Naval mine

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A naval mine is a self-contained explosive device placed in water to destroy ships or submarines. Unlike depth charges, they are deposited and left to wait until they are triggered by the approach of an enemy ship. Naval mines can be used offensively, to hamper enemy ships or lock them into a harbor; or defensively, to protect friendly ships and create "safe" zones.

Mines can be laid in many ways: by purposebuilt minelayers, refitted ships, submarines, airplanes and even by dropping them into a harbour by hand. They can be inexpensive: some variants can cost around a thousand United States dollars (USD) or so, although more sophisticated mines can cost millions of USD, be equipped with several kinds of sensors, and deliver a warhead by rocket or torpedo.

Their flexibility and cost-effectiveness make mines attractive weapons in uneven contests. The cost of producing and laying a mine is usually anywhere from 0.5% to 10% of the cost to remove it, and it can take up to 200 times as long to clear a minefield than to lay it. Parts of some World War II minefields still exist because they are too spread out and expensive to clear—and theoretically, some of these mines might stay active for hundreds of years.

There are three main uses of mines: offensive, defensive and psychological. Offensive mines are placed in enemy waters, outside harbours and in important shipping routes to sink civilian and military ships. Defensive minefields protect a coast from enemy ships and submarines and force them into areas that are easier to defend. Psychological minefields are usually placed in trade routes, and are used to stop shipping to an enemy nation. They are also spread out thinly, to create a feeling of random minefields in large areas. A single mine in a route can stop shipping for days until the entire area is swept.

International law requires nations to declare when they mine an area, in order to make it easier for civil shipping to avoid the mines. The warnings do not have to be specific; during World War II, Britain declared simply that it had mined the English Channel, North Sea and French coast.

Contents 1 History 2 Types 2.1 Contact mines 2.1.1 Limpet mines 2.1.2 Floating contact mines 2.1.2.1 Drifting contact mines 2.1.3 Bottom contact mines 2.1.4 Remotely controlled mines 2.1.5 Moored mines 2.1.6 Bottom mines 2.2 Influence mines 3 Unusual mines 4 Mine laying 5 Damage 6 Countermeasures 6.1 Passive countermeasures 6.2 Active countermeasures 6.2.1 Mine sweeping 6.2.2 Mine hunting 6.2.3 Mine breaking 7 National arsenals 7.1 US Mines 8 See also 9 Notes 10 Further reading 11 External Links

[edit] History

Chinese records tell of first partical naval mines in the 16th century to fight against Japanese pirates Wokou.This kind of naval mine was loaded in wooden box,sealed by Putty.General Qi Jiguang made several timing explosive drifting mine to destroy pirates' ships.[1]

The Dutch inventor Cornelius Drebbel was employed in the Office of Ordnance by King Charles I of England to make weapons, including a "floating petard" which proved a failure.^[1] Weapons of this type were apparently tried by the English at the Siege of La Rochelle in 1627.^[2]

However, an American, David Bushnell invented the first western practical mine for use against the British in the American War of Independence. It was a watertight keg filled with gunpowder that was floated toward the enemy. It was detonated by a percussion lock if it struck a ship.

In 1812 Russian engineer Pavel Shilling exploded an underwater mine using electrical circuit. In 1854, during unsuccessful attempt of Anglo-French fleet to seize Kronshtadt fortress, British steamships HMS Merlin, HMS Vulture and HMS Firefly were damaged by underwater explosions of Russian naval mines. Generally, more than 1500 naval mines, or infernal machines were set by Russian naval specialists in the Gulf of Finland during Crimea War.^{[citation needed]}

The American Civil War saw the first western successful use of mines, by both sides. The first ship sunk by a mine was the USS Cairo in 1862 in the Yazoo River. Rear Admiral David Farragut's famous statement, "Damn the torpedoes, full speed ahead!" refers to a minefield laid at Mobile, Alabama.

In the 19th century, mines were called torpedoes, a name likely conferred by Robert Fulton after the torpedo fish, which gives powerful electric shocks. A spar torpedo was a mine attached to a long pole and detonated when the ship carrying it rammed another one. The H. L. Hunley used one to sink the USS Housatonic on February 17, 1864. A Harvey Torpedo was a type of floating mine towed alongside a ship, and was briefly in service in the Royal Navy in the 1870s. Other "torpedoes" attached to ships or even launched under their own power. One such weapon, called the Whitehead Torpedo after its inventor, eventually drew the appellation from static devices to self-propelled underwater missiles.

The next major use of mines was in the Russo-Japanese War in 1904, sinking the Russian battleship Petropavlovsk, killing the fleet commander, Admiral Makaroff, and most of the crew. On the other side, two Japanese battleships were sunk by Russian mines in one day.

Many of early mines were fragile and dangerous to handle, with glass containers filled with nitroglycerin or mechanical devices that activated them upon tipping. Several mine-laying ships were destroyed when their cargo exploded.

The U-boat fleet, which dominated much of the battle of the Atlantic, was small at the beginning of the war and much of the early action by German forces involved mining convoy routes and ports around Britain. The German submarines also operated in the Mediterranean Sea and its coasts, in the Caribbean Sea, and along U.S. coasts.

Initially contact mines were employed -- meaning that a ship had to physically strike one of the mines to detonate it -- usually tethered at the end of a cable just below the surface of the water. By the beginning of World War II most nations had also developed mines that could be dropped from aircraft, making it possible to lay them in enemy harbours (although they simply floated on the surface). The use of dredging and nets was effective against this type of mine, but this process was time consuming and involved closing harbors while it was completed.

Into this arena came a new mine threat. Most contact mines leave holes in ship's hulls, but some ships survived mine blasts, limping into port with buckled plates and broken backs. This appeared to be due to a new type of magnetic mine, detonating at a distance from the ship, and doing damage with the shockwave of the explosion. Often ships that had successfully run the gauntlet of the Atlantic crossing were destroyed entering freshly mineswept harbors on Britain's coast. More shipping was being lost than could be replaced, and Churchill ordered that the intact recovery of one of these new mines was of highest priority.

The British experienced a stroke of luck in November 1939. A German mine was dropped from an aircraft onto the mud flats of the Thames estuary, above the waterline. As if this was not sufficiently good fortune, the land belonged to the army, and a base with men and workshops was at hand. Experts were dispatched from London to investigate the mine. They had some idea that the mines used magnetic sensors, so everyone removed all metal, including their buttons, and made tools out of non-magnetic brass. They disarmed the mine and rushed it to labs at Portsmouth, where scientists discovered a new type of arming mechanism.

The mechanism had a sensitivity level that could be set, and the units of the scale were in milligauss. Gauss is a measurement for the strength of a magnetic field, demonstrating how it went off before coming into contact with the ship. Using the detector from the mine, they were able to study the effect of a ship passing near it. A ship or large ferrous object passing through the earth's magnetic field will concentrate the field at that point. The mine's detector was designed to go off at the mid-point of the ship passing overhead.

From this data, methods were developed to clear the mines. Early methods included the use of large electromagnets dragged behind ships, or on low-flying aircraft (a number of older bombers like the Vickers Wellington were used for this). Both of these methods had the disadvantage of "sweeping" only a small strip. A better solution was found in the form of electrical cables dragged behind ships, passing a large current through the seawater. This induced a large magnetic field and swept the entire area between the two ships. The older methods continued to be used in smaller areas. The Suez Canal continued to be swept by aircraft, for instance.

While these methods were useful for clearing mines from local ports, they were of little or no use for enemy-controlled areas. 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. This 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, energised by the ship's electrical system whenever in suspected magnetic-mined waters. Some of the first to be so-fitted being the carrier HMS Ark Royal and the liners RMS Queen Mary and RMS Queen Elizabeth which were used as troopships. This was felt to be impracticable for the myriad of smaller warships and merchant vessels, not least due to the amount of copper that would be required. It was found that sailing a vessel over coils laid in shallow water and energised from shore temporarily 'wiped' the ships' magnetic signature sufficiently to nullify the threat. This started in late 1939, and by 1940 merchant vessels and the smaller British warships were largely immune for the few months at a time until they once again built up a field. Many of the boats that sailed to Dunkirk were degaussed in a marathon four day effort by degaussing stations.

The Germans had also developed a pressure-activated mine and planned to deploy it as well, but they saved it for later use when it became clear the British had defeated the magnetic system.

Since World War II, mines have damaged or sunk 14 US Navy ships, but air and missile attacks have damaged four.

During the Korean War, mines laid by North Korean forces damaged 11 U.S. naval vessels.

During the Iran-Iraq War from 1980 to 1988, the belligerents mined several areas of the Persian Gulf and nearby waters. On April 14, 1988, the USS Samuel B. Roberts (FFG-58) struck an Iranian M-08/39 mine in the central Gulf shipping lane, wounding 10 sailors.

During the Gulf War, Iraqi naval mines severely damaged USS Princeton (CG-59) and USS Tripoli (LPH-10).

[edit] Types

Naval mines may be classified into two major groups.

[edit] Contact mines

The earliest mines were usually of this type. They are still used today, as they are extremely low cost compared to any other anti-ship weapon and are effective, both as a terror weapon and to sink enemy ships. Contact mines need to be very close to the target before they detonate, limiting the damage. (Read the section on damage, below, for explanation).

Early mines had mechanical mechanisms to detonate them, but these were superseded in the 1870s by the Hertz Horn (or chemical horn), which was found to work reliably even after the mine had been in the sea for several years. The mine's upper half is studded with hollow lead protuberances, each containing a glass vial filled with sulfuric acid. When a ship's hull crushes the metal horn, it cracks the vial inside it, allowing the acid to run down a tube and into a lead-acid battery which until then contains no acid electrolyte. This energizes the battery, which detonates the explosive.

Earlier forms of the detonator used a vial filled with sulfuric acid, surrounded by the mixture of potassium perchlorate and sugar. When the vial was crushed, the acid ignited the perchlorate-sugar mix, and the resulting flame ignited the gunpowder charge.

During World War I the British heavily mined the English Channel and later large areas of the North Sea to prevent German submarines from using it. As the submarine could be at any depth down to the seabed, an American invention, the antenna mine, was widely used. This had a copper wire attached to a buoy that floated above the mine. The top part of the cable connecting the buoy to the weight on the seabed was also made of copper. The copper wire was insulated from the steel cable below it. If a submarine's steel hull touched the copper wire, the slight voltage produced because of the contact between two dissimilar metals was amplified and detonated the explosive.

[edit] Limpet mines

Limpet mines are a special form of contact mine which are attached to the target by magnets and left, and are so named because of the superficial similarity to the mollusk limpet. A swimmer or diver usually performs this task. Normally they are directly attached, but the warhead of the human torpedo was linked to the magnets by wires about one foot (30 cm) long.

Usually they are set off by a time fuze. They may also have an anti-removal system making it explode if the mine is torn off by enemy divers or by other explosions. Sometimes the limpet mine had a small propeller which would detonate when the ship has sailed a certain distance. This ensures that the ship was likely to sink in deep water out of reach of easy salvage and makes it harder to determine the reason for the sinking.

Typically they have special compartments within them to ensure that the mine has only a slight negative buoyancy, making them easier to handle.

An example of the use of limpet mines by British special forces was in Operation Frankton which had the objective of disabling and sinking merchant shipping moored at Bordeaux, France in 1942. The operation was also the subject of a feature film titled The Cockleshell Heroes. The "limpets" used by the British during World War II contained only 4 kg of explosive, but placed 2 meters below the water line they caused a hole in a ship one meter wide.

Another well known use was the sinking of the Rainbow Warrior by the French DGSE in Auckland harbour, New Zealand, on July 10, 1985. This was a standard covert use of mines.

• Images of a limpet mine: [2] [3] [4]
• Image of limpet mine used in Operation Frankton
• Image of limpet mine recovered by Australian Clearance Divers at Vung Tau in Vietnam in 1969

[edit] Floating contact mines

The original mine type floats anywhere from just below the surface of the water to several hundred meters down. A cable connecting the mine to an anchor on the seabed prevents them from drifting away. The explosive and detonating mechanism is contained in a metal or plastic shell, which also has considerable buoyancy. The depth below the surface at which the mine floats can be set so that only deep draft vessels such as aircraft carriers, battleships or large cargo ships are at risk. This avoids a "less valuable" ship detonating the mine.

These mines usually have a weight of 200 kg, including 80 kg of explosives (TNT).

During WWII mine traps were used for blocking port entrances. Two floating mines were anchored some distance apart on either side of a shipping channel, linked by a chain. When a deep draft vessel passed through the trap, the chain would be pulled along by it, and drag both mines into opposite sides of the ship. The resulting double explosion often sank the ship. This system was not used extensively, but proved effective in blocking ports.

[edit] Drifting contact mines

Drifting mines were occasionally used during World War I and World War II. However, they were more feared than effective. A drifting mine is simply a floating mine without any mooring. Sometimes floating mines break from their moorings and become drifting mines, but modern mines should be constructed to deactivate in this event. After several years at sea, the deactivation mechanism might not function as intended and the mines may remain active. Admiral Jellicoe's British fleet did not pursue and destroy the outnumbered German High Seas Fleet when it turned away at the Battle of Jutland because he thought they were leading him into a trap. He believed that the Germans either were leaving floating mines in their wake, or were drawing him towards submarines. Both dangers were imaginary - the German fleet did not carry mines.

Churchill promoted "Operation Royal Marine" in 1940 and again in 1944 where floating mines were put into the Rhine in France to float down the river, becoming active after a fixed interval by which time they should have reached German territory.

After World War I the drifting contact mine was banned, but was occasionally used during World War II. The drifting mines were much harder to remove after the war and they caused about as much damage to both sides.

These mines usually weighed 120 kg, including 80 kg of explosives (TNT)

[edit] Bottom contact mines

A bottom contact mine is the simplest form of mine. It is merely an explosive charge and a trigger lying on the seafloor. They have been used against submarines, as submarines sometimes lie on the seafloor to reduce their acoustic signature. They are also used to prevent landing craft from reaching the shore and were a major obstacle during the D-Day landings. The Germans used antitank mines here with minor modifications to make them more reliable underwater, attaching the mines to the front of many of the obstacles seen in photos of the landing.

These mines usually weighed 2 to 50 kg, including 1 to 40 kg of explosives (TNT or hexatonal).

[edit] Remotely controlled mines

Frequently used in combination with coastal artillery and hydrophones, remote controlled (or command detonation) mines can be in place in peacetime, which is a huge advantage in blocking important shipping routes. The mines are usually equipped to be turned into "normal" mines with a switch (which prevents the enemy from simply capturing the controlling station and deactivating the mines), detonated by hand or be allowed to detonate on their own. The earliest ones were developed around 1812 by Robert Fulton. The first use was moored mines used in the American Civil War, detonated electrically from shore. These were seen as superior to contact mines because they only deprived the waterway to the enemy.

Modern examples usually weigh 200 kg (440 lb), including 80 kg (175 lb) of explosives (TNT or hexatonal).

[edit] Moored mines

The moored mine is the backbone of modern mine systems. They are deployed where water is too deep for bottom mines. Using several kinds of instruments to detect an enemy, usually a combination of acoustic, magnetic and pressure sensors. More exotic ones include optical shadows or electro potential sensors. These cost many times more than contact mines. Moored mines are effective against most kinds of ships. Being cost-efficient compared to other anti-ship weapons, they can be deployed in large numbers, making them useful area denial or "channelizing" weapons. Moored mines usually have lifetimes over 10 years, and some almost unlimited. These mines usually weigh 200 kg (440 lb), including 80 kg (175 lb) of explosives (hexatonal). In excess of 150 kg (330 lb) of explosives the mine becomes inefficient, as it becomes too large to handle and the extra explosives add little to the mine's effectiveness.

[edit] Bottom mines

Bottom mines are used when the water is no more than 60 m (180 ft) deep or when mining for submarines down to around 200 m (660 ft). They are much harder to detect and sweep, and can carry a much larger payload than a moored mine. Bottom mines commonly use pressure sensitive exploders, which are less sensitive to sweeping.

These mines usually weigh 150-1500 kg (330-3300 lb), including 125-1400 kg (275-3090 lb) of explosives (hexatonal).

[edit] Influence mines

Modern mines typically actuate based on the influence of a ship rather than direct contact.

[edit] Unusual mines

Several specialized mines have been developed for other purposes than the common minefield.

Anti sweep mine
The anti sweep mine is a very small mine (40 kg warhead) with as small a floating device as possible. When the wire of a mine sweep hits the mine, it "sinks", letting the sweep wire drag along the anchoring wire of the mine until the sweep hits the mine. That detonates the mine and cuts the sweeping wire. They are very cheap and usually used in combination with other mines in a minefield to make sweeping more difficult.

Rocket mine
A Russian invention, the rocket mine is a bottom distance mine that fires a homing rocket (not torpedo) upwards towards the target. It is intended to allow a bottom mine to attack surface ships from a greater depth.

Torpedo mine
This is a self-propelled variety, able to lay in wait for a target and pursue it (such as CAPTOR mine), or swim into a harbor inaccessible to the laying ship.

The U.S. Mark 24 "mine", code-named FIDO, was actually an ASW homing torpedo. The mine designation was disinformation to conceal its function.

Bouquet mine
The bouquet mine is a single anchor attached to several floating mines. It is designed so that when one mine is swept/detonated, another takes its place. It is a very sensitive construction and lacks reliability.

Ascending mine
The ascending mine is a floating distance mine that may cut its mooring or in some other way float higher when it detects a target. It lets a single floating mine cover a much larger depth range.

[edit] Mine laying

Historically several methods were used to lay mines. During the First and Second World Wars, the Germans used U-boats to lay mines around the UK. In the Second World War, aircraft came into favour for mine laying

Laying a minefield is a relatively fast process with specialized ships, which is still today the most common method. These minelayers can carry several thousand mines and manoeuvre with high precision. The mines are dropped at a predefined interval into the water behind the ship. Each mine is recorded for later clearing, but it is not unusual for these recordings to be lost together with the ships. Therefore many countries demand that all mining operations shall be planned on land and records kept so the mines can later be recovered more easily.

Other methods to lay minefields includes:

• Converted merchant ships
• Airplanes
• Submarines
• Combat boats
• Camouflaged boats
• Dropping from the shore
• Attack divers

Most mines are automatically activated when in the water, after a safety has been removed, and can both safely and easily be delivered in almost any method imaginable.

[edit] Damage

The damage of a mine depends on the distance from the detonation, and is not always less because the detonation is some distance away.

Direct damage
Usually only created by contact mines, direct damage is a hole blown in the ship. Among the crew, shrapnel wounds are most common. This rarely sinks the ship, but might flood one or two compartments–— usually in the bow.

Bubble jet effect
If the mine detonates in the water some distance from the ship, the bubble jet effect happens. The explosion creates a "hole" in the water, and due to the difference in pressure, this sphere will collapse from the bottom. This creates a "pillar" of water that can go over a hundred meters into the air. The damage to the ship is heavy. The water breaks a meter wide hole straight through the ship, flooding one or more compartments, and might break the ship apart. The crew in the areas hit by the pillar are usually killed instantly. Other damage is usually limited.

Shaking effect
If the mine detonates at a distance from the ship, the change in water pressure causes the ship to resonate. This is frequently the most deadly type of explosion, if strong enough. The whole ship is roughly shaken, and everything is tossed around. Engines rip from their beds, cables from their holders, etc. A badly shaken ship usually sinks quickly, with hundreds, or thousands of small leaks all over the ship and no way to power the pumps. The crew fare no better, as the violent shaking tosses them around. One of the most common wounds is broken femur close to the hip. This is due to the violent upward motion of the ship. To counter this, minesweeper crews are ordered to walk and stand with their knees slightly bent at all times — the "minesweeper walk".

• Photos of damage done to the USS Samuel B. Roberts (FFG 58) by an Iranian M-08 moored mine in 1988.

[edit] Countermeasures

Weapons are frequently a few steps ahead of countermeasures, and mines are no exception. Currently, with modern mine hunting, countermeasures are beginning to catch up (including the use of military dolphins to detect and flag mines). However, the next generation of rocket mines may very well change that.

[edit] Passive countermeasures

By building ships with as low signature as possible one can avoid detonating mines. This is especially true for minesweepers and mine hunters that work in minefields. These ships are built out of glass fibre or even wood instead of steel to avoid magnetic signatures, they use special propulsion, such as Voith-Schneider propellers to limit the acoustic signature. They are built with hulls that produce a low-pressure signature. These measures create other problems. They are expensive, slow, and vulnerable to enemy fire. Therefore, they need protection. Many modern ships have a mine warning sonar—a simple sonar looking forward and warning the crew if it detects possible mines ahead. It is only effective when moving slowly.

A ship can be degaussed (more correctly, deoerstedted or depermed) using a special degaussing station that contains many large coils and induces a magnetic field in the hull with alternating current. This is a rather problematic solution, as magnetic compasses need recalibration and all metal objects must be kept in exactly the same place. Ships slowly regain their magnetic field as they travel through the Earth's magnetic field, so the process has to be repeated every six months.

A variation on this technique, called wiping, was developed by Dr. Charles F. Goodeve, RCNVR, which saved time and resources.

Between 1941 and 1943 the US Naval Gun factory (a division of the Naval Ordinance Laboratory) in Washington D.C. built physical models of all US Naval ships. Three kinds of steel were used in shipbuilding: mild steel for bulkheads, a mixture of mild steel and high tensile steel for the hull, and special treatment steel for armor plate. The models were placed within coils which would simulate the earth's magnetic field at any location. The magnetic signatures were measured with degaussing coils. The objective was to reduce the vertical component of the Earth's field combined with the ships field at the usual depth of German mines. From the measurements, coils were placed and coil currents determined to minimize the chance of detonation for any ship at any heading at any latitude.

Some ships are built with magnetic inductors, large coils placed along the ship to counter the ship's magnetic field. Using magnetic probes in strategic parts of the ship the strength of the current in the coils can be adjusted to minimize the total magnetic field. This is a heavy and clumsy solution, suited for smaller ships.

[edit] Active countermeasures

Active countermeasures are ways to clear a path through a minefield or remove it completely. This is one of the most important tasks of any mine warfare flotilla.

[edit] Mine sweeping

A sweep is either a contact sweep, a wire dragged through the water by one or two ships to cut the mooring wire of floating mines, or a distance sweep that mimics a ship to detonate the mines. The sweeps are dragged by minesweepers, either military ships or converted trawlers. Each run covers between one and two hundred meters, and the ships must move slowly in a straight line, making them vulnerable to enemy fire. This was exploited by the Turkish army in the Battle of Gallipoli in 1915, when mobile howitzer batteries prevented the British and French from clearing a way through minefields.

If a contact sweep hits a mine, the wire of the sweep rubs against the mooring wire until it is cut. Sometimes "cutters", explosive devices to cut the mine's wire, are used to lessen the strain on the sweeping wire. Mines cut free are recorded and collected for research or shot with a deck gun.

Minesweepers protect themselves with an oropesa or paravane instead of a second minesweeper. These are torpedo-shaped towed bodies, similar in shape to a Harvey Torpedo, that are streamed from the sweeping vessel thus keeping the sweep at a determined depth and position. Some large warships were routinely equipped with paravane sweeps near the bows in case they inadvertently sailed into minefields — the mine would be deflected towards the paravane by the wire instead of towards the ship by its wake. More recently, heavy-lift helicopters have dragged minesweeping sleds, as in the 1991 Persian Gulf War.

The distance sweep mimics the sound and magnetism of a ship and is pulled behind the sweeper. It has floating coils and large underwater drums. It is the only sweep effective against bottom mines.

During the Second World War, RAF Coastal Command used Vickers Wellington bombers fitted with degaussing coils to trigger magnetic mines.

Modern distance mines are more sensitive and much harder to sweep. They often contain anti-sweeping mechanisms such as sensitivity only to the noise of certain types of ship or will detonate only after their mechanism has been triggered a specified number of times. They may also only arm themselves (or disarm automatically - known as self-sterilization) after a set time.

[edit] Mine hunting

Mine hunting is very different from sweeping, even if some minehunters can do both tasks. When mine hunting, the mines are located using sonar, then inspected and destroyed either by divers or ROVs (remote controlled unmanned mini submarines). It is slow, but also the most secure way to remove mines. Mine hunting started during the Second World War, but it was only after the war that it became a truly effective method.

Sea mammals (mainly the Bottlenose Dolphin) have also been trained to hunt and mark mines, most famously by the U.S. Navy Marine Mammal Program. Mine-clearance dolphins were deployed to the Persian Gulf during the Iraq War in 2003. The Navy claims that these dolphins were effective in helping to clear more than 100 antiship mines and underwater booby traps from the port of Umm Qasr.^[3]

[edit] Mine breaking

A more drastic method is simply to take a cargo ship, load it with cargo that makes her less vulnerable to sinking (wood for example) and drive her through the minefield, letting the ship to be protected follow the same path. This method was employed by the German Kriegsmarine during WWII, using converted ships known as Sperrbrechers. Alternatively, a shallow draught vessel can be steamed through the minefield at high speed to generate a pressure wave sufficient to trigger mines, with the minesweeper moving fast enough to be sufficiently clear of the pressure wave so that triggered mines do not destroy the ship itself. These techniques are the only way to sweep pressure mines and modern doctrine calls for such weapons to be hunted rather than swept.

An updated form of mine breaking is the use of small unmanned ROVs that simulate the acoustic and magnetic signatures of larger ships and are built to survive exploding mines.

[edit] National arsenals

[edit] US Mines

The United States Navy MK56 ASW mine (the oldest still in use by the US) was developed in 1966. More advanced mines include the MK60 CAPTOR (short for "encapsulated torpedo"), the MK62 and MK63 Quickstrike and the MK67 SLMM (Submarine Launched Mobile Mine). Today, most U.S. naval mines are delivered by aircraft.

MK67 SLMM Submarine Launched Mobile Mine
The SLMM was developed by the United States as a submarine deployed mine for use in areas inaccessible for other mine deployment techniques or for covert mining of hostile environments. The SLMM is a shallow-water mine and is basically a modified MK37 torpedo.

General Characteristics

• Type: Submarine-laid bottom mine
• Detection System: Magnetic/seismic or magnetic/seismic/pressure target detection devices (TDDs)
• Dimensions: 485 mm by 4.09 m (19 by 161 in)
• Depth Range: Shallow water
• Weight: 754 kg (1658 lb)
• Explosives: 230 kg (510 lb) high explosive
• Date Deployed: 1987

MK65 Quickstrike
The Quickstrike is a family of shallow-water aircraft-laid mines used by the United States, primarily against surface craft. The MK65 is a 2,000-lb (900 kg) mine. Other Quickstrike versions (MK62, MK63, and MK64) are converted 500-lb (230 kg) and 1000-lb (450 kg) general-purpose bombs.

General Characteristics

• Type: aircraft-laid bottom mine
• Detection System: Magnetic/seismic/pressure target detection devices (TDDs)
• Dimensions: 740 mm by 3.25 m (29 by 128 in)
• Depth Range: Shallow water
• Weight: 1086 kg (2390 lb)
• Explosives: Various loads
• Date Deployed: 1983

MK56
General Characteristics

• Type: Aircraft laid moored mine
• Detection System: Total field magnetic exploder
• Dimensions: 570 mm by 2.9 m (22.4 by 114.3 in)
• Depth Range: Moderate depths
• Weight: 909 kg (2000 lb)
• Explosives: 164 kg (360 lb) HBX-3
• Date Deployed: 1966

[edit] See also

• Royal Navy's Admiralty Mining Establishment
• Land mine

[edit] Notes

[edit] Further reading

• Hartmann, Gregory K. with Scott C. Truver (1991). Weapons That Wait: Mine Warfare in the U.S. Navy. Annapolis: Naval Institute Press. ISBN 0-87021-753-4.  (Canonical general text about U.S. mine warfare)
• Hewitt, James Terrance (1998). Desert Sailor: A War of Mine. Clementsport: The Canadian Peacekeeping Press. ISBN 1-896551-17-3.  (Personal account of mine countermeasures operations in Operation Desert Storm during the Gulf War 1991, including the mining of USS Tripoli.)
• Peniston, Bradley (2006). No Higher Honor: Saving the USS Samuel B. Roberts in the Persian Gulf. Annapolis: Naval Institute Press. ISBN 1-59114-661-5.  (Describes mine damage to a U.S. frigate)

[edit] External Links

• Henry Norton Sulivan : a depiction of early Naval Mine
• Our Sailors by W.H.G. Kingston