The Upholder class of four (4) submarines, also known as the Type 2400 (due to their displacement of 2,400 tonnes), were diesel-electric fleet submarines designed in the UK in the late 1970s to supplement the Royal Navy's nuclear submarine force. They were decommissioned with the end of the Cold War after a short length of service in the Royal Navy. In 1998, Canada purchased the submarines and a suite of trainers from the Royal Navy to replace the decommissioned Oberon class of submarines.
[u]Names of Submarines[/u]
• S 40 HMS Upholder
• S 41 HMS Unseen
• S 42 HMS Ursula
• S 43 HMS Unicorn
[u]Class specifications[/u]
• Length: 70,26 meters (230.5 ft)
• Beam: 7,2 meters (24 ft)
• Draft: 7,6 meters (25 ft)
• Displacement: 2455 tons (submerged)
• Speed: 12 knots (22 km/h) surfaced / 20 knots (37 km/h) submerged
• Range: 8000 NM (15000 km)
• Complement: 48
[u]Propulsion: [/u]
• Diesel-Electric
• 2 x Paxman Valenta 1600 RPA SZ diesel engines (2035 hp / 1.517 MW)
• 1 x GEC electric motor (5 MW)
• 1 shaft / 1 propeller
[u]Armament:[/u]
• 6 x 21 inches (533mm) torpedo tubes for Mark 48 torpedoes
HMS UNSEEN entered service in 1990. Initially she was (in common with the remainder of the class) unable to fire torpedoes and the first three were refitted in 1992 and 1993 to have this fixed at a cost of £9 million. There was a design issue between the interlocks between the inner and outer doors which under certain conditions allowed both doors to be opened at the same time.
They were operating from HMS Dolphin (at Gosport) but with only four submarines the base was deemed uneconomic and they transferred to Devonport Naval Base.
In their short period in service, the class operated mostly in the Atlantic Ocean, the Mediterranean and UK waters. The exception was Unicorn, which completed a 6-month deployment east of Suez completing operations and exercises in the Mediterranean, the Gulf of Oman and Indian Ocean and in the Persian Gulf. Her return in October 1994 to decommission marked the end of service of this class, following a defence review by the UK government that decided to maintain an all-nuclear-powered submarine fleet rather than a mix of diesel with fewer nuclear submarines.
[b]HMS UNSEEN seen leaving Portsmouth on the 5 May 1992[/b]
