Naval mine

Similar to anti-personnel and other land mines, and unlike purpose launched naval depth charges, they are deposited and left to wait until, depending on their fuzing, they are triggered by the approach of or contact with any vessel.

[1] Although international law requires signatory nations to declare mined areas, precise locations remain secret, and non-complying parties might not disclose minelaying.

Defensive minefields safeguard key stretches of coast from enemy ships and submarines, forcing them into more easily defended areas, or keeping them away from sensitive ones.

The warnings do not have to be specific; for example, during World War II, Britain declared simply that it had mined the English Channel, North Sea and French coast.

[citation needed] Naval mines were first invented by Chinese innovators of Imperial China and were described in thorough detail by the early Ming dynasty artillery officer Jiao Yu, in his 14th-century military treatise known as the Huolongjing.

[7] The Dutch inventor Cornelius Drebbel was employed in the Office of Ordnance by King Charles I of England to make weapons, including the failed "floating petard".

In 1842 Samuel Colt used an electric detonator to destroy a moving vessel to demonstrate an underwater mine of his own design to the United States Navy and President John Tyler.

In the decade following 1868, Major Henry Larcom Abbot carried out a lengthy set of experiments to design and test moored mines that could be exploded on contact or be detonated at will as enemy shipping passed near them.

A similar fate occurred with the gunboat schooner Covadonga in front of the port of Chancay, on 13 September 1880, which having captured and checked a beautiful boat, it exploded when hoisting it on its side.

Two mines blew up when the Petropavlovsk struck them near Port Arthur, sending the holed vessel to the bottom and killing the fleet commander, Admiral Stepan Makarov, and most of his crew in the process.

[27] Beginning around the start of the 20th century, submarine mines played a major role in the defense of U.S. harbours against enemy attacks as part of the Endicott and Taft Programs.

[29] It was also during World War I, that the British hospital ship, HMHS Britannic, became the largest vessel ever sunk by a naval mine[citation needed].

By the beginning of World War II, most nations had developed mines that could be dropped from aircraft, some of which floated on the surface, making it possible to lay them in enemy harbours.

These were typically visited by warships, and the majority of the fleet then underwent a massive degaussing process, where their hulls had a slight "south" bias induced into them which offset the concentration-effect almost to zero.

Initially, major warships and large troopships had a copper degaussing coil fitted around the perimeter of the hull, energized by the ship's electrical system whenever in suspected magnetic-mined waters.

The U.S. effort against Japan, for instance, closed major ports, such as Hiroshima, for days,[37] and by the end of the Pacific War had cut the amount of freight passing through Kobe–Yokohama by 90%.

On 14 April 1988, USS Samuel B. Roberts struck an Iranian mine in the central Persian Gulf shipping lane, wounding 10 sailors.

Contact mines need to be touched by the target before they detonate, limiting the damage to the direct effects of the explosion and usually affecting only the vessel that triggers them.

[51] During the initial period of World War I, the Royal Navy used contact mines in the English Channel and later in large areas of the North Sea to hinder patrols by German submarines.

If a submarine's steel hull touched the copper wire, the slight voltage change caused by contact between two dissimilar metals was amplified[clarification needed] and detonated the explosives.

Similarly, the original broadband hydrophones of 1940s acoustic mines (which operate on the integrated volume of all frequencies) have been replaced by narrow-band sensors which are much more sensitive and selective.

Mines can now be programmed to listen for highly specific acoustic signatures (e.g. a gas turbine powerplant or cavitation sounds from a particular design of propeller) and ignore all others.

One such design is the Mk 67 Submarine Launched Mobile Mine[61] (which is based on a Mark 37 torpedo), capable of traveling as far as 16 km (10 mi) through or into a channel, harbour, shallow water area, and other zones which would normally be inaccessible to craft laying the device.

In others, a safety lanyard is pulled (one end attached to the rail of a ship, aircraft or torpedo tube) which starts an automatic timer countdown before the arming process is complete.

[72] B-24 Liberators, PBY Catalinas and other bomber aircraft took part in localized mining operations in the Southwest Pacific and the China Burma India (CBI) theaters, beginning with a successful attack on the Yangon River in February 1943.

In Japan, much of the B-29 mine-laying work had been performed at high altitude, with the drifting on the wind of mines carried by parachute adding a randomizing factor to their placement.

[85] The Baengnyeong incident, in which the ROKS Cheonan broke in half and sank off the coast South Korea in 2010, was caused by the bubble jet effect, according to an international investigation.

[85] This shaking is powerful enough to cause disabling injury to knees and other joints in the body, particularly if the affected person stands on surfaces connected directly to the hull (such as steel decks).

Boats typically lack the generators and space for the solution, while the amount of power needed to overcome the magnetic field of a large ship is impractical.

[100][101] An updated form of this method is the use of small unmanned ROVs (such as the Seehund drone) that simulate the acoustic and magnetic signatures of larger ships and are built to survive exploding mines.