Naval mine in the context of "Naval operations in the Dardanelles campaign"

Anti-submarine warfare (ASW, or in the older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typically carried out to protect friendly shipping and coastal facilities from submarine attacks and to overcome blockades.

Successful ASW operations typically involve a combination of sensor and weapon technologies, along with effective deployment strategies and sufficiently trained personnel. Typically, sophisticated sonar equipment is used for first detecting, then classifying, locating, and tracking a target submarine. Sensors are therefore a key element of ASW. Common weapons for attacking submarines include torpedoes and naval mines, which can both be launched from an array of air, surface, and underwater platforms. ASW capabilities are often considered of significant strategic importance, particularly following provocative instances of unrestricted submarine warfare and the introduction of submarine-launched ballistic missiles, which greatly increased the lethality of submarines.

Coastal defence (or defense) and coastal fortification are measures taken to provide protection against military attack at or near a coastline (or other shoreline), for example, fortifications and coastal artillery. Because an invading enemy normally requires a port or harbour to sustain operations, such defences are usually concentrated around such facilities, or places where such facilities could be constructed. Coastal artillery fortifications generally followed the development of land fortifications, usually incorporating land defences; sometimes separate land defence forts were built to protect coastal forts. Through the middle 19th century, coastal forts could be bastion forts, star forts, polygonal forts, or sea forts, the first three types often with detached gun batteries called "water batteries". Coastal defence weapons throughout history were heavy naval guns or weapons based on them, often supplemented by lighter weapons. In the late 19th century separate batteries of coastal artillery replaced forts in some countries; in some areas these became widely separated geographically through the mid-20th century as weapon ranges increased. The amount of landward defence provided began to vary by country from the late 19th century; by 1900 new US forts almost totally neglected these defences. Booms were also usually part of a protected harbor's defences. In the middle 19th century underwater minefields and later controlled mines were often used, or stored in peacetime to be available in wartime. With the rise of the submarine threat at the beginning of the 20th century, anti-submarine nets were used extensively, usually added to boom defences, with major warships often being equipped with them (to allow rapid deployment once the ship was anchored or moored) through early World War I. In World War I railway artillery emerged and soon became part of coastal artillery in some countries; with railway artillery in coast defence some type of revolving mount had to be provided to allow tracking of fast-moving targets.

In littoral warfare, coastal defence counteracts naval offence, such as naval artillery, naval infantry (marines), or both.

Naval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for more specialized roles in surface warfare such as naval gunfire support (NGFS) and anti-aircraft warfare (AAW) engagements. The term generally refers to powder-launched projectile-firing weapons and excludes self-propelled projectiles such as torpedoes, rockets, and missiles and those simply dropped overboard such as depth charges and naval mines.

HMS Belfast is a Town-class light cruiser that was built for the Royal Navy. She is now permanently moored as a museum ship on the River Thames in London and is operated by the Imperial War Museum.

Construction of Belfast, the first ship in the Royal Navy to be named after the capital city of Northern Ireland and one of ten Town-class cruisers, began in December 1936. She was launched on Saint Patrick's Day 1938. Commissioned in early August 1939 shortly before the outbreak of the Second World War, Belfast was initially part of the British naval blockade against Germany. In November 1939, Belfast triggered a German mine and, in spite of fears that she would be scrapped, spent more than two years undergoing extensive repairs. Belfast returned to action in November 1942 with improved firepower, radar equipment and armour. She saw action escorting Arctic convoys to the Soviet Union during 1943 and in December 1943 played an important role in the Battle of North Cape, assisting in the destruction of the German warship Scharnhorst. In June 1944, Belfast took part in Operation Overlord supporting the Normandy landings. In June 1945, she was redeployed to the Far East to join the British Pacific Fleet, arriving shortly before the end of the Second World War. Belfast saw further combat action in 1950–52 during the Korean War and underwent an extensive modernisation between 1956 and 1959. A number of further overseas commissions followed before she entered reserve in 1963.

A torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such a device was called an automotive, automobile, locomotive, or fish torpedo; colloquially, a fish.

The term torpedo originally applied to a variety of devices, most of which would today be called mines. From about 1900, torpedo has been used strictly to designate a self-propelled underwater explosive device.