Cheval de frise
The portable type comprised cast-iron tetrapod spikes a bit bigger than your fist that could be scattered very quickly in the path of threatening cavalry. With four spikes, no matter how they landed, one spike would always point upwards to maim any horse that trod on it, and its rider when he fell off. One problem that remained - these were the ancient equivalent of today's land-mines; they needed to be removed after the threat was over, otherwise they remained a severe threat to the innocent passer-by.
A modern development of this tetrapod concept is the use of huge (blunt) concrete tetrapods used for sea defence works.
The fixed type was an obstacle consisting of a portable frame (sometimes just a simple log) covered with many projecting long iron or wooden spikes or spears. They were principally intended as an anti-cavalry obstacle but could also be moved quickly to help block a breach in another barrier. They remained in occasional use until they were replaced by wire obstacles just after the American Civil War. During the Civil War, the Confederates used this type barrier more often than the Union forces. During World War I, armies used chevaux de frise to temporarily plug gaps in barbed wire. Chevaux de frise of barbed wire were used in jungle fighting on south Pacific islands during World War II.
French: Cheval de frise means "Frisian horse". The Frisians, having few cavalry, relied heavily on such anti-cavalry obstacles in warfare. The term came to be used for any spiked obstacle, such as broken glass embedded in mortar on the top of a wall.
An anti-ship version was designed by Robert Erskine as a means of keeping British warships from proceeding up the Hudson River during the American Revolutionary War. A cheval-de-frise was placed between Fort Washington at northern Manhattan and Fort Lee in New Jersey in 1776. The following year construction began on another north of West Point at Pollepel Island, but it was overshadowed by completion of The Great Chain across the Hudson in 1778, which was used through 1782.
Similar devices planned by Ben Franklin were used in the Delaware River near Philadelphia, in between Fort Mifflin and Fort Mercer. A cheval-de-frise was retrieved from the Delaware River in Philadelphia on November 13, 2007 in excellent condition, after more than two centuries in the river.
- http://japanfocus.org/-Catherine-Knight/3292 third picture
- Mahan, Peter, Chevaux-de-frise, NPS.
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- Chevaux de Frise, Charleston footprints, 2011-02-24.
- Friesian horse.
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- "Revolutionary War Artifact from the Depths of the Delaware River". Independence Seaport Museum. Retrieved 2008-08-05.