HMS Plym (K271) was a River class frigate

River class frigate

The River class frigate was a class of 151 frigates launched between 1941 and 1944 for use as anti-submarine convoy escorts in the North Atlantic....

 that served in 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...

 between 1943 and 1952.

Construction

Plym was built to the Royal Navy's specifications as a Group II River class frigate. She was laid down at Smiths Dock Co.

Smiths Dock Company

Smiths Dock Company, Limited, often referred to simply as Smiths Dock, was a British shipbuilding company.-History:The company was originally established by Thomas Smith who bought William Rowe's shipyard at St. Peter's in Newcastle upon Tyne in 1810 and traded as William Smith & Co. The company...

, South Bank-on-Tees

South Bank, Middlesbrough

South Bank is a small town which forms part of the Middlesbrough urban area that lies 2.3 miles from Middlesbrough centre, in North East England. As the name suggests, it lies on the south bank of the River Tees. Although it is part of the Middlesbrough conurbation, it is a ward of Redcar and...

 on 1 August 1942 and launched on 4 February 1943.

She was commissioned into the RN on 16 May 1943 as HMS Plym (K271) and was named after the River Plym

River Plym

The River Plym is a river in Devon, England. Its source is some 450m above sea level on Dartmoor, in an upland marshy area called Plym Head. From the upper reaches which contain antiquities and mining remains the river flows roughly southwest and enters the sea near to the city of Plymouth, where...

 in Devon

Devon

Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 which flows into the English Channel

English Channel

The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...

 at Plymouth

Plymouth

Plymouth is a city and unitary authority area on the coast of Devon, England, about south-west of London. It is built between the mouths of the rivers Plym to the east and Tamar to the west, where they join Plymouth Sound...

.

War service

Plym saw extensive service on Atlantic

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 convoy escort missions.

Plym, along with , and , provided anti-submarine escort to the convoy WS-33 which arrived in South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 from the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 on 9 October 1943 with critical reinforcements for service in Burma.

Operation Hurricane

Plym was used as the detonation platform for the UK's first nuclear weapon

Nuclear weapon

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...

 in Operation Hurricane

Operation Hurricane

Operation Hurricane was the test of the first British atomic device on 3 October 1952. A plutonium implosion device was detonated in the lagoon between the Montebello Islands, Western Australia....

. A 25 kiloton atom bomb was detonated a few seconds before 09:30 local time on 3 October 1952 approximately 400 metres from the island of Trimouille in the Monte Bello Islands, Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

.

Although data acquisition would have been simplified by detonating the bomb from a tower above the ground or sea surface, it was conducted aboard the Plym in order to simulate the effects of a nuclear weapon being smuggled into a British harbour aboard a ship, which was considered a real possibility at the time.