| GENE SLOVER'S US NAVY PAGES NAVAL ORDNANCE AND GUNNERY VOLUME 1, NAVAL ORDNANCE CHAPTER 13 MINES |
| HOME INDEX MINES A. General B. Aircraft mines C. Mine Warefare |
| C. Mine Warfare 13C1. Definitions Mine warfare is the strategic and tactical employment of naval mines and mine countermeasures in the conduct of war. Types of operations. Minelaying operations are classified as follows: 1. Physical position of field-defensive or offensive. 2. Relationship to other military operations-strategic or tactical. 3. Purpose of field-closure or attrition. 4. Method of laying-aircraft, submarine, or surface. Types of fields. Mine fields are defined as follows: 1. Defensive fields are those in waters under friendly control, where enemy sweeping would be improbable. These fields are laid by minelayers whose only escort is an antisubmarine screen or combat air patrol. The area to be mined is carefully surveyed. Beach markers may be used as additional aids to navigation. Buoys are sometimes anchored in advance to mark the beginning and end of the field, and every effort is made to lay the mines in the exact location designated. Controlled mines, to which reference has been made repeatedly in this chapter, are used in some types of defensive fields. 2. Offensive fields are those laid in disputed or enemy-controlled waters, and may be subdivided into two classes: (1) those designed to prevent passage of enemy vessels (closure mining) and (2) those in which passing of enemy ships is welcomed because they will be destroyed (attrition mining). a. Closure fields are frequently laid around an area or harbor to prevent passage of enemy vessels. b. Attrition mine fields are laid primarily to destroy enemy vessels, not to deny their passage. They are laid in ship lanes where enemy traffic has been observed. The utmost secrecy is essential. For this mission, aircraft or submarines are employed. Strategic versus tactical. Strategic and tactical mining are defined as follows: 1. Strategic mining is a mining program, independent of other military operations, conducted over an extended period of time for the purpose of blockading enemy ports and strangling enemy supply systems. The term implies that the program does not have as its objective an immediate attack on any specific enemy force. Strategic mining is a very powerful offensive weapon when carried out by aircraft or submarines against waterways vulnerable to mine attack. Against an island empire, it may be the decisive factor in a military campaign. 2. Tactical mining in an engagement is now conceived as a function of aircraft or light, high-speed minelayers. The use of drifting mines, for turning the enemy battle line, has been outmoded by the increased speed of the modern battleship. However, tactical use of drifting mines to cover the retirement of a surface raiding or bombardment force is highly practicable. Such mines, as well as other types, may be used to prevent the escape of enemy vessels from a base or lagoon where such ships are under attack by aircraft or forced to sortie for any other reason. Moored or ground mines may be used in tactical mining operations such as preventing pursuit of own forces to a base, and denying a channel to enemy forces operating tactically against own forces. 13C2. Command problems The importance of offensive mine warfare is rapidly increasing. A sudden, massive attack by minelaying aircraft is considered to be one of the greatest threats to any maritime power that exists today. So great, in fact, that the possibility of such an attack requires major expenditures of manpower and equipment in conducting countermeasure operations, whether a single mine has been laid or not. Offensive minelaying by surface craft, including PT boats, has comparatively limited application in enemy-held waters. The utmost secrecy can, of course, be obtained by laying mines from submarines. However, a submarine cannot replenish the interior of an existing mine field without itself being exposed to an unacceptable amount of danger. That brings us to the use of aircraft. The aircraft naturally leads in its ability to lay mines suddenly and in great quantity. It is, further, the only craft capable of replenishing a large existing field without danger from the field itself. Offshore shipping lanes can be mined by bombers and patrol planes whenever the depth of water is not too great. Mining of enemy-held rivers and harbors would generally be effected by tactical aircraft under conditions of low visibility or under cover of diversionary raids. 13C3. Mine countermeasures Mine countermeasures include all actions taken primarily to protect own or friendly shipping against mines. Protection is accomplished in two general ways: (1) by reducing the effectiveness of enemy mines and (2) by clearing areas mined by friendly forces, after these areas have served their purpose. The three major types of mine countermeasures are ship treatment, mine hunting, and minesweeping. We’ll consider each of these very briefly. Ship treatment. Ships are capable of being treated to reduce their magnetic and acoustic fields of influence. Such treatment gives them a measure of immunity to mines designed to be actuated by those fields. It is possible that eventually hull design will be improved to reduce pressure signals as well. When protection against magnetic mines is mentioned, degaussing is the word most likely to come to the mind of the Navy man. The degaussing process is the most effective means of reducing the magnetic influence of a steel ship. This process makes use of electric cable installed either (1) in a single large coil surrounding the hull or (2) in a large coil plus a system of lesser coils. Direct current is sent through each coil in such a direction as to create a magnetic field opposite in polarity to the corresponding component of the ship’s magnetic signature. The installation of the degaussing system is often preceded by an electromagnetic process called deperming. This preliminary process reduces the ship’s inherent magnetism to a value regarded as standard for vessels of the given class. After a ship has been depermed, mass-production techniques, rather than custom methods, may be used in installing the degaussing equipment. An older process called flashing or wiping is similar to deperming, but is normally applied only to small vessels that are not intended to be fitted with degaussing coils. To reduce the danger from acoustic mines, ships are being designed and treated to eliminate unnecessary cruising noises. Mine hunting. The methodic detection, location, and neutralization of mines is appropriately called mine hunting. Some craft and their highly trained personnel specialize in this work. The shipboard devices used in mine detection are called ordnance locators. The sensing component of an ordnance locator is called an ordnance detector. The term ordnance detector can also refer, however, to a small, man-carried ordnance locator in its entirety. Minesweeping. The process of clearing a given region of mines is called minesweeping. Mechanical devices, explosive charges, and apparatus for producing influence fields may all be needed in the sweeping of a single field. Moored contact mines are swept by means of a paravane rig, which is an underwater kite towed by the minesweeper. The sweep cable contacts the mine-anchor cable, guiding it into the cutter jaws of the paravane. These jaws cut the mine adrift, allowing it to rise and be destroyed harmlessly on the surface. Some magnetic mines are capable of being swept by towing a buoyed electric cable over them. The strong magnetic field set up by this cable causes the mine to detonate. Since these mines are designed to function as the peak of the magnetic field passes, they are not set off by the relatively weak field of the minesweeper. Through use of advanced degaussing systems, and nonmagnetic construction materials, new designs of minesweepers reduce their magnetic fields to a minimum. Some acoustic mines are swept by creating underwater sounds of proper intensity and quality to actuate the mine-firing mechanism. Noise makers are of various types, some being towed astern by a sweep wire and others being located in the bow of the minesweeper to direct the noises ahead of the vessel. New types of engine mountings and other noise-reducing devices are at present being applied to minesweepers to reduce acoustic disturbances produced by their own propulsion equipment, and thus improve their ability to sweep acoustic mines with safety. As yet the sweeping of pressure mines and subsonic acoustic mines has presented great difficulties. Other countermeasures. In addition to the three major types of countermeasures, various other protective measures may be taken. These include mine watching, prevention of enemy minelaying action, and the use of long-range detecting and actuating devices. |