A moment later, the sonar took another sample of the incoming sound, and then another. Each sample extended the line, pushing the earlier sample down the screen. This created a “waterfall” effect. Random noise that appeared and faded quickly showed up as faint dots or misshapen blobs, but a constant sound showed up as a line, marching down the display.
It could still be a “biologic,” a school of mackerel warning of a predator, for instance. But man-made mechanical sounds tended to be narrow, sharp lines, while natural sounds were broad, even fuzzy. That’s why sonar operators went to school. Jiang had gone to the same school as his sonar operators, and then done another six months of theoretical work on top of that.
The operator listened carefully to the sound, as well as watching the distribution of acoustic energy on the computer display. He needed both senses to solve this problem. Classifying a contact was a slow, exacting process. They’d had dozens of false contacts that afternoon, each one analyzed and examined until it could be confirmed as “not a submarine.” This time, the operator was taking longer, and Jiang fought the urge to grab a second set of headphones. He could see the screen, and the line was narrow and very bright.
The rating looked up at his captain and nodded confidently. “It’s not natural.”
That was all Jiang needed to hear. He picked up the handset for the intership phone system and ordered, “Launch the helicopter and send it northeast. We’ll give them a precise steer once they’re in the air.” With that urgent task done, he ordered, “Put the crew at combat alert against submarines. Add that it is not a drill.” He’d run the crew ragged practicing, and he didn’t want anyone making foolish assumptions.
The sonar techs ignored the alarm klaxon and the bustle behind them as more people came into the space. As soon as Jiang hung up the phone, the tracking operator reported, “He’s tracking right, with a fast bearing drift. He’s close.”
Which meant he was close to firing. Jiang had no illusions. Any modern submarine’s sonar was going to be better than his equipment. If he could hear the sub, it was nearby. His only advantage was surprise.
Jiang ordered sharply, “Check the datalink.”
The tracking operator reported, “The link is up. We are sending.”
Jiang smiled approvingly. He picked up the phone again. “Warn the tanker, ‘Sub off your starboard bow, prepare—’”
“Torpedoes in the water, Captain!” Jiang could see the weapons appear on the display, three bright strong lines.
“ —belay that, tell him to turn
now
to … one zero zero, and warn our helmsman to watch for his stern!” Jiang had taken the time earlier to brief Captain Xin on torpedo evasion.
Yancheng
had to steer a straight course, unfortunately. If she turned, the towed array streaming behind her would kink at the point where she turned, and be useless until it stabilized. He couldn’t afford to lose his primary search sensor for even a few moments, much less several minutes. Luckily, his ship wasn’t the target.
A rating stood at the door. “Helicopter is airborne.”
Good, things were happening fast, as they had drilled. Jiang acknowledged the report, then instructed the sonar team, “Watch for the sub’s signal to separate from the torpedoes. He’s not expecting an escort, so he won’t try to clear his firing point as quickly.” The operators nodded their understanding, already deep into the search.
Jiang stepped from the sonar cabin into the command center, now fully manned at combat alert. He found the helicopter controller, one of his junior officers, hunched over his display screen. “We don’t have a range yet. Run him straight down the towed array’s bearing and have him search at five kilometers.” Certainly the sub had been at least that far away when he fired. The controller acknowledged the order and began guiding the aircraft.
Jiang noted the time. Forty-five seconds since the torpedoes had been launched. It was unfortunate, but one useful piece of information would be the time it took for the weapons to strike their target. Most torpedoes cruised at roughly forty knots, or just over one kilometer a minute. The time of their detonation would give him a rough idea of how far away the sub was when it fired.
With the rest of his men, Jiang watched the time fall away, seconds passing as distinct moments. He glanced at the navigational radar. “Is the tanker turning yet?”
The phone talker passed the question forward to the bridge. “They’ve just started,” he replied.
Jiang shook his head. “Too late, far too late.” The trick was to be somewhere else when the torpedoes’ own sonars activated. If there was nothing in front of them, the weapons would have to circle and search, which dramatically reduced the chance of a hit. And while they circled, the target moved in the general direction of away. But the tanker, like all tankers, turned like a cement truck.
Running back up to the bridge, Jiang arrived to see the distance between the two ships growing slowly. Another reason for the turn was to get some separation from the torpedoes’ intended target. He didn’t want to be nearby, and in nautical terms, that was measured in miles.
He didn’t get miles. Luckily,
Da Qing 435
’s new course took her almost directly away from the frigate, but she was still a little less than a mile away when the vessel seemed to shake, as if she’d struck a submerged object. The water around her hull churned to a milky froth, then erupted in a white tower. It all happened silently, until the sound reached him a few seconds later, first as a deep rumble, then an explosive roar that staggered him and rattled the frigate’s hull.
The perfect geometry of the column was destroyed a moment later, when the second torpedo detonated. The force of the first explosion, just a little aft of amidships, had actually pushed the massive tanker up out of the water by a meter. Jiang could clearly see a band of red showing below the ship’s normal waterline. Now the second explosion, just a little forward of the first, pushed the tanker’s bow up even farther, so that the bow stem actually cleared the water for a moment.
Amidships, the ruin created by the two weapons extended well up from the waterline, and the ship began to sag in the middle, like a swayback horse. Thick coils of black smoke were starting to appear, and through binoculars he could see the crew struggling across the tilting deck to reach the lifeboats.
His first impulse, from years of training, was to get his own boats in the water and go to their aid, but he checked the thought almost immediately. He would have to stop to lower any boats, which would not only disrupt his towed sonar, but would also make him a sitting duck if the submarine chose to attack. First things first.
Jiang stepped back into the command center, checking his watch. Just over four minutes. Call it four and a half kilometers. Pleased with his close guess, he started to talk to the helicopter controller, when sonar announced, “The third weapon has missed the tanker. It passed underneath without detonating.”
So the turn had made a difference, just not enough. “Fine,” Jiang acknowledged, “keep tracking it, but don’t stop looking for the submarine.”
“Understood, sir.” The sonar rating turned to go back in the sonar compartment when a shout came out of the open door. “The third torpedo! The bearing drift is changing! It’s turning!”
Jiang felt ice form in his chest, but he quickly told the controller, “Keep working with the helicopter,” then turned and hurried toward the sonar space. The door was open, and he called, “Which way?” before he’d even stepped inside.
The answer, in a relieved tone, was, “Starboard, away from us!” and Jiang could breathe again.
Many torpedoes had “wire guidance,” thin wires that actually spooled out as the torpedo left the submarine. Miles long, the wire allowed the sub to see what the torpedo’s own seeker saw, and the launching sub could also steer the torpedo if the target maneuvered radically. In this case, the submarine captain knew the third weapon had missed, and was turning it back toward the tanker. Miles away and underwater, he didn’t know that the merchant ship was finished.
“Where’s the sub now?” Jiang demanded.
“Heading south, Captain, and speed has increased to eight knots.”
Jiang smiled. “Good, keep feeding those bearings to the helicopter—”
The other sonar operator, tracking the weapon, reported, “Sir, it’s still turning. It’s gone past an intercept course for the tanker, and is turning toward us!”
The guidance wire can break. If that happens, the torpedo automatically circles and searches on its own. But Jiang quickly discarded the idea. He couldn’t take the chance.
He picked up the handset again. “Bridge, increase speed to flank, turn us to starboard, and pass as close as we can to the sinking tanker!”
“Sir, the towed array…”
“Forget that! Do it now!”
Jiang didn’t wait for an acknowledgement, but hung up the phone, and hurried out of the sonar cabin, through the combat center, and onto the bridge. The sinking tanker, with black smoke pouring out of the hull, was swinging across his field of view as the deck officer turned the frigate hard to starboard. The deck, tilting with the sharp turn, vibrated as the screws tried to push the hull faster and faster.
“Steady us on … one one five,” Jiang ordered after taking a bearing, and the deck officer acknowledged with a worried look. Jiang knew his bridge watchstanders would be too cautious and pass too far away from the hulk. They’d hidden behind the tanker before, now perhaps the dying ship could absorb the torpedo meant for his frigate. The tanker would appear as a much larger target to the weapon.
“Sonar, what’s the torpedo doing?” he demanded.
“We’ve lost it on the towed array, but our bow sonar still sees it, sir. It’s headed straight for us. Very strong signal.”
He’d guessed right, then. Jiang stepped out onto the port bridge wing. The burning hulk loomed fine on the port bow, and Jiang tried to judge if he could steer closer.
Yancheng
was responding wonderfully, speed building from twelve knots, and was already past twenty-two. It was much more responsive than any tanker, but it still took some time for 3,800 tons of steel to accelerate. They had to close the distance between …
The deck officer put down the intership phone. “Captain, sonar reports the torpedo’s seeker has activated, and the weapon’s speed has increased!”
“Hard left rudder! New course back toward the weapon!” Jiang sighed. He’d lost the race. At attack speed, the torpedo would swim at forty-five knots or more. Their only hope now was a sharp turn inside the weapon’s arc.
Yancheng
was continuing to accelerate, and the bow swung sharply to port, putting the tanker on the other side now. A cold wind cut at his face and tugged his clothes. He stepped back into the bridge and studied the plot, watching the angles. He ordered the deck officer, “Tell all hands to brace for impact!”
4 September 2016
1830 Local Time
Shinkansen Control Center, Kansai Region
Japan
The Japanese “bullet train” system is one of the most efficient and fastest in the world. With speeds close to two hundred miles per hour, trains operate on dedicated rail lines, separated from slower-moving freight and local trains. First operating in the early 1960s, the ever-expanding network has dramatically shortened travel times across the mountainous country, revolutionizing transportation and commerce in Japan.
Obata Takeshi had the duty at the Kansai control center when the trouble began. The three large flat-screen displays didn’t give any indication, and none of the communications staff had reported any problems.
The central display showed the Kansai region, his responsibility, in the south central part of Japan’s main island of Honshu. Heavily urbanized and populated, it holds Kyoto, Osaka, and many other major Japanese cities. The electronic map showed not only the cities and the rail lines, but could display local traffic, emergencies like fires, and even precipitation levels.
The position of each bullet train was updated constantly, using transmitters on the trains and sensors placed along the track. The Osaka–Tokyo line, one of the major runs in the system, could have as many as a dozen trains an hour in each direction, neatly separated by five-minute intervals.
The phone at the control desk connected to the first responders rang, and Obata grabbed it quickly. Nothing showed on the board, but it could be a drill, or a warning. “Obata, Kansai Control.”
“This is Battalion Chief Kawaguchi at the Fushima station. We’re rolling everything we’ve got. Who is the on-scene commander?” The firefighter’s tone was urgent, but professional.
“What?” Obata’s astonished question was loud enough to attract the attention of others in the center, and he punched a button that put the conversation on the loudspeaker. In the background, they could hear sirens and the roar of diesel engines.
“Who is in charge at the scene, dammit? We’re losing time. Can’t you people follow your own procedures? It’s bad enough we had to hear about this from civilians who saw the accident. I need to know if I should sound another alarm. Two—no, three trains, what is that? It’s over a thousand passengers per train.”
“Battalion Chief, I’m not showing any problems on any of the lines.” Obata’s confusion was obvious.
Kawaguchi replied quickly, “Your board is wrong. We’ve gotten dozens of mobile phone calls about trains colliding about five kilometers west of Shin-Osaka Station. At first, it was just two trains, but we’re getting word of a third train that’s plowed into the mess. And you don’t show any of this?” The firefighter’s question, shouted a little to be heard over the sirens, ran through Obata like an electric charge. The rest of the staff had the same reaction, and began furiously checking their systems.
Obata, thinking in terms of time and distance, shouted, “Emergency stop all trains to Shin-Osaka now! Call them on the secondary circuits!” Dozens of questions leapt into his mind, and he fought to control them. Did the trains’ conductors see what he saw here? If what Kawaguchi said was true, then the third train might be followed by a fourth, and others unless they could be warned off. “Don’t depend on the readouts! Get voice confirmation.”