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, for electric power transmission, military, or other purposes. Cable ships are distinguished by large cable sheaves for guid ...

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. Established in England in the 17th century, the GPO was a state monopoly covering the dispatch of items from a specific ...

(GPO) for the laying and repair of

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

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 TAT-1 (Transatlantic No. 1) was the first submarine transatlantic telephone cable system. It was laid between Kerrera, Oban, Scotland and Clarenville, Newfoundland. Two cables were laid between 1955 and 1956 with one cable for each direction. I ...

. 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 most commonly refers to: * First, the ordinal form of the number 1 First or 1st may also refer to: Acronyms * Faint Images of the Radio Sky at Twenty-Centimeters, an astronomical survey carried out by the Very Large Array * Far Infrared a ...

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 pow ...

(Swan, Hunter & Wigham Richardson, Ltd), as hull 1768 at the Neptune Yard,

Walker-on-Tyne Walker is a residential suburb and electoral ward in the south-east of Newcastle upon Tyne, in the county of Tyne and Wear, England. History The place-name 'Walker' is first attested in 1242, where it appears as ''Waucre''. This means 'wall-car ...

(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 to 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. History The practice of having a government official ...

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 ste ...

, 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 a constant current power supply 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 system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

hut; signal platform. * Navigating

Bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

: 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 communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...

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 ...

( whalers) and one 30-foot wooden

motorboat A motorboat or powerboat is a boat that is exclusively powered by an engine; faster examples may be called "speedboats". Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the inter ...

. * 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 optimised for propulsion by oars. Galleys were historically used for naval warfare, warfare, Maritime transport, trade, and piracy mostly in the seas surrounding Europe. It developed in the Mediterranean world during ...

; 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 mem ...

: 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 Seaman may refer to: * Sailor, a member of a marine watercraft's crew * Seaman (rank), a military rank in some navies * Seaman (name) (including a list of people with the name) * ''Seaman'' (video game), a 1999 simulation video game for the Seg ...

, 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 (ship), compartment where the machinery for marine propulsion is located. The engine room is generally the largest physical compartment of the machinery space. It houses the vessel's prime move ...

, 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 an engine generator. A diesel compress ...

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), immediately above the hold Hold may refer to: Physical spaces * Hold (compartment), interior cargo space * Baggage hold, cargo space on an airplane * Stronghold, a castle or ...

: 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 a ship or airplane compartment. Description Cargo in holds may be either packaged in crates, bales, etc., or unpackaged (bulk cargo). Acc ...

; 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, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

cables all over the world, including

in 1956, HAW-1 (the telephone cable between the continental

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

) in 1957, the second transatlantic telephone cable

TAT-2 TAT-2 was AT&T Corporation's second transatlantic telephone cable. It was in operation from 1959 to 1982, initially carrying 48 telephone circuits on two cables between Penmarch, France and Clarenville, Newfoundland. It was operated by AT&T ...

in 1959, the first Canadian transatlantic telephone cable CANTAT-1 in 1961, the Commonwealth Pacific Cable System (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 city, capital and the most populous 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 Rew ...

and

Auckland Auckland ( ; ) is a large metropolitan city in the North Island of New Zealand. It has an urban population of about It is located in the greater Auckland Region, the area governed by Auckland Council, which includes outlying rural areas and ...

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, New Zealand, North Shore of Auckland, New Zealand. The suburb is an isthmus between Shoal Bay, New Zealand, Shoal Bay, arm of the Waitematā Harbour, and the Hauraki Gulf. Lake Pupuke, a volca ...

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 Gene ...

,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 and civil parish in North East Lincolnshire, England, on the south-west bank of the Humber, Humber Estuary, northwest of Grimsby. It was relatively unpopulated until the early 1900s, when the Great Central Railway began de ...

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 province of Pontevedra, Pontevedra, within the Autonomous communities of Spain, autonomous community of Galicia (Spain), Galicia, Spain. Located in the northwest ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, and then

Bermuda Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest. Bermuda is an ...

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

Blyth, Northumberland Blyth () is a port town, port and seaside town as well as a civil parish in southeast Northumberland, England. It lies on the coast, to the south of the River Blyth, Northumberland, River Blyth. It has a population of 39,731 as of the 2021 cens ...

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 Unit ...

London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...

has a

model A model is an informative representation of an object, person, or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin , . Models can be divided in ...

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

in Porthcurno Telegraph Museum’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 shi ...

is on display at the latter.