HOW THE LUSITANIA WAS FOUND

Evening Post, Volume CXXI, Issue 21, 25 January 1936, Page 26

HOW THE LUSITANIA WAS FOUND

In locating the wreck of the Lusitania and sending a diver down to her, the salvage ship Orphir successfully demonstrated the value in salvage work of two remarkable inventions, writes R. A. Monson in the. "Daily Telegraph.'"

One, the Hughes' echo sounder, was designed to do away with the necessity for long dragging operations, and the other—the Tritonia diving dress, or Iron Man —was to enable a diver to work in the deepest oceans.

The echo sounder —an Admiralty patent —is a comparatively new invention, but already it has been widely and successfully used to chart the sea bottom and to locate wrecks, shoals of fish, and other submarine objects.

Briefly, the echo sounder employs sound waves to draw on a "tape" the picture of the sea bed, to show its depth, to indicate anything lying on the bottom or between the bottom and the surface of the sea. It will accurately give the extent of the object, be it a wreck, rock, bank, shoal of fish, or even a single whale.

From the hull of the searching ship an apparatus gives out a lound sound four times every second, the sound travels to the sea bed and is reflected as an echo. The receiver on the searching ship picks up the echo, and this causes an electrical impulse to flow through the stylus of the apparatus. ■

The stylus is moving back and forth across a chemically-treated paper "tape," five, inches in width, that is slowly unrolling from the machine. The stylus will not mark the "tape" unless a current is flowing through it. The instant the echo returns and re-

leases the current, a brown mark is made on the "tape."

The speed of sound in salt water ia known, and so the time taken by the sound to travel to the sea bottom (or to any intervening object such as a wreck) and for its echo to return to the apparatus can be translated into feet and shown on the scale.

If the sound strikes an object at a lesser depth than the sea bottom the echo returns so much sooner, and the stylus commences making its mark proportionately sooner. It is, in fact, drawing the foreign object on the chart— and drawing it to scale! The distance travelled by the searching ship while actually over the object can be observed, and this is the length of the object.

None of us aboard the Orphir will ever forget the thrill of the moment when, standing on the ship's bridge, scanning the "tape" unrolling from the sounder, we saw the outline of the Lusitania suddenly commence to take form.

We were in fifty fathoms The seabed, as shown-on our "tape," had remained constant at that depth all the morning. Then the great outline of some object showed up on the chart, rising 80ft from the sea bottom. We travelled a measured distance of 801) feet over it before the outline faded.

We knew we had passed over a wreck 800 ft in length and 80ft in height. We checked our distances and measurements twenty times. We knew then it was the Lusitania we had found. Diver Jarratt in the Iron Man walked upon the hull.

Next year a diver will descend to the wreck and direct salvage opera tions.