Kitchen rudder
{{short description|Type of directional propulsion system for vessels}}
Image:USPatent1186210 Kitchen rudder.png
Image:Kitchen-rudder-us-patent-489509.gif
Image:reverse.thrust.klm.fokker70.arp.jpg Fokker 70 with reverse thrust applied. The two surfaces behind the engine can be seen in the deployed position, diverting the engine exhaust gases (hence thrust) forward. This is similar to the Kitchen rudder in "Full astern" position]]
The Kitchen rudder is the familiar name for "Kitchen's Patent Reversing Rudders", a combination rudder and directional propulsion delivery system for relatively slow speed displacement boats which was invented in the early 20th century by John G. A. Kitchen of Lancashire, England. It turns the rudder into a directional thruster, and allows the engine to maintain constant revolutions and direction of drive shaft rotation while altering thrust by use of a control which directs thrust forward or aft. Only the rudder pivots; the propeller itself is on a fixed shaft and does not.
"Kitchener gear" or "Kitchener rudder" have been common misnomers for the Kitchen rudder.
It is held under British Provisional Patent No. 3249/1914 and US Patent No. 1186210 (1916) and has been improved with the design in US Patent 4895093 (1990).
Description
The rudder consists of a pair of slightly conical (usually but not always - designs vary), semi-cones mounted on a pivot either side of the propeller with the long axis of the cone running fore and aft when the helm is midships. They are pivoted about a vertical axis such that the cone may close off the propeller thrust aft of the propeller, directing the thrust forwards and thus creating motion astern.
In addition to the "jaws" of the cone being controlled the direction of thrust is also controlled by rudder direction. In this way, it is unlike the azimuth thrusters used on many medium and large vessels, or the outboard motors or stern drives used by some small boats, since these all use the directed thrust to avoid the need of a rudder altogether.
Modern equivalent include certain types of pump jets or Kort nozzle.
While not strictly Kitchen rudder technology, the "bucket" on some aircraft jet engines is an aeronautical derivative of the device.{{citation needed|date=May 2022}} When the deflectors are deployed, directing thrust forwards, they are equivalent to the Kitchen rudder in the "full astern" position.
Operation
The operation of the Kitchen rudder is performed with the propeller engaged, even when the boat is stationary.{{cite web|url=http://www.proboat-digital.com/proboat/200608/?pg=63 |title=Rudders, Medium to Rare |publisher=Professional Boatbuilder |accessdate=2007-10-12 |date=August 2006 |last=Dave |first=Gerr |url-status=dead |archiveurl=https://web.archive.org/web/20071028102848/http://www.proboat-digital.com/proboat/200608/?pg=63 |archivedate=2007-10-28 }} The rudder is controlled by a small wheel on the tiller.{{cite web |url=http://www.defence.gov.au/news/navynews/editions/4916/pdf/RN8.pdf |title=New lease of life for 65-year-old navy cutter |last=Dunning |first=Steve |accessdate=2007-10-12 |publisher=Reserve News (Royal Australian Navy) |date=2006-09-07 |quote=A small wheel attached to the tiller is used to control two curved metal plates that surround the propeller enabling the boat to go ahead, go astern or remain stationary without any change of engine speed or reversing of the propeller. |url-status=dead |archiveurl=https://web.archive.org/web/20110608020039/http://www.defence.gov.au/news/navynews/editions/4916/pdf/RN8.pdf |archivedate=2011-06-08 }}
=Neutral=
=Moving ahead=
=Moving astern=
See also
- {{annotated link|Azipod}}
- {{annotated link|Ducted propeller}}
- {{annotated link|Pleuger rudder}}
- {{annotated link|Schilling rudder}}
- {{annotated link|Sterndrive}}
Notes
{{reflist}}
External links
- [http://www.hmsconway.org/relics_artifacts.html Description near the foot of the article under Pinnace]
- [https://web.archive.org/web/20060604004255/http://www.pcez.com/~artemis/SLAkitchen.gif Kitchen Rudder - Diagrams]
- [https://web.archive.org/web/20070311014837/http://www.boatdesign.net/forums/showthread.php?t=418&highlight=Kitchen+rudder Kitchen Rudder - Discussion and diagrams]
- [http://patimg2.uspto.gov/.piw?Docid=04895093&idkey=NONE Manoeuvring device for boats: United States Patent 4895093], expiring in fall 2007
- [http://www.boatdesign.net/forums/attachment.php?attachmentid=279&d=1031890494 Special rudders and manoeuvering devices]
- [https://patents.google.com/patent/US1186210A/en?oq=US+1%2c186%2c210 U.S. patent 1,186,210]
- [https://patents.google.com/patent/US4895093A/en?oq=US+4%2c895%2c093 U.S. patent 4,895,093]