Naval mine
Naval mines are anti-ship or anti-submarine weapons which, like landmines, are static weapons deposited and left to wait until they are triggered by the approach of an enemy ship. They are extremely effective and relatively cheap weapons, having caused more damage to US Navy ships since World War II than any other weapon. Fourteen US Navy ships have been sunk or damaged by mines since 1945; in comparison, only four US warships have been damaged by air and missile attack. Naval mines can be used both offensively, to hamper the enemy's shipping and lock him into his harbours, as well as defensively to protect friendly shipping and create "safe" zones.= Early History =
The first naval mines may have been tried by the English at the Siege of Rochelle in 1627 where they launched "floating petards" unsuccessfully against the French navy.
However, the first practical ones were invented by an American, David Bushnell, for use against the British in the American War of Independence. It was a watertight keg filled with gunpowder and fired by a percussion lock when the keg stuck a ship.
The first successful use occurred during the American Civil War, where mines were widely used by both sides. The first ship sunk was USS Cairo in 1863 in the Yazoo River. Rear-Admiral David Farragut's famous quote, Damn the torpedoes, full speed ahead! refers to a minefield laid at Mobile, Alabama.
In the nineteenth century, mines were universally called torpedoes, a term probably first adopted by Robert Fulton, and named after a fish which can give powerful electric shocks. Only later was it reserved for self-propelled underwater missiles, originally called Whitehead Torpedoes after the inventor. As well as self-propelled torpedoes and fixed mines, there were types of "torpedoes" which were attached to an attacking ship.
A spar torpedo was a mine attached to a long pole and detonated by the ship carrying it ramming another one. Perhaps the best known use was the destruction of USS Housatonic by CSS Hunley on February 17 1864.
A Harvey Torpedo was a type of floating mine which was towed alongside a ship, and was briefly in service in the Royal Navy in the 1870s.
The next major use came in the Russo-Japanese War in 1904, where the Russian battleship Petropavlovsk was sunk, killing most of the crew including the fleet commander, Admiral Makaroff.
Many of the early mines were extreamly fragile and dangerous to handle, with either glass containers filled with Nitrogryserine or mechanical devices which activated them uppon tipping. Several minelaying ships were destroyed when their cargo exploded too early.
=Types= Naval mines may be classified into two groups and several types.
Early mines had mechanical mechanisms to detonate them, but these were superseded in the 1870s by the Hertz Horn, which was found to work reliably even after the mine had been in the sea for several years. In this, the top of the mine has hollow studs a few inches long made out of lead. Each of these contains a glass vial filled with sulphuric acid. When a ship strikes the mine, the metal horn is crushed, destroying the vial inside it. The acid then runs down a tube and into a lead-acid battery which until then contains no acid electrolyte. At this point the battery is energised, which detonates the explosive.
During the 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, a US invention, the antenna mine, was widely used. This had a copper wire which the floated on a buoy above the mine, and the top part of the cable connecting it to the weight on the seabed was also made of this metal. It was insulated from the steel cable below it. If a submarine's steel hull touched the copper wire then the slight voltage produced because of the two dissimilar metals was amplified and detonated the explosive.
Usual weight: 200 kg, 80 kg of explosives (trotyl).
Churchill promoted "Operation 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 1 the drifting contact mine was banned, even if it was occasionally used during world war 2. The drifting mines were much harder to remove after the war and they caused about as much damage to both sides.
Usual weight: 120 kg, 80 kg of explosives (trotyl)
Usual weight: 2-50 kg, 1-40 kg of explosives (trotyl or hexatonal)
These are mines which do not need physical contact with the ship to detonate it. The earliest ones were moored mines used in the American Civil war and detonated electrically by observers on the shore. These were seen as superior to contact mines because they only deprived the waterway to the enemy. Distance mines uses several kind of instruments to detect if an enemy is nearby, most frequently a combination of acoustic, magnetic and pressure sensors, even if more exotic solutions exists, such as optical shadows or electro potential sensors. These are modern mines and frequently many times as expensive as the contact mines. Still they are very cheap compared to other anti ship weapons and can be deployed in large numbers.
Usual weight 200 kg, 80 kg of explosives (trotyl of hexatonal)
Usual weight 200 kg, 80 kg of explosives (hexatonal)
Usual weight 150-1500kg, 125-1400kg of explosives (hexatonal)
A ship can be degaussed using a special degaussing station that contains lots of large coils and induces a magnetic field in the hull. This is a rather problematic solution however, as the navigational equipment needs recalibration afterwards and everything made of metal has to be kept in exactly the same place. Ships slowly regain their magnetic field as they adjust to the earthÃÂÃÂs magnetic field, so the process has to be redone frequently, every six months.
If a contact sweep hits a mine the wire of the sweep (which is made of high quality steel) rubs against the wire mooring the mine until it's cut. Sometimes "cutters", explosive devices to cut the mine's wire, are used to make the strain on the sweeping wire less. Any mine cut free is recorded and either collected for research or simply shot with the deck cannon.
To make the minesweepers less vulnerable a paravane can be used instead of a second minesweeper. A paravane is a torpedo-shaped float similar in shape to a Harvey Torpedo and so pulled away sideways from the ship towing it. This also allows the sweepers to cover twice as much ground in the same time. 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.
The distance sweep tries to mimic the sound and magnetism of a ship and is pulled behind the sweeper. It's floating coils and large underwater drums. It's the only sweep effective against bottom mines.
Modern distance mines are much 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.
Minefields can be placed by traditional minelayers, large ships carrying thousands of mines, smaller costal ships, submarines, airplanes and even by just dropping them into a harbour by hand.
During the Gulf War, Iraqi naval mines severely damaged USS Princeton (CG-59) and USS Tripoli (LPH-10).
The United States Navy MK56 ASW mine (the oldest still in use by the US) was developed in 1966. Since that time, more advances in technology have given way to the development of the MK60 CAPTOR (short for "encapsulated torpedo"), the MK62 and MK63 Quickstrike and the MK67 SLMM (Submarine Launched Mobile Mine). Most mines in the USN's arsenal today are delivered by aircraft to target.
General Characteristics
General Characteristics
General Characteristics
General Characteristics
Contact mines
The earliest mines were usually of this type. They are still used today as they are extremely cheap compared to any other anti ship weapon and still very effective both as a terror weapon and to sink enemy ships. Contact mines have to be very close to the enemy before they detonate, which limits the damage they make to "direct" damage. Floating contact mines
Floating anywhere from just below the surface of the water to several hundred meters down this is the original mine type. They are prevented from drifting by cables connecting them to an "anchor" on the seabed. The explosive and detonating mechanism is contained in a metal or plastic shell which also has a 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 is useful to avoid having a "less valuable" ship detonate the mines.Drifting contact mines
Drifting mines were occasionally used during world war 1 and 2, although usually the fear of them was more effective than they were themselves. A drifting mine is simply a floating mine without any mooring. Sometimes floating mines rip their moorings and become drifting mines, but modern mines should be constructed to deactivate themselves if this happens. However, after several years at sea, this might not function as intended and the mines may still function. 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 either the Germans were leaving floating mines in their wake, or were drawing him towards submarines. Both dangers were imaginary - the German fleet did not carry any mines.Bottom contact mines
A bottom contact mine is the simplest form of mine imaginable. It's just a collection of explosive and a trigger lying on the bottom. They have been used against submarines, as submarines sometimes lie on the bottom to lower their signature. They are also used to prevent landing crafts from reaching the shore and were a major obstacle during the landings on the d-day. Anti tank mines were used here with minor modifications to make them more reliable underwater. These were attached to the front end of many of the obstacles that can be seen on photos of the landing. Distance mines
Remote controlled mines
Frequently used in combination with costal artillery and hydrophones the remote controlled mines can be in place even in peacetime, which is a huge advantage when it comes to blocking important shipping routs to defend harbours. The mines are usually modified distance mines and can 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. Floating distance mines
The floating distance mine is the backbone of any mine system today, they are deployed everywhere the deep is too much for bottom distance mines. Usually equipped with magnetic or acoustic sensors a floating distance mine is effective against most kinds of ships. A floating distance mine usually has a lifetime of more than 10 years, some of them almost unlimited. The floating mines are limited by the fact that that they have to float, so they cannot carry unlimited amount of explosives. More than 150 kg is simply a waste of money, as the mine gets too large to handle and don't get too much more effect. Bottom distance mines
When possible (down to around 60 meters deep) or when mining for submarines (down to around 200 meters) the bottom distance mines are used. They are much harder to detect and clear, and they can carry a much larger payload than a floating mine. Bottom mines also use pressure sensitive instruments, which are less sensitive to sweeping than any other sort. Unusual mine systems
There have been several specialized mines developed for other purpose and functions than the common minefield.Anti sweep mine
The anti sweep mine is a very small mine (40 kg warhead) with as small 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 harder. Rocket mine
Originally 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 deep. Torpedo mine
The torpedo mine is simply a torpedo placed on the bottom with a system to fire it when an enemy is nearby. It has good range, but is sensitive to anti torpedo system, such as screens. Bouquet mine
The bouquet mine is a single anchor with several floating mine upon it, designed so that when one mine is swept/detonates another takes its place. It's a very sensitive construction and might not always work.Ascending mine
The ascending mine is a floating distance mine that may cut it's mooring or in some other way float higher when it detects a target. It lets a single floating mine cover a much large deep span. Homing mine
The homing mine is a floating distance mine with a small engine that lets it move closer to it's intended target before it detonates. Active mine
An active mine is a mine that moves on it's own when it's deployed. The most common way to deploy active mines is by using a submarine and let the mine have the form of a torpedo. That way the mine can be deployed deep inside an enemy harbour. 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, the direct damage is simple a hole blown in a part of 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 (which is the area where the enlisted traditionally sleeps and explains why enlisted are far more likely to die in a mine detonation than officers)Bubble jet effect
If the mine detonates in the water some distance from the ship something called the bubble jet effect happens. The mine will create a "hole" in the water, and due to the difference in pressure this sphere will collapse from the bottom. This creates the famous "pillar" of water that can go well over a hundred meters up in the air. The damage to the ship is heavy, the water breaks a meter wide hole straight through the ship which floods one or several compartments. The structural damage might break the ship apart. The crew in the areas hit by the water pillar is usually killed instantly. Other damage is usually limited.The shaking effect
If the mine detonates at a distance from the ship the change in water pressure gets the ship to resonate. This is frequently the most fatal sort of explosion, if strong enough. The whole ship is roughly shaken, and everything, bolted down or not, is tossed around. Engines rip free from their beds, cables from their holders etc 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. The reason for this is the violent "upwards" motion of the ship. To counter this the crew commanded asked to walk and stand with their knees slightly bent at all time "minesweeper walk".Countermeasures
Frequently the weapons have been a few steps before the countermeasures, and mines are no exception. It's first in modern day with mine hunting that they countermeasures are beginning to catch up. However, the next generation of rocket mines may very well change that. Passive countermeasures
By building ships with as low signature as possible you can avoid detonating mines. This is especially true for minesweepers and mine hunters that have to work inside minefields. These ships are built out of glass fibre or even wood instead of steel to avoid magnetic signatures, they use special engines to limit the acoustic signatures and they are made with such a hull that the pressure signature is low. Of course this creates other problems. The ships are expensive, slow and vulnerable to enemy fire. Therefore they need protection. Many modern ships has also a mine warning sonar, a simple sonar looking forward and warning the crew if it spots something that might be a mine in the water before the ship. It's only effect when going slowly. Active countermeasures
The active countermeasures are the ways to clear a path through a minefield (or to remove it completely. This is one of the most important tasks of any mine warfare flotilla. Mine sweeping
A sweep is either a contact sweep, a simple metal wire dragged through the water by one or two ships to cut the mooring wire of floating mines, or a distance sweep which tries to mimic a ship to get the mines to detonate. The sweeps are dragged by minesweepers, either military ships or converted trawlers. Each run covers between one and two hundred meters, and the ships have to go slowly and strait, which makes them very vulnerable to enemy fire. This was most famously exploited by the Turkish army in the Dardanelles in 1915, where mobile howitzer batteries prevented the British and French from clearing a way through. Mine hunting
Mine hunting is very different from sweeping, even if the same ships are usually used for both tasks. When mine hunting the mines are located using sonar, then destroyed either by divers or ROV (remote controlled unmanned mini submarines). It's slow, but also the most secure way to remove mines. Mine hunting started during the Second World War, but it was first after the war it became a truly effective method. 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 that should be protected follow the same path. It has been used several times during war, and not always successfully. Modern usage of mines against and by the USA
During the Iran-Iraq War from 1980 to 1988, several areas of the Persian Gulf and nearby waters were mined by each side. On April 14, 1988, the USS Samuel B. Roberts struck one such mine in the Gulf, wounding 10 sailors.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 consisting basically of a modified MK37 torpedo.MK65 Quickstrike
The Quickstike 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 general purpose bombs of the 500 lb (230 kg) and 1000 lb (450 kg) sizes.MK60 CAPTOR
The CAPTOR is the United States Navy's primary anti-submarine weapon. This deep water mine is designed to be laid by aircraft or submarine, and is anchored to the ocean floor. Upon detection of a hostile submarine, the CAPTOR launches a MK46 Mod 4 torpedo.MK56