Rudder

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Modern ship rudder (the long red rectangle behind the propeller) Brosen propelersterntychy.jpg
Modern ship rudder (the long red rectangle behind the propeller)
RMS Olympic's rudder turned Olympic stern and rudder.jpg
RMS Olympic's rudder turned

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 afterend. Often rudders are shaped 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 link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical linkages or hydraulics.

Contents

History of the rudder

Generally, a rudder is "part of the steering apparatus of a boat or ship that is fastened outside the hull, " denoting all 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 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 [lower-alpha 1] classify a steering oar as a rudder, others [lower-alpha 2] 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 can 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] [10] [11] [12] [13] In regards to the ancient Phoenician (1550300 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, 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. [14]

The steering oar or steering board is an oversized oar or board to control the direction of a ship or other watercraft before 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

Ancient Egypt

Stern-mounted steering oar of an Egyptian riverboat depicted in the Tomb of Menna (c. 1422-1411 BC) Maler der Grabkammer des Menna 013.jpg
Stern-mounted steering oar of an Egyptian riverboat depicted in the Tomb of Menna (c. 1422–1411 BC)

Rowing oars set aside for steering appeared on large Egyptian vessels long before the time of Menes (3100 BC). [15] In the Old Kingdom (2686 BC – 2134 BC) as many as five steering oars are found on each side of passenger boats. [15] 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). [16] Both the tiller and the introduction of an upright steering post abaft reduced the usual number of necessary steering oars to one each side. [17] Single steering oars put on the stern can be found in several tomb models of the time, [18] particularly during the Middle Kingdom when tomb reliefs suggest them commonly employed in Nile navigation. [19] 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"). [20] [21]

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

Steering oar of a Roman boat, 1st century AD (RG-Museum, Cologne) Rudder of a Roman Boat (RG Museum Koeln, Germany).JPG
Steering oar of a Roman boat, 1st century AD (RG-Museum, Cologne)

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. [22] The strength of the steering oar lay in its combination of effectiveness, adaptability and simpleness. [22] Roman quarter steering oar mounting systems survived mostly intact through the medieval period. [22]

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. [23] The boat already featured a spritsail, adding to the mobility of the harbour vessel. [24] Further attested Roman uses of stern-mounted steering oars includes barges under tow, transport ships for wine casks, and diverse other ship types. [25] [26] [27] A large river barge found at the mouth of the Rhine near Zwammerdam featured a large steering gear mounted on the stern. [28] [29] According to new research, the advanced Nemi ships, the palace barges of emperor Caligula (37-41 AD), may have featured 14 m long rudders. [30]

Sternpost-mounted rudder

Ancient China

An Eastern Han (25-220 AD) Chinese pottery boat fit for riverine and maritime sea travel, with an anchor at the bow, a steering rudder at the stern, roofed compartments with windows and doors, and miniature sailors Eastern Han pottery boat.JPG
An Eastern Han (25220 AD) Chinese pottery boat fit for riverine and maritime sea travel, with an anchor at the bow, a steering rudder at the stern, roofed compartments with windows and doors, and miniature sailors
An early Song dynasty (960-1279) painting on silk of two Chinese cargo ships accompanied by a smaller boat, by Guo Zhongshu (c. 910-977 AD); notice the large sternpost-mounted rudder on the ship shown in the foreground Guo Zhongshu-Traveling on the River in Snow.jpg
An early Song dynasty (960–1279) painting on silk of two Chinese cargo ships accompanied by a smaller boat, by Guo Zhongshu (c. 910–977 AD); notice the large sternpost-mounted rudder on the ship shown in the foreground

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] [11] [31] 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. [11] One of oldest known depictions of the Chinese stern-mounted rudder (duò) 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). [32] [33] It was discovered in Guangzhou in an archaeological excavation carried out by the Guangdong Provincial Museum and Academia Sinica of Taiwan in 1958. [32] [33] Within decades, several other Han dynasty ship models featuring rudders were found in archaeological excavations. [34] The first solid written reference to the use of a rudder without a steering oar dates to the 5th century. [31]

Chinese rudders are attached to the hull by means of wooden jaws or sockets, [35] while typically larger ones were suspended from above by a rope tackle system so that they could be raised or lowered into the water. [35] 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. [36]

Pottery boat from Eastern Han dynasty showing the earliest known representation of a rudder Pottery boat from Eastern Han Dynasty showing rudder.jpg
Pottery boat from Eastern Han dynasty showing the earliest known representation of a rudder

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. [31]

Ancient India

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. [37] [38]

Medieval Near East

Arab ships also used a sternpost-mounted rudder. [39] 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." [39] 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. [40]

Medieval Europe

Pintle-and-gudgeon rudder of the Hanseatic league flagship Adler von Lubeck (1567-1581), the largest ship in the world at its time Adler von Lubeck. Model ship 05.jpg
Pintle-and-gudgeon rudder of the Hanseatic league flagship Adler von Lübeck (1567–1581), the largest ship in the world at its time

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, [10] [31] the oldest known depiction of a pintle-and-gudgeon rudder can be found on church carvings of Zedelgem and Winchester dating to around 1180. [10] [31]

A ship's rudder carved in oak, 15th century, Bere Ferrers church, Devon. Heraldic badge of Cheyne and Willoughby families. RudderBereFerrersBenchEnd.jpg
A ship's rudder carved in oak, 15th century, Bere Ferrers church, Devon. Heraldic badge of Cheyne and Willoughby families.

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. [41] 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. [42] From the Age of Discovery onwards, European ships with pintle-and-gudgeon rudders sailed successfully on all seven seas. [42]

Historian Joseph Needham holds that the stern-mounted rudder was transferred from China to Europe and the Islamic world during the Middle Ages. [7] [32] [31]

Modern rudders

Conventional rudders have been essentially unchanged since Isambard Kingdom Brunel introduced the balanced rudder on the SS Great Britain in 1843 [43] and the steering engine in the SS Great Eastern in 1866. [44] If a vessel requires extra maneuverability at low speeds, the rudder may be supplemented by a manoeuvring thruster in the bow, [45] or be replaced entirely by azimuth thrusters.

Boat rudders details

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. [46]

Types of rudders

Various types of rudders are used in the marine industry, including spade rudders, [47] semi-spade rudders, high-lift rudders, and balanced rudders.


Rudder control

Large ships (over 10,000 ton gross tonnage) have requirements on rudder turnover time. To comply with this, high torque rudder controls are employed. [48] 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. [49]

Aircraft rudders

Movement caused by the use of rudder Aileron yaw.gif
Movement caused by the use of rudder
The rudder is controlled through rudder pedals on the bottom rear of the yoke in this photo of a Boeing 727 cockpit. MM00756-4.jpg
The rudder is controlled through rudder pedals on the bottom rear of the yoke in this photo of a Boeing 727 cockpit.
The water rudders on this Cessna 208 Caravan floatplane are the small vertical surfaces on the rear end of each float. Their setting is controlled from the cockpit. Cessna 208 Caravan 1 floatplane (G-MDJE) at Gloucestershire Airport (England) 24May2017 arp.jpg
The water rudders on this Cessna 208 Caravan floatplane are the small vertical surfaces on the rear end of each float. Their setting is controlled from the cockpit.

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

Notes

  1. 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]
  2. Joseph Needham, Lefèbre des Noëttes, K.S. Tom, Chung Chee Kit, S.A.M. Adshead, John K. Fairbank, Merle Goldman, Frank Ross, and Leo Block. [7] [8] [9]

Footnotes

  1. 1 2 rudder.Encyclopædia Britannica. Retrieved August 8, 2008, from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD
  2. William F. Edgerton: “Ancient Egyptian Steering Gear”, The American Journal of Semitic Languages and Literatures, Vol. 43, No. 4. (1927), pp. 255-265
  3. R. O. Faulkner: Egyptian Seagoing Ships, The Journal of Egyptian Archaeology, Vol. 26. (1941), pp. 3-9
  4. 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
  5. Timothy J. Runyan: “Review of The Development of the Rudder: A Technological Tale“, Speculum, Vol. 74, No. 4, (1999), pp. 1096-1098 (1098)
  6. The Concise Oxford Dictionary of English Etymology
  7. 1 2 3 4 5 6 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 103104.
  8. 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.
  9. 1 2 3 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.
  10. 1 2 3 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 627628.
  11. Fairbank, John K. and Merle Goldman. (1998). China: A New History, Enlarged Edition. Cambridge: Harvard University Press. ISBN   0-674-11673-9. Page 93.
  12. 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.
  13. Block, Leo. (2003). To Harness the Wind: A Short History of the Development of Sails. Annapolis: Naval Institute Press. ISBN   1-55750-209-9. 89.
  14. 1 2 William F. Edgerton: "Ancient Egyptian Steering Gear", The American Journal of Semitic Languages and Literatures, Vol. 43, No. 4. (1927), pp. 255
  15. William F. Edgerton: "Ancient Egyptian Steering Gear", The American Journal of Semitic Languages and Literatures, Vol. 43, No. 4. (1927), pp. 257
  16. William F. Edgerton: "Ancient Egyptian Steering Gear", The American Journal of Semitic Languages and Literatures, Vol. 43, No. 4. (1927), pp. 260
  17. 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.
  18. Mohamed Ata: “Egypt from Past to Present. Through the Eyes of an Egyptian”, Cairo 2007, p.68
  19. Herodot: Histories, 2.96
  20. William F. Edgerton: “Ancient Egyptian Steering Gear”, The American Journal of Semitic Languages and Literatures, Vol. 43, No. 4. (1927), pp. 263
  21. 1 2 3 Lawrence V. Mott, The Development of the Rudder, A.D. 100-1600: A Technological Tale, Thesis May 1991, Texas A&M University, p.1
  22. 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)
  23. 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)
  24. 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.
  25. Lionel Casson: “Ships and Seamanship in the Ancient World”, ISBN   0-8018-5130-0, S.XXVIII, 336f.; Fig.193
  26. Tilmann Bechert: Römisches Germanien zwischen Rhein und Maas. Die Provinz Germania inferior, Hirmer, München 1982, ISBN   3-7774-3440-X, p.183, 203 (Fig.266)
  27. 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.
  28. M. D. de Weerd: Römerzeitliche Transportschiffe und Einbäume aus Nigrum Pullum / Zwammerdam, in: Studien zu den Militärgrenzen Roms II (1977), 187ff.
  29. Deutschlandfunk: Römische Schiffsversuchsanstalt in den Albaner Bergen
  30. 1 2 3 4 5 6 Johnstone, Paul and Sean McGrail. (1988). The Sea-craft of Prehistory. New York: Routledge. ISBN   0-415-02635-0. Page 191.
  31. 1 2 3 Needham, Volume 4, Part 3, 649-650.
  32. 1 2 Fairbank, 192.
  33. 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.
  34. 1 2 Needham, Volume 4, Part 3, 362.
  35. Needham, Volume 4, Par634.
  36. 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.
  37. Guy, John (1999). "A Boat Model and State Ritual in Eastern India". Bulletin de l'École française d'Extrême-Orient. 86: 105–126. doi:10.3406/befeo.1999.3407. ISSN   0336-1519. JSTOR   43732572.
  38. 1 2 Lawrence V. Mott, p.93
  39. Lawrence V. Mott, p.92f.
  40. 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.
  41. 1 2 Lawrence V. Mott, The Development of the Rudder, A.D. 100-1600: A Technological Tale, Thesis May 1991, Texas A&M University, S.118f.
  42. Vaughan, Adrian (1991) [1991]. Isambard Kingdom Brunel (2nd ed.). London: John Murray. p. 160. ISBN   0-7195-4636-2.
  43. Bennett, S. (1986). A History of Control Engineering, 1800-1930. Peregrinus. p. 98. ISBN   9780863410475 . Retrieved 2015-01-10.
  44. Osmotech UK on Uses and advantages of bow thrusters Archived July 26, 2013, at the Wayback Machine
  45. "Barrel Type Rudder Makes Quicker Turns" Popular Mechanics, October 1934, bottom-right pg.495
  46. Desk, NV Tech (2024-07-22). "Understanding Marine Rudders: Types, Usage, and Design Considerations". Nautical Voice. Retrieved 2024-07-22.{{cite web}}: |last= has generic name (help)
  47. 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.
  48. "Understanding Steering Gear in Ships". Marine Insight. 2019-02-20. Retrieved 2021-06-03.

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<span class="mw-page-title-main">Birlinn</span> Middle ages Scottish ship

The birlinn or West Highland galley was a wooden vessel propelled by sail and oar, used extensively in the Hebrides and West Highlands of Scotland from the Middle Ages on. Variants of the name in English and Lowland Scots include "berlin" and "birling". The Gaelic term may derive from the Norse byrðingr, a type of cargo vessel. It has been suggested that a local design lineage might also be traceable to vessels similar to the Broighter-type boat, equipped with oars and a square sail, without the need to assume a specific Viking design influence. It is uncertain, however, whether the Broighter model represents a wooden vessel or a skin-covered boat of the currach type. The majority of scholars emphasise the Viking influence on the birlinn.

<span class="mw-page-title-main">Model yachting</span>

Model yachting is the pastime of building and racing model yachts. It has always been customary for ship-builders to make a miniature model of the vessel under construction, which is in every respect a copy of the original on a small scale, whether steamship or sailing ship. There are fine collections to be seen at both general interest museums such as the Victoria and Albert Museum in London and at many specialized maritime museums worldwide. Many of these models are of exquisite workmanship, every rope, pulley or portion of the engine being faithfully reproduced. In the case of sailing yachts, these models were often pitted against each other on small bodies of water, and hence arose the modern pastime. It was soon seen that elaborate fittings and complicated rigging were a detriment to rapid handling, and that, on account of the comparatively stronger winds in which models were sailed, they needed a greater draught. For these reasons modern model yachts, which usually have fin keels, are of about 15% or 20% deeper draught than full-sized vessels, while rigging and fittings have been reduced to absolute simplicity. This applies to models built for racing and not to elaborate copies of steamers and ships, made only for show or for " toy cruising."

Self-steering gear is equipment used on sail boats to maintain a chosen course or point of sail without constant human action.

Medieval ships were the vessels used in Europe during the Middle Ages. Like ships from antiquity, they were moved by sails, oars, or a combination of the two. There was a large variety, mostly based on much older, conservative designs. Although wider and more frequent communications within Europe meant exposure to a variety of improvements, experimental failures were costly and rarely attempted. Ships in the north were influenced by Viking vessels, while those in the south by classical or Roman vessels. However, there was technological change. The different traditions used different construction methods; clinker in the north, carvel in the south. By the end of the period, carvel construction would come to dominate the building of large ships. The period would also see a shift from the steering oar or side rudder to the stern rudder and the development from single-masted to multi-masted ships. As the area is connected by water, people in the Mediterranean built different kinds of ships to accommodate different sea levels and climates. Within the Mediterranean area during the Medieval times ships were used for a multitude of reasons, like war, trade, and exploration.

<span class="mw-page-title-main">Stern</span> Back or aft-most part of a ship or boat

The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Originally, the term only referred to the aft port section of the ship, but eventually came to refer to the entire back of a vessel. The stern end of a ship is indicated with a white navigation light at night.

<span class="mw-page-title-main">Coxless four</span> Boat class used in competitive rowing

A coxless four, abbreviated as a 4- and also called a straight four, is a racing shell used in the sport of competitive rowing. It is designed for four persons who propel the boat with sweep oars, without a coxswain.

<i>Baris</i> (ship) Type of ancient Egyptian boat

A baris is a type of Ancient Egyptian ship, whose unique method of construction was described by Herodotus, writing in about 450 BC. Archeologists and historians could find no corroboration of his description until the discovery of the remains of such a ship in the waters around Thonis-Heracleion in Aboukir Bay in 2003.

<span class="mw-page-title-main">Benawa</span>

Benawa or banawa is a type of ship from Gowa, an old principality in the southwest corner of Sulawesi, Indonesia. The earliest record of this vessel is from Hikayat Banjar, which was written in or not long after 1663. In the present, this vessel is already extinct; being replaced by vessels with a similar hull, namely palari and padewakang.

<span class="mw-page-title-main">Stern sculling</span> Rowing technique

Stern sculling is the use of a single oar over the stern of a boat to propel it with side-to-side motions that create forward lift in the water. The strict terminology of propulsion by oar is complex and contradictory, and varies by context. Stern sculling may also simply be referred to as "sculling", most commonly so in a maritime situation. In fresh water, and particularly in sport rowing, sculling is use of two oars on either side of the boat by each person, in contrast to sweep rowing, whereby each boat crew member employs a single oar, complemented by another crew member working on the opposite side with their oar.

This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water. Some remain current, while many date from the 17th to 19th centuries. The word nautical derives from the Latin nauticus, from Greek nautikos, from nautēs: "sailor", from naus: "ship".

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