A Nuclear Depth Bomb is the nuclear

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

 equivalent of the conventional depth charge

Depth charge

A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 and can be used in Anti-Submarine Warfare

Anti-submarine warfare

Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....

 (ASW) for attacking submerged submarines. The Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

, Soviet Navy

Soviet Navy

The Soviet Navy was the naval arm of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy would have played an instrumental role in a Warsaw Pact war with NATO, where it would have attempted to prevent naval convoys from bringing reinforcements across the Atlantic Ocean...

 and United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 had nuclear depth bombs in their arsenals at one point.

Due to the use of a nuclear warhead of much greater explosive power than that of the conventional depth charge, the Nuclear Depth Bomb considerably increases the likelihood (to the point of near certainty) of the destruction of the attacked submarine.

Because of this much greater power some NDBs feature a variable

Variable yield

Variable yield — or dial-a-yield — is an option available on most modern nuclear weapons. It allows the operator to specify a weapon's yield, or explosive power, allowing a single design to be used in different situations...

 yield

Nuclear weapon yield

The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...

, whereby the explosive energy of the device may be varied between a low setting for use in shallow or coastal waters, and a high yield for deep water open-sea use[vermelho]. This is intended to minimize damage to peripheral areas and shipping

Shipping

Shipping has multiple meanings. It can be a physical process of transporting commodities and merchandise goods and cargo, by land, air, and sea. It also can describe the movement of objects by ship.Land or "ground" shipping can be by train or by truck...

.