HMTS MONARCH (4)
Renamed CS SENTINEL (2)
Built in 1946 by Swan, Hunter & Wigham Richardson Ltd
Length 479.8' Breadth 55.7' Depth 27.8' Gross tonnage 8962
The loss of CS Faraday (2) and CS Monarch (3) left British cable companies without a cable ship capable of cable laying, so the GPO decided to have a new cable ship built. The design was prepared by the Engineer in Chief of the GPO and was completed in 1942. The keel was laid in 1944, the ship was launched on the 8th August 1945 and handed over to the GPO in February 1946.
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Cable engine sheaves for Monarch (4) during manufacture
by Garton & King, Exeter
Foundry, Exeter, Devon.
Images courtesy of the Garton & King history website. |
HMTS Monarch (4) was the largest cable ship afloat at that time, with four cable tanks, each 41 ft in diameter, having a storage capacity of 125,000 cubic feet and providing storage for 2500 nm of deep sea telegraph cable. When laying deep sea coaxial telephone cable and repeaters, 1500 nm of deep sea cable could be carried.
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HMTS Monarch moored at Greenwich |
Loading cable into tanks aboard Monarch |
All the cable machinery, which consisted of a double picking up-paying machine forward and a single paying out machine aft, was electrically driven. A trough ran from the repeater storage to the stern, along which the repeaters travelled on a trolley to the stern, where they were launched with a small parachute attached to prevent them from sinking too quickly.

Taking on cable for TAT 1 (1955/56) at
Submarine Cables Ltd. Ocean Works, Erith |
The cable machinery and bow and stern sheaves were changed and modified a number of times. The final change was in 1968 when the bow sheaves consisted of three sheaves of which the port one was 6 ft 10 in. in diameter with a flat profile and the other two were the normal 'V' sheaves 6.0 ft in diameter. The stern one was a 7.0 ft diameter 'V' sheave fitted on the port side.

HMTS Monarch (4) after the 1968 refit
Image courtesy of Roger
Horton |

Educational/promotional poster showing Monarch after the refit |
The first task undertaken was the repair and renovation of existing cable networks, which had been neglected during World War II. One example was the repair of the former Direct United States Company cable, between Porthcurno - Newfoundland and Halifax, Nova Scotia which required 1200 nm of new cable to be laid to get it back into working order.
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HMTS Monarch laying lightweight
coaxial cable over the stern sheave |
Chief Testing Officer in Testing Room
Detail of test equipment |
Telegraph Museum Porthcurno has a three-metre model of the ship, and provides a guided tour of it in this video:
On the 1st October 1969 all of the GPO cable fleet lost the prefix HMTS and became CS. This was due to the GPO ceasing to be a Government department. Monarch was sold to Cable & Wireless Ltd., on the 13th October 1970 and was renamed CS Sentinel (2). Based at Bermuda Sentinel was used for cable maintenance in the Atlantic and also for trials of the Scarab submersible. Arrived at Blyth, Northumberland on the 25th October 1977 for scrapping.

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(Above)
Painting by Jack Pountney
HMTS Monarch on the Thames at Greenwich, 1959.
Old Royal Naval College in the background
Image copyright © 2009 Keir Pountney
(Below)
HMTS Monarch (4) anchored off Sesimbra during
the
laying of the 1969 UK-Portugal cable
Image courtesy of Roger Horton
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CABLE WORK
1947 |
Aldeburgh, England - Domburg, Holland No 6 |
1950 |
Weyborne, England - Fano, Denmark |
1950 |
Römo, Denmark - Leeuwarden, Holland |
1952-4 |
Cape Canaveral - Vero Beach - Jupiter Inlet, Florida - Grand Bahama Island (two landings) - Great Stirrup Cay - Great Egg Island - Eleuthera Island (two landings) - Cat Island - San Salvador - Long Island - Acklins Island - Mayaguana Island - North Caicos - Grand Turk.
From Grand Turk two cables ran to Port Daiman, Dominican Republic and from there one cable to Cape La Roca - Grand Estero River - Savana La Mer - Port Macao, all in the Dominican Republic.
Final section was Port Macao - Desecheo Island - Guanajibo Point, Puerto Rico, for the USAF. |
1953 |
Recife, Brazil - St Vincent, Cape Verde Islands |
1954 |
Four power cables across the St Lawrence River from Manicouagan - Petit Metis |
1956 |
TAT-1 Oban, Scotland - Clarenville, Newfoundland - Sydney Mines, Nova Scotia |
1957 |
HAW-1: San Francisco, USA - Hawaii |
1958 |
138kv power cables Vancouver Island - British Columbia mainland |
1958 |
Bournemouth, England - Jersey, Channel Islands |
1959 |
TAT-2 Penmarc'h, France - Clarenville, Newfoundland - Sydney Mines, Nova Scotia |
1960 |
Marske by the Sea, England - Gothenburg, Sweden |
1960 |
USA - Puerto Rico |
1961 |
CANTAT 1 Oban, Scotland - Hampden, Newfoundland; Corner Brook, Newfoundland - Grosses Roches, Quebec |
1961 |
Cape Dyer, Baffin Island - White Bay, Newfoundland |
1962 |
COMPAC Sydney, Australia - Auckland, New Zealand - Suva, Fiji - Hawaii - Port Alberni - Vancouver, British Columbia |
1963 |
Winterton, England - Borkum, Germany (Two cables laid) |
1963 |
Winterton, England - Esbjerg, Denmark |
1964 |
Covehithe, England - Katwijk, Norway |
1964 |
SEACOM I Jessleton (Sabah) - Singapore |
1964 |
SEACOM I Jessleton - Hong Kong |
1965 |
SEACOM II Hong Kong - Guam - Madang, Papua New Guinea - Cairns, Australia |
1967 |
Kristiansand, Norway - Thisted, Denmark |
1968 |
Scarborough, England - Kristiansand, Norway |
1968 |
SAT 1 |
1969 |
Sesimbra, Portugal - Goonhilly, England
CS Alert (4) laid the shore ends |
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CS Sentinel (2) formerly HMTS Monarch (4) |
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