HMTS ''Monarch'', launched on 8 August 1945 and completed during February 1946, was the fourth

cable ship A cable layer or cable ship is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electric power transmission, military, or other purposes. Cable ships are distinguished by large cable sheaves for guiding cabl ...

with that name. The ship was built for the

General Post Office The General Post Office (GPO) was the state postal system and telecommunications carrier of the United Kingdom until 1969. Before the Acts of Union 1707, it was the postal system of the Kingdom of England, established by Charles II in 1660. ...

(GPO) for the laying and repair of

submarine communications cable A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables laid beginning in the 1850s carried tel ...

and was the largest cable ship in the world when completed and the first cable ship to have all electric cable machinery. The ship was first engaged in repair and update of existing cables which had been neglected during the war. ''Monarch'' laid the first transatlantic telephone cable TAT-1. In 1969 When the GPO became a public corporation, the Post Office, the designation "Her Majesty's Telegraph Ship" (H.M.T.S.) became the more conventional, commercial designation "Cable Ship" (CS). In 1970 the ship was sold to Cable & Wireless and renamed ''Sentinel''.A fifth, smaller, ''Monarch'' for the Post Office was launched in 1975.

Background

The war loss of left Britain without a large cable ship. The government decided the national need for such a ship should be met by construction of a modern cable ship to be assigned to the General Post Office. Cable ships have unique requirements related to having long idle periods in port between cable laying or repairs, operation at low speeds or stopped at sea during cable operations, long periods running astern, high maneuverability, and a fair speed to reach operation areas. Electric drive was considered, but with the war were difficult to obtain. The design thus settled on oil fired boilers and two triple expansion steam engines driving two shafts. After design and model tests with design later coordinated with the builders to refine the final construction plans. This was to be the fourth cable ship to bear the name ''Monarch'' (the

first First or 1st is the ordinal form of the number one (#1). First or 1st may also refer to: *World record, specifically the first instance of a particular achievement Arts and media Music * 1$T, American rapper, singer-songwriter, DJ, and rec ...

was built in 1830 and was the first to be fitted out permanently as a

; the second ''Monarch'', sunk by a mine in 1915, had been the first cable ship built for the General Post Office; the third ''Monarch'' was sunk by a mine in 1944).

Construction

''Monarch'' was designed by General Post Office engineers under the Engineer in Chief with the design completed in 1942 but construction delayed by war needs until late 1944. The ship was built at

Swan Hunter Swan Hunter, formerly known as Swan Hunter & Wigham Richardson, is a shipbuilding design, engineering, and management company, based in Wallsend, Tyne and Wear, England. At its apex, the company represented the combined forces of three powe ...

(Swan, Hunter & Wigham Richardson, Ltd), as hull 1768 at the Neptune Yard, Walker-on-Tyne (Low Walker), and launched on 8 August 1945. The ship, largest cable ship in the world at the time of its launch, was completed and handed over it the

Postmaster General A Postmaster General, in Anglosphere countries, is the chief executive officer of the postal service of that country, a ministerial office responsible for overseeing all other postmasters. The practice of having a government official respons ...

in February, 1946.

Dimensions & capacities

The ship, as built, was , , fully loaded displacement of 14,000 tons, length overall,

length between perpendiculars Length between perpendiculars (often abbreviated as p/p, p.p., pp, LPP, LBP or Length BPP) is the length of a ship along the summer load line from the forward surface of the stem, or main bow perpendicular member, to the after surface of the ster ...

, breadth, and a draft, fully loaded, of . Four diameter cable tanks of total volume were capable of holding of coiled cable. The tanks held of deep sea telegraph cable or of coaxial telephone cable with repeaters. A hold, forward of the cable tanks, was available for lines and cable buoys. Oil bunkers had a 2,000 ton capacity with boiler feed and fresh water capacity each of 400 tons.

Cable machinery

''Monarch'' differed from all previous cable ships in having all electric cable machinery. That avoided the need to run high pressure steam piping through forward parts of the ship and condensation problems in cold weather but had disadvantages regarding even torque and variable cable load from zero to full load. The ship's three cable engines, two forward (160 h.p. motors) for picking up or paying out and one aft (90 h.p) used for braking in stern laying, were supplied power by an unusual system of two separate power supplies to meet the requirements of cable laying. The cable machinery forward was for laying cable in shallower water or picking up and retrieving cable in all depths. The aft machinery would be used for long deep water cable runs. The motors were fitted to the cable drum with reduction gears to give a slow speed at 20 ton load of per hour to a fast speed at 6.5 ton load of per hour. The novel arrangement allowed electric motors to stall yet still exert holding effect similar to that of steam driven cable machinery. The system also allowed regenerative power so that energy developed by cable being paid out can be used to provide electrical power to the ship's lighting and other systems. The anchor windlass and capstan motors were electrically powered. The most prominent external feature of cable ships until some recently designed were the bow sheaves and often stern sheaves that are included in length overall and are subject to change as cable machinery and needs change, thus will be a factor in length overall measurement as ships are modified.Photos of show the change in bow sheaves after a modernization. In that case the entire ship was essentially rebuilt. The ''Monarch'' (4) page at History of the Atlantic Cable & Undersea Communications has
painting of ''Monarch'' anchored off Sesimbra during 1969
operations showing the drastic change in the ship's bow after the 1968 modernization. After a 1968 modification ''Monarch'' had three bow sheaves, a flat surface sheave and two "V" sheaves, and one "V" stern sheave. The model at the Telegraph Museum Porthcurno shows an original configuration in which a "V" sheave was in the center flanked by two flat sheaves.

Ship's power

Four main oil fired boilers, in diameter and long, provided steam for the main engine and steam driven auxiliaries. Two triple expansion engines with cylinders , , and with a stroke develop 4,500 horsepower for a top speed of . Electricity for both cable machinery and general ship's electrical power was provided by two steam turbines, with their own condensers and pumps making them independent of the main engine steam system, each driving through gearing two 100 kilowatt generator sets. The solution to electrical cable machinery involved combined use of constant voltage at 220 volts, used for both the machinery and general ship's service, and another providing constant current at 300 amperes used in the cable machinery solution. One generator set of each system is dual purpose while the other is permanently connected to the constant voltage board. In addition to the main generator sets there were two 100 kilowatt generator sets driven by two eight cylinder, 192 bhp, Paxman-Ricardo diesels that are for emergency use or when the ship is in port with the boilers are shut down. One of the sets is for dual use, constant current or constant voltage while the other is only for constant voltage so that either or both could be used for the 220 volt ship's service or, for emergency cable operation, one could be providing constant 220 volts and the other 300 ampere constant current.

Deck layout in 1946

The ''Monarchs deck layout as outlined in ''The Shipbuilder & Marine Engine-Builder'', April 1946, Plates IV and V,Detailed inboard profile and plans are on pages 132—133 of A. J. Gill's "H.M.T.S. ''Monarch''" in ''The Post Office Electrical Engineers' Journal''. can be described as follows: * Wheelhouse Top:

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

hut; signal platform. * Navigating

Bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

: the wheelhouse; chart-room; radio-room. * Captain’s Bridge: captain’s day-cabin; captain’s bedroom; cable engineer’s quarters; cable representative’s quarters; 26-foot cutters; 30-foot general service launches. * Boat Deck (and Docking Bridge): mostly officers’ quarters, including deck officers,

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

officers, and engineers; drawing office; five 30-foot wooden

lifeboats Lifeboat may refer to: Rescue vessels * Lifeboat (shipboard), a small craft aboard a ship to allow for emergency escape * Lifeboat (rescue), a boat designed for sea rescues * Airborne lifeboat, an air-dropped boat used to save downed airmen A ...

( whalers) and one 30-foot wooden

motorboat A motorboat, speedboat or powerboat is a boat that is exclusively powered by an engine. Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the internal combustion engine, the gea ...

. * Shelter Deck (weather deck): cable hatches; testing room; chief electrician’s quarters; dining saloon and pantry; purser’s office; cabins of the cable engineers; engineers’ duty mess; cabins for the ship’s electricians, deck engineers, and

officers;

galley A galley is a type of ship that is propelled mainly by oars. The galley is characterized by its long, slender hull, shallow draft, and low freeboard (clearance between sea and gunwale). Virtually all types of galleys had sails that could be used ...

; crew’s library and writing room; surgery and ship’s hospital. *

Main Deck The main deck of a ship is the uppermost complete deck extending from bow to stern. A steel ship's hull may be considered a structural beam with the main deck forming the upper flange of a box girder and the keel forming the lower strength memb ...

: lamp room; cable stores; various workshops such as the carpenter’s shop, the blacksmith’s shop, and the joiner’s shop; cabins for cable staff, quartermasters, domestic staff, petty officers, cable hands, stewards, engine-room ratings, and seamen, as well as mess-spaces; butcher’s shop; crew galley; officers’ laundry; bakery. * Lower Deck: mostly taken up by the upper portions of the four cable tanks, oil-fuel bunkers, the boiler room, and the

engine room On a ship, the engine room (ER) is the compartment where the machinery for marine propulsion is located. To increase a vessel's safety and chances of surviving damage, the machinery necessary for the ship's operation may be segregated into vari ...

, as well as the chain locker and rope stowage spaces; paint store; carpenter’s wood store; cargo space; bosun’s store; electrical spare-gear store; joiner’s store;

diesel generator A diesel generator (DG) (also known as a diesel Genset) is the combination of a diesel engine with an electric generator (often an alternator) to generate electrical energy. This is a specific case of engine generator. A diesel compression- ...

s; meat room and vegetable room; refrigerating machinery space; engineer’s paint store. *

Orlop Deck The orlop is the lowest deck in a ship (except for very old ships). It is the deck or part of a deck where the cables are stowed, usually below the water line. According to the ''Oxford English Dictionary'', the word descends from Dutch Dut ...

: fore-peak;

cargo hold 120px, View of the hold of a container ship A ship's hold or cargo hold is a space for carrying cargo in the ship's compartment. Description Cargo in holds may be either packaged in crates, bales, etc., or unpackaged (bulk cargo). Access to ho ...

; chain locker; rope stowage; cable tanks No. 1, No. 2, No. 3, and No. 4, each 41 feet in diameter; fresh water tanks; deep ballast tanks; oil-fuel bunkers; boiler room;

; feed water tanks; after peak tank.

1968 refit

The ship was radically changed during the 1968 refit with removal of the centre mast, a new deck house forward and major change to the bow sheaves.

Career

Over the course of its career, it laid or helped lay

telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...

cables all over the world, including TAT-1 in 1956, HAW-1 (the telephone cable between the continental

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

) in 1957, the second transatlantic telephone cable TAT-2 in 1959, the first Canadian transatlantic telephone cable

CANTAT-1 CANTAT-1 was the first Canadian transatlantic telephone cable, between Hampden, Newfoundland and eventually Grosses-Roches, Quebec and Oban, United Kingdom, which followed on from the success of TAT-1. It was conceived and approved as stage one ...

in 1961, the

Commonwealth Pacific Cable System COMPAC, the Commonwealth Pacific Cable System, was an undersea telephone cable system connecting Canada with New Zealand and Australia. It was completed by closing the last gap in Honolulu Harbor, Hawaii, at 6:25 a.m. B.S.T. on October 10, 1 ...

(COMPAC) in 1963, and the South Atlantic cable SAT-1 in 1968. As one of the largest

submarine cable Submarine cable is any electrical cable that is laid on the seabed, although the term is often extended to encompass cables laid on the bottom of large freshwater bodies of water. Examples include: *Submarine communications cable *Submarine power ...

laying ships, the ''Monarch'' was much in demand. It was chartered by Cable & Wireless for COMPAC, where it worked with the company's ships CS ''Retriever''CS ''Retriever'', fifth cable ship with that name, , built 1961, Cammell Laird & Co., Birkenhead. and the CS ''Mercury''CS ''Mercury'', , built 1962 by Cammell Laird & Company, Birkenhead. in the southern Pacific. The ship's operation on the COMPAC segment between

Suva Suva () is the capital and largest city of Fiji. It is the home of the country's largest metropolitan area and serves as its major port. The city is located on the southeast coast of the island of Viti Levu, in Rewa Province, Central Divi ...

and

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by po ...

is an example of an oceanic cable layer connecting shore ends and terminal stations. ''Monarch'' arrived in Suva in October 1962 to pick up the shore end already laid by CS ''Retriever'', which had also laid the shore end at

Takapuna Takapuna is a suburb located on the North Shore of Auckland, New Zealand. The suburb is situated at the beginning of a south-east-facing peninsula forming the northern side of the Waitematā Harbour. While very small in terms of population, it ...

in New Zealand, that was buoyed some off the Samabula area of Suva. After testing to make sure the shore end was fully operational the shore end was spliced to the of cable in ''Monarch's'' tanks. ''Monarch'' began the oceanic lay at dawn, 20 October, paying out cable at . The ship arrived off Takapuna 28 October, picked up the shore end there and made the final splice on 29 October to complete the second link of COMPAC. In 1969, as a result of the

Post Office Act 1969 The Post Office Act 1969 (c.48) is an act of the Parliament of the United Kingdom that changed the General Post Office from a department of state to a public corporation, known as the Post Office. It also abolished the office of Postmaster Gener ...

,The legislation changed the General Post Office from a department of state to a public corporation, known as the Post Office. It also abolished the office of Postmaster General of the United Kingdom. all General Post Office cable ships, including the ''Monarch'', lost the use of the prefix ‘HMTS’ and became ‘CS’ (Cable Ship). The ''Monarch'' was sold in October of the following year to Cable & Wireless, who renamed it CS ''Sentinel'', the second cable ship to bear the name. After an extensive refit at

Immingham Immingham is a town, civil parish and ward in the North East Lincolnshire unitary authority of England. It is situated on the south-west bank of the Humber Estuary, and is north-west from Grimsby. The region was relatively unpopulated and un ...

that prioritised its cable repair facilities over cable laying, it entered operational service in March 1971.''The Zodiac'', ‘CS Sentinel joins the Company’s fleet’, pp 2-3, May 1971 Its first captain as CS ''Sentinel'' was G. H.C. Reynolds. It had a crew of 26 officers and 89 petty officers and ratings. It was based in

Vigo Vigo ( , , , ) is a city and Municipalities in Spain, municipality in the province of Pontevedra, within the Autonomous communities of Spain, autonomous community of Galicia (Spain), Galicia, Spain. Located in the northwest of the Iberian Penins ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

, and then

Bermuda ) , anthem = "God Save the King" , song_type = National song , song = " Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , e ...

. CS ''Sentinel'' arrived 25 October 1977 at

Blyth, Northumberland Blyth () is a town and civil parish in southeast Northumberland, England. It lies on the coast, to the south of the River Blyth and is approximately northeast of Newcastle upon Tyne. It has a population of about 37,000, as of 2011. The port o ...

and scrapped the next month.

Ship models

The

National Maritime Museum The National Maritime Museum (NMM) is a maritime museum in Greenwich, London. It is part of Royal Museums Greenwich, a network of museums in the Maritime Greenwich World Heritage Site. Like other publicly funded national museums in the United ...

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

has a

model A model is an informative representation of an object, person or system. The term originally denoted the Plan_(drawing), plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a mea ...

(to 1:192 scale) of the ''Monarch'', and there is a 10-foot (304 cm)

Porthcurno Telegraph Museum PK Porthcurno is a museum located in the small coastal village of Porthcurno Cornwall, UK. Porthcurno was the point at which many submarine telegraph cables—transatlantic and to other locations—came ashore. The first cables were direct curr ...

’s collection. The

ship's bell A ship's bell is a bell on a ship that is used for the indication of time as well as other traditional functions. The bell itself is usually made of brass or bronze, and normally has the ship's name engraved or cast on it. Strikes Timing of s ...

is on display at the latter.