History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network

HMTS Monarch (4) - later CS Sentinel (2)
by Bill Glover

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.

It 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.

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.

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. 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.

HMTS Monarch laying lightweight coaxial cable over the stern sheave	Chief Testing Officer in Testing Room Detail of test equipment

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.

CABLE WORK

Research Material Needed

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You can help - if you have cable material, old or new, please contact me. Cable samples, instruments, documents, brochures, souvenir books, photographs, family stories, all are valuable to researchers and historians.

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