Spar torpedo at Alden Park, Mare Island, Vallejo, California, August 2012.
The term “sea mine” was first applied in the early 16th century when the Dutch loaded vessels with large amounts of explosives and sent these drifting mines against an enemy ship or shore installations. In 1585 Federico Gianibelli, an Italian working for the Dutch, sent two “bomb ships” to drift into a bridge over the river Scheldt at Antwerp, Belgium, demonstrating the potential of such a device.

In the late 18th and early 19th centuries, American inventors David Bushnell, Robert Fulton and Samuel Colt investigated stationary torpedoes (mines):

  • Bushnell has become known as the father of mine warfare. As a student at Yale University, he worked on the development of underwater explosives. In his research, he discovered that gunpowder could be exploded underwater. During the American Revolution Bushnell was authorized to design a sea mine (which he usually referred to as a “torpedo”) to be used against the British fleet. He filled kegs with gunpowder and assembled a flintlock mechanism adjusted so that a light shock would release the hammer and fire the powder. Bushnell sent the floating kegs down the Delaware River in December 1777 with the hope that one or all of these kegs would drift into the British ships anchored at Philadelphia. Although this attempt by Bushnell is referred to in history books as the “Battle of the Kegs,” there was no actual battle and the keg mines did not meet with success. One of the kegs that had been spotted by two boys exploded when they tried to retrieve it, killing them and alerting the British to be on the lookout for the kegs. The British destroyed the rest of the kegs by firing into them as they floated by.
  • Fulton continued the development of floating mines. In 1797, he proposed to the British that they use drifting mines to attack the French fleet. These mines were supplied with a clockwork mechanism which could be started when the mine was released and would explode five to ten minutes later. This attempt failed when the French fired on the small boats carrying the mines and they had to be released early. Around 1800, Fulton may have been the first to apply the word “torpedo” in describing a device with an enclosed mass of gunpowder which was to be exploded beneath enemy ships—chosen due to the similarity in the way in which the device and the torpedo fish both communicated shock, or simply because detonation of the charge rendered fish torpid. Thereafter, the term was generally applied to all underwater explosive devices through most of the nineteenth century. In 1801, he sank a small ship using a submarine mine with an explosive charge of 20 pounds of gunpowder at Brest, France. In his next experiment Fulton attempted to destroy a French frigate by building a weapon that consisted of a cable with a mine connected to each end. Fulton released the mine and cable such that the cable would snag the ship’s bow drawing the mines into contact with the ship’s sides as it sailed by. This attempt failed: the mines exploded without sinking the ship, possibly because they were not submerged. In 1805, while working in England, Fulton succeeded in sinking the 200-ton brig Dorothea. Fulton made each mine heavier so that it would sink beneath the surface and the connecting cable would draw the mine underneath the ship where it was most vulnerable. This successful experiment led to the conclusion that a weighted mine beneath the surface was more effective than a floating surface mine in destroying a ship’s hull.
  • Colt, later known for developing the revolver, perfected the use of electric current to detonate a mine in 1844 on the Potomac River. He used an electric current that flowed through a wire to heat the powder and set off the explosion. Colt also invented a moored minefield that could be detonated on command by an operator on shore when a ship passed over. Colt conceived the moored minefield as a defensive controlled-weapon system and was very concerned about not only firing the moored mines, but about firing each at the right time when a target vessel would be over a particular mine or within damage range.

During the Crimean War (1854–1856), the Russian government used stationary torpedoes on a large scale—in the defense of Sebastapol, at the entrance to the Sea of Azov in the Black Sea, and at Cronstadt and Sweaborg in the Baltic Sea, where it exploded them under four English ships, damaging all four.

During the American Civil War, both sides employed stationary torpedoes. The Confederate Navy achieved the greater success, sinking 22 Union ships and damaging 12; the Union Navy destroyed six Confederate ships.

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Fulton may have been the first to conceive of a torpedo’s “offensive” potential when he proposed a boom-mounted explosive charge. During the Civil War, both North and South used such a “spar” configuration—notably by Lt. William Barker Cushing in sinking the Confederate ram Albemarle at Plymouth, North Carolina in October 1864.

In 1858, British engineer Robert Whitehead started producing big ship engines for the Austrian Navy. Two years later, Captain Giovanni Biagio Luppis conceived of a “coast guard,” an explosive boat for coastal defense. In 1864, Luppis joined Whitehead in an attempt to develop the new weapon but the following year, Whitehead turned to developing an explosive “fish” which looked like tuna and moved under the surface. In 1866, he presented his “mine-ship” (Minenschiff) to the Austrian Navy.

In 1870, Whitehead tested more than a hundred torpedoes: speed, 7 knots; range, 500 meters—useful, thought the Ministry of War technical committee, only against stationary targets. But development continued: with a depth regulator, with counter-rotating propellers from Royal Navy workshops in Woolwich in 1871, with a 3-cylinder radial engine for increased speed in 1875. Through 1881, Whitehead sold torpedoes to countries around the world: 254 to England, 250 to Russia, 218 to France, 203 to Germany, 100 to Austria-Hungary, 83 to Denmark and 70 to Italy, and smaller numbers to Argentina, Belgium, Greece, Portugal and others.

In 1889, Whitehead began increasing the calibre of the torpedo, ultimately to 533mm, which made possible a large steel air reservoir for greater speed and range. In 1894, Ludovico Obry, a former Whitehead colleague from from Rijeka, developed and patented a gyroscope for directing the torpedo—an invention refined by the turn of the century by a mechanic named Czerny.

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After it established a Torpedo Station at Newport, Rhode Island in 1869, the US Navy investigated a number of torpedo designs, two of which it sought to develop:
  • The Fish torpedo was the first torpedo tested at Newport in 1871. It was powered by a compressed air tank and was the first torpedo driven by a propeller. With a range of 200 yards, the bronze torpedo was 12 feet long, carried a 100-pound dynamite charge and travelled at a speed of up to 8 knots. Depth control was maintained by a hydrostatic bellows system but direction control was a concern and circular runs were recorded. Development of the Fish was discontinued in 1873.
  • The Howell torpedo was the first American-designed torpedo. Two shafted propellers were driven by a flywheel, which was spun up by a small steam turbine mounted on the torpedo tube. With its flywheel acting as a gyroscope, the Howell torpedo did not leave a wake and could steer a straighter course than the Whitehead. It was also smaller and cheaper and did not require an air flask, a difficult thing for the United States to manufacture at the time. In 1889, the Navy ordered 30 Howells; in 1894, it ordered 20 more. These were placed in service in 1895 but removed in 1903, after difficulties and delays in production led the Navy to adopt the Whitehead design.

The US Navy finally licensed the Whitehead torpedo in 1891 and established an office at Weymouth as well as the Torpedo Station at Newport. On 19 May of that year, it awarded a contract for 100 torpedoes to the E. W. Bliss company. These proved better in depth control but less accurate than the Howell. A lengthened version, known as the “5.0 m x 45 cm Whitehead” when first manufactured, was designated as the “Type B” in 1913. The last 40 of these were the first American torpedoes to incorporate Obry’s gyro, which improved the horizontal deviation by 300 per cent compared to the earlier Mark 1 torpedoes to ±8 yards (7 m) at 800 yards (730 m).

References: History of the Sea Mine and its Continued Importance in Today's Navy; A Brief History of U.S. Navy Torpedo Development by E. W. Jolie, A Brief History of U.S. Navy Torpedo Development by E. W. Jolie, United States of America, Torpedoes Pre-World War II and Torpedo of Rijeka, Muzej Grada Rijeke, Rijeka, Croatia.