Admiralty Research Laboratory - Underwater Viewing Systems
Birth of portable underwater viewing systems
Upon hearing that HM Submarine Affray was missing as of 1100hrs Tuesday 17th April 1951, Lionel Crabb had offered his services as a (freelance) diver, maintaining that if the submarine was lying is less than 120ft of water, he using his frogman's gear could reach it considerably quicker than a diver equipped with the bulky standard diving outfit - the time required to position the diving vessel, and prepare and deploy a standard diver could be a critical factor in the rescue of the crew. Approximately 36 hours after AFFRAY had first dived Lionel Crabb was aboard HMS RECLAIM, the RN Deep Diving and Submarine Rescue vessel involved in the search for the submarine. However he saw no action as all likely seabed contacts located up to the first week in May 1951 had been in depths greater than his diving limit. And so Lionel Crabb returned to shore to challenge Rosse Stamp at ARL to produce a remote underwater viewing system employing (closed-circuit) television technology, suitable for seabed searches. He had in mind that a remote viewing system, being much faster to deploy than a standard diver and with unlimited endurance, would speed-up the search for AFFRAY; this was proved conclusively once ARL's hastily constructed, world's first, portable underwater viewing system had been embarked upon RECLAIM.
Following a meeting with ARL’s Superintendent Dr Nyman Levin, Rosse Stamp ably assisted by John (Jack) Revie and R.B. (Jock) Phillips proceeded to design and construct an underwater enclosure to house a television camera, under the Top Secret codename of LACQUER. It was left to Rosse Stamp to convince the officer in charge of the search, Capt William (Bill) Shelford, that an underwater viewing system would help overcome some of the difficulties and hazards of diving in strong tidal conditions such as they were experiencing. Prevailing conditions in the English Channel, at the time of the search, made the identification of bottom contacts located by acoustic means a slow and tedious operation.
The camera used was similar to that which the BBC hired from Marconi Wireless Telegraph Company of Chelmsford for its outside broadcasts; notably the 1949 University Boat Race, where the camera and associated electronics had been fitted to a small boat. For the ARL system, the camera was modified such that it could be controlled remotely over 500ft of watertight cable specially manufactured by BICC with an additional (outer) polythene sheathing. The camera was mounted vertically with its single wide-angle lens immediately behind a thick plate-glass window in the base of the enclosure. A tubular metal frame was built and attached to the camera’s enclosure, to which a light source (1.5kW Tungsten standard diver’s lamp) was attached. Whilst far from elegant the underwater assembly (nick-named The Ugly Duckling) was soundly engineered and proved more than adequate for the job. A truly remarkable achievement as the portable underwater viewing system was designed and constructed in a bare three weeks of work that included modifications to the camera's electronics for remote control.
The only suitable space onboard RECLAIM for the majority of the system's electronics for processing and display of the video signals from the camera, was the captain's cabin.
At sea, it was found that the system, deployed in a matter of minutes, provided trouble-free viewing to a distance of 15 foot, whereas deep sea diver deployment was laborious and time-consuming, and a diver's visibility was limited to some 5 feet.
So effective was the viewing system that by the end of May RECLAIM had completely re-searched the originally defined search area and commenced searching a newly defined area to the south of the track assumed to have been taken by AFFRAY; all without the need for a single deployment of divers. On the 12th June, some twelve days later, the Frigate HMS Loch Insh (a member of the search force) made sonar contact with a large object on the seabed. This object had failed to be detected on two separate occasions that the area had previously been searched, on the 17th and 18th April 1951. The fact that the large contact was missed by the UK and US ships of the original search force, may be attributed to the combined operation of the frigate's main sonar (type 170) and side-looking sonar type 162 that resulted in the (sonar) Range Recorder displaying a cigar-shaped object on the seabed - a concept proposed by ARL. This was the first sonar contact (detected) of similar size and shape to AFFRAY, in the two months of searching for the submarine.
A deployment of RECLAIM's diving chamber containing three divers established that the object found was in all probability AFFRAY. Despite the water depth being almost 100 feet deeper than the design-depth of 200 feet, Lionel Crabb took a calculated risk and deployed the underwater camera. There followed, in rapid succession, two quirks of fate. Firstly, the camera just happened to be lowered directly over the Fin (Conning Tower) of the submarine, and instantly it was possible to surmise that it had been operating at periscope depth when disaster had stuck. Secondly, the camera slowly rotated (under the effect of the strong tidal flow) such that the submarine's nameplate (on the side of the Fin) could be easily read; thus establishing irrefutably the final resting place of AFFRAY.
The underwater remote viewing system continued to be of use as an aid to the positioning of divers for best effect whilst they conducted their lengthy investigation of the sunken submarine. As a consequence the underwater camera continued to be deployed at a depth significantly greatly than that designed for, and for a period lasting many weeks - a true testament to its design, construction and assembly.
Following the search for AFFRAY, a minor equipment requirement was raised for a permanent remote viewing system for RECLAIM, and PYE Ltd of Cambridge was awarded (on the basis of cost) the contract to supply the equipment, much to the disappointment of the Marconi Company who had hoped they would be selected on the basis of their supply of the original television equipment.
The success achieved by underwater television as applied to the search for AFFRAY opened up the field for further developments. Underwater casings were built to carry out trials, in the first instance, to ascertain the performance of television with particular reference to its application to mine countermeasures (MCM) in UK coastal waters. During these experiments which were carried out aboard HMS WELFARE, the relationship was established between water turbidity as measured by the hydrophotometer and the range of vision of the underwater camera. Around this time Rosse Stamp was invited to take part in a BBC Home Service programme "Science Survey" - click hear to listen to a recording, broadcast at 10.30 p.m. on 23rd May 1952.
Later a casing was designed and built for operation at a depth of 1000 feet. An investigation was carried out with this equipment aboard RRS DISCOVERY II in co-operation with the National Institute of Oceanography (the new name for ARL's Wave Group) to explore the uses of underwater television for oceanographical and marine biological research, also to evaluate the problems of working at greater depths.
The first television camera to be designed specifically for underwater use was completed in July 1953. Constructed in a compact cylindrical form round an Image Orthicon tube, it fitted into a pressure-tight case measuring only 10" diameter by 21" long and weighed less than 1 cwt in air. Another even smaller underwater camera, containing the much less sensitive but simpler "Vidicon" type tube, had been completed by 1954. The casing, which measures 8" dia by 16" long, was designed to be hand-held by a diver.
In January 1954, at the time of the de Havilland Comet G-ALYP (Yoke Peter) crash in the Tyrrhenian sea off the Island of Elba, ARL was once again called upon to provide underwater CCTV to aid the search. ARL's George Macneice was flown out and operated the CCTV to great effect, at depths between 400 and 600 ft, embarked upon RFA SEA SALVOR.
Over eleven weeks of searching, a remarkable amount of the aircraft was recovered and re-assembled by a crash investigation team at the Royal Aircraft Establishment Farnborough. (Click here for more info and photo of the (partial) reconstruction of G-ALYP, on the RAF Museum site.)
The underwater viewing research and development by ARL's Instrumentation Group addressed various subsidiary problems. Clear water containers to extend the camera's range of vision in very dirty water were investigated out of which the "Diver's Clear Vision Viewer" was evolved.
By 1955 ARL work on underwater viewing systems
was run-down in favour of design and development of higher-resolution underwater
photography and cine-photography techniques to support ARL's Fluid Dynamics Group work.
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