Control surface for fluid-dynamic steering in the yaw axis
A
rudder
is a primary control surface used to steer a
ship
,
boat
,
submarine
,
hovercraft
,
airship
, or other vehicle that moves through a
fluid
medium (usually
air
or
water
). On an
airplane
, the rudder is used primarily to counter
adverse yaw
and
p-factor
and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the
hull
or
fuselage
, thus imparting a turning or
yawing
motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with
hinges
to the craft's
stern
, tail, or after end. Often rudders are shaped so as to minimize
hydrodynamic
or
aerodynamic drag
. On simple
watercraft
, a
tiller
?essentially, a stick or pole acting as a lever arm?may be attached to the top of the rudder to allow it to be turned by a
helmsman
. In larger vessels, cables,
pushrods
, or hydraulics may be used to link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical linkages or hydraulics.
History of the rudder
[
edit
]
Generally, a rudder is "part of the steering apparatus of a boat or ship that is fastened outside the hull", that is denoting all different types of oars, paddles, and rudders.
[1]
More specifically, the steering gear of ancient vessels can be classified into side-rudders and stern-mounted rudders, depending on their location on the ship. A third term,
steering oar
, can denote both types. In a
Mediterranean
context, side-rudders are more specifically called quarter-rudders as the later term designates more exactly the place where the rudder was mounted. Stern-mounted rudders are uniformly suspended at the back of the ship in a central position.
[2]
[3]
Although some
[a]
classify a
steering oar
as a rudder, others
[b]
argue that the steering oar used in ancient Egypt and Rome was not a true rudder and define only the stern-mounted rudder used in ancient
Han dynasty China
as a true rudder. The steering oar has the capacity to interfere with the handling of the sails (limiting any potential for long ocean-going voyages) while it was fit more for small vessels on narrow, rapid-water transport; the rudder did not disturb the handling of the sails, took less energy to operate by its
helmsman
, was better fit for larger vessels on ocean-going travel, and first appeared in
ancient China
during the 1st century AD.
[7]
[9]
[10]
[11]
[12]
In regards to the ancient
Phoenician
(1550–300 BC) use of the steering oar without a rudder
in the Mediterranean
, Leo Block (2003) writes:
A single sail tends to turn a vessel in an upwind or downwind direction, and rudder action is required to steer a straight course. A steering oar was used at this time because the rudder had not yet been invented. With a single sail, a frequent movement of the steering oar was required to steer a straight course; this slowed down the vessel because a steering oar (or rudder) course correction acts as a brake. The second sail, located forward, could be trimmed to offset the turning tendency of the mainsail and minimize the need for course corrections by the steering oar, which would have substantially improved sail performance.
[13]
The steering oar or steering board is an oversized oar or board to control the direction of a ship or other watercraft prior to the invention of the rudder. It is normally attached to the starboard side in larger vessels, though in smaller ones it is rarely if ever, attached.
Steering oar/gear
[
edit
]
Ancient Egypt
[
edit
]
Rowing oars set aside for steering appeared on large Egyptian vessels long before the time of
Menes
(3100 BC).
[14]
In the
Old Kingdom
(2686 BC ? 2134 BC) as many as five steering oars are found on each side of passenger boats.
[14]
The
tiller
, at first a small pin run through the stock of the steering oar, can be traced to the fifth dynasty (2504?2347 BC).
[15]
Both the tiller and the introduction of an upright steering post abaft reduced the usual number of necessary steering oars to one each side.
[16]
Single steering oars put on the stern can be found in a number of tomb models of the time,
[17]
particularly during the
Middle Kingdom
when tomb reliefs suggests them commonly employed in
Nile
navigation.
[18]
The first literary reference appears in the works of the
Greek
historian
Herodotus
(484-424 BC), who had spent several months in
Egypt
: "They make one rudder, and this is thrust through the
keel
", probably meaning the crotch at the end of the keel (as depicted in the "Tomb of Menna").
[19]
[20]
In
Iran
, oars mounted on the side of ships for steering are documented from the 3rd millennium BCE in artwork, wooden models, and even remnants of actual boats.
Ancient Rome
[
edit
]
Roman navigation used sexillie quarter steering oars that went in the Mediterranean through a long period of constant refinement and improvement, so that by Roman times ancient vessels reached extraordinary sizes.
[21]
The strength of the steering oar lay in its combination of effectiveness, adaptability and simpleness.
[21]
Roman quarter steering oar mounting systems survived mostly intact through the medieval period.
[21]
By the first half of the 1st century AD, steering gear mounted on the stern were also quite common in
Roman
river and harbour craft as proved from
reliefs
and archaeological finds (
Zwammerdam
,
Woerden
7). A tomb plaque of
Hadrianic
age shows a harbour tug boat in
Ostia
with a long stern-mounted oar for better leverage.
[22]
The boat already featured a
spritsail
, adding to the mobility of the harbour vessel.
[23]
Further attested Roman uses of stern-mounted steering oars includes barges under tow, transport ships for wine casks, and diverse other ship types.
[24]
[25]
[26]
A large river barge found at the mouth of the Rhine near
Zwammerdam
featured a large steering gear mounted on the stern.
[27]
[28]
According to new research, the advanced
Nemi ships
, the palace barges of emperor
Caligula
(37-41 AD), may have featured 14 m long rudders.
[29]
Sternpost-mounted rudder
[
edit
]
Ancient China
[
edit
]
The world's oldest known depiction of a sternpost-mounted rudder can be seen on a pottery model of a Chinese
junk
dating from the 1st century AD during the
Han dynasty
, predating their appearance in the West by a thousand years.
[7]
[10]
[30]
In China, miniature models of ships that feature steering oars have been dated to the
Warring States period
(c. 475?221 BC).
[7]
Sternpost-mounted rudders started to appear on Chinese ship models starting in the 1st century AD.
[7]
However, the Chinese continued to use the steering oar long after they invented the rudder, since the steering oar still had practical use for inland rapid-river travel.
[10]
One of oldest known depictions of the Chinese stern-mounted rudder (
duo
舵
) can be seen on a 2-foot (61 cm) pottery model of a
junk
dating from the 1st century AD, during the
Han dynasty
(202 BC – 220 AD).
[8]
[31]
It was discovered in
Guangzhou
in an archaeological excavation carried out by the
Guangdong Provincial Museum
and
Academia Sinica
of
Taiwan
in 1958.
[8]
[31]
Within decades, several other Han dynasty ship models featuring rudders were found in archaeological excavations.
[32]
The first solid written reference to the use of a rudder without a steering oar dates to the 5th century.
[30]
Chinese rudders are attached to the hull by means of wooden jaws or sockets,
[33]
while typically larger ones were suspended from above by a rope
tackle
system so that they could be raised or lowered into the water.
[33]
Also, many junks incorporated "fenestrated rudders" (rudders with holes in them, supposedly allowing for better control). Detailed descriptions of Chinese junks during the
Middle Ages
are known from various travellers to China, such as
Ibn Battuta
of
Tangier
,
Morocco
and
Marco Polo
of
Venice
,
Italy
. The later Chinese encyclopedist
Song Yingxing
(1587?1666) and the 17th-century European traveler Louis Lecomte wrote of the junk design and its use of the rudder with enthusiasm and admiration.
[34]
Paul Johnstone and Sean McGrail state that the Chinese invented the "median, vertical and axial" sternpost-mounted rudder, and that such a kind of rudder preceded the pintle-and-gudgeon rudder found in the West by roughly a millennium.
[30]
Ancient India
[
edit
]
A
Chandraketugarh
(West Bengal) seal dated between the 1st and 3rd centuries AD depicts a steering mechanism on a ship named ''Indra of the Ocean'' (Jaladhisakra), which indicates that it was a sea-bound vessel.
[35]
[36]
Medieval Near East
[
edit
]
Arab
ships also used a sternpost-mounted rudder.
[37]
On their ships "the rudder is controlled by two lines, each attached to a crosspiece mounted on the rudder head perpendicular to the plane of the rudder blade."
[37]
The earliest evidence comes from the
Ahsan al-Taqasim fi Marifat al-Aqalim
('The Best Divisions for the Classification of Regions') written by
al-Muqaddasi
in 985:
- The captain from the crow's nest carefully observes the sea. When a rock is espied, he shouts: "Starboard!" or 'Port!" Two youths, posted there, repeat the cry. The helmsman, with two ropes in his hand, when he hears the calls tugs one or the other to the right or left. If great care is not taken, the ship strikes the rocks and is wrecked.
[38]
Medieval Europe
[
edit
]
Oars mounted on the side of ships evolved into quarter steering oars, which were used from
antiquity
until the end of the
Middle Ages
in
Europe
. As the size of ships and the height of the freeboards increased, quarter steering oars became unwieldy and were replaced by the more sturdy rudders with
pintle
and
gudgeon
attachment. While steering oars were found in Europe on a wide range of vessels since Roman times, including light war galleys in Mediterranean,
[9]
[30]
the oldest known depiction of a pintle-and-gudgeon rudder can be found on church carvings of
Zedelgem
and
Winchester
dating to around 1180.
[9]
[30]
While earlier rudders were mounted on the stern by the way of rudderposts or tackles, the iron hinges allowed the rudder to be attached to the entire length of the sternpost in a permanent fashion.
[39]
However, its full potential could only to be realized after the introduction of the vertical sternpost and the full-rigged ship in the 14th century.
[40]
From the
Age of Discovery
onwards, European ships with pintle-and-gudgeon rudders sailed successfully on all seven seas.
[40]
Historians like
Joseph Needham
hold that the stern-mounted rudder was transferred from China to Europe and the Islamic world during the Middle Ages.
[7]
[8]
[30]
Modern rudders
[
edit
]
Conventional rudders have been essentially unchanged since
Isambard Kingdom Brunel
introduced the
balanced rudder
on the
SS
Great Britain
in 1843
[41]
and the
steering engine
in the
SS
Great Eastern
in 1866.
[42]
If a vessel requires extra maneuverability at low speeds, the rudder may be supplemented by a
manoeuvring thruster
in the bow,
[43]
or be replaced entirely by
azimuth thrusters
.
Boat rudders details
[
edit
]
Boat rudders may be either outboard or inboard. Outboard rudders are hung on the stern or transom. Inboard rudders are hung from a keel or skeg and are thus fully submerged beneath the hull, connected to the steering mechanism by a rudder post that comes up through the hull to deck level, often into a cockpit. Inboard keel hung rudders (which are a continuation of the aft trailing edge of the full keel) are traditionally deemed the most damage resistant rudders for off shore sailing. Better performance with faster handling characteristics can be provided by skeg hung rudders on boats with smaller fin keels.
Rudder post and mast placement defines the difference between a ketch and a yawl, as these two-masted vessels are similar. Yawls are defined as having the mizzen mast abaft (i.e. "aft of") the rudder post; ketches are defined as having the mizzen mast forward of the rudder post.
Small boat rudders that can be steered more or less perpendicular to the hull's longitudinal axis make effective brakes when pushed "hard over." However, terms such as "hard over," "hard to starboard," etc. signify a maximum-rate turn for larger vessels. Transom hung rudders or far aft mounted fin rudders generate greater moment and faster turning than more forward mounted keel hung rudders. Rudders on smaller craft can be operated by means of a tiller that fits into the rudder stock that also forms the fixings to the rudder foil. Craft where the length of the tiller could impede movement of the helm can be split with a rubber universal joint and the part adjoined the tiller termed a tiller extension. Tillers can further be extended by means of adjustable telescopic twist locking extension.
There is also the
barrel type rudder
, where the ship's screw is enclosed and can be swiveled to steer the vessel. Designers claim that this type of rudder on a smaller vessel will answer the helm faster.
[44]
Rudder control
[
edit
]
| This section
is missing information
about other types of steering gear, such as rotary type steering gear.
Please expand the section to include this information. Further details may exist on the
talk page
.
(
June 2021
)
|
Large ships (over 10,000 ton gross tonnage) have requirements on rudder turnover time. To comply with this, high torque rudder controls are employed.
[45]
One commonly used system is the
ram type steering gear
. It employs four hydraulic rams to rotate the rudder stock (rotation axis), in turn rotating the rudder.
[46]
Aircraft rudders
[
edit
]
On an aircraft, a
rudder
is the directional
control surface
along with the rudder-like
elevator
(usually attached to the horizontal tail structure, if not a slab elevator) and
ailerons
(attached to the wings) that control pitch and roll, respectively. The rudder is usually attached to the
fin
(or
vertical stabilizer
), which allows the pilot to control
yaw
about the vertical axis, i.e., change the horizontal direction in which the nose is pointing.
Unlike a ship, both
aileron
and rudder controls are used together to turn an aircraft, with the ailerons imparting roll and the rudder imparting yaw and also compensating for a phenomenon called
adverse yaw
. A rudder alone will turn a conventional fixed-wing aircraft, but much more slowly than if ailerons are also used in conjunction. Sometimes pilots may intentionally operate the rudder and ailerons in opposite directions in a maneuver called a
slip
or sideslip. This may be done to overcome crosswinds and keep the fuselage in line with the runway, or to lose altitude by increasing drag, or both.
Another technique for yaw control, used on some
tailless aircraft
and
flying wings
, is to add one or more drag-creating surfaces, such as split ailerons, on the outer wing section. Operating one of these surfaces creates drag on the wing, causing the plane to yaw in that direction. These surfaces are often referred to as drag rudders.
See also
[
edit
]
Look up
rudder
in Wiktionary, the free dictionary.
Notes
[
edit
]
- ^
Lawrence Mott in his comprehensive treatment of the history of the rudder,
[4]
Timothy Runyan,
[5]
the
Encyclopædia Britannica
,
[1]
and The Concise
Oxford Dictionary of English Etymology
[6]
- ^
Joseph Needham
,
Lefebre des Noettes
, K.S. Tom, Chung Chee Kit, S.A.M. Adshead, John K. Fairbank, Merle Goldman, Frank Ross, and Leo Block.
[7]
[8]
[9]
- ^
a
b
rudder.Encyclopædia Britannica. Retrieved August 8, 2008, from
Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
- ^
William F. Edgerton: “Ancient Egyptian Steering Gear”,
The American Journal of Semitic Languages and Literatures
, Vol. 43, No. 4. (1927), pp. 255-265
- ^
R. O. Faulkner:
Egyptian Seagoing Ships
,
The Journal of Egyptian Archaeology
, Vol. 26. (1941), pp. 3-9
- ^
Lawrence V. Mott,
The Development of the Rudder, A.D. 100-1600: A Technological Tale
, Thesis May 1991, Texas A&M University, p.2f., 92
- ^
Timothy J. Runyan: “Review of The Development of the Rudder: A Technological Tale“,
Speculum
, Vol. 74, No. 4, (1999), pp. 1096-1098 (1098)
- ^
The Concise Oxford Dictionary of English Etymology
- ^
a
b
c
d
e
f
Tom, K.S. (1989).
Echoes from Old China: Life, Legends, and Lore of the Middle Kingdom
. Honolulu: The Hawaii Chinese History Center of the University of Hawaii Press.
ISBN
0-8248-1285-9
. Page 103–104.
- ^
a
b
c
d
Needham, Volume 4, Part 3, 649-650.
- ^
a
b
c
d
Adshead, Samuel Adrian Miles. (2000).
China in World History
. London: MacMillan Press Ltd. New York: St. Martin's Press.
ISBN
0-312-22565-2
. Page 156.
- ^
a
b
c
Needham, Joseph. (1986).
Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics
. Taipei: Caves Books Ltd. Pages 627–628.
- ^
Fairbank, John K. and Merle Goldman. (1998).
China: A New History, Enlarged Edition
. Cambridge: Harvard University Press.
ISBN
0-674-11673-9
. Page 93.
- ^
Block, Leo. (2003).
To Harness the Wind: A Short History of the Development of Sails
. Annapolis: Naval Institute Press.
ISBN
1-55750-209-9
. Page 123.
- ^
Block, Leo. (2003).
To Harness the Wind: A Short History of the Development of Sails
. Annapolis: Naval Institute Press.
ISBN
1-55750-209-9
. 8–9.
- ^
a
b
William F. Edgerton: "Ancient Egyptian Steering Gear",
The American Journal of Semitic Languages and Literatures
, Vol. 43, No. 4. (1927), pp. 255
- ^
William F. Edgerton: "Ancient Egyptian Steering Gear",
The American Journal of Semitic Languages and Literatures
, Vol. 43, No. 4. (1927), pp. 257
- ^
William F. Edgerton: "Ancient Egyptian Steering Gear",
The American Journal of Semitic Languages and Literatures
, Vol. 43, No. 4. (1927), pp. 260
- ^
Francesco Tiradritti (ed.): “The Treasures of the Egyptian Museum”, The American University in Cairo Press, Cairo 1999,
ISBN
978-977-424-504-6
, p.92f.
- ^
Mohamed Ata: “Egypt from Past to Present. Through the Eyes of an Egyptian”, Cairo 2007, p.68
- ^
Herodot
:
Histories
, 2.96
- ^
William F. Edgerton: “Ancient Egyptian Steering Gear”,
The American Journal of Semitic Languages and Literatures
, Vol. 43, No. 4. (1927), pp. 263
- ^
a
b
c
Lawrence V. Mott, The Development of the Rudder, A.D. 100-1600: A Technological Tale, Thesis May 1991, Texas A&M University, p.1
- ^
Lionel Casson:
Harbour and River Boats of Ancient Rome
,
The Journal of Roman Studies
, Vol. 55, No. 1/2, Parts 1 and 2 (1965), pp. 31-39 (plate 1)
- ^
Lionel Casson, Harbour and River Boats of Ancient Rome,
The Journal of Roman Studies
, Vol. 55, No. ½, Parts 1 and 2. (1965), pp. 35 (Pl. I); 36, Fn.43 (Pl.II,1)
- ^
Lawrence V. Mott, The Development of the Rudder, A.D. 100-1600: A Technological Tale, Thesis May 1991, Texas A&M University, p.84, 95f.
- ^
Lionel Casson: “Ships and Seamanship in the Ancient World”,
ISBN
0-8018-5130-0
, S.XXVIII, 336f.; Fig.193
- ^
Tilmann Bechert: Romisches Germanien zwischen Rhein und Maas. Die Provinz Germania inferior, Hirmer, Munchen 1982,
ISBN
3-7774-3440-X
, p.183, 203 (Fig.266)
- ^
M. D. de Weerd: Ships of the Roman Period at Zwammerdam / Nigrum Pullum, Germania Inferior, in: Roman Shipping and Trade: Britain and the Rhine Provinces. (The Council for) British Archaeology, Research Report 24, 1978, 15ff.
- ^
M. D. de Weerd: Romerzeitliche Transportschiffe und Einbaume aus Nigrum Pullum / Zwammerdam, in: Studien zu den Militargrenzen Roms II (1977), 187ff.
- ^
Deutschlandfunk: Romische Schiffsversuchsanstalt in den Albaner Bergen
- ^
a
b
c
d
e
f
Johnstone, Paul and Sean McGrail. (1988).
The Sea-craft of Prehistory
. New York: Routledge.
ISBN
0-415-02635-0
. Page 191.
- ^
a
b
Fairbank, 192.
- ^
Deng, Gang. (1997).
Chinese Maritime Activities and Socioeconomic Development, c. 2100 B.C.-1900 A.D
. Westport: Greenwood Press.
ISBN
0-313-29212-4
. Page 42.
- ^
a
b
Needham, Volume 4, Part 3, 362.
- ^
Needham, Volume 4, Par634.
- ^
Barnes, Ruth; Parkin, David (2015-12-22).
Ships and the Development of Maritime Technology on the Indian Ocean
. Routledge.
ISBN
978-1-317-79342-7
.
- ^
Guy, John (1999). "A Boat Model and State Ritual in Eastern India".
Bulletin de l'Ecole francaise d'Extreme-Orient
.
86
: 105?126.
doi
:
10.3406/befeo.1999.3407
.
ISSN
0336-1519
.
JSTOR
43732572
.
- ^
a
b
Lawrence V. Mott, p.93
- ^
Lawrence V. Mott, p.92f.
- ^
Lawrence V. Mott,
The Development of the Rudder, A.D. 100-1600: A Technological Tale
, Thesis May 1991, Texas A&M University, S.2, 92f.
- ^
a
b
Lawrence V. Mott,
The Development of the Rudder, A.D. 100-1600: A Technological Tale
, Thesis May 1991, Texas A&M University, S.118f.
- ^
Vaughan, Adrian (1991) [1991].
Isambard Kingdom Brunel
(2nd ed.). London: John Murray. p. 160.
ISBN
0-7195-4636-2
.
- ^
Bennett, S. (1986).
A History of Control Engineering, 1800-1930
. Peregrinus. p. 98.
ISBN
9780863410475
. Retrieved
2015-01-10
.
- ^
Osmotech UK on Uses and advantages of bow thrusters
Archived
July 26, 2013, at the
Wayback Machine
- ^
"Barrel Type Rudder Makes Quicker Turns"
Popular Mechanics
, October 1934, bottom-right pg.495
- ^
Molland, Anthony F. (2011-10-13).
The Maritime Engineering Reference Book: A Guide to Ship Design, Construction and Operation
. Elsevier.
ISBN
978-0-08-056009-0
.
- ^
"Understanding Steering Gear in Ships"
.
Marine Insight
. 2019-02-20
. Retrieved
2021-06-03
.
References
[
edit
]
Wikimedia Commons has media related to
Rudders
.