|Place of origin||United Kingdom|
|In service||Royal Australian Navy|
Warshot has an incremental payload.
|Diameter||533 mm (21.0 in)|
The Stonefish naval influence mine is manufactured by a British defence company (BAE Systems). It has been exported to friendly countries such as Australia, which has both warstock and training versions of Stonefish. There has been conjecture that South Africa, Chile, Iraq, Libya and possibly other countries may have gained access to either some early Stonefish information or to similar technology. The mine is named after the stonefish, a venomous fish of the same name.
Stonefish mines generally have two suspension lugs in order to facilitate handling operations e.g. winching. They can be deployed by fixed-wing aircraft, helicopters, surface vessels and submarines. It is a cylindrically shaped, modular weapon, comprising three separate sections which are joined together to form one unit:
There are four different versions of the Stonefish mine, only one of which is intended for use in combat. The other three versions are intended for training or target acquisition purposes. These are:
Two sizes of Stonefish explosive warhead are available for warstock mines, 100 kilograms (220 lb) and 300 kilograms (660 lb). However, the destructive power of a Stonefish mine can be adjusted by coupling multiple warheads together in different combinations. In this way, a Stonefish mine can have a warhead which weighs 100, 200, 300, 400, 500 or 600 kg. The ability to change the warhead size allows Stonefish to be deployed against small targets in shallow coastal waters or against large targets in deep ocean. Depending on the warhead configuration, a Stonefish mine can have a total weight of up to 990 kilograms (2,180 lb). The physical measurements of a Stonefish mine are such that it can easily be loaded into the torpedo tubes of submarines, then deployed using a small charge of compressed air to expel it. Alternatively, if an optional air-drop kit is fitted it can also be deployed by maritime patrol aircraft such as the P-3 Orion (connected to the aircraft via suspension lugs and an arming lanyard) its descent to the ocean surface slowed by a parachute retard pack.
The computerised exploder in a Stonefish mine is microprocessor-based. It features acoustic, magnetic and water pressure displacement target detection sensors. The DSP circuitry includes such features as the ability to set thresholds regarding the signal strength and adjust sterilisation delay times (how long before the mine renders itself inoperative). A portable electronic presetting kit can be used to reprogram the mine (e.g. uploading a new library of acoustic target signatures or increasing the arming delay from one hour to 10 days) before the mine is deployed.
The operating depth of Stonefish ranges between 30 and 200 metres (98 and 656 ft). Its shelf life is 20 years, and it has an operational lifetime of 700 days after being deployed on the seabed. Stonefish incorporates arming delays, ship counting and self-sterilisation features which can be configured by the user.