At least, that was the tactical idea….
"Speed twenty knots, Captain! Heading now one-eight-zero!"
"Sonar! Range to torpedo?"
"Sir… estimate range… four hundred meters! Time to impact… one minute, twenty seconds!"
"Continue to give me range data."
"Yes, sir! Torpedo range now three hundred seventy meters… three hundred fifty meters…"
Jian closed his eyes, forming a mental image of the tactical situation. Yinbi was running south at flank, the enemy torpedo close behind. The American submarine must be somewhere farther north… how far north was unknown. American ADCAP torpedoes had a range of at least thirty-five kilometers.
He would have to be a lot closer than that, however. He could not possibly have detected Yinbi's movements at a range greater than, say two kilometers, and that was giving him a great deal of the benefit of the doubt.
"Range to torpedo now three hundred twenty meters… three hundred meters…"
No homing sonar yet. That meant the enemy torpedo was being wire-guided, which, in turn, meant the American had a sonar fix on them.
Damn it… how?
"We're closing the range between Junior and Sierra One-oh-three, Captain," Carpenter announced. "Three hundred yards!"
"Sonar! Position on Sierra One-oh-three?"
"He's due west of us now, Skipper. Bearing two-seven-zero, range one hundred eighty yards!"
It was tempting to fire a snapshot now, with the enemy's position so firmly locked in. Torpedoes armed themselves, however, after a set passage of time, a safeguard to prevent a torpedo from acquiring a target lock on the firing submarine, and circling back for what was euphemistically referred to as an own goal. Virginia's ADCAPs were set with a thirty-second delay, which translated to about eight hundred yards of travel. The time delay could be reduced, but that was not seen as a healthy tactic. Blowing your own submarine out of the water was not a move calculated to enhance a naval officer's career.
And so, Garrett waited.
On the control room monitor, a dark gray shadow was slowly taking shape, all but hidden in the murk. Garrett found himself fascinated. There'd been times during the Cold War when American subs had passed close enough to a Russian sub to be able to photograph the other vessel's hull through the periscope, but never had this level of detail been possible. He was actually seeing the enemy sub, not less than a hundred yards ahead of the remote UUV.
"Torpedo now at one hundred meters, Captain, closing at ten knots!"
Close enough. "Release countermeasures!"
"Countermeasures released, sir!"
"Down planes! Submerge to three hundred meters!"
"Submerge to three hundred meters, yes, sir!"
Jian grabbed hold of a handhold on the periscope housing as the deck tilted sharply beneath his feet. With just a little luck, the American guiding that torpedo would lose his lock on the Yinbi as the vessel vanished behind an expanding cloud of bubbles. In that brief moment of invisibility, Yinbi would dive, dropping beneath the thermocline and disappearing from the enemy's sonar screens.
Down… down… and down further still. Would the American torpedo follow?
If they could break the enemy's targeting lock, Yinbi could go deep, then circle back around toward the north.
Toward the enemy….
On the monitor, a cloud of silver bubbles exploded across the screen as Junior's lights cast weirdly shifting vistas of shadow and rainbow. For a moment, nothing was visible but the rushing bubbles; then the UUV burst into the clear. The ocean ahead was empty and dark.
"Lost him!" Carpenter exclaimed.
Once behind its countermeasures screen, the Kilo could have turned right or left, gone up or down. "Take Junior down," he ordered. "I'm betting the bastard is going deep."
That, after all, was what Garrett would have done, plunging beneath the thermocline to evade enemy sonar detection.
At first, nothing was visible but darkness. Then, as the UUV continued to descend, once again a dark shadow loomed ahead, barely visible against the even darker night of the ocean depths.
"Got him!" Carpenter exclaimed. "You were right, Skipper!"
"Switch on Junior's active sonar," Garrett ordered. "Let's shake this guy up."
Faintly, the chirp of a sonar pulse sounded through Virginia's bulkhead.
"Captain! Sonar," Queensly said over his headset. "We're below the thermocline, too. We may be illuminating ourselves!"
"Noted, Queenie. But our friend has other things on his mind right now. Keep tracking him!"
The Kilo was diving fast, still moving at a good twenty knots. The rush of water past his hull would drown out any sonar echo bouncing back from the Virginia. In any case, the Kilo's sonar people were probably completely focused on the UUV right now.
"Helm," he said. "Continue coming left… but open it up a bit. I want to swing around very gently and come in right on the bad guy's tail."
"Aye aye, sir. Continue turn to put us on Sierra One-oh-three's six."
"Diving Officer, take us down to eight hundred feet. But slowly. I want him to pull out ahead of us. Make revolutions for five knots."
"Yes, sir. Make depth eight hundred feet. Make revolutions for five knots, aye aye, sir!"
Gently, the deck tilted forward, canted slightly to port as Virginia continued her wide turn. The faint chirp of sonar continued to ring and echo in the distance.
"Captain?" Carpenter said. "We're going to have contact with Sierra One-oh-three in another few seconds."
Garrett glanced at the forward monitor. Junior's lights were illuminating the deck and the aft part of the Kilo's sail, now. The UUV was shuddering slightly as it passed through the Kilo's wake; the image steadied as it left the cone of disturbed water astern the Chinese sub, and passed slowly along the afterdeck.
"Slow the UUV, Weps. Have it keep pace with the target, if you can."
"Aye, Skipper. I'll do my best."
"And keep pinging him. I want to keep driving the bastard."
The range between hunter and hunted continued to widen….
PING!…
The sonar pulse hammered through the control room bulkhead, a shrill ring assaulting the ears… and the mind.
"Captain?" The sonar operator sounded unsure of himself… a bad sign.
"What is it?"
"Sir… the enemy torpedo. It's slowed to match our speed."