Upholder class submarine

The Upholder-class submarines (now known as the Victoria class in Canada, and also known as the Type 2400 due to their displacement of 2,400t) were diesel-electric hunter-killer (SSK) submarines designed in Britain the late 1970s to supplement the Royal Navy's nuclear submarine force. That force was intended to comprise 18 nuclear-powered attack boats (SSNs) and four ballistic missile boats (SSBNs), but construction of the SSNs fell behind schedule, and the construction plans were altered to include ten modern SSKs as well. The price of each was intended to be about one-third that of one of the SSNs, and was finally published at US$215 million, but actual cost after correcting the design flaws was higher. After all four subs were leased to the Canadian navy, the Canadian forces renamed them as the Victoria class.

The design included an updated version of the fire-control system being installed on the SSNs under construction at the same time, a state-of-the-art French passive sonar system, the then-current towed array, and a passive ranging set.

They are the first conventional submarines to feature the hydrodynamic tear-drop shape seen in nuclear powered submarines, and also the first to feature sound-absorbing tiling on the outer surface of the submarine; both features greatly reducing the sound levels produced by the boat while cruising. The design was effectively that of an nuclear powered submarine, but without the reactor, leaving the submarine with a far shorter range and smaller performance, but also much quieter, an important advantage in under-water warfare.

A large double-armature motor was powered by a 9000-ampere-hour battery or a pair of Paxman Valenta diesel engines. Slow patrolling would require only 30 to 60 minutes of snorkling per day; an eight-knot transit would require snorkling some 30% of the time. Top speed matched any comparable SSK class and could be sustained for some 90 minutes.

However, the design did contain flaws. It was highly automated to reduce manning, and the weapon-discharge system that controlled the operations of the torpedo tubes could, under certain conditions, open the torpedo tube slide valve while the rear door was open. Had such an event actually occurred, unrestricted flooding could have resulted. The flaw was quickly fixed in the first three boats and the modifications included in the fourth boat while still under construction.

Miscalculations were made in the design of the main motor. During sea trials of the lead ship of the class, it was noticed that an emergency reversal ("crash back") would generate currents of more than 60,000 amperes, which resulted in catastrophic complete loss of propulsion.

The diesels were originally designed for use in railway locomotives, and were not intended to be rapidly stopped and started. Shutting them down after snorkling led to many failures. Similarly, the motor-generators were operated at full power for longer than expected, and consumed brushes and filters rapidly.

Acceptance of the class into service was delayed for three years while such problems were corrected. The result of those corrections, however, was an extremely capable design. When operating on battery power, Upholders were almost undetectable on passive sonar, and when snorkling, their acoustic signature was comparable to their SSN contemporaries in normal operation. They were physically small, and thus difficult to detect by magnetic anomaly or other non-acoustic means.

A local area network was built into the Upholders, supporting most of the sensors and fire-control systems, including remote viewing through the periscopes using both low-light television and infrared, an unmanned helm, and direct control of the main motor from the conn. The boat could fight with a team of four in the sonar room and a conn team of eight. Fire-suppression in unmanned compartments could be initiated remotely, and watch-keeping logs were automatically recorded. In port, the boats could be electronically linked such that one duty watchstander could monitor several submarines.

In 1993, HM Government decided to halt construction with only four boats launched, and furthermore to decommission the four in service in favour of a rationalisation of the submarine fleet to nuclear only. In 2002, Canada accepted the four Upholders as replacements for their old O-class submarines. One will operate in the Pacific fleet, three in the Atlantic.

See Victoria class submarine for post-sale information.

Ships in Class

• ex-Upholder (S-40), now HMCS Chicoutimi (SSK 879)
• ex-Unseen (S-41), now HMCS Victoria (SSK 876)
• ex-Ursula (S-42), now HMCS Cornerbrook (SSK 878)
• ex-Unicorn (S-43), now HMCS Windsor (SSK 877)

General Characteristics

• Displacement: 2200 tons surfaced, 2400 tons submerged
• Length: 70.3 m
• Beam: 7.2 m
• Height: 7.6 m
• Engines: two Paxman Valenta 16 RPA diesel generators, 4,070 hp (3,035 kW)
• Motor-Generators: two GEC, 5,000 kW
• Speed: 12 knots surfaced, 20+ knots submerged
• Armament: six 21 in (533 mm) torpedo tubes, 24 torpedoes
• Range: 10,000 nautical miles (18,500 km) at 12 knots (22 km/h)
• Complement: seven officers, 40 men

Upholder-class submarine

Upholder | Unseen | Ursula | Unicorn

List of submarines of the Royal Navy List of submarine classes of the Royal Navy