Azimuth thruster

An Azimuth thruster is a configuration of ship propellers placed in pods that can be rotated in any horizontal direction, making a rudder unnecessary. These give ships better maneuverability than a fixed propeller and rudder system. Primary advantages are electrical efficiency, better use of ship space, and lower maintenance costs. Ships with azimuth thrusters do not need tugs to dock, though they still require tugs to maneuver in difficult places.

There are two major variants, based on the location of the motor:
# Mechanical transmission, where a motor inside the ship is connected to the pod by gearing. The motor may be diesel or diesel-electric. Depending on the shaft arrangement the mechanical azimuth thruster 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 an horizontal input shaft, vertical shaft in the azimuthing column and a horizontal output shaft with two right-angle gears.
# Electrical transmission, where an electric motor is 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 Mr. F.W. Pleuger and Mr. F. Busmann ("Pleuger Unterwasserpumpen GmbH"), ABB "Azipod" was the first product using this technology.

Types of Mechanical Azimuth Thrusters

Mechanical azimuth thrusters are available as fixed installed, retractable and underwater-mountable. Mechanical azimuth thrusters are available with fixed pitch propellers FPP and controllable pitch propellers CPP.
# Fixed installed thrusters are used for tugs, ferries and supply-boats.
# Retractable thrusters are used as auxiliary propulsion for DP-vessels and take-home propulsion for military vessels.
# Underwater-mountable thrusters are used as DP-propulsion for very large vessels such as semi-submersible drill rigs.

History

The first azimuth thrusters, using the mechanical Z-drive transmission, were built by Hollming in Finland in the 1960s under the "Aquamaster" brand name. [ [http://www.hollming.fi/english/history_business.html Hollming Group - History] ] The business was later sold to Rolls-Royce, after the merger of Finnish shipyards into Finnyards.

Later, subsidiaries of ABB, also based in Finland, developed the "Azipod" thruster, with the motor located in the pod itself. This kind of propulsion was first patented in 1955 by Pleuger of Germany.

ee also

* Azipod
* Pleuger rudder
* The Voith-Schneider marine propulsion system can also quickly change the direction of thrust.

References

External links

* " [http://marine.rolls-royce.com/Azimuthing-thrusters-for-marine-vessels/ Ulstein Aquamaster azimuth thrusters] ", Rolls-Royce plc, including videos of operation
* " [http://answers.google.com/answers/threadview?id=186174 Propulsion system for LNG Carriers] ", Google Answers thread, April 2003
* " [http://www.abb.com/global/seitp/seitp161.nsf/0/364634347b7f8355c1256f550048ebd0?OpenDocument 1990 - World’s first podded propulsion system] ", ABB
* " [http://www.ship-technology.com/contractors/propulsion/azimuth.html Azimuth Thrusters] ", Ship-Technology.com
* " [http://www.thrustmastertexas.com/products/azimuthThrusters.html Azimuth Thrusters Types and Configurations] ", Thrustmaster of Texas
* " [http://www.flowserve.com/vgnfiles/Files/Literature/ProductLiterature/Pumps/pss-90-8.1-e.pdf Flowserve] ", L-drive Flowserve Pleuger thruster from flowserve.com
* " [http://www.youtube.com/watch?v=PzjFEe47bzA Youtube] ", movie azimuth thruster L-drive from flowserve.com
* "http://www.hrp.nl", hrp.nl