The Goblin Killers

(3 of 8)

Probing the Deeps. Hidden from the sun, the black bottom is an unimaginably terrifying land of ancient mountain ranges and valleys, somnolent volcanoes, Gargantuan canyons, bottomless chasms (see map)—a land filled with hiding places for a future generation of deeper-diving submarines. Knowledge of this topography as well as of the mysterious currents that flow there will decide the future's underwater wars. Though the seas cover 70% of the earth's surface, oceanographers have carefully mapped only about a third of the world's ocean floor. The Russians have gone full steam on oceanography, have built the world's biggest fleet of floating oceanographic laboratories—14 large vessels v. the U.S.'s half-dozen*—and have explored much of the floor of the Arctic Ocean.

The ocean floor, fortunately, is a fixed topography; its changes are minute in time. But detecting the underwater enemy is the first job of Thach and his ASW team, and like the submariner, Thach faces the bewildering phenomenon of the sea itself: its lack of homogeneity, its massive motion, its madness, its strange, deep rivers. One undercurrent, recently discovered in the Pacific, is 200 miles wide, 500 to 1,000 ft. deep, flows east along the equator, 100 ft. below the westerly-flowing surface.

Lost in an Echo. The captious sea is at once Admiral Jimmy Thach's ally and enemy. Sound, his chief means of detection, travels almost five times faster through water than through air, and it plays more tricks than a Soviet delegate at a peace conference. "The ocean," says Thach, "is a liquid jungle. Survival depends on how well we know this environment and whether, like Tarzan, we can tell the friendly sounds from the unfriendly ones—the monkeys from the tigers."

Thach and his men, and the civilian scientists working on ASW problems, hunt this jungle with sonar and radar equipment that has grown in sophistication over the years but is still far from perfect. Heavy seas, hammering the hull of a destroyer, can override the sonar-transmitted sounds of distant submarine screws or reduction gears. The sun heats the thin layer of air over smooth water, and this in turn can bend radar waves. Sometimes a thermal layer, 100 to 300 feet deep, distorts sound—and a knowledgeable sub skipper plays this layer like a shield. He can confound enemy sonar by hiding in the clacking wake of a destroyer, or by backing the submarine through his own wake to lose himself in his own echo.

Most frustrating to Thach's goblin killers is the sea's own natural cacophony. Antisubmarine-warfare hands are trained to differentiate the sound of a sub from that of a destroyer or a rowboat. But they must also learn that a school of shrimp sounds like fish frying, that sea robins cluck, that the white whale creaks like the lid on Davy Jones's locker, that the eel makes a zizz like water on a hot stove, and the whistling, jocular porpoise makes enough noise to give any sonarman a headache. Most deceptive of all for Thach's sound detectives are the pings, for all the world like those from submarines, that bounce off sunken wrecks. And for precisely that reason, the wise enemy submariner would be most likely to launch his attack from the area of Cape Hatteras, historic graveyard for ships.