Editing Naval mine (section)

== Types ==
[[File:Types of Naval mine 001.svg|thumb|Types of naval mines:<br> '''A'''-underwater, '''B'''-bottom, '''SS'''-submarine. '''1'''-drifting mine, '''2'''-drifting mine, '''3'''-moored mine (long wire), '''4'''-moored mine (short wire), '''5'''-bottom mines, '''6'''-torpedo mine/CAPTOR mine, '''7'''-rising mine]]
Naval mines may be classified into three major groups; contact, remote and influence mines.

=== 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 psychological weapon and as a method to sink enemy ships. 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.

Early mines had mechanical mechanisms to detonate them, but these were superseded in the 1870s by the "Hertz horn" (or "chemical horn"), which was found to work reliably even after the mine had been in the sea for several years.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 contained no acid electrolyte. This energizes the battery, which detonates the explosive.<ref name="hartshorn.us">{{cite web |url=http://www.hartshorn.us/Navy/navy-mines-01.htm |title=Moored-contact |first=Derick S. |last=Hartshorn |publisher=Mineman Memories |date=2010-04-17 |access-date=2011-12-31 |archive-date=12 July 2012 |archive-url=https://web.archive.org/web/20120712040904/http://www.hartshorn.us/Navy/navy-mines-01.htm |url-status=dead }}</ref>

Earlier forms of the detonator employed a vial of sulfuric acid surrounded by a 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.<ref>{{cite book |title=The Russian Rockefellers: the Saga of the Nobel Family and the Russian Oil Industry |last=Tolf |first=Robert W. |year=1982 |publisher=Hoover Institution Press |isbn=978-0-8179-6581-5 |page=[https://archive.org/details/russianrockefell00robe/page/18 18] |url-access=registration |url=https://archive.org/details/russianrockefell00robe/page/18 }}</ref>

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. Later, the American antenna mine was widely used because submarines could be at any depth from the surface to the seabed. This type of mine had a copper wire attached to a buoy that floated above the explosive charge which was weighted to the seabed with a steel cable. If a submarine's steel hull touched the copper wire, the slight voltage change caused by contact between two dissimilar metals was amplified{{clarify|reason=amplified by what?|date=December 2015}} and detonated the explosives.<ref name="hartshorn.us"/>

==== Limpet mines ====
{{Main|Limpet mine}}
Limpet mines are a special form of contact mine that are manually attached to the target by magnets and remain in place. They are named because of the similarity to the [[limpet]], a [[mollusk]].

==== Moored contact mines ====
[[File:Mine (AWM 304925).jpg|thumb|A German contact mine [[Axis naval activity in Australian waters|laid in Australian waters]] during World War II]]

Generally, this type of mine is set to float just below the surface of the water or as deep as five meters. A steel cable connecting the mine to an anchor on the seabed prevents it from drifting away. The explosive and detonating mechanism is contained in a buoyant metal or plastic shell. 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, saving the mine from being used on a less valuable target. In [[littoral]] waters it is important to ensure that the mine does not become visible when the sea level falls at low tide, so the cable length is adjusted to take account of tides. During WWII there were mines that could be moored in {{cvt|300|m|ft|adj=on}}-deep water.

Floating mines typically have a mass of around {{cvt|200|kg|lb}}, including {{cvt|80|kg|lb}} of explosives e.g. [[Trinitrotoluene|TNT]], [[Minol (explosive)|minol]] or [[amatol]].<ref>{{Cite web|url=http://victoriancollections.net.au/items/4f72bb6697f83e03086060cb|title=World War 2 Era Contact Sea Mine - Victorian Collections|website=victoriancollections.net.au|access-date=2019-10-26|archive-date=15 November 2023|archive-url=https://web.archive.org/web/20231115004947/https://victoriancollections.net.au/items/4f72bb6697f83e03086060cb|url-status=live}}</ref>

===== Moored contact mines with plummet =====
[[File:Legen_einer_Ankertaumine.svg|thumb|Sequence of laying a moored contact mine with a plummet]]
A special form of moored contact mines are those equipped with a plummet. When the mine is launched (1), the mine with the anchor floats first and the lead plummet sinks from it (2). In doing so, the plummet unwinds a wire, the deep line, which is used to set the depth of the mine below the water surface before it is launched (3). When the deep line has been unwound to a set length, the anchor is flooded and the mine is released from the anchor (4). The anchor begins to sink and the mooring cable unwinds until the plummet reaches the sea floor (5). Triggered by the decreasing tension on the deep line, the mooring cable is clamped. The anchor continues sinking down to the bottom of the sea, pulling the mine below the water surface to a depth equal to the length of the deep line (6). Thus, even without knowing the exact seafloor depth, an exact depth of the mine below the water surface can be set, limited only by the maximum length of the mooring cable.

==== Drifting contact mines ====
Drifting mines were occasionally used during World War I and World War II. However, they were more feared than effective. Sometimes floating mines break from their moorings and become drifting mines; modern mines are designed to deactivate in this event. After several years at sea, the deactivation mechanism might not function as intended and the mines may remain live. [[John Jellicoe, 1st Earl Jellicoe|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 it possible that the Germans were either leaving floating mines in their wake, or were drawing him towards submarines, although neither of these was the case.

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 than tethered mines after the war, and they caused about the same damage to both sides.<ref>{{cite web|url=https://www.strausscenter.org/hormuz/mines.html|title=Mines – Hormuz|access-date=26 October 2015|archive-date=30 July 2019|archive-url=https://web.archive.org/web/20190730230012/https://www.strausscenter.org/hormuz/mines.html|url-status=dead}}</ref>

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 time calculated to be long enough to reach German territory.

=== Remotely controlled mines ===
Frequently used in combination with coastal artillery and hydrophones, [[controlled mines]] (or command detonation mines) can be in place in peacetime, which is a huge advantage in blocking important shipping routes. The mines can usually be turned into "normal" mines with a switch (which prevents the enemy from simply capturing the controlling station and deactivating the mines), detonated on a signal or be allowed to detonate on their own. The earliest ones were developed around 1812 by [[Robert Fulton]]. The first remotely controlled mines were moored mines used in the American Civil War, detonated electrically from shore. They were considered superior to contact mines because they did not put friendly shipping at risk.<ref>[https://books.google.com/books?id=19kDAAAAMBAJ&dq=Popular+Science+1933+plane+%22Popular+Mechanics%22&pg=PA813 "How Mines Help Guard America's Harbors"] {{Webarchive|url=https://web.archive.org/web/20230506033912/https://books.google.com/books?id=19kDAAAAMBAJ&dq=Popular+Science+1933+plane+%22Popular+Mechanics%22&pg=PA813 |date=6 May 2023 }} ''[[Popular Mechanics]]'', December 1940</ref> The extensive American fortifications program initiated by the [[Board of Fortifications]] in 1885 included [[Submarine mines in United States harbor defense|remotely controlled mines]], which were emplaced or in reserve from the 1890s until the end of World War II.<ref>{{cite book |editor-last=Berhow |editor-first=Mark A. |title=American Seacoast Defenses, A Reference Guide |edition=Third |publisher=CDSG Press |year=2015 |pages=333–374 |isbn=978-0-9748167-3-9}}</ref>

Modern examples usually weigh {{convert|200|kg|lb|abbr=on}}, including {{convert|80|kg|lb|abbr=on}} of explosives ([[TNT]] or [[torpex]]).{{Citation needed|date=March 2011}}

=== Influence mines ===
[[File:Luftmine (LM).jpg|thumb|upright|German parachute-retarded magnetic mine. Dropped by [[Luftwaffe]] bomber during WWII and landed on the ground. Fuze mechanisms are visible]]
These mines are triggered by the influence of a ship or submarine, rather than direct contact. Such mines incorporate sensors designed to detect the presence of a vessel and [[Detonation|detonate]] when it comes within the [[explosion|blast]] range of the [[warhead]]. The fuzes on such mines may incorporate one or more of the following sensors: [[magnetic]], passive [[Acoustic signature|acoustic]] or water [[pressure]] displacement caused by the proximity of a vessel.<ref>{{cite web |url=https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld001.htm |title=Title Slide |last=Garrold |first=Tim |work=Mine Warfare Introduction: The Threat |publisher=Surface Warfare Officers School Command, U.S. Navy |date=December 1998 |access-date=2011-12-31 |archive-date=19 July 2016 |archive-url=https://web.archive.org/web/20160719131338/http://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld001.htm |url-status=live }} Slide 1 of 81. Hosted by Federation of American Scientists.</ref>

First used during WWI, their use became more general in WWII. The sophistication of influence mine fuzes has increased considerably over the years as first [[transistor]]s and then [[microprocessor]]s have been incorporated into designs. Simple magnetic sensors have been superseded by total-field [[magnetometer]]s. Whereas early magnetic mine fuzes would respond only to changes in a single component of a target vessel's magnetic field, a total field magnetometer responds to changes in the magnitude of the total background field (thus enabling it to better detect even degaussed ships). Similarly, the original broadband [[hydrophone]]s 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 signature]]s (e.g. a [[gas turbine]] powerplant or [[cavitation]] sounds from a particular design of [[Screw propeller|propeller]]) and ignore all others. The sophistication of modern electronic mine fuzes incorporating these [[digital signal processing]] capabilities makes it much more difficult to detonate the mine with [[electronic countermeasures]] because several sensors working together (e.g. magnetic, passive acoustic and water pressure) allow it to ignore signals which are not recognised as being the unique signature of an intended target vessel.<ref name="fas.org">{{cite web |url=https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld017.htm |title=World War II |last=Garrold |first=Tim |work=Mine Warfare Introduction: The Threat |publisher=Surface Warfare Officers School Command, U.S. Navy |date=December 1998 |access-date=2011-12-31 |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402112226/http://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld017.htm |url-status=live }} Slide 17 of 81. Hosted by Federation of American Scientists.</ref>

Modern influence mines such as the [[Stonefish (mine)|BAE Stonefish]] are [[embedded computer system|computerised]], with all the programmability this implies, such as the ability to quickly load new [[acoustic signature]]s into fuzes, or program them to detect a single, highly distinctive target signature. In this way, a mine with a passive acoustic fuze can be programmed to ignore all friendly vessels and small enemy vessels, only detonating when a very large enemy target passes over it. Alternatively, the mine can be programmed specifically to ignore all surface vessels regardless of size and exclusively target submarines.

Even as far back as WWII it was possible to incorporate a "ship counter" function in mine fuzes. This might set the mine to ignore the first two ships passing over it (which could be minesweepers deliberately trying to trigger mines) but detonate when the third ship passes overhead, which could be a high-value target such as an [[aircraft carrier]] or [[oil tanker]]. Even though modern mines are generally powered by a long life [[Lithium metal battery|lithium battery]], it is important to conserve power because they may need to remain active for months or even years. For this reason, most influence mines are designed to remain in a semi-dormant state until an unpowered (e.g. deflection of a [[mu-metal]] [[magnetic compass|needle]]) or low-powered sensor detects the possible presence of a vessel, at which point the mine fuze powers up fully and the passive acoustic sensors will begin to operate for some minutes. It is possible to program computerised mines to delay activation for days or weeks after being laid. Similarly, they can be programmed to [[self-destruct]] or render themselves safe after a preset period of time. Generally, the more sophisticated the mine design, the more likely it is to have some form of [[anti-handling device]] to hinder clearance by divers or remotely piloted submersibles.<ref name="fas.org"/><ref name="ReferenceA">{{cite web |url=https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld031.htm |title=Mechanism |last=Garrold |first=Tim |work=Mine Warfare Introduction: The Threat |publisher=Surface Warfare Officers School Command, U.S. Navy |date=December 1998 |access-date=2011-12-31 |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402115148/http://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld031.htm |url-status=live }} Slide 31 of 81. Hosted by Federation of American Scientists.</ref>

==== Moored mines ====
The moored mine is the backbone of modern mine systems. They are deployed where water is too deep for bottom mines. They can use several kinds of instruments to detect an enemy, usually a combination of acoustic, magnetic and pressure sensors, or more sophisticated optical shadows or electro potential sensors. These cost many times more than contact mines. Moored mines are effective against most kinds of ships. As they are cheaper than other anti-ship weapons they can be deployed in large numbers, making them useful [[area denial]] or "channelizing" weapons.
Moored mines usually have lifetimes of more than 10 years, and some almost unlimited. These mines usually weigh {{convert|200|kg|lb|abbr=on}}, including {{convert|80|kg|lb|abbr=on}} of explosives ([[RDX]]). In excess of {{convert|150|kg|lb|abbr=on}} of explosives the mine becomes inefficient, as it becomes too large to handle and the extra explosives add little to the mine's effectiveness.{{Citation needed|date=March 2011}}

==== Bottom mines ====
Bottom mines (sometimes called ground mines) are used when the water is no more than {{convert|60|m|ft|abbr=off|sp=us}} deep or when mining for submarines down to around {{convert|200|m|ft|abbr=off|sp=us}}. They are much harder to detect and sweep, and can carry a much larger warhead than a moored mine. Bottom mines commonly use multiple types of sensors, which are less sensitive to sweeping.<ref name="ReferenceA"/><ref>{{cite web |url=https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld033.htm |title=Influence Mines |last=Garrold |first=Tim |work=Mine Warfare Introduction: The Threat |publisher=Surface Warfare Officers School Command, U.S. Navy |date=December 1998 |access-date=2011-12-31 |archive-date=9 March 2016 |archive-url=https://web.archive.org/web/20160309054149/https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld033.htm |url-status=live }} Slide 33 of 81. Hosted by Federation of American Scientists.</ref>

These mines usually weigh between {{convert|150|and|1500|kg|lb|abbr=on}}, including between {{convert|125|and|1,400|kg|lb|abbr=on}} of explosives.<ref>{{cite web |url=https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld040.htm |title=Russian UDM-E Bottom Cylindrical |last=Garrold |first=Tim |work=Mine Warfare Introduction: The Threat |publisher=Surface Warfare Officers School Command, U.S. Navy |date=December 1998 |access-date=2011-12-31 |archive-date=22 December 2015 |archive-url=https://web.archive.org/web/20151222143202/https://fas.org/man/dod-101/navy/docs/swos/cmd/miw/Sp6-4-1/sld040.htm |url-status=live }} Slide 40 of 81. Hosted by Federation of American Scientists.</ref>

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

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

==== Anti-sweep mine ====
[[File:Ochraniacz pola minowego MuzMarWoj A 23.jpg|thumb|Soviet anti-sweep mine MZ-26 on exposition in Naval Museum, Gdynia, Poland]]
The anti-sweep mine is a very small mine ({{cvt|40|kg|lb}} warhead) with as small a floating device as possible. When the wire of a mine sweep hits the anchor wire of the mine, it drags the anchor wire along with it, pulling the mine down into contact with the sweeping wire. 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. One type is the Mark 23 used by the United States during World War II.

==== Oscillating mine ====
The mine is hydrostatically controlled to maintain a pre-set depth below the water's surface independently of the rise and fall of the tide.

==== 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.

==== Homing mines ====
[[File:Mark 60 CAPTOR-DF-ST-90-11649.JPEG|thumb|A [[CAPTOR mine]] being loaded onto a [[B-52 Stratofortress]] in 1989]]

These are mines containing a moving weapon as a warhead, either a torpedo or a [[rocket (weapon)|rocket]].

====Rocket mine====
A Russian invention, the rocket mine is a bottom distance mine that fires a homing high-speed rocket (not torpedo) upwards towards the target. It is intended to allow a bottom mine to attack surface ships as well as submarines from a greater depth. One type is the [[Te-1 rocket propelled mine]].

====Torpedo mine====
A torpedo mine is a self-propelled variety, able to lie in wait for a target and then pursue it e.g. the [[Mark 60 CAPTOR]]. Generally, torpedo mines incorporate [[embedded computer system|computerised]] acoustic and magnetic fuzes. The [[Mark 24 Mine|U.S. Mark 24 "mine"]], code-named Fido, was actually an [[Anti-submarine warfare|ASW]] [[homing torpedo]]. The mine designation was disinformation to conceal its function.

==== Mobile mine ====
The mine is propelled to its intended position by propulsion equipment such as a torpedo. After reaching its destination, it sinks to the seabed and operates like a standard mine. It differs from the homing mine in that its mobile stage is set before it lies in wait, rather than as part of the attacking phase.

One such design is the Mk 67 [[Submarine Launched Mobile Mines|Submarine Launched Mobile Mine]]<ref>[https://fas.org/man/dod-101/sys/ship/weaps/mk-67.htm MK 67 Submarine-Laid Mobile Mine (SLMM)] {{Webarchive|url=https://web.archive.org/web/20151014032600/http://fas.org/man/dod-101/sys/ship/weaps/mk-67.htm |date=14 October 2015 }}. Fas.org. Retrieved on 2010-12-02.</ref> (which is based on a [[Mark 37 torpedo]]), capable of traveling as far as {{cvt|10|mi|km|order=flip}} through or into a channel, harbour, shallow water area, and other zones which would normally be inaccessible to craft laying the device. After reaching the target area they sink to the sea bed and act like conventionally laid influence mines.

==== Nuclear mine ====
During the Cold War, a test was conducted with a naval mine fitted with tactical nuclear warheads for the "Baker" shot of [[Operation Crossroads]]. This weapon was experimental and never went into production.<ref>{{cite web |url=http://www.navalminewarfare.com/ |title=Australian Mine Warfare |first=Cameron |last=Stewart |work=Naval Mine Warfare |date=2011-10-30 |access-date=2011-12-31 |archive-date=7 February 2011 |archive-url=https://web.archive.org/web/20110207155953/http://navalminewarfare.com/ |url-status=dead }}</ref> The [[Seabed Arms Control Treaty]] prohibits the placement of nuclear weapons on the seabed beyond a 12-mile coast zone.

==== Daisy-chained mine ====
This comprises two moored, floating contact mines which are tethered together by a length of steel cable or chain. Typically, each mine is situated approximately {{cvt|60|ft|m|order=flip}} away from its neighbor, and each floats a few meters below the surface of the ocean. When the target ship hits the steel cable, the mines on either side are drawn down the side of the ship's hull, exploding on contact. In this manner it is almost impossible for target ships to pass safely between two individually moored mines. Daisy-chained mines are a very simple concept which was used during World War II. The first prototype of the Daisy-chained mine and the first combat use came in Finland, 1939.<ref>{{Cite web|title=The Origins of Military Mines: Part II|url=https://man.fas.org/dod-101/sys/land/docs/981100-schneck.htm|access-date=2021-08-31|website=man.fas.org|archive-date=31 August 2021|archive-url=https://web.archive.org/web/20210831095928/https://man.fas.org/dod-101/sys/land/docs/981100-schneck.htm|url-status=live}}</ref>

==== Dummy mine ====
Plastic drums filled with sand or concrete are periodically rolled off the side of ships as real mines are laid in large mine-fields. These inexpensive false targets (designed to be of a similar shape and size as genuine mines) are intended to slow down the process of mine clearance: a mine-hunter is forced to investigate each suspicious sonar contact on the sea bed, whether it is real or not. Often a maker of naval mines will provide both training and dummy versions of their mines.<ref name="MN103-MANTA Sea Mines">{{cite web |archive-url=https://web.archive.org/web/20110716034740/http://www.sei-spa.com/mantaing.html |url=http://www.sei-spa.com/mantaing.html |title=MN103-MANTA Sea Mines |publisher=Sei Spa |archive-date=2011-07-16 |access-date=2011-12-31 |url-status=dead }}</ref>