Editing Naval mine (section)

=== 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 Simple magnetic sensors have been superseded by total-field [[magnetometer]]s. Whereas early magnetic mine fuzes would respond only to changes in a single component of a target vessel's magnetic field, a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broadband [[hydrophone]]s of 1940s acoustic mines (which operate on the integrated volume of all frequencies) have been replaced by narrow-band sensors which are much more sensitive and selective.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>