Underwater Camera For Cable Route

Press, Volume C, Issue 29633, 2 October 1961, Page 10

Underwater Camera For Cable Route

(New Zealand Press Association)

WELLINGTON, Oct. 1. A piece of a Meccano set, a part from a domestic reading meter, and a generous chunk of ingenuity—these are just a few of the ingredients of a unique deepunderwater camera devised and constructed by engineers and technicians at the New Zealand Electricity Department. It has now completed the vital job of photographing the ocean bed along the proposed Cook Strait electric cable route.

Its “eye” was seeking out jagged rocks that might damage the cable in. addition to recording other information about the type of material on the seabed. The 150 photographs taken at mile intervals from the Royal New Zealand Navy ship, Tui, confirmed the sampling and other tests carried out by the Navy and various divisions of the Department of Scientific and Industrial Research. They showed that the recommended route was satisfactory. The story of how the camera was developed was told today by the department engineer in charge of its construction, Mr D. H. Rowe. Describing it modestly as a

“Heath Robinson” affair, partly made of “junk,” he said the equipment was built quite independently and was the only one of its kind in the world. Although the department knew that different types of deep underwater cameras had been made in other parts of the world it had not borrowed ideas from them. The suggestions of many different people had contributed ti the equipment. Mr Rowe explained that the toughest problem in constructing a camera of this sort was to make it capable of withstanding the high underwater pressures. This had been achieved by encasing the camera itself, a standard German variety, and the specially-developed electronic flashlight in two separate steel cylinders. The back plate of each cylinder had been made up of steel three-quarters of an inch thick and the front was composed of inch-thich perspex. The device was designed to withstand pressures of 8101 b to the square inch. The camera was fired off in a simple but original way On top of the frame was a switch which was normally held open by a heavy spring. The weight of the equipment closed the switch but as 'soon as the camera hit the sea bottom the weight was taken off and the switch opened. Then the weight was taken off and the switch opened. At this juncture the photograph was taken.

This happened immediately, before the mud could rise and obscure the vision. So as io ensure that unwanted photographs could not be taken, the .camera had to be lifted clear of the bottom for two minutes and dropped again before another shot could be taken, Mr Howe .paid.