Page 33 of Clive Cussler Ghost Soldier

“Did we get an audio recording?”

“Nothing that I could make out.” The CPO grunted. “The algorithm must be smarter than my ears.”

“Not likely,” Cho said, clapping his old friend on the shoulder.

The chief had served with Cho on other boats for several years patrolling hostile waters. With or without audio confirmation, the chief knew what a torpedo door opening looked like on a spectrograph.

Equally important, his sonar computer had access to the U.S. Navy database storing tens of thousands of previously recorded audio and electromagnetic signatures of combatant vessels, including the sound of torpedo doors opening on every variety of North Korean submarines. No doubt the sonar’s computer matched up the spectrograph reading with a similar signature in the database.

In some cases, the specific submarine could be detected by the unique sound of its own particular doors. However, in this instance, no submarine was identified because not enough of the sound signature had been captured by the sonar computer.

“Where is it?” the captain asked.

The sonar tech then dragged the B-scan display forward, showing both the range and bearing of an object relative to their destroyer.

“Eleven thousand two hundred meters, bearing oh-eight-seven degrees.”

“No other signatures?”

“None.”

The captain breathed a sigh of relief. No other signatures meant no submarines in the water—or any of their “fish” racing toward them. Cho wondered if his sonar arrays had picked up the clanking of lost shipping containers colliding in the water or the industrial noise of a commercial fishing trawler instead of a torpedo door.

He turned to the radar technician.

“Anything?”

“No, sir.”

“Anything on the cameras?” Cho asked. A sub running at periscope depth would leave a thin, feathering wake on the surface.

The watch stander monitoring the optronic mast shook his head.

“Nothing, sir.”

Cho and his chief exchanged a relieved look.

“Log it in the computer as an anomaly.”

“Aye, sir.”

Captain Cho stood and stretched, and cracked his neck. He was still on his break. Time enough to go topside and finish his smoke.

“Keep me posted if anything else pops up. I’ll be back in fifteen.”

“Sir.”

Cho turned for the exit.

Alarms suddenly blared, and warning lights flashed.

Another sonar tech shouted, “Fish in the water!”

Cho whipped around and barked orders at his crew.

“Evasive maneuvers! Sound battle stations! Reports! Bearing, speed, range!”

The chief shouted back. “Torpedo bearing oh-eight-seven degrees relative. Speed…Wait…That can’t be right.”