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Jack (flag)

Jack (flag) 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 Jack (flag) rather than just read about it. In short: A jack is a flag flown from a short jackstaff at the bow (front) of a vessel, while the ensign is worn [flown] on the stern (rear). Jacks on bowsprits or foremasts appeared in the 17th century.

Jack (flag) — main illustration
Jack (flag) — illustration

Key takeaways

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

Reference excerpt

A jack is a flag flown from a short jackstaff at the bow (front) of a vessel, while the ensign is worn [flown] on the stern (rear). Jacks on bowsprits or foremasts appeared in the 17th century. A country may have different jacks for different purposes, especially when (as in the United Kingdom and the Netherlands) the naval jack is forbidden to other vessels. The United Kingdom has an official civil jack; the Netherlands has several unofficial ones. In some countries, ships of other government institutions may fly the naval jack, e.g. the ships of the United States Coast Guard and the National Oceanic and Atmospheric Administration in the case of the US jack. Certain organs of the UK's government have their own departmental jacks. Commercial or pleasure craft may fly the flag of an administrative division (state, province, land) or municipality at the bow. Merchant ships may fly a house flag. Yachts may fly a club burgee or officer's flag or the owner's private signal at the bow. Practice may be regulated by law, custom, or personal judgment.

Etymology "Jack" occupies 6 pages of the complete second edition of the Oxford English Dictionary and the use of the word in English goes back to the 14th century, appearing as a forename in Piers Plowman. Quite early on it was used as a name for a peasant or "a man of the lower orders". It continued the low class connotations in phrases such as "jack tar" for a common seaman, "every man jack", or the use of jack for the knave in cards. The diminutive form is also seen in "Jack of all trades, master of none", where Jack implies a poor tradesman, possibly not up to journeyman standard. The term was taken into inanimate objects and denoted a small (or occasionally inferior) component: jack-pit (a small mine shaft), jackplug (single pronged, low current), jack-shaft (intermediate or idler shaft), jack (in bowling: the small ball) or jack-engine (a donkey or barring engine). Incidentally, a jack is a garment for the upper body (quotes from 1375 onwards), a jacket is derived from this and is a small jack; not the other way around. As a further example of this usage, in 1686 Robert Plot writing about gins (i.e. horse engines) to pump water out of mines says: "they draw it [the water] up by Gin, which is made bigger, or less ... the less they call a Jack". As a flag, "jack" followed this usage. A jack flag was a small flag, used to distinguish it from the large ensign or pennants. The OED mentions the theory of its derivation from James I or from a leathern jacket but dismisses both: "neither of these conjectures covers the early use of the word". Originally, the jack would have been flown from the bowsprit topmast head: "You are alsoe for this present service to keepe in yor Jack at yor Boultspritt end" (sailing instructions 1633 as quoted in OED2). In 1667 Samuel Pepys, naval administrator and diarist, recorded the Dutch taking the Royal Charles and a man "struck her flag and jacke" – clearly two different things. By 1692 the jackstaff had been developed to fly the jack: "Jack staff and Jack".

Usage

A naval jack is usually flown when the ship is not under way, but is moored or at anchor, or when it is dressed overall on special occasions. The Union Jack of the Royal Navy must be run up when the first line is ashore when coming alongside. The same regulations are applied by the Royal Canadian Navy. In the United States, the jack is also used as embroidered sleeve patches by the US Navy on its uniforms.

Shapes and designs Naval jacks are usually rectangular, often square, and smaller than the national ensign or war flag. Some countries fly a smaller version of the national or war flag, or its canton on its own. France and some other countries use the same flag or ensign for all purposes, civil or military, and also as their naval jack. Japan and some other countries with civil and war ensigns of different designs fly the civil ensign as a jack and the war ensign at the ship's stern. A shortened, square version of the national flag is used by some countries. A larger group of jacks show the country's national coat of arms, either as a banner of arms, or as a badge displayed on the field. Most countries have chosen a completely different design for their naval jacks, often with some national or maritime symbol, and usually with the same colours as in their flags.

War ensign as jack Countries that use their war ensign also as a jack will usually fly a smaller version at the bow.

War flag as jack

Square version of national flag as jack

Canton of national ensign as jack

National coat of arms as jack

National flag as jack

National flag in canton as jack

Jacks of special design

Cross and Saltire Jacks

Union jacks

United or confederated states have in many cases adopted a jack representing their national union. The best known is the Union Jack of the United Kingdom's Royal Navy, composed in 1606 by joining the flags of England and Scotland. When the Kingdom of Ireland merged with Great Britain in 1801, a red saltire (Saint Patrick's Cross) was added to form the present Union Flag. The design of the UK's Union Jack probably inspired later jacks of other states, such as Russia, the Sweden-Norway, Estonia, and Latvia. The Russian jack in its turn inspired the jack of Bulgaria. From 1777 to 1975, 1977 to September 2002, and June 2019 to the present, the United States Navy has flown a "union jack", consisting of the blue canton with white stars from the US national ensign. In 1975 and 1976, and then again from September 11, 2002, to June 4, 2019, the US Navy flew the First Navy Jack, allegedly used in 1775 and 1776, with a rattlesnake and the motto "DONT TREAD ON ME" [sic] superimposed on thirteen alternating red and white stripes. The Confederate States of America followed the same pattern for its first naval jack (1861–1863), using the canton of its first naval ensign, with seven stars forming a circle on a "medium blue" field. Later versions had up to fifteen stars. The second Confederate naval jack was a rectangular cousin of the Confederate army's battle flag and was in use from 1863 until 1865. The Union Jack of Sweden and Norway (1844–1905) was a rectangular cross flag divided per saltire, combining the national colours of Sweden (hoist and fly) and Norway (top and bottom). The naval jack was also used as a flag for the common diplomatic representations abroad.

See also

Notes

References

… excerpt ends here. Continue reading the full article.

Illustrations

Jack (flag): Royal Netherlands Navy jack on HNLMS Walrus (1985), 2008
Royal Netherlands Navy jack on HNLMS Walrus (1985), 2008
Jack (flag): The US naval jack (2002–2019) being hoisted on USS Kitty Hawk's jackstaff in December 2001
The US naval jack (2002–2019) being hoisted on USS Kitty Hawk's jackstaff in December 2001
Jack (flag): Naval jack of the Irish Naval Service
Naval jack of the Irish Naval Service
Jack (flag): Russian Navy submarine Sankt Peterburg displaying the Russian naval jack at the bow and the naval ensign at the stern
Russian Navy submarine Sankt Peterburg displaying the Russian naval jack at the bow and the naval ensign at the stern
Jack (flag) illustration

Worked examples

Example 1 — a first encounter with Jack (flag)

Start with the simplest possible case. Write down what Jack (flag) 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 Jack (flag) 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 Jack (flag) 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 Jack (flag)

In research
Jack (flag) 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 Jack (flag) 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
Jack (flag) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Jacks (flags), Maritime culture, Maritime flags, so understanding it makes those chapters shorter.
In everyday life
Look for Jack (flag) 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 Jack (flag) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Jack (flag) 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 Jack (flag) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jack (flag) in simple terms?

A jack is a flag flown from a short jackstaff at the bow (front) of a vessel, while the ensign is worn [flown] on the stern (rear). Jacks on bowsprits or foremasts appeared in the 17th century.

Why does Jack (flag) 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 Jack (flag)?

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 Jack (flag).

Tags

  • Jacks (flags)
  • Maritime culture
  • Maritime flags
  • Types of flags

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