lower maintenance costs. Ships with azimuth thrusters do not need tugboats to dock, though they may still require tugs to maneuver in difficult places.