HMS Unrivalled (P45) was a U-class

British U class submarine

The British U class submarines were a class of 49 small submarines built just before and during the Second World War...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 built for the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. So far she has been the only ship of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 to bear the name Unrivalled. Completed in 1942, the boat spent most of the war in the Mediterranean. She sank a number of small merchant ships and naval auxiliaries, but major success eluded her during the war. Too small and slow for the post-war environment, Unrivalled was scrapped

Ship breaking

Ship breaking or ship demolition is a type of ship disposal involving the breaking up of ships for scrap recycling. Most ships have a lifespan of a few decades before there is so much wear that refitting and repair becomes uneconomical. Ship breaking allows materials from the ship, especially...

 in 1946.

Design and description

HMS Unrivalled was one of the second group of U-class submarines ordered on 23 August 1940. These submarines differed from their predecessors in that they were lengthened by 5 feet (1.5 m) "to give a more streamlined shape aft and to improve the flow of water over the propellers."

The submarine was 195 inch long and 15 in 9 in (4.8 m) abeam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

. Unrivalled had a single hull

Submarine hull

The term light hull is used to describe the outer hull of a submarine, which houses the pressure hull, providing hydrodynamically efficient shape, but not holding pressure difference...

 with internal ballast tank

Ballast tank

A ballast tank is a compartment within a boat, ship or other floating structure that holds water.-History:The basic concept behind the ballast tank can be seen in many forms of aquatic life, such as the blowfish or argonaut octopus, and the concept has been invented and reinvented many times by...

s and had a draft of 15 in 19 in (5.05 m) when surfaced. She displaced 735 long tons (746.8 t) while submerged, but only 648 long tons (658.4 t) on the surface. The submarine was equipped with two diesel engine

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

s and twin General Electric

General Electric

General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 electric motor

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

s—for surfaced and submerged running, respectively. They were coupled together with a diesel-electric transmission. Unrivalled had a surface speed of up to 11.25 knots (6.1 m/s) and could go as fast as 9 knots (4.9 m/s) while underwater. The boat could carry up to 55 long tons (55.9 t) of diesel fuel, giving her a range of 5000 nautical miles (9,260 km) at 10 knots (5.4 m/s). Her electric motors and batteries provided a range of 120 nautical miles (222.2 km) at 2 knots (1.1 m/s) while submerged.

HMS Unrivalled was equipped with four 21 inches (53 cm) bow torpedo tube

Torpedo tube

A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...

s and could carry eight torpedo

British 21 inch torpedo

There have been several British 21-inch diameter torpedoes used by the Royal Navy since their first development just before the First World War.They were the largest size of torpedo in common use in the RN...

es. The submarine was also armed with a 3 inches (7.6 cm) QF Mk I gun

QF 3 inch 20 cwt

The QF 3 inch 20 cwt anti-aircraft gun became the standard anti-aircraft gun used in the home defence of the United Kingdom against German airships and bombers and on the Western Front in World War I. It was also common on British warships in World War I and submarines in World War II...

 deck gun

Deck gun

A deck gun is a type of artillery cannon mounted on the deck of a ship or submarine.The deck gun was used as a defensive weapon against smaller boats or ships and in certain cases where torpedo use was limited. Typically a crew of three; gunner, loader, and layer, operated the gun, while others...

. She had a crew of 33 men.

Career

HMS Unrivalled was ordered on 23 August 1940 as part of the 1940 naval construction programme from Vickers-Armstrong

Vickers

Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

 at Barrow-in-Furness

Barrow-in-Furness

Barrow-in-Furness is an industrial town and seaport which forms about half the territory of the wider Borough of Barrow-in-Furness in the county of Cumbria, England. It lies north of Liverpool, northwest of Manchester and southwest from the county town of Carlisle...

. She was laid down

Keel

In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

 on 12 May 1941, launched on 16 February 1942 and commissioned on 3 May 1942.

Apart from a work-up patrol in the Norwegian Sea, she spent the bulk of the war in the Mediterranean. While working up, Unrivalled fired a torpedo at what was thought to be a submerged enemy submarine. Only the periscope was sighted, and the torpedo was fired in the direction detected by the hydrophone

Hydrophone

A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...

s, but no German submarine was in the area. Whilst in service in the Mediterranean, she sank a number of small merchantmen and small naval auxiliary vessels with both torpedoes and gunfire. These included the Italian auxiliary submarine chaser O 97 / Margherita, the Italian merchants Maddalena, Mostaganem and Pasubio, the Italian tugs Genova and Iseo, the Italian sailing vessels Triglav, Albina, Margherita, Sparviero and Ardito, the German auxiliary submarine chasers UJ 2201/Bois Rose and UJ 2204/Boréal, the Italian tanker Bivona, the small Italian merchant Santa Mariana Salina, the Italian auxiliary minesweeper R 172 / Impero and the small Italian vessel San Francisco di Paola A.

Unrivalled also damaged the on 3 December 1942, but neither sank or damaged any Axis ships after 28 July 1943. During Operation Husky in July 1943, she was stationed offshore to mark the landing beaches for the 1st Canadian Infantry Division

1st Canadian Infantry Division

The 1st Canadian Infantry Division was a formation mobilized on 1 September 1939 for service in the Second World War. The division was also reactivated twice during the Cold War....

. The boat survived the war, but was too slow for requirements and was not retained after the war. She was scrapped at Briton Ferry

Briton Ferry

Briton Ferry is a town and community in the county borough of Neath Port Talbot, Wales. The town encompasses the electoral wards of Briton Ferry East and Briton Ferry West....

, Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

, beginning on 22 January 1946.