# Azimuth thruster > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Azimuth_thruster > Markdown URL: https://mediated.wiki/source/Azimuth_thruster.md > Source: https://en.wikipedia.org/wiki/Azimuth_thruster > Source revision: 1342885043 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{short description|Steerable propulsion pod under a watercraft}} {{Refimprove|date=September 2012}} [[Image:Siemens Schottel Propulsor.jpg|thumb|[Siemens](/source/Siemens) [Schottel](/source/Schottel_(company)) azimuth thrusters]] An '''azimuth thruster''' is a configuration of marine [propeller](/source/propeller)s placed in pods that can be rotated to any horizontal angle ([azimuth](/source/azimuth)), making a [rudder](/source/rudder) redundant. These give [ship](/source/ship)s better maneuverability than a fixed propeller and rudder system. ==Types of azimuth thrusters== [[File:Oued el Kebir-IMG 9346.jpg|thumb|upright|Azimuth thrusters on the tug ''Oued el Kebir'', with [Kort nozzle](/source/Kort_nozzle)s]] There are two major variants, based on the location of the motor:{{cn|date=November 2014}} # [Mechanical transmission](/source/Transmission_(mechanics)), which connects a motor inside the ship to the outboard unit by [gear](/source/gear)ing. The motor may be [diesel](/source/Diesel_engine) or [diesel–electric](/source/Diesel%E2%80%93electric_transmission). Depending on the shaft arrangement, mechanical azimuth thrusters are divided into [L-drive](/source/L-drive) and [Z-drive](/source/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](/source/Diesel%E2%80%93electric_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](/source/Diesel_engine) or [gas turbine](/source/gas_turbine). Invented in 1955 by [Friedrich W. Pleuger](/source/Friedrich_W._Pleuger) and [Friedrich Busmann](/source/Friedrich_Busmann) (Pleuger Unterwasserpumpen GmbH), [ABB](/source/ABB)'s [Azipod](/source/Azipod) was the first product using this technology. The most powerful podded thrusters in use are the four 21.5 MW Rolls-Royce Mermaid units fitted to {{RMS|Queen Mary 2}}.{{cite web| url=https://www.wartsila.com/encyclopedia/term/mermaid-propulsion-unit| title=Mermaid propulsion unit| publisher=[Wärtsilä](/source/W%C3%A4rtsil%C3%A4)| access-date=1 February 2020}} Mechanical azimuth thrusters can be fixed installed, retractable or underwater-mountable. They may have fixed pitch propellers or [controllable pitch propeller](/source/controllable_pitch_propeller)s. Fixed installed thrusters are used for tugboats, ferries and supply-boats. Retractable thrusters are used as auxiliary propulsion for dynamically positioned vessels and take-home propulsion for military vessels. Underwater-mountable thrusters are used as dynamic positioning propulsion for very large vessels such as [semi-submersible](/source/semi-submersible) [drilling rig](/source/drilling_rig)s and [drillship](/source/drillship)s. ==Advantages and disadvantages== [[File:BPC Dixmude.jpg|thumb|The [French Navy](/source/French_Navy) [Mistral-class amphibious assault ship](/source/Mistral-class_amphibious_assault_ship) [''Dixmude''](/source/French_ship_Dixmude_(L9015)) manoeuvering in Jounieh bay; the wake at the stern is perpendicular to the ship, indicating the use of her azimuth thrusters.]] Primary advantages are maneuverability, electrical efficiency, better use of ship space, and lower maintenance costs.{{Citation needed|date=October 2010}} Ships with azimuth thrusters do not need [tugboat](/source/tugboat)s to dock, though they may still require tugs to maneuver in difficult places.{{citation needed|date=October 2020}} The major disadvantage of azimuth drive systems is that a ship with azimuth drive maneuvers differently from one with a standard propeller and rudder configuration, necessitating specialized pilot training.{{citation needed|date=October 2020}} Another disadvantage is they increase the draught of the ship.{{citation needed|date=October 2020}} ==History== English inventor [Francis Ronalds](/source/Francis_Ronalds) described what he called a ''propelling rudder'' in 1859 that combined the propulsion and steering mechanisms of a boat in a single apparatus. The propeller was placed in a frame having an outer profile similar to a rudder and attached to a vertical shaft that allowed the device to rotate in plane while spin was transmitted to the propeller.{{Cite book|title = Sir Francis Ronalds: Father of the Electric Telegraph|last = Ronalds|first = B.F.|publisher = Imperial College Press|year = 2016|isbn = 978-1-78326-917-4|location = London}} The modern azimuth thruster using the Z-drive transmission was invented in 1951 by Joseph Becker, the founder of [Schottel](/source/Schottel_(company)) in Germany, and marketed as the Ruderpropeller. Becker was awarded the 2004 [Elmer A. Sperry Award](/source/Elmer_A._Sperry_Award) for the invention.{{cite web |url=http://www.sperryaward.org/awardbooklets/2004%20Sperry%20Award%20Booklet.pdf|title=Presentation of The Elmer A. Sperry Award for 2004|publisher=Sperryaward.org|access-date=24 November 2014}} This kind of propulsion was first patented in 1955 by [Pleuger](/source/Pleuger_rudder).{{cite web|url=https://patents.google.com/patent/US2714866|title=Patent US2714866 - Device for propelling a ship|access-date=24 November 2014}} In the late 1980s Wärtsilä Marine, Strömberg and the Finnish National Board of Navigation developed the [Azipod](/source/Azipod) thruster with the motor located in the pod itself.{{cn|date=November 2014}} ==See also== * {{annotated link|Pleuger rudder}} * {{annotated link|Cyclorotor}} * {{annotated link|Voith Schneider Propeller}} * {{annotated link|Saildrive}} * {{annotated link|Z-drive}} * {{annotated link|Outboard motor}} ==References== {{commonscat|Azimuth thrusters}} {{Reflist}} {{DEFAULTSORT:Azimuth Thruster}} Category:Marine propulsion --- Adapted from the Wikipedia article [Azimuth thruster](https://en.wikipedia.org/wiki/Azimuth_thruster) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Azimuth_thruster?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.