HMS Challenger was a unique vessel in 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...

 service, purpose built to support deep sea operations and saturation diving

Saturation diving

Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness when they work at great depth for long periods of time....

. Built by Scotts

Scotts Shipbuilding and Engineering Company

Scotts Shipbuilding and Engineering Company Limited, often referred to simply as Scotts, was a Scottish shipbuilding company based in Greenock on the River Clyde.- History :...

 at Greenock

Greenock

Greenock is a town and administrative centre in the Inverclyde council area in United Kingdom, and a former burgh within the historic county of Renfrewshire, located in the west central Lowlands of Scotland...

, the ship was launched on 19 May 1981, but not commissioned until 1984, during a time when the Royal Navy was cutting back on expenditure. The consequence was that the £80m Challenger was seen as an extravagance that the Admiralty

Admiralty

The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 could not afford. As a consequence, after only a few years service, in 1990 the ship was laid up and offered for sale.

In 1993 the ship was purchased by a company called Subsea Offshore, to be converted for work decontaminating hazardous waste dumped in the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 and North Atlantic.

The vessel was later bought by the Namibian Minerals Corporation (NAMCO), and fitted with equipment to recover diamond

Diamond

In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...

s from the sea floor. The ship was converted at the Nauta Shipyard in Gdynia

Gdynia

Gdynia is a city in the Pomeranian Voivodeship of Poland and an important seaport of Gdańsk Bay on the south coast of the Baltic Sea.Located in Kashubia in Eastern Pomerania, Gdynia is part of a conurbation with the spa town of Sopot, the city of Gdańsk and suburban communities, which together...

, Poland, and made its first diamond recoveries in December 2000. The ship was bought by De Beers

De Beers

De Beers is a family of companies that dominate the diamond, diamond mining, diamond trading and industrial diamond manufacturing sectors. De Beers is active in every category of industrial diamond mining: open-pit, underground, large-scale alluvial, coastal and deep sea...

in April 2003 for US$20 million.