The Upholder/Victoria-class submarines, also known as the Type 2400 (due to their displacement of 2,400 tonnes), are the class of the diesel-electric submarines built in the United Kingdom in the 1980s to supplement the nuclear submarines in the Submarine Service of the British Royal Navy.
The boats were originally named the Upholder class, after the most renowned vessel of the former U class. Their British service life was short, with the vessels being decommissioned in 1994. After an unsuccessful bid to transfer these submarines to the Pakistan Navy in 1993–1994, the Canadian government eventually purchased the submarines and a suite of trainers from the Royal Navy for Canadian Forces Maritime Command (renamed to Royal Canadian Navy in 2011) to replace their decommissioned s in 1998.
In Canadian service, the submarines are classified as the Victoria class. These submarines initially suffered from serious electrical problems and were beset by mechanical operational incidents that limited their active service and the scope of their deployments. These problems have largely been overcome and the subs have achieved full operational capability.
Design and development
In the late 1970s the United Kingdom Ministry of Defence (MoD) proposed a diesel-electric submarine design to replace the Oberon class. The new submarine class was intended to provide a more cost-effective alternative for training and in coastal defence. The announcement for the new design took place in September 1979. Five designs were put forward, with the MoD selecting the 1,960-ton design. However, the need for export potential upped the displacement limit to 2,400 tons to allow for flexibility in construction if the need for alternative machinery and systems arose.
The Vickers Shipbuilding & Engineering Ltd. (VSEL) Type 2400 diesel-electric patrol submarine design was selected. The design displaces between 2,168 and 2,220 tons surfaced and 2,400–2,455 tons submerged. The submarines are long overall with a beam of and a draught of . The submarines had a complement between 44 and 47 with the Royal Navy.
The submarines have a single-skinned, teardrop-shaped hull constructed from NQ1 high tensile steel. The hull is fitted with elastomeric acoustic tiles to reduce the submarine's acoustic signature. The class has a reported dive depth of over .
Machinery
The submarines are powered by a single-shaft diesel-electric system. They are equipped with two Paxman Valenta 1600 RPS SZ diesel engines, each driving a GEC electric alternator. There are two 120-cell Chloride batteries. The batteries have a 90-hour endurance at . The submarine is propelled by a GEC dual armature electric motor turning a seven-blade fixed pitch propeller. This gives the vessels a maximum speed of on the surface and submerged. They have a diesel fuel capacity of 200 tons, giving a range of at and at snorting depth.
Armament
The class is equipped with six torpedo tubes in the bow. In British service, the submarines were supplied with up to 18 Marconi Mk 24 Tigerfish Mod 2 torpedoes; they were also capable of using UGM-84 Sub-Harpoon missiles. They could also be adapted for use as a minelayer. The DCC Action Information Organisation and Fire Control System (AIS/FC), developed from the DCA/DCB systems in service at that time aboard Royal Navy nuclear-powered submarines, was based on two Ferranti FM1600E computers with a digital data bus linked to three dual-purpose consoles. Up to 35 targets could be tracked, and automatic guidance could be provided for four torpedoes against four separate targets.
During the refit for Canadian service, the Sub-Harpoon and mine capabilities were removed and the submarines were equipped with the Lockheed Martin Librascope Submarine fire-control system (SFCS) to meet the operational requirements of the Canadian Navy. Components from the fire control system of the Oberon-class submarines were installed. This gave the submarines the ability to fire the Gould Mk 48 Mod 4 torpedo. This torpedo, operating at , is deployed against targets over a range of . The torpedo range is at speeds up to . The type uses active and passive homing to approach the designated target. In 2014, the Government of Canada purchased 12 upgrade kits that will allow the submarines to fire the Mk 48 Mod 7AT torpedo.