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Technology: Run Silent, Run Electromagnetic

4 minute read

Like a well-trained dolphin, the miniature experimental submarine maneuvered docilely around the waters of California’s Santa Barbara yacht basin. No propellers, no jets were visible along its sleek, 10-ft.-long hull, yet the sub was obviously moving under its own power, gliding silently at about 2 m.p.h. 3 ft. under the surface. There was not a motor on board, but the odd little boat was being propelled by the same electrical phenomenon that causes rotors in electric motors to turn: electromagnetic force.

Bow to Stern. In schoolroom demonstrations, an electromagnetic force is produced by passing electric current through a wire or other conductor suspended in a magnetic field. The current generates a magnetic field around the wire that pushes against the field of the magnet. In an electric motor, current flowing through the armature reacts in the same way against a magnetic field generated by electromagnets. The resulting push, or torque, turns the rotor.

The electromagnetic submarine (EMS-1) in Santa Barbara works on the same principle. Its storage batteries send current through a large coil wound bow to stern, inside the cylindrical section of the hull, setting up a magnetic field in the surrounding sea water. The same batteries send electric current through the salty water between two electrodes, one on each side of the sub. Because the current flows at right angles to the magnetic field generated by the coil, electromagnetic force is exerted against the conductor—which in this case is the sea water itself. As the sea water is pushed back—like the armature of a motor—the sub reacts by moving forward.

Super Magnets. EMS 1 is the brainchild of Westinghouse Mechanical Engineer Stewart Way, a specialist in magnetohydrodynamics. As far back as 1958, he recalls, “I had a hankering to develop an electrical submarine without propellers or jets.” But in those days there was one insurmountable problem: to develop a magnetic field strong enough to propel a full-size sub, Way calculated, would require a conventional magnet weighing 500,000 tons—almost 80 times as heavy as an entire Polaris submarine. Working out some method of propelling a small-scale experimental sub seemed a waste of time.

In the early 1960s, Way’s problem was theoretically solved by the development of compact superconducting magnets, which, when cooled close to absolute zero ( — 460° F.), can produce intense magnetic fields. Such magnets, Way calculated, would take up no more than 20% of a submarine’s weight while providing a magnetic field strong enough for propulsion.

Convinced at last that a full-size sub was possible, Way figured that it was worthwhile to try a small version. Last year, while on leave from Westinghouse to teach at the University of California’s Santa Barbara branch, he handed his senior engineering class a term project: the design of an experimental electromagnetic submarine.

Tingling Sensation. Under Way’s guidance, and with about $1,600 worth of storage batteries, the electromagnetic coil, aluminum tubing and fiberglass reinforced plastic paid for by the university, the engineering seniors completed the EM51 during the spring semester. They successfully demonstrated it for the first time this June. Subsequent experiments uncovered a few problems, though none seem impossible of solving in the construction of a full-scale sub. Electric current passing through the water between the electrodes produces some electrolysis; molecules of water break down into hydrogen and oxygen, which rises to the surface in the form of gas bubbles that could signal the sub’s presence below. Swimmers who guided the sub felt a tingling but harmless sensation caused by the electric current. “It is almost exhilarating,” explains Way.

Though the electromagnetic submarine’s silent, virtually undetectable operation makes it of prime interest to the Navy, Way is convinced that its greatest future lies in the development of super submarine tankers. Since the efficiency of an electromagnetic submarine increases with size, the visionary engineer is already looking forward to the day when 100,000-ton monsters will move silently beneath the surface of the world’s oceans, carrying vast quantities of crude oil and gasoline safe from the storm-tossed water above them.

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