Korea Strait (34 page)

“I ran some possibilities last night. Since I didn't have much else to do.”

Henrickson pulled his own computer over on the desk and flipped up the screen. The notebook hummed as the hard drive powered up.
“We don't know what they're carrying, but I'm assuming it's some version of the 53-65. Wake-homing, antiship, six-hundred-pound warhead. Range twenty thousand yards at full speed. The Russians sold them to the Chinese. This is a smart fish. It picks up wake turbulence and follows it to its source. You can't jam it or decoy it. And it runs out at fifty knots, so unless you have a long head start, you can't outsprint it either.”

“None of this sounds promising. You think that's what hit
Mok
Po? A wake homer?”

“That's consistent with the stern damage, and she had her Nixie streamed and turned on. So it was either a wake homer, or a real lucky shot with a straight runner.”

Dan contemplated the screen, which now displayed the 53-65's wavy approach course as it acquired a wake. Henrickson went on, “This is really a good torpedo. Even if you spoof it, it presses on through the countermeasure and reenables on the other side. Team Charlie got their hands on three of them four years ago. We gave one to DARPA, one to DIA, and kept the one that had the fewest bullet holes in it. We took it apart, put it back together, and did fifteen instrument runs down at Tongue of the Ocean. There really isn't a soft kill possibility. The only way to evade it is the Dingo.”

Dan had never heard of a Dingo, but this was the second time he'd heard a Team Charlie mentioned. He'd understood from the briefings back at TAG that there were only two teams, though. As for the other acronyms Henrickson had just used, DARPA was the Defense Advanced Research Projects Agency; DIA, the Defense Intelligence Agency. He filed it and pressed on with the immediate problem. “Dingo—what's that? An evasive tactic?”

“Yeah. As soon as you hear the thing coming, fire a Mark 46 on straight run, surface mode, shallow setting, off the side the detection's coming from. Simultaneously you go to all ahead flank and hard rudder and buttonhook back, just like a Williamson turn, as soon as the 46 clears the tube. With me so far?”

“I'm with you. Then—”

“Then, as soon as you pass about one twenty off your original track, you go to full-power reverse. If you do it right, you end up dead in the water, but with your bow headed back down your own track.”

“Dead in the water, during a torpedo attack?”

“Just hear me out, okay? In our tests, the 65 either lost the ship's wake and reenabled on the Mark 46, if it was tracking near center-line, or followed the quarter-wave, if it was offset.”

He fingered the keyboard. The display changed, and Dan watched the tactic play out. The hostile torpedo bored in from astern. The target ship executed its turn. The torpedo overshot, carrying on along its original course, apparently following the original bow wave, which had been generated before the turn. It went into its sidewinder wriggle again as it reenabled and started searching again; then suddenly snapped back into homing mode and tracked steadily off the screen to the left.

Henrickson said, “A Mark 46 running shallow at top speed generates just enough turbulence to engage the seeker. Usually, that is… When it does, the 65 heads away after it. Eventually it overtakes, it's faster than the 46, but by then it's outside reacquisition parameters for its original target. It goes back into search mode and chases its tail till it exhausts its fuel, deactivates, and sinks.”

“That's a complicated tactic,” Dan said. “And isn't it suicide, if it's
not a
wake homer? Going to zero speed, backing down?”

“Yeah, that's your downside of Dingo. If it's not a wake homer they kicked out at you, if it's an acoustic homer, you just cut your Nixie cable during the buttonhook and walked right into the punch.”

“And I suppose there's no way to tell which one's coming at you?”

“Not till two thousand yards out, when the acoustics turn on their active homer. And by then it's too late.”

“Shit.” Dan swiveled, blowing out, trying to pull his eyebrows down off the overhead. “This isn't an approved tactic, is it?”

“We put it out in a tacmemo last year. So it's not in ATP 28, no, but it's on the street.”

“To the Koreans? Are they on distribution?”

“No. U.S. only.”

He rubbed his mouth again, wishing he wasn't so dog-tired. He had the feeling he was missing something. This wasn't the way to do tactical development: on a notebook computer, at general quarters, charging in on a confirmed hostile at thirty-four knots. “What about our Mark 46s? There's something fucked there. The air-dropped ones
didn't work any better than ours. We keep firing them but we don't get kills.”

“We can hear them running. They're just not hard-locking, for some reason.”

“Countermeasures? Jamming?”

“I'd guess some kind of new countermeasure. If I had to wing it.” The analyst bared his teeth at his computer. “But I don't know what it is, so I can't tell you how to increase P sub K. Just keep throwing weapons in the water till one acquires. That's all Jung can do. And I'll tell you another thing.”

“What?”

“This first contact might be bait. That's a tactic the DPRK uses a lot. Hang a fat, juicy target out there, wait till you go for it, then clobber you from ambush.”

“We'd better tell the commodore about this. The whole wake-homer thing, this Dingo business. You mind briefing him?”

Henrickson said he'd be happy to, as long as he could borrow the battery module to Dan's computer.

THE heading indicator was spinning like a roulette wheel. Dan assumed they'd reached the nine-thousand-yard point and were coming to the parallel course. Nine thousand yards was inside torpedo range, of course, but it was far enough from the farthest on circle, the possible location of the sub given the elapsed time since detection, that they should have enough warning to turn away and outrun anything fired at them. Though at the cost, again, of burning more precious fuel.

Jung received Henrickson's briefing with a weary scowl. Before the analyst was done he snapped, “What you're saying is, there's no way to counter a wake homer without putting our own ships in just as much danger from the acoustic homers. So all the sub has to do is fire one of each, and you're nailed.”

“Well, that's not quite true, sir—”

“You just said it was.”

Dan stepped in. “Sir, what you haven't let us get to yet is the possibility of combining both tactics. It'll take close attention by the son-armen, but it might work. We call it Dingo Plus.”

“I'm waiting.”

He explained. On a “torpedo in the water” warning—the sound of high-speed screws on a constant, incoming bearing—the target ship would execute Dingo. Or rather, start to. But instead of coming to the reciprocal of its original course, it would keep its rudder hard over, continue its turn, and steady up heading away from the original incoming bearing. By then its speed would have dropped below the turbulence-generation point, losing a wake homer.

At that point, the sonarmen would take another bearing on the sound of the incoming weapon. If they showed a drift in the direction of the ship's original direction of travel, then their pursuer was a wake homer; they had only to stand by till its fuel was exhausted. If there was no bearing drift, it was either a straight runner or an acoustic torpedo running passive, and odds were against a hit, since they'd altered their original course and with the engines stopped there was little machinery noise.

But if they heard active pulses, it was acoustic running active. They'd instantly flip the Nixie on, slam the throttles forward, and take off again, full turbine power, full speed.

Jung turned to Hwang. “Did you follow that, Commander?”

“I think so,
Jeon daejang mm.”

“Good, because I'm not sure I did. What if they do like I said? Fire both types at once?”

Dan cleared his throat. That was where Henrickson's model got wobbly. “Commodore, that solution seems to be sensitive to which one comes out of the tube first. If they fire the wake homer first, then the chances of evading are about fifty-fifty. The wake homer follows the wake away from the stopped ship, and the Nixie decoys the acoustic homer.”

Hwang said, “Fifty-fifty each, or fifty-fifty for evading both?”

“Fifty percent probability of evading both shots.”

“Well, that's better than nothing. What if they fire the acoustic torpedo first?”

“Then the chances of evasion drop to about ten percent,” Henrick-son said. “Of course, you multiply that by the reliability rate and the usual probability of kill for both types.”

“The result then?”

“Maybe thirty percent.”

“Kill, or survive?” Jiang asked.

“Seventy percent kill,” Henrickson said. “Thirty percent survive.”

“These numbers suck,” said Hwang.

“Maybe, but they're better than the tactics you have,” Dan pointed out. “At least against the 53-65s.”

“Not by much.”

“It still gives your attacking ship a chance,” Dan told him, suddenly exasperated. “If the target turns on him. You want tactical advice? That's our tactical advice. You can take it or leave it, but there it is.”

Jung discussed it in Korean with Hwang. Lieutenant Kim, the ASW officer, listened respectfully. Once or twice he got asked a question, which he answered with an eager bob of the head. Finally Jung nodded to the Americans coldly. “Thank you for your suggestions, gentlemen. We'll take them under advisement.”

Monty went back into Sonar. Leaning against the plot table, Dan watched Jung cough and wipe his mouth and and chain-light another cigarette. Fuel: that was what worried him now. He said in low voice to Lieutenant Kim, “How we doing on gas, anyway?”

The ASW officer looked grave. “Below thirty percent.”

Dan sucked air. He'd known the high-speed regimes, running on the turbines, gulped enormous amounts of fuel. But he hadn't expect the tanks to be
that
low. U.S. Navy practice was to bunker up whenever you got below seventy. He thought of approaching the commodore about it, but one look at Jung brooding decided him against it. He'd bothered the man enough. Instead he drew a deep breath, coughing at the smoke, and went topside.

THE wind had risen even more and the sky was black as a seam of Pennsylvania bituminous. A band of charcoal clouds dangled tendrils that occasionally twisted into spirals, like the business end of a corkscrew. They ran from one horizon to the other. He tensed with the primeval anxiety that wind and darkness, the oncoming storm, triggered in terrestrial animals. The seas, kicked steep by the shoaling shelf, were short and already breaking.
Chung Nam
surged through them, bulling up bursts of snowy spume that lofted on the windward side, hung in midair like loops of Christmas tinsel, then
blew down and apart across the forecastle. Cables still snaked about from the system checks, but the crew had taken cover, except for two swarthy boatswains, older than the rest of the crew, who were frapping down the pelican hooks with bright yellow line. They wore blue coveralls and battle helmets and the bulky orange life jackets. A young officer watched them, arms akimbo. The forward gun was elevated as high as it would go. A black plastic trash bag flapped where it had been duct-taped over the tompion. Dan stood shivering. The wind was turning cool. He remembered when all he had to worry about was getting his division's tackle secured for sea. It felt like ages ago.

He shaded his eyes, then borrowed binoculars from the machine-gun crew. The gray upperworks and white sensor bubble of an Ulsan-class were just visible far out to port. Either
Mesan
or
Cheju,
one of the two new joins. The white sphere really stood out in the dimming light. He judged they were ten thousand yards distant.

He watched them for a few minutes, but they didn't turn or vary their speed, just steered a steady course. This wasn't good. Ten seconds' periscope exposure, and that great aiming point… He searched to right and left, but didn't see the other prosecutor, nor any of the patrol air, though they might be above the clouds, monitoring sonobuoys from there.

But at some point, as the wind rose, they'd have to leave. Then Jung would be nearly blind, like a man in a smoke-filled cave whose flashlight beam stops two feet from the lens.

He searched the rest of the way around the horizon, and was surprised when he saw another Ulsan-class pitching doggedly a thousand yards astern. He'd forgotten
Kim Chon
was still with them. A tiny figure on the port wing was waving. He lifted a hand in return, figuring it was Carpenter. At least out here Rit couldn't get in more girl trouble.

When he went back inside, Captain Yu gave him a dirty look from his perch in the skipper's chair. Dan saluted but Yu turned his nose away. Lenson rattled down the ladder to CIC again. Everyone was standing, leaning, sitting just as they had when he'd left, still as a Dutch painting, their attention on the plot table.

Henrickson told him in an off-line murmur that
Chang Bo Go
had reported in. The 209 was off the port of Ulsan; she'd transited back
on a straight line from the original operating area. She too was getting low on fuel, but had been opconned to 213.3. Jung had ordered her to take up an antisubmarine barrier position along the one-hundred-meter line off Pusan Harbor.

“She won't use much fuel there,” the analyst said. “Just lie on the bottom and listen, probably. Play goalie, in case we drop the ball.”

“What sport exactly have you got in mind, Monty?”

“Ah, forget it. Forget it.”

They talked one of the petty officers out of a large-scale chart of Pusan Harbor and unrolled it on the Harpoon console. One of the other Koreans saw them with it, and brought over a port guidebook that was printed in both Korean and English.