Science: Ocean Frontier

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Columbus Iselin's pet gadget is a monstrous underwater noisemaker developed at Woods Hole. Ordinary echo-sounding devices for exploring the bottom use relatively feeble waves of ultrasound whose delicate echoes are apt to get lost in background noise. Another common system is to explode TNT and pick up the echoes of the powerful shock waves that it sends to the bottom. But explosions are cumbersome, expensive and dangerous.

The "Imp" (for impulse generator) is a massive steel casting with two flexible hoses for high-pressure hydraulic fluid sticking out of one end. At the other end is a metal diaphragm about eight inches in diameter. Inside are extremely powerful springs, cocked by hydraulic pressure. When the springs are released, an internal hammer hits the diaphragm and a single, enormously powerful pulse of energy strikes through the water. The Imp now at Woods Hole gives a shock equivalent to the explosion of a good-sized block of TNT, and Imps several hundred times as powerful are a possibility. They can be suspended under a ship or built into its hull, sending down waves that will strike through the bottom sediments far into the rock beneath.

Pistols & Trolley Cars. Iselin has not forgotten that his money comes chiefly from the Navy. Though he does not say so out loud, it is obvious that a device like Imp, which simulates the effect of a controlled explosion, could be far more effective against subs than present electronic devices for echo ranging. Says Iselin: "We know that sound pushed out by explosives can go, at some levels, for thousands of miles. There isn't an ocean in the world big enough to lose the sound of a pistol fired at the right depth." He is fully conscious of what such an improvement could mean for U.S. security. "If Mr. Eisenhower could say to Khrushchev, 'We can see every one of your submarines in the seas around us,' we would be in a far better cold-war position today." Iselin is unimpressed with present nuclear subs. The power plants are too noisy. "Going to war in a nuclear sub is like going duck hunting in a trolley car," he says.

Oceanographers are also busy producing detailed maps of new currents, temperature gradients and the topography of the ocean floor, so that a U.S. submarine, submerged for days, can have an accurate idea of where it is when it launches its missiles. "Any future war at sea will be one between Indians and city boys," he explains. "We want to be sure our boys become the Indians. They can learn to take advantage of the terrain they live in." Even study of waves can prove useful. "On an aircraft carrier, the system now is for a guy to stand at the end of a flight deck. He feels the rhythm of the waves through the crepe soles of his shoes, and lets the plane land or waves it off depending on the feeling he gets underfoot. A machine could do this far better, perhaps also introduce balancing stability effects to make more landings possible."

Today U.S. oceanographers have a wary eye on the Russians, some of whose vessels are far in advance of anything the U.S. has at sea. Partly because of this pressure, U.S. legislators did not flinch at a report by the National Academy of Sciences recommending an appropriation of $58 million for oceanography for 1960, and there is a good prospect it will be voted.