The Ley class was a class

Ship class

A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....

 of inshore minehunter

Minehunter

Minehunters are mine countermeasure vessels that actively detect and destroy individual naval mines. Minesweepers, on the other hand, clear mined areas as a whole, without prior detection of mines...

 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...

 in the mid-1950s. They had pennant number

Pennant number

In the modern Royal Navy, and other navies of Europe and the Commonwealth, ships are identified by pennant numbers...

s in the series M2001. Eleven ships were built in the early 1950s, most of which were subsequently disarmed and used as training vessels, RNXS tenders, URNU

University Royal Naval Unit

A University Royal Naval Unit is a Royal Navy training establishment connected to a university, or a number of universities concentrated in one area...

 vessels etc.

Unlike traditional minesweepers

Minesweeper (ship)

A minesweeper is a small naval warship designed to counter the threat posed by naval mines. Minesweepers generally detect then neutralize mines in advance of other naval operations.-History:...

, they were not equipped for sweeping moored or magnetic mines. Their work was to locate individual mines and neutralise them. This was a then new role, and the class was configured for working in the shallow water of river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

s, estuaries

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 and shipping channels.

They were of composite construction, that is, wood and non-ferrous metal

Non-ferrous metal

In metallurgy, a non-ferrous metal is a metal that is not ferrous, that is, any metal, including alloys, that does not contain iron in appreciable amounts...

s, to give a low magnetic signature

Magnetism

Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...

, important in a vessel that may be dealing with magnetically detonated mines. They displaced 164 tons fully laden, were armed with a Bofors 40 mm gun

Bofors 40 mm gun

The Bofors 40 mm gun is an anti-aircraft autocannon designed by the Swedish defence firm of Bofors Defence...

 and were powered by a pair of Paxman

Paxman (engines)

Paxman is a major British brand of diesel engines. Ownership has changed on a number of occasions since the company's formation in 1865, and now the brand is owned by MAN SE, as part of MAN Diesel & Turbo. At its peak, the Paxman works covered 23 acres and employed over 2,000 people. Engine...

 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.

The class shared the same basic hull as their inshore minesweeper counterpart the Ham-class

Ham class minesweeper

The Ham class was a class of inshore minesweepers , known as the Type 1, of the British Royal Navy. The class was designed to operate in the shallow water of rivers and estuaries. It took its name from the fact that all the ship names were British place names ending in -"ham"...

 and the Echo-class

Echo class survey ship (1957)

The Echo class was a class of inshore survey vessel built for the British Royal Navy in 1958–1959. The class was designed to operate in close waters such as harbour approaches, shipping lanes, rivers and estuaries...

inshore survey craft.