UNDERWATER TV NOW PERFECTED

Press, Volume XCV, Issue 28259, 23 April 1957, Page 14

UNDERWATER TV NOW PERFECTED

[By PETER LAMBERt)

It has taken just 10 years of research and experiment to obtain perfectly clear pictures from underwater television cameras. This is the boast of a team of French TV engineers who have recently been demonstrating some ultra-modern underwater equipment in the North Sea.

In the past all underwater inspection of vessels or wrecks had to be undertaken by divers. But often the diver was not an expert in the problem he was inspecting —ancient wrecks is a classic example—and he was forced to report his findings to the specialists on the surface. This, of course, too often resulted in the experts receiving information that was not everything they required. That is why research workers had the idea of applying the possibilities of television to underwater exploration. The presentday diver walks about under the water carrying a camera, while the experts and technicians remain on the deck of the ship or on the quayside. Linked by microphones to the diver-cameraman, they can give him their orders to cover minute inspections of all underwater objects, and by photographing the television screen they can obtain visual records for later detailed examination. In 1947, at the time of the atomic explosion at Bikini, a team of experts used a television camera for the first time under the water. They were observing the damage to sunken ships and studying the effect of the atomic bomb on the sea bed. The working and the setting of the camera in a watertight container was controlled from the deck of the ship. Four years later the English submarine Affray sank in the Channel with 75 men aboard. The Admiralty started looking for the site of the wreck. In a perimeter of 108 miles about 20 wrecks were examined—submarines of the first and second world wars, cargo boats and vessels of all shapes and sizes. On June 14 they found a wreck lying on its side. A television camera was lowered to 240 feet, and one can imagine the feelings of the English sailors when they saw the name “Affray” on the screen of the portable TV set they had installed on board. On this occasion they were using a portable camera used by the 8.8. C., enclosed in a watertight compartment. Cousteau’s Discovery

In 1952 the Calypso, the lovely white boat of Commander Cousteau, now world-famous for his remarkable film, “The Silent World,” was cruising off Marseilles when his divers discovered a wreck half-buried in sand and mud at a depth of 120 feet. It was a Greek galley containing amphorae of wine—some with wine still in them —and dishes. Thanks to underwater television the archaeologists on board the Calypso could see the various parts of the site and could take photos and make sketches at their leisure, their instructions being transmitted by microphone to the diver.

It was just two years later that a comet airliner exploded over the Mediterranean near Elba Aeronautical experts the world over were wondering if this accident would not condemn commercial jet flying altogether, and the resultant inquiry needed fairly precise photographs of the wreckage to determine the causes of the accident. So one of the ships on the spot was equipped with an underwater television camera which helped in the recovery of the greater part of the airliner. During these 10 years of research underwater television equipment has improved continually, thanks mainly to the work of Commander Cousteau. The result of these experiments is the ultra modern piece of equipment which the Thomson-Houston company has just demonstrated to a specialised public on the coasts of the Channel and the North Sea. This French manufactured equipmen thas caused great interest among observers of many countries. Many have already given orders, among them the United States, Japan, Great Britain, Germany and Scandinavia. This new camera, cylindrical in shape, measures 35 centimetres long and 20 centimetres in diameter. It weighs just over 201 b in the sir, and contains a special lens which corrects the refraction

between water and air. The camera also contains apparatus for remote control, sound equipment, a microphone to keep the diver in touch with the surface, and an indicator to warn of leaks. Despite all this equipment if is the smallest television camera ever made.

Defeating the Mud A cone of clear water is placed in front of the eye of the camera so that filming can be done in muddy water. .Divers who work 'in ports or rivers know that in general they can rely only on their hands for information about the objects they are working with. Often they are in absolute darkness. The cloudiness of the water in the Thames, for example, is such that it is impossible to see the light of an electric lamp at anything over six inches. To get round this problem Cousteau decided to replace this mass of muddy water in front of the lens with a similar mass of clear water. This idea resulted in what is now called the “cone of clear water,” which assures reasonable visibility in the muddiest waters. In practice the idea consists of a plastic pyramid filled with clear water. The base of the pyramid is made up of a plexiglass window which is applied against the object to be televised. This new equipment is a compact little machine which is so necessary to underwater explorers today. The main characteristics are resistance to pressure, no weight in water, communication over a distance, the use of a corrective window and good visibility whatever the conditions.

The applications of underwater television are many. The exploration of wrecks is obviously the most spectacular, but there are also underwater Researches—technical, archaeological, geological and biological ... the examination of ships without them going into dry 'dock, surveys of all kinds, including underwater oil prospecting, and work on locks and dams whether in connexion with their building or upkeep. In the military field immense services cam be rendered by this “eye under the sea,” in the defence of ports, detection of mines and tracking of torpedoes. (Central Press Service.)