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Junk rig

Junk rig is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Junk rig rather than just read about it. In short: The junk rig, also known as the Chinese lugsail, Chinese balanced lug sail, or sampan rig, is a type of sailing rig in which rigid members, called battens, span the full width of the sail and extend the sail forward of the mast. While relatively uncommon in use among modern production sailboats, the rig's advantages of easier use and lower maintenance for blue-water cruisers have been explored by individuals such as…

Junk rig — main illustration
Junk rig — illustration

Key takeaways

  • Junk rig belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Junk rig to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Junk rig from memory before moving on to harder problems.

Reference excerpt

The junk rig, also known as the Chinese lugsail, Chinese balanced lug sail, or sampan rig, is a type of sailing rig in which rigid members, called battens, span the full width of the sail and extend the sail forward of the mast. While relatively uncommon in use among modern production sailboats, the rig's advantages of easier use and lower maintenance for blue-water cruisers have been explored by individuals such as trans-Atlantic racer Herbert "Blondie" Hasler and author Annie Hill.

Etymology

The English word "junk" comes from Portuguese junco from Malay jong. The word originally referred to (with or without junk rigs) the Javanese djong, very large trading ships that the Portuguese first encountered in Southeast Asia. It later also included the smaller flat-bottomed Chinese chuán, even though the two were markedly different vessels. After the disappearance of the jong in the 17th century, the meaning of "junk" (and other similar words in European languages) came to refer exclusively to the Chinese ship.

History

The origin of the junk sailing rig is not directly recorded. The Chinese adopted the sail design from other cultures, although the Chinese made their own improvements over time. Paul Johnstone attribute the invention of this type of sail to Austronesian peoples from Indonesia. They were originally made from woven mats reinforced with bamboo, dating back to at least several hundred years BCE. They may have been adopted by the Chinese after contact with Southeast Asian traders (K'un-lun po) by the time of the Han dynasty (206 BCE to 220 CE). However, Chinese vessels during this era were mostly fluvial (riverine) while others were made to cross shorter distances over the seas (littoral zones); China did not build true ocean-going fleets until the 10th century Song dynasty. The Chinese were using square sails during the Han dynasty; only in the 12th century did the Chinese adopt the Austronesian junk sail. Sinologist Joseph Needham also argues that Chinese balanced lug sails developed from Indonesian tilted sails. Iconographic remains show that Chinese ships before the 12th century used square sails. A ship carving from a stone Buddhist stele shows a ship with square sail from the Liu Sung dynasty or the Liang dynasty (ca. 5th or 6th century). Dunhuang cave temple no. 45 (from the 8th or 9th century) features large sailboats and sampans with inflated square sails. A wide ship with a single sail is depicted in the Xi'an mirror (after the 9th or 12th century).

Needham thinks a ship in the Borobudur relief may have been the first to depict a junk sail. The ship is distinct from the reliefs of other ships and could be the oldest depiction of a Chinese seafaring ship. This is disputed by D.A. Inglis, who concluded that the ship described was more like Indian Ocean ships operating from Arabia and South Asia after conducting an on-the-spot investigation of the relief. The ship has protruding deck beams, a single mast (not a bipod or tripod), and a square sail that has a yard and boom. The oldest depiction of a battened junk sail comes from the Bayon temple at Angkor Thom, Cambodia. This depiction may feature a Chinese ship, but this is disputed by Nick Burningham, who points out that the ship had a keel and that Chinese ships generally did not have a sternpost (extension of the keel at the rear of the ship). The rudder has a thin blade, different from the Chinese rudder which usually has a long blade. These characteristics may suggest a quarter rudder mounted on the beams of the rear gallery. From its characteristics and location, it is likely that this ship is a Southeast Asian ship.

Junk sail rigged boats As the origins of the junk sail remain unknown, no particular rig can claim to be the original or correct way to rig a junk sail. Some sailors have demonstrated the junk sails ability to work even in the presence of some standing rigging, such as the Colvin rig, although more care must be taken to prevent damage while sailing. Some ships that have been known to use junk sails include:

Casco, a flat-bottomed barge originally used by the Tagalog people along the Pasig River and Manila Bay. Tongkang or "Tong'kang". A light boat used commonly in the early 19th century to carry goods along rivers. Twakow, a type of vessel with one mast and junk rig. They were a common sight in the Singapore river in the mid-19th century. Djong, a ship with pointed hull, some are equipped with bowsprit and bowsprit sail. Bedar, a type of ship from Malaya. Pinas, a Malay ship, originally rigged with schooner rig. Lorcha, a light Chinese sailing vessel. This ship combined a western-style hull of Portuguese influence, with Chinese-style mast and sail. The lorcha were found in the Gulf of Siam and in Philippine waters as well. The Vũng Tàu shipwreck consists of the remains of a late 17th-century lorcha from the South China Sea off the islands of Con Dao, about 160 km from Vũng Tàu, Vietnam. There is no one specific junk sail plan and various designs exist. Square headed junk sails have parallel yards and booms and resemble rectangles. Fan-headed junk sails have yards angled forward at varying degrees. Split panel junk sails separate the sail plan in two sections, a main section behind the mast, and a smaller section forward the mast. This is done in an effort to mimic the effect of the "slot" created by separating the headsail and mainsail in Bermuda rigs, although the benefits of the "slot effect" are disputed. Hybrids between a Bermuda sail and junk sail exist as well, attempting to join the junk sail rigs ease of use with tried and true Bermuda triangular sail plans, some examples being the Aerorig and Aerojunk.

General sail construction

Sail terminology

The junk sail has essentially the same sides and corner names as the traditional gaff rigged four-corner sail. Knowing the names of the sides and corners help understand the running rigging and sail trim of the junk sail. The four corners of the junk sail are:

the peak or the top corner; the throat down the yard from the peak, close to the mast. the tack at the base of the mast and boom, which is "tacked" on to the boat and does not move. the clew at the end of the boom, connected to the sheet. The four sides of the junk sail are:

… excerpt ends here. Continue reading the full article.

Illustrations

Junk rig: The Keying was a Chinese ship that employed a junk sailing rig.
The Keying was a Chinese ship that employed a junk sailing rig.
Junk rig: Scale model of a Tagalog outrigger ship with junk sails from Manila, 19th century
Scale model of a Tagalog outrigger ship with junk sails from Manila, 19th century
Junk rig: Early European illustration of Southeast Asian djongs and other smaller craft (D'Eerste Boeck, c. 1599), note the junk rig and the double rudders which distinguished Southeast Asian ships from the Chinese chuán which had a central rudder[3]
Early European illustration of Southeast Asian djongs and other smaller craft (D'Eerste Boeck, c. 1599), note the junk rig and the double rudders which distinguished Southeast Asian ships from the Chinese chuán which had a central rudder[3]
Junk rig: A bronze mirror of Tang, Wudai, or Song era, shows a ship with a square sail. Shaanxi Provincial Museum, Xi'an.
A bronze mirror of Tang, Wudai, or Song era, shows a ship with a square sail. Shaanxi Provincial Museum, Xi'an.
Junk rig: Ship with battened sails from the Bayon temple at Angkor Thom, Cambodia. 12–13th century CE.
Ship with battened sails from the Bayon temple at Angkor Thom, Cambodia. 12–13th century CE.

Worked examples

Example 1 — a first encounter with Junk rig

Start with the simplest possible case. Write down what Junk rig claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Junk rig before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Junk rig ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Junk rig

In research
Junk rig appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Junk rig in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Junk rig is common in secondary-school and first-year university syllabi. It links to neighbouring topics Indonesian inventions, Naval history of China, Sailing rigs and rigging, so understanding it makes those chapters shorter.
In everyday life
Look for Junk rig outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Junk rig in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Junk rig means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Junk rig out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Junk rig in simple terms?

The junk rig, also known as the Chinese lugsail, Chinese balanced lug sail, or sampan rig, is a type of sailing rig in which rigid members, called battens, span the full width of the sail and extend the sail forward of the mast. While relatively uncommon in use among modern production sailboats, th…

Why does Junk rig matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Junk rig?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Junk rig.

Tags

  • Indonesian inventions
  • Naval history of China
  • Sailing rigs and rigging
  • Ships of China

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