Medium clipper
Encyclopedia
A Medium clipper is a type of clipper
Clipper
A clipper was a very fast sailing ship of the 19th century that had three or more masts and a square rig. They were generally narrow for their length, could carry limited bulk freight, small by later 19th century standards, and had a large total sail area...

 designed for both cargo carrying capacity and speed. An evolutionary adaptation of the extreme clipper
Extreme clipper
An extreme clipper is a clipper designed to sacrifice cargo capacity for speed. They had a bow lengthened above the water, a drawing out and sharpening of the forward body, and the greatest breadth further aft. Extreme clippers were built in the period 1845 to 1855.-Medium and extreme clippers:From...

, the medium clipper had been invented by 1851, when the hull type appeared in U.S. shipyards. Medium clippers continued to be built until 1869, when the Glory of the Seas, one of the last known medium clipper ships to be built, was launched by the firm of Donald McKay & Co.
Donald McKay
Donald McKay was a Canadian-born American designer and builder of sailing ships.He was born in Jordan Falls, Shelburne County on Nova Scotia's South Shore. In 1826 he moved to New York, working for shipbuilders Brown & Bell and Isaac Webb...


Innovation

The 1850s saw two major gold rushes
Gold rush
A gold rush is a period of feverish migration of workers to an area that has had a dramatic discovery of gold. Major gold rushes took place in the 19th century in Australia, Brazil, Canada, South Africa, and the United States, while smaller gold rushes took place elsewhere.In the 19th and early...

 in the English-speaking world - in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 and Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...

 - as well as continued development of placer gold mining in the Sierra Nevada mountains of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

.

As these precious metal mining activities matured, the working populations of the affected gold and silver mining belts began to demand large quantities of manufactured goods. Shippers began to look for a ship design that would speed large quantities of boxed, barrelled, or crated cargo to Melbourne
Melbourne
Melbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...

 or San Francisco.

As the decade of the 1850s began, the dominant fast sailing ship design was the extreme clipper, properly defined as a cargo vessel with a 40-inch-or-more dead rise at half floor. This refers to a sail-powered cargo hull with a relatively flat-floored rear half, tapering as one moves forward along the hull to a relatively sharp forward half.

Extreme clippers successfully served the 49ers
California Gold Rush
The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The first to hear confirmed information of the gold rush were the people in Oregon, the Sandwich Islands , and Latin America, who were the first to start flocking to...

 who reached California placer fields during the opening years of the rush, but negative aspects of the design soon became apparent. The sharp-floored forward halves could not carry as much cargo as a full flat hull. In addition, the sharp-floored forward halves lacked the buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

 of the rounded rear halves, and this asymmetrical buoyancy tended to strain and weaken the hull. The working lifespan of an extreme clipper ship tended to be short.

By 1852 U.S. shipbuilders such as Donald McKay had begun to develop a new type of clipper ship hull, which combined a flat-floored hull for maximal cargo capacity with a clipper bow resembling that of the extreme clipper chip. The stern, masts, spars, and sail area also resembled the extreme clipper ship. The half floor dead rise of the true extreme clipper ship was, however, no longer to be seen.

Period of design

In 1851, shipbuilders in Medford, Massachusetts
Medford, Massachusetts
Medford is a city in Middlesex County, Massachusetts, in the United States, on the Mystic River, five miles northwest of downtown Boston. In the 2010 U.S. Census, Medford's population was 56,173...

 built the Antelope. Often called the Antelope of Boston
Antelope of Boston
Antelope was a medium clipper built in 1851 near Boston, in Medford, MA. She sailed in the San Francisco, China, and Far East trades. She was known for her fine finish work and for her crew’s escape from pirates...

to distinguish it from other ships of the same name, this vessel is sometimes called one of the first medium clipper ships. A ship-design journalist noted that "the design of her model was to combine large stowage capacity with good sailing qualities." However, the Antelope was relatively flat-floored and had only an 8-inch dead rise at half floor.

Shippers responded positively to the new hull design and instructed shipbuilders accordingly. By 1854, the numbers of medium clippers on the stocks were far outpacing the remaining extreme clippers. The last true extreme clipper was built in 1855.

By the 1860s, the time of the medium clipper was also coming to an end. Construction of a network of coaling stations around the world was making it possible for ocean-going steamships to cover global trade routes with a speed, frequency, and reliability of service that no medium clipper ship could match.

In the 1860s a final generation of clipper ships, the clipper-built composite ship
Composite ship
The technique of composite ship construction emerged in the mid-19th century as the final stage in the evolution of fast commercial sailing ships....

, featured wooden planking over a wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

 frame; the strength of the iron frame protected the composite clipper from the hogging and sagging that had bedevilled its predecessor, the extreme clipper. The surviving clipper ships of the world as of 2010, such as the Cutty Sark
Cutty Sark
The Cutty Sark is a clipper ship. Built in 1869, she served as a merchant vessel , and then as a training ship until being put on public display in 1954...

, are clipper-built composite ships; no true extreme clipper or medium clipper ships are known to survive.
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