Eight hundred meters to iceberg.
“We have also increased speed,” Plecas said. “Why?”
Fedorov pondered Plecas’s question, unable to determine the answer. Regardless of Kazan’s course and speed, when they turned away, the Americans would detect the maneuver and also turn away at the same spot.
“I do not know,” Fedorov answered.
“You will understand once we slow.”
“When will that be?” Fedorov glanced nervously at the sonar display.
Six hundred meters to iceberg.
Plecas answered. “When we first detected the American submarine, you wanted to shift to the electric drive, reducing our sound signature so they could not follow us. I said then was not the right time. Remember?”
Fedorov nodded and Plecas continued, “Now is the right time.” He turned to Captain Lieutenant Urnovitz. “Shift to electric drive.”
Urnovitz relayed the order to the Engine Room as Plecas checked the clock. The seconds counted down as Kazan sped toward the iceberg.
Four hundred meters to impact.
Fedorov glanced again at the rapidly closing red blotch on the ice-detection sonar. “Captain—”
A report came across the Command Post speakers, interrupting Kazan’s First Officer. “Command Post, Engine Room. Propulsion has been shifted to the electric drive. All main engine machinery has been secured.”
Plecas responded, “Steersman, hard left rudder! Steady course two-nine-zero!”
“Conn, Sonar. Loss of Master one.”
“Sonar, Conn. Aye.” Buglione examined the Sonar display on the Conn. He expected to see the tonal fade, indicating Kazan had pulled too far away to be detected. Instead, Master one’s tonal had abruptly disappeared.
Lieutenant Reese, the Officer of the Deck, also noted the sudden disappearance. “They must have secured whatever was producing the tonal.”
This was bad news. Kazan had been their beacon, charting a safe course through the Marginal Ice Zone. Buglione had two choices: activate Pittsburgh’s under-ice sonar, giving away their presence, or close the gap on Kazan to regain contact. After a moment of indecision, he chose the latter.
He picked up the microphone and selected the 7-MC. “Maneuvering, Conn. Make normal full turns.”
The Throttleman in the Engine Room opened the ahead throttles and Pittsburgh surged forward.
Buglione studied the narrowband display, looking for the reappearance of Master one’s fifty Hertz tonal. After closing the gap at ahead full for several minutes, there was still no sign of Master one, and Pittsburgh was approaching the point where Kazan disappeared from the display. Pittsburgh was barreling forward, and there was no guarantee the path ahead was safe.
Buglione decided to slow as he evaluated his options. “Helm, ahead two-thirds.”
As Pittsburgh slowed, Petty Officer Alex Rambikur, seated at his console inside the Sonar shack, was listening to the audio output from the spherical array sonar.
“Sonar Sup, I’m hearing an unusual noise. Like someone dropped an Alka-Seltzer tablet into the water.”
The Sonar Supervisor replied, “Let me listen.”
Rambikur transferred the headphones to Chief Bob Bush, who pressed them against his ears. Unlike Rambikur, who had never been on a Northern Run, Bush had made several, and immediately recognized the fizzing sound created when an iceberg melts, releasing tiny, pressurized air bubbles trapped in the ice.
Bush grabbed the microphone. “Conn, Sonar. We’re picking up a bergy-seltzer on broadband. It’s close. I’ve never heard one this loud before.”
“Helm, all stop,” Buglione ordered.
He turned to the under-ice sonar operator. “Energize the High Frequency Array.”
The monitor flickered to life. A huge patch of red appeared on the display, directly ahead at a range of five hundred yards, barely four ship-lengths away.
“Helm, back emergency!” Buglione shouted. “Hard right rudder!”
26
MARGINAL ICE ZONE
Plecas studied the fire control display, watching the American submarine approach the iceberg. It had been a difficult decision — whether to set this trap for their adversary. If the American submarine rammed into the iceberg, it would be severely damaged, and if its pressure hull ruptured, it would sink to the bottom of the Barents Sea. However, Plecas had been trailed by Americans before and knew how difficult it was to shake them. In the end, it had come down to a simple edict.
Kazan could not be trailed.
Plecas examined the sonar display, searching for clues to their adversary’s fate. If the American submarine crashed into the iceberg, they would hear it. He picked up the microphone.
“Hydroacoustic, Captain. Put broadband audio on speaker.”
The Command Post speakers activated, emitting static noise from surface waves and biologics. The static was interrupted by a loud burst of noise; the distinct sound of high-speed screw cavitation. The American captain had ordered back emergency.
Hydroacoustic’s report emanated from the Command Post speakers, temporarily overriding the broadband audio. “Cavitation from Hydroacoustic five. Downshift in frequency. Contact is decreasing speed and turning away.”
The Americans had discovered the trap and were trying to maneuver around the iceberg. But had they realized their peril in time?
Commander Buglione felt tremors in the deck as Pittsburgh’s rudder dug into the water and the submarine’s screw churned the water in reverse. He glanced at the under-ice sonar display. They were closing rapidly on the red blotch.
Three hundred yards.
Pittsburgh was so close to the iceberg that it filled the entire display. They weren’t turning fast enough to avoid it, and they weren’t going to stop in time — they were just now dropping under twenty knots. As Buglione prepared for the inevitable collision, a thought occurred to him. They couldn’t swerve around the iceberg, but could they go under it?
Buglione checked the charted water depth: 750 feet.
“Dive, make your depth seven hundred feet! Use thirty down!”
As Pittsburgh tilted downward, Buglione had no idea if they would get deep enough in time, or if there was enough clearance between the iceberg and the ocean bottom.
Two hundred yards.
Buglione ordered the Chief of the Watch, “Sound the Collision Alarm!”
The high-pitched wail sounded throughout the ship.
Buglione shouted, “All hands brace for impact!”
The cavitation from broadband audio continued, indicating the American captain was still slowing and turning. Then the cavitation was pierced by several loud pops.
Hydroacoustic reported the unusual sound. “Receiving hull pops from Hydroacoustic five.”
As submarines went deeper, their hulls compressed slightly due to the higher ocean pressure. The decks inside the submarine weren’t welded to the hull — they rested atop deck clips, which let the hull compress without crumpling the decks. However, the heavy decks didn’t ride smoothly on the clips, adjusting in increments, with each adjustment creating a loud pop.
The American submarine was going deep, trying to pass beneath the iceberg.