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Monarch


Vessel type Cableship
Year launched 1946
Cargo type Cable
Country of build United Kingdom

In three decades of service, the cableship Monarch (later renamed Sentinel) helped to pave the way for modern telecommunications, taking part in many major projects – including key work on laying the first transatlantic telephone cable, TAT-1.

Built for purpose

When completed in February 1946, as HMTS (His Majesty's Telegraph Ship) Monarch, the vessel was the largest cableship in the world – with the ability to carry up to 2,500nm of deepsea telegraph cable in four 41ft-diameter cable tanks.

Significantly larger than all previous General Post Office (GPO) cableships, the 8,541grt Monarch had been ordered by the government to replace the 5,533grt Faraday – which had been the victim of a Second World War German air attack off the coast of Wales in March 1941 – but its launch had been delayed by the war.

The build

Built at the Swan, Hunter & Wigham Richardson yard in Wallsend, Monarch incorporated many special and innovative design and equipment features, and was the first cableship to have all-electric cable machinery. Diesel-electric or turbo-electric drive had been suggested, but 'after careful consideration' it was agreed that the ship would be powered by two three-cylinder triple expansion engines developing 4,500hp and driving twin screws.

After comfortably achieving 14.5 knots on builders' trials, Monarch conducted successful cable laying trials off Scotland and the Scilly Isles before working on cables between the UK, the Netherlands and Denmark.

Transatlantic trailblazer

In 1952, Monarch laid a series of cables for the US Air Force, from Cape Canaveral in Florida to the Bahamas, and on to Grand Turk, the Dominican Republic and Puerto Rico.

Between 1955 and 1965, Monarch did the bulk of the work to lay the 2,240-mile TAT-1 transatlantic telephone cable between Oban, Scotland, and Clarenville, Newfoundland, in a joint British, American and Canadian project. Monarch was the only cableship capable of carrying out the work to lay 1,500nm of cable in one piece across the deepest part of the Atlantic.

It was during this project that Monarch helped the UK Meteorological Office to complete its State of the Sea guide for seafarers, by supplying some much-needed photographs of force 11 and 12 sea conditions.

Connecting the world

Monarch also worked on laying the second transatlantic telephone cable, TAT-2, in 1959, the HAW-1 cable between the US mainland and Hawaii in 1957, and Canada's transatlantic CANTAT-1 cable in 1961.

Between 1962 and 1963 Monarch worked with two Cable & Wireless ships to lay the 9,400-mile Commonwealth Pacific Cable System (COMPAC) that connected Canada with New Zealand and Australia.

In 1968 Monarch helped to complete sections of the SAT-1 telephone cable between South Africa and Portugal and in the following year the ship's prefix changed from HMTS to CS when the GPO's status went from being a government department to a statutory corporation.

The later years

Monarch was sold to Cable & Wireless in October 1970 and renamed CS Sentinel. Based in Bermuda, the ship then became used mainly for Atlantic cable maintenance and repair, as well as trials of the Scarab remote submersible for surveying, recovering and re-burying existing buried cables, before being sent to Blyth for scrapping in October 1977.

Monarch fact file


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