The Victoria class consists of four diesel-powered Canadian Navy submarines acquired from the Royal Navy (formerly known as the Upholder class) and replacing the old Oberon-class subs. The boats are named after Canadian port cities:

• HMCS Victoria (formerly the HMS Unseen )
• HMCS Windsor (formerly the HMS Unicorn )
• HMCS Corner Brook (formerly the HMS Ursula )
• HMCS Chicoutimi (formerly the HMS Upholder).

Victoria operates out of Esquimalt, British Columbia and works in the Pacific Ocean, while the remaining boats are based in Halifax, Nova Scotia and work in the Atlantic and Arctic oceans.

The boats were originally built by the UK, but saw only brief service before being mothballed in favour of an all nuclear force. They are essentially identical to modern nuclear submarines (with the distinctive nuclear shape and sonar-deflecting tiles) but run on diesel engines instead of nuclear reactors (which limits their range, but conversely makes them quieter and more manoeuvrable). It is foreseen that with the maturity of fuel cell technology the ships will be converted over to that power system, which could allow them to operate at sea almost indefinitely without the problems, real and perceived, of nuclear power.

There have been arguments over the quality of the submarines with some suggestions that the purchase price of £244m will be at least spent again putting things right. Canadian opposition parties are demanding that the British government fund any further costs, however it cost the Royal Navy £900m to build the submarines and even if there are some minor problems Stephen Saunders, editor of Jane's Fighting Ships, argues that "there is not something inherently wrong with the class of submarines." On Tuesday October 5 2004 HMCS Chicoutimi, sailing from Faslane, Scotland to Nova Scotia declared an emergency north-west of Ireland following a fire onboard. The submarine lost power and was rescued by the Royal Navy frigates HMS Montrose and HMS Marlborough on October 6. This episode will further complicate the issue of the sale of the submarines.

Statistics

• Displacement: 2,400 tons submerged
• Dimensions: 70.26 by 7.6 by 5.5 m
• Propulsion: Diesel-electric, 2 diesels, 1 shaft, 20 knots (37 km/h)
• Crew: approx. 44
• Sonar: Type 2040 bow, Type 2041 flank, unknown towed array
• Fire Control: unknown
• EW: Decca Porpoise intercept
• Armament: 6 21 inch (533 mm) torpedo tubes (18 Mark 48 torpedoes)