Jake leaned and spoke into Renard’s ear. He divulged his thoughts, and when he finished, Renard stood straight.
“Dear God, man!” Renard said. “This counters everything I have learned in my career.”
“Technology is driving the new way of submarine warfare,” Jake said. “Now’s the time to embrace it.”
Two hours later, the Hai Lang drifted, and Jake sat at the forward-most Subtics dual-stacked monitor station. Staring at the adjacent monitor, a Taiwanese sailor with negligible English skills sat beside him. Ye stooped between them and translated.
“The drone is ten nautical miles ahead,” Ye said.
“Yeah,” Jake said. “That was patient driving.”
“Conserving the drone’s fuel,” Ye said. “We still have seventy percent fuel remaining. Petty Officer Zhu is ready for you to give drone orders.”
“Have him turn it one full rotation,” Jake said.
Ye nodded and translated. Zhu tapped buttons on his keypad.
“He really knows which keys give which commands?”
“He wrote the program that converts keystrokes into drone commands,” Ye said. “He also worked closely with the engineers who built the drone.”
“I guess you left the dumb ones back in Taiwan.”
Reacting to Jake’s tone, Zhu winked. Jake smiled, but his expression waned as he studied the monitor.
An overhead view of the drone showed it driving a tight circle, but its acoustic input showed nothing but marine life — a random waveform of static in the higher broadband frequencies. Jake put a headset over his ears to listen but heard nothing but crackling shrimp.
He yelled across the line of Subtics monitors.
“Antoine, can you listen to the drone’s hydrophones?”
Antoine Remy glanced up from his monitor. He nodded, told the Taiwanese sonar operator beside him to keep listening for the Hamza through the Hai Lang’s sensors, and flipped a switch on his console. He pressed his phones against his ears and closed his eyes.
“Nothing,” he said. “Sorry, Jake.”
Jake peeked over his shoulder and was surprised to see Renard looking at him.
“Go ahead, Jake,” Renard said. “Transmit active.”
Jake grabbed Ye’s shoulder.
“Let’s see if we can find him or at least flush him out,” Jake said.
“You mean maximum power?” Ye asked.
“Yeah. There’s no need to finesse this. It’s time to challenge the Hamza to a dual.”
Ye translated, and Zhu tapped the keyboard. Jake watched a wall of sound walk up his monitor.
“Turn twenty degrees to the right and try again.”
Ye nodded and translated. Again no active return.
“Keep turning,” Jake said. “Twenty-degree intervals.”
On the sixth turn, Jake saw a fuzzy trace — a target six miles from the drone. He flipped through images on his monitor to correlate the trace with anything the Hai Lang itself heard and was disappointed to see that the drone’s new discovery matched an inbound fishing trawler Remy had classified fifteen minutes ago.
“At least this validates that the drone works,” he said. “And the range is impressive. How much power do you guys pump through that little thing?”
“With no warhead, the engineers had room for a larger active seeker,” Ye said. “The greater power permitted a lower frequency, which gives greater range.”
“But shitty accuracy,” Jake said. “Like closing your eyes in an auditorium and trying to point at the tuba. You can’t get a good bearing unless you guys embedded a mini-Cray computer in that thing for some heavy integration.”
“The guidance wire sends raw data to Subtics for processing,” Ye said. “It is no strain on Subtics, and the minimal onboard intelligence leaves more room for fuel and hydrophones. We plan to even install an integrated video, heat seeking, and particulate detection sensor—”
“Just tell me about the one in the water,” Jake said.
A cloud of smoke rose above Jake. He turned over his shoulder, and Renard was glaring.
“Not one-eighty, please,” Renard said.
“Yeah,” Jake said. “Almost forgot. Skip ahead to two-hundred degrees. Let’s not ping ourselves.”
On the final turn-and-ping interval, Jake reclined in his chair. Frustrated, he looked to Remy.
“Any activity Antoine?” Jake asked. “You have better hydrophones on the Hai Lang. The drone might miss what you can hear. Any chance we forced him into repositioning?”
“What do you think I’ve been listening for?”
Jake felt silly for having asked and shook his head. A hand slapped his shoulder.
“Don’t give up,” Renard said. “I’m starting to like this scenario. All sensors on our ship are optimized while we drift, and with your drone ten miles out, we’ve set up a corridor through which the Hamza must move if it wishes to attack a harbor-bound vessel. Keep at it, man.”
Jake nodded and flipped a switch on his console to bring up a sound propagation display.
I’ve got to try something else, he thought.
On his lower monitor, wavy lines near the ocean’s surface diverged, converged, and diverged again into the distance. Other lines diverged and curved into the depths, never to touch again. He grabbed Commander Ye’s shoulder and pointed.
“You see here,” Jake said. “All sound bends toward colder temperature. If you know your environment’s temperature gradients, you can use it to your advantage. See how the sound bends?”
“I have trained to use this tactical data, but I’ve never had a chance to test it,” Ye said.
“We dropped a bathythermograph thirty minutes ago, so this map — this environment — is pretty accurate. Let me call it up in three-dimension. It shows volumes.”
Ye nudged Jake as he squinted.
“It looks like both the Hai Lang and the drone are too shallow to hear deeper sounds.”
Jake pointed at arced lines that rose from the deep.
“But if we can take the drone deeper,” he said, “we can intercept some of the deep sound as it bounces off the ocean bottom. And look here. Even with the angled slope leading up to the islands, the bottom-bounce propagation path returns shallow about twelve miles out.”
“If the Hamza is that far out,” Ye said, “it must reposition to attack. Either that, or it would have to shoot a well-timed, slow torpedo to extend its range. But then its target would have time to detect the attack and evade.”
“Maybe,” Jake said. “But we assume the Hamza is shallow and relying on periscope visual detection and extending a radio mast to listen to harbor chatter. If this guy’s really good, he can ascend and descend without leaving his position. He could listen, look, and descend periodically, and with all the radio chatter, he’d have plenty of warning before the carrier comes in.”
“You believe he’s waiting deep, then?”
“It’s worth listening,” Jake said. “And the sound environment supports it.”
Jake looked at the propagation paths again. He tapped his keyboard, and the shallow-water paths disappeared. Gazing at the bottom-bounce paths, he let his mind play the game of trying to position the drone in a sound channel that resembled a slanted McDonald’s restaurant arch.
“You said the drone can go to more than a thousand meters,” Jake said. “That’s design. Can it go deeper?”
“How deep do you need?” Ye asked.
“Sixteen hundred meters,” Jake said.
Ye exchanged words with Petty Officer Zhu, the Taiwanese sailor who spoke no English but seemed to know everything about Jake’s drone. Ye nodded.