Oar

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Traditional wooden oars OarCollection01.JPG
Traditional wooden oars

An oar is an implement used for water-borne propulsion. Oars have a flat blade at one end. Rowers grasp the oar at the other end.

Contents

The difference between oars and paddles is that oars are used exclusively for rowing. In rowing the oar is connected to the vessel by means of a pivot point for the oar, either an oarlock, or a thole. The oar is placed in the pivot point with a short portion inside the vessel, and a much larger portion outside. The rower pulls on the short end of the oar, while the long end is in the water. By contrast, paddles, are held in both hands by the paddler, and are not attached to the vessel.

Rowers generally face the stern of the vessel, reach towards the stern, and insert the blade of their oar in the water. As they lean back, towards the vessel's bow, the blade of their oars pivots in the oarlock, and the end in the water moves towards the stern, providing forward thrust.

For thousands of years vessels were powered either by sails, or by the mechanical work of rowers, or by paddlers. Some ancient vessels were propelled by both oars and sail, depending on the speed and direction of the wind.

History

Rowing oars have been used since the early Neolithic period. Wooden oars, with canoe-shaped pottery, dating from 5000–4500 BC have been discovered in a Hemudu culture site at Yuyao, Zhejiang, in modern China. [1] [2] In 1999, an oar measuring 63.4 cm (2 ft) in length, dating from 4000 BC, was unearthed in Ishikawa Prefecture, Japan. [3]

Athletes of the sport of rowing using oars in tandem to move their boat in Japan, 2016

Construction

Oars have traditionally been made of wood. The form is a long shaft (or loom) with a flat blade on the end. Where the oar connects to the boat there is a "collar" (or button), often made of leather, which stops the oar slipping past the rowlock. Oars usually have a handle about 150mm long, which may be a material sleeve or alternatively an ovoid shape carved to fit the hands.

Physics

Oars are levers. Which class of lever depends on the frame of reference. From the rower's perspective, the oar can be seen as a Class I lever. The oar is fixed in the oarlock, the rower pulls on the handle, and the blade moves in the opposite direction to propel the boat. The blade is further from the oarlock than the rower's hands. So, the heavy force of a short rowing motion becomes a smaller force over a greater distance. [4]

From an observer on the shore, the oar is instead a Class II lever. Here, the fulcrum is the blade, planted in the water. The rower pulls on the handle and the boat moves along with them. The "Class II" perspective is important to competitive rowing. Effective rowers learn to lever the boat past the end of the blade, rather than pulling the blade through the water. [4] The World Rowing Federation rulebook defines oars as Class II. [5]

Both the Class I and Class II perspectives can be used to calculate the forces on the rower, boat, and water, with equivalent results. The calculations are simpler for the Class I perspective. The mechanical advantage of the oar depends on the length of the oar from the oarlock to the blade, compared to the length from the oarlock to the rower's hand(s). The further away from the oarlock the blade is, the more difficult it is to row and the more distance each stroke will move. [4]

Balanced oar

This is a normal, usually wooden oar to which weight has been added at the inboard end so that the blade end is noticeably lighter and easier for a rower to operate without fatigue. The two methods of adding weight are to either have a much larger section in the oar immediately next to the handle for a distance of about 450 millimetres (18 in) or to drill an 18-millimetre (0.71 in) hole inside the handle for a distance of about 150 millimetres (5.9 in) and add about 12 oz of lead secured by epoxy resin glue. For a 7-foot (2.1 m) oar the balance point is about 12 inches outboard of the rowlock. Often surplus wood is removed from the blade's width and thickness and at the neck between the blade and the shaft to further reduce outboard weight. As the rower is expending less energy accelerating the (now-reduced) mass of the oar back-and-forth, and will experience less fatigue constantly exerting downward force on the handle (vs. an unbalanced version) -- this type of oar is more efficient and thus preferable for long-range rowing.

Oars used for transport

The oars used for transport come in a variety of sizes. The oars used in small dinghies or rafts can be less than 2 metres long. In classical times warships were propelled by very long oars that might have several oarsmen per oar. These oars could be more than a dozen metres long.

Oars used for competitive rowing

A pair of carbon fibre sculling oars used for sport rowing Croker Sculling Oars.jpg
A pair of carbon fibre sculling oars used for sport rowing
Trophy oars of the seven founding member clubs of the Remenham Club Trophyoars.JPG
Trophy oars of the seven founding member clubs of the Remenham Club

The oars used in competitive rowing are long (250–300 cm) poles with one flat end about 50 cm long and 25 cm wide, called the blade. The part of the oar the oarsman holds while rowing is called the handle. While rowing, the oars are supported by metal frames attached to the side of the boat called riggers, while the oar fits into the oarlocks at the ends of each rigger. Classic oars were made of wood, but modern oars are made from synthetic material, the most common being carbon fibre.

Oars used as trophies

The sport of competitive rowing has developed a tradition of using an oar as a memento of significant race wins. A 'trophy oar' is not presented at the end of the race as a more familiar precious metal cup might be, but rather given by the club, school or university that the winning crew or rower represented.

A trophy oar is a competition oar that has been painted in the club colours and has then had the details of the race signwritten on the face of the blade. The most common format would have the coat of arms or crest of the club or school positioned in the centre, with the crew names and the race details arranged around this.

Many older universities (Oxford and Cambridge would be prime examples, as well as Yale and Harvard) and their colleges have long histories of using the trophy oar and many examples are on display in club houses around the world.

In culture

Crossed silver oars in the coat of arms of Enonkoski Enonkoski.vaakuna.svg
Crossed silver oars in the coat of arms of Enonkoski

The Norwegian municipalities of Fedje and Herøy both have oars in their coat-of-arms.

Oars have been used to describe various animals with characteristics that closely resemble the said rowing implement. The members of the Family Regalecidae, elongated deep-sea fishes, are called oarfish because their body shape is similar to that of an oar. [6] The hawksbill turtle's genus of Eretmochelys is derived from the Greek root eretmo, which roughly translates to oar. The turtle was so-named because of the oar-like shape of its front flippers. [7]

See also

Related Research Articles

<span class="mw-page-title-main">Rowing (sport)</span> Sport where individuals or teams row boats by oar

Rowing, sometimes called crew in the United States, is the sport of racing boats using oars. It differs from paddling sports in that rowing oars are attached to the boat using oarlocks, while paddles are not connected to the boat. Rowing is divided into two disciplines: sculling and sweep rowing. In sculling, each rower holds two oars—one in each hand, while in sweep rowing each rower holds one oar with both hands. There are several boat classes in which athletes may compete, ranging from single sculls, occupied by one person, to shells with eight rowers and a coxswain, called eights. There are a wide variety of course types and formats of racing, but most elite and championship level racing is conducted on calm water courses 2 kilometres (1.2 mi) long with several lanes marked using buoys.

<span class="mw-page-title-main">Dinghy</span> Type of small boat

A dinghy is a type of small boat, often carried or towed by a larger vessel for use as a tender. Utility dinghies are usually rowboats or have an outboard motor. Some are rigged for sailing but they differ from sailing dinghies, which are designed first and foremost for sailing. A dinghy's main use is for transfers from larger boats, especially when the larger boat cannot dock at a suitably-sized port or marina.

<span class="mw-page-title-main">Paddle</span> Tool for propelling a boat, or for mixing liquids and/or other states of matter.

A paddle is a handheld tool with an elongated handle and a flat, widened distal end, used as a lever to apply force onto the bladed end. It most commonly describes a completely handheld tool used to propel a human-powered watercraft by pushing water in a direction opposite to the direction of travel. It is different to an oar in that the latter is attached to the watercraft via a fulcrum.

<span class="mw-page-title-main">Rafting</span> Recreational outdoor activity

Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a part of the experience.

<span class="mw-page-title-main">Cutter (boat)</span> Type of boat

A cutter is a type of watercraft. The term has several meanings. It can apply to the rig of a sailing vessel, to a governmental enforcement agency vessel, to a type of ship's boat which can be used under sail or oars, or, historically, to a type of fast-sailing vessel introduced in the 18th century, some of which were used as small warships.

<span class="mw-page-title-main">Sculling</span> Type of rowing when a rower has two oars

Sculling is the use of oars to propel a boat by moving them through the water on both sides of the craft, or moving one oar over the stern. A long, narrow boat with sliding seats, rigged with two oars per rower may be referred to as a scull, its oars may be referred to as sculls and a person rowing it referred to as sculler.

<span class="mw-page-title-main">Rowing</span> Act of propelling a boat using the motion of oars in the water

Rowing is the act of propelling a boat using the motion of oars in the water by displacing water to propel the boat forward. Rowing and paddling are similar. However, rowing requires oars to have a mechanical connection with the boat, while paddles are hand-held and have no mechanical connection.

<span class="mw-page-title-main">Racing shell</span> Rowing boat designed for sport

In watercraft, a racing shell is an extremely narrow, and often comparatively long, rowing boat specifically designed for racing or exercise. It is outfitted with long oars, outriggers to hold the oarlocks away from the boat, and sliding seats. The boat's long length and semicircular cross-section reduce drag to a minimum. This makes the boat both fast and unstable. It must be balanced by the rowers to avoid tipping. Being able to balance – or "set" – the boat while putting maximum effort into the oars is therefore an essential skill of sport rowing.

In competitive rowing, the following specialized terms are important in the corresponding aspects of the sport:

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

A rowlock, sometimes spur, oarlock (USA) or gate, is a brace that attaches an oar to a boat. When a boat is rowed, the rowlock acts as a fulcrum for the oar.

<span class="mw-page-title-main">Oar (sport rowing)</span>

In rowing, oars are used to propel the boat. Oars differ from paddles in that they use a fixed or sliding fulcrum, an oarlock or rowlock attached to the side of the boat, to transfer power from the handle to the blade, rather than using the athlete's shoulders or hands as the pivot-point as in canoeing and kayaking.

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

In rowing, the stroke is the action of moving the oar through the water in order to propel the boat forward. The two fundamental reference points in the stroke are the catch where the oar blade is placed in the water, and the extraction where the oar blade is removed from the water. After the blade is placed in the water at the catch, the rower applies pressure to the oar levering the boat forward which is called the drive phase of the stroke. Once the rower extracts the oar from the water, the recovery phase begins, setting up the rower's body for the next stroke.

Paddling Manually propelling a boat using a paddle

Paddling with regard to watercraft is the act of manually propelling a boat using a paddle. The paddle, which consists of one or two blades joined to a shaft, is also used to steer the vessel. The paddle is not connected to the boat.

Boats used in the sport of rowing may be adjusted in many different ways according to the needs of the crew, the type of racing, and anticipated rowing conditions. The primary objective of rigging a boat is to accommodate the different physiques and styles of rowing of the crew in such a way that the oars move in similar arcs through the water, thus improving the crew's efficiency and cohesiveness.

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

A coxless four is a rowing boat used in the sport of competitive rowing. It is designed for four persons who propel the boat with sweep oars, without a coxswain.

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

Sweep rowing is one of two disciplines of the sport of rowing. In sweep rowing each rower has one oar, usually held with both hands. As each rower has only one oar, the rowers have to be paired so that there is an oar on each side of the boat. In the United Kingdom, rowing generally refers to sweep rowing only. The term pulling was also used historically. In the other rowing discipline, sculling, each rower holds two oars, one in each hand.

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

Fórcola is the typical Venetian rowlock providing a variety of fulcrum positions, each having its own effect on the rower's oar.

A remèr is a craftsman specialised in the making of traditional rowlocks – called fórcolas – and oars for Venetian boats.

<span class="mw-page-title-main">Human-powered watercraft</span>

Human-powered watercraft are watercraft propelled by human power.

<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. It is distinguished from sculling, which is rowing with two oars on either side of the boat and from sweep rowing, whereby each boat crew member employs a single oar, complemented by another crew member on the opposite side with an oar, usually with each pulling an oar with two hands.

References

  1. Deng, Gang. (1997). Chinese Maritime Activities and Socioeconomic Development, c. 2100 B.C.-1900 A.D. Westport: Greenwood Press. ISBN   0-313-29212-4, p. 22.
  2. Miriam T. Stark (15 April 2008). Archaeology of Asia. John Wiley & Sons. p. 130. ISBN   978-1-4051-5303-4 . Retrieved 5 October 2012.
  3. The Japan Times . (February 10, 1999). Oldest oar unearthed from Ishikawa ruins. Retrieved on 2008-08-13.
  4. 1 2 3 Dudhia, Anu. "Basic Physics of Rowing". Physics of Rowing. Oxford University Department of Physics. Retrieved 17 October 2021.
  5. World Rowing Federation. "2019 Complete Rule Book - English" . Retrieved 17 October 2021. ...using oars as simple levers of the second order...
  6. Howard, Brian. "5 Surprising Facts About the Oarfish That Has Been Washing Up on Beaches". National Geographic. Retrieved 2 March 2017.
  7. Beltz, Ellin. "Translations and Original Descriptions: Turtles". Scientific and Common Names of the Reptiles and Amphibians of North America – Explained. ebeltz.net. Retrieved 2007-02-06.