War of the Whales (46 page)

Nothing about the training exercises was simulated except the live fire of “target acquisition.” Search, detection, classification, and targeting were performed under actual battle conditions. The final measure of the group’s combat readiness was simple: Could it find and kill the enemy submarines before coming under attack?

As the battle group entered Providence Channel between Eleuthera and Abaco Islands, the squadron commander directed all battle crews to switch over to encrypted communication. With only a slender new moon hanging over the channel, the squadron began its search for the two enemy submarines lurking somewhere in the 20-mile-wide-by-100-mile-long canyon.

Locating silent and stationary submarines is extremely difficult, even with a broad spectrum of sensors. The cloak of darkness gives the submarines an added advantage. In daylight and in calm seas, a surveillance plane can make out the subtle surface wake from a submerged submarine—if the sub is moving. The squadron commander understood that the only way to locate enemy subs in the dark was to light up the channel with whatever acoustic sensors he could bring to bear.

He radioed the destroyers
Cole
and
Donald Cook
—using their call signs “Fox” and “Zebra”—to dispatch their helicopters up and over the top and lay a “picket fence” of passive sound buoys on both sides of the advancing battle group.

The choppers released their sonobuoys 300 feet above the water. A small parachute slowed the sonobuoys’ descent before they splashed down and sank to a depth of 20 feet before leveling off. The Seahawks continued dropping sonobuoys at two-mile intervals until the fence was complete. If the passive sound buoys picked up a potential target, the Seahawks could lower their active dipping sonar by a cable and get a more precise fix before launching their antisubmarine torpedoes.

•  •  •

Miles ahead of the surface ships and 700 feet below them, the battle group’s two escort subs advanced along their preassigned search paths. To protect themselves from friendly fire, the hunter-killer subs made sure to stay inside the sonobuoy picket lines. Submarines are the most effective passive sonar platform for detecting other submarines because they can search at variable depths, and they emit very little noise that can clutter the sound field. In good conditions, a submarine can hear another sub’s movement within 50 miles, about twice the listening range of a sonobuoy.

But passive sonar has a fundamental limitation: it can hear an enemy sub only when it’s moving. If a submarine is hiding motionless along a canyon wall, 600 feet below the surface, the only way to “see” it is with active sonar. Of course, the squadron commander knew that once the destroyers and frigates turned on their active sonar, they would be broadcasting their location to the enemy submarines, making them easy torpedo targets. But he also knew that only a suicidal submarine—or a sub that had been detected and feared attack—would fire on a warship in a battle group. If he located an enemy sub, the commander would have a brief interval to decide whether to take defensive countermeasures or attack.

The commander ordered the two frigates to turn on their omnidirectional active sonar and proceed between the picket fence of sonobuoys in a zigzag pattern, creating a moving search field. The destroyers followed five miles behind the frigates, advancing in a straight line down the middle of the channel, sweeping their directional active sonar beams at different depths and frequencies than the frigates’.

The sonar transmitters mounted on the front hull of the warships emitted a “ping” every 24 seconds. But it only sounded like a “ping” from inside the ship. In the water, each “ping” created a pressure wave of 230- to 240-decibel sound that hurtled through the channel at a mile per second—five times the speed of sound in air.

Ordinarily, the decibel level dropped off geometrically as the sound moved away from the ship. But that night in the channel, a stronger than normal surface duct of warm water trapped the sound energy in the upper 500 feet of the channel, focusing the sound the way a Fresnel lens amplifies a lighthouse beam in air. Meanwhile, other sonar sound waves angled toward the steep canyon walls before bouncing back toward the ships. Minute by minute, mile by mile, the choke point canyon filled with reverberating sound.

The sonar supervisor’s display panel alerted him that the active sonar on one of the frigates had detected two moving objects near the surface. Shipboard radar had also made a contact. The undersea warfare evaluator radioed the ensign stationed on the deck of the
Hawes
. “Possible submarine contact bearing zero-two-niner, range five hundred feet. Confidence low. Can you provide visual confirmation?”

The ensign swiveled his tripod-mounted “big-eye” binoculars 12 degrees to his left and scanned the surface, which appeared in grainy green through the night vision scope. A moment earlier, he might have spotted two beaked whales surfacing to breathe. But by the time he panned across the horizon line, they had already ducked back under the water, leaving barely a ripple in their wake.

“Negative visual confirmation at zero-two-niner,” the ensign radioed back. “Continuing to scan.”

As soon as the whales descended for their hunting dive, they were buffeted by a pressure wave from the frigate’s sweeping sonar. They quickly rolled away from the sound and retracted their small pectoral fins into concealed pockets in their flanks. With their drag reduced, they fluked downward through the water column, absorbing the oxygen from their lungs into their blood and muscle tissue.

At 200 feet, the water pressure compressed their lungs and contracted their hyperflexible rib cages. With their buoyancy reduced and their fuselage further streamlined, the whales stopped fluking and glided downward like birds falling through the air, conserving energy as they plummeted through the water.
⁴

At 500 feet, the whales slowed down their heartbeat and diverted blood from skeletal muscles to the brain and heart muscles, which require steady oxygenation. To cope with the increasingly intense pressure of the water column, the whales continuously calibrated the pressure of the air sacs in their ears and sinuses.

At 600 feet, the whales entered the twilight zone and began to hunt for squid. Four miles to the east, one of the “enemy” subs hovered motionless along the east canyon wall, listening to the sonar clicks of the beaked whales seeking prey and the chirp-and-bark patter they used to stay in contact with each other.

In the target-rich environment below 1,000 feet—well beneath submarine depth now—the whales deployed a click-buzz sonar pattern to locate and capture their prey. In search mode, the whales emitted two midrange clicks a second that cast a narrow-focused signal, like a flashlight beam. To increase their search field, the whales rolled in a spiral pattern as they descended, turning their heads from side to side. Once a whale indentified a desired target by its echo profile—not too big, not too small, not too spiny—it homed in on its prey with a high-frequency buzz pattern of 250 to 300 clicks per second, approached to within a meter of its prey, and then sucked the squid into its mouth.

After ingesting squid for the next half hour, and with the lactic acid from oxygen debt building up in their tissue, the whales began their ascent to the surface. By ascending slowly and gradually, decompressing in sync with the decreasing hydrostatic pressure, they could reabsorb nitrogen back into their bloodstream. If they ascended too quickly, the nitrogen could form painful and potentially lethal bubbles in their muscle tissue and fat. Normally, on returning to the surface, the whales would make a half dozen shallow recovery dives to allow the dissolved nitrogen in their blood to diffuse into the lungs, and the accumulated lactic acid in their muscle tissue to slowly absorb back into their bloodstream—much the way that marathon runners walk off their oxygen debt and lactic acid buildup after finishing a race.

But on this night, nothing was normal. At 500 feet below the surface, the ascending whales collided against a ceiling of sound waves trapped in the surface duct of warm water. Instinctively, they dove back down to where the pressure waves were less intense. They tried to gather intelligence from other whales in their pod, but all their normal communication frequencies were jammed with intense, head-rattling pressure waves that pounded the tiny air pockets inside their sinuses and ears. They couldn’t distinguish their own panicked calls from those of the whales around them, couldn’t find the early-morning light above the water’s surface, couldn’t tell up from down. They were drowning in sound.

The whales that couldn’t penetrate the surface duct of funneled noise were overcome by oxygen debt and a lethal buildup of lactic acid. Without air in their lungs, their bodies surrendered to free fall, and they swooned downward through the perpetual darkness of the midnight zone, finally settling four miles below on the canyon floor, alongside the bones of their ancestors.

Some of the whales were able to fight their way through the surface duct to the open air. But then the oxygen in their lungs competed for absorption with the nitrogen bubbling in their blood and tissue. There seemed to be no escape from the acoustic storm—except the shallow shelf beyond the canyon walls.

A female Blainville’s separated from her hunting party, fluking frantically away from the hammering noise in the canyon. The water turned warm and shallow, and though her ears still pounded, she could steer by the sunlight that shimmered off the white sand bottom. She was too tired to avoid the clusters of sharp-edged coral that sprouted up around her.

She didn’t see the shark until after it hit her tail and circled away through the reddening water. The whale turned to flee back toward the canyon. The shark hit her again, higher up on her trunk this time. Another shark darted in and retreated, its jaws filled with flesh.

Five miles away, another whale fled from the sound storm in the canyon. As he entered the shallows, he was disoriented by the warmth of the water and the unfamiliar sight of sand beneath him. His head ached, and his eyes stung from the bright sun. When he felt his belly lodge against the sandy bottom, he tried to break free. But his fluking only drove his belly deeper into the sand.

He could hear waves lapping on the beach nearby, but it wasn’t a sound he recognized or understood. He couldn’t see anything but the glare reflecting off the white sand, couldn’t feel anything but the sun baking his back and the blood running hot in his veins.

A shape moved through the water nearby. It loomed above him, blocking the sun, and then lowered itself into the water beside him. The whale felt something gentle touch his head, just behind the blowhole.

“What in the world are you doing here?” Balcomb murmured, as much to himself as to the whale.

* See map of Navy ship movements and whale strandings in the Bahamas on the back endpaper of this book.

PART FOUR

WHALES V. NAVY

This is a court of law, young man, not a court of justice.

24

God and Country v. the Whales

On the day before the new year, a holiday, Joel Reynolds was the only person working in NRDC’s Los Angeles office. He was never eager to leave his family during Christmas vacation. But he felt an urgency to get a head start on the battle that he knew was looming. The
Washington Post
was spread open on his desk to Rick Weiss’ article about the Navy and Fisheries’ interim report: