Deep Sound Channel (41 page)

"But presumably they won't know about the hot vent lensing," Bell said.

"So we hope," Jeffrey said.

"Jan isn't likely to think of it," Ilse said. "He's not exactly in tune with the environment."

"He has a crew, remember," Morse cautioned, "an XO and sonar experts and so on." Ilse frowned and nodded.

"As long as they don't go active," Jeffrey said, "we may be able to fool them about our actual range."

"Yes," Morse said. "When they hear the Mark 88s doing end-game runs without prior active searches, they'll guess at our range based on what they know of Challenger's sonar sensitivity, and underestimate. They'll probably launch a snap shot spread, a nuclear shotgun blast—they've done that twice already since making contact at Durban—but it ought to all fall safely short of us."

"Concur," Jeffrey said. "So let's hope ter Horst doesn't go active. It would be a toss-up for him, revenge versus self-preservation, offensive accuracy versus his ping helping our own fish home in."

"Oooh," Ilse said, "I wouldn't want to count on anything there, knowing Jan."

"Mmph," Jeffrey said.

"Sir," Bell said, "we have an improved range estimate to Sierra 1 now, still too far to engage. Target speed appears to be ten or fifteen knots. I am repositioning the units from tubes one and five to intercept based on the latest 3-D TMA."

"What's target depth?" Jeffrey said.

"Fifteen thousand feet, sir," Sessions said. "The acoustic shadowing along the bottom is more than offset by ray path focusing at the intersection of the two big vent plumes, our main telescope lens."

"Good," Jeffrey said, "just as we predicted."

"But we still have a serious problem," Morse said.

Jeffrey nodded. "We were counting on using our Mark 88s for a slow-speed stealth attack against a more or less stationary target. Since Voortrekker's moving, they'll be much harder to hit, and our TMA will be rather crude with this lensing effect."

"Plus there's the sonar reception time delay," Ilse said. "At thirty miles, say, until our torpedoes pick him up themselves and we can target directly through the fiber-optic wires, there'll be a half-minute lag between Challenger's latest raw data and where Jan actually is."

"Correct," Jeffrey said. "So now the weapons will need to ping and make their end-game runs at high speed, from ten thousand yards away or more, and ter Horst will hear them coming. Against ceramic-composite hulls at this depth, Mark 88 warheads have a lethal range of only a nautical mile or so, two thousand yards. The enemy'll be able to counterfire low-yield warheads to intercept our incoming fish, and he'll spoil the whole attack."

"Still nothing, sir," Van Gelder said. "Again, query going active. Challenger may fear we were alerted by their mechanical transient. They may have withdrawn to widen the range."

"Don't go active yet, Gunther," ter Horst said. "Let's get just a little closer, try to spot them on ambient or hole-in-ocean first. I also want to get the far side of the vent field further in range of our weapons, in case, as you say, Wilson did decide to run."

"Understood, Captain," Van Gelder said.

"De-enable weapon active pinging, so the units don't waste fuel by driving heavily loaded turbogenerators or give themselves away prematurely. We'll rely on passive search instead, narrowband tonals only, with guiding through the fiber-optic wires."

"De-enable weapon active pinging, aye," Van Gelder said. "Presets completed, Captain, and we have a second full salvo prepositioned on the holding racks."

"Excellent," ter Horst said. "Now, begin varying our course and speed at random, say twenty-five percent more or fewer shaft revolutions and twenty-degree port and starboard rudder applications. I want to throw off Challenger's TMA."

"Sir," Bell said, "latest data put Sierra 1 in extreme range of our weapons. Sierra 1 is zigzagging and fuel in both our units is running low."

Morse stood up straight and looked Jeffrey in the eye. "It's now or never, Captain Fuller."

"I don't like this setup," Jeffrey said. "The best that's gonna happen is a draw—we escape their fire 'cause they don't know our range, and they escape ours using nukes as AT

rockets. A draw's a loss for us. They'd still be straddling our homeward track."

"We can't clear datum and start over again," Morse said. "No more good ammo."

"We could try to lure Voortrekker to shallower depth and then engage with ADCAPs," Bell said.

Jeffrey shook his head. "The crashing waves up there

give a perfect white noise backdrop. We'd only make ourselves a better target."

"Sorry, sir," Bell said. "I was just trying to help." Ilse saw Jeffrey get that faraway look again. "I think you did, Fire Control, I think you actually did."

"Sir," Bell said, obviously confused, "target is now passing point of closest approach to our units. Recommend engaging promptly."

"Very well," Jeffrey said. "We only get one chance. Fire Control, bring the units up to ten thousand feet and maintain them at that depth. Keep them equidistant from Sierra 1

on opposite sides of her track best as you can. Commence high-speed run-in when both weapons are ten thousand yards from target. Give me continual unit and target location on my tactical screen, and prepare to detonate both weapons on my mark."

"But sir," Bell said, "they'll hear the units for sure that way, and why so shallow?"

"Enable active search on end-game run," Jeffrey said, "and use the data coming through the wire to enhance the TMA, but retain manual control of unit depth and course."

"Torpedo in the water!" the sonar chief shouted. "Incoming torpedo bearing zero one five!"

"Curious," ter Horst said. "That's dead abeam to starboard."

"Second incoming torpedo bearing one nine five!" "Dead abeam to port. What's their range, Number One?"

Van Gelder read his screens. "Just inside nine thousand meters, sir. Approach speed of both is . . . sixty-five knots!"

"Ahead flank maximum revs!" ter Horst roared. "Maintain present course or we'll just end up closer to one of them!"

"Aye aye," the helmsman said smartly.

"Sir," Van Gelder said, "both torpedoes have started active search." The sonar chief put it on the speakers. A high-pitched bell-like ting-ting sounded, two-tone, Van Gelder realized, because each fish used a different frequency to avoid false echoes from the other. Beneath the tings there was a steady whine, the torpedo propulsion systems, and a nasty hiss, Voortrekker's flank-speed flow noise.

"Number One," ter Horst ordered, "tubes one and two, snap shots on incoming torpedo bearings, minimum yield, shoot."

"Tube one fired," Van Gelder said. "Tube two fired." "Both weapons are operating properly," the sonar chief said.

The propulsion noise got louder, with four torpedoes in the water now, but above it all Van Gelder heard the sweet ting-ting again, like a bellhop paging someone in a hotel lobby. "Sonar," he said, "what's incoming torpedo depth?"

"Both steady at three thousand meters, sir."

"Fifteen hundred shallower than us," ter Horst said, "which gives us extra separation. Good. Wilson must be afraid they might malfunction lower down. Incoming torpedo range?"

"Both now seventy-seven hundred meters, Captain," Van Gelder said. "Our units are climbing to meet them, time to intercept two minutes." Both American torpedoes pinged again.

"We'll smack them easily," ter Horst said. "Number One, snap shot tubes three through eight, aimed at Challenger's last known bearing. Use maximum warhead yield. Detonate the weapons at staggered ranges, every ten thousand meters starting at twenty thousand meters, so their lethal circles will just overlap. Program in the detonation points in case we lose the wires, especially the ones that have to penetrate that vent field. Delay the detonations of the ones closest to us, to avoid warhead shock wave fratricide."

"Understood," Van Gelder said. "Sir, recommend we let the last fish go till end of run. It'

ll blow then automatically and might lock on a target sooner."

"Concur, a very good idea, and preset it to go active if it makes a passive contact but then loses it. What's time to interception of the incoming torpedoes?"

"Ninety seconds, Captain," Van Gelder said. He worked his console. "All weapons ready."

"Very well," ter Horst said. "Tubes three through eight, shoot."

"Tube three fired," Van Gelder said. "Tube four fired. Tube five. Tube six. Tube seven. Tube eight fired. Reloading all tubes now with nuclear torpedoes." Again the ting-ting sounded.

"There'll be a lot of shadow masking at our depth," ter Horst said, "and I wouldn't want to go any shallower now, but since Challenger's obviously found us, let's try for a proper firing solution on her. Sonar, using maximum power on the bow sphere, ping."

"Torpedoes in the water!" Sessions shouted. "Six, seven, eight torpedoes in the water!"

"This has to be a record," Morse said.

"Two are on divergent bearings," Sessions said. "Assess as countershots against our units. Six more on constant bearings, signal strength increasing—assess as snap shots aimed at Challenger. Sir, we're inside their effective range."

"Steady," Jeffrey said, "steady. Fire Control, pass control of the units to me and keep updating the TMA. I'll work one weapon with my joy stick and the other with my trackmarble."

"Sir," Bell said, "urgently recommend we move away. At this depth a one-KT warhead has a lethal radius of at least five thousand yards, and Voortrekker's close enough to get us through the vent field."

"Sir," Sessions shouted, "datum on acoustic intercept! Voortrekker just pinged, strong enough to get an echo off us!"

"So now they'll know exactly where we are," Jeffrey said, "but it's too soon to pull back. We might lose the weapon wires."

"No target returns yet off our ping," Van Gelder said. "In thirty seconds we should get some kind of echo off the vent field plumes."

"What's depth of the incoming torpedoes?" ter Horst said.

"Unchanged," Van Gelder said, "both still three thousand meters. Range declining to six thousand meters now. Intercept by our units in one minute."

Again both incoming weapons pinged, the silvery bell tones coming faster as they rangegated on Voortrekker's hull. Suddenly the pinging ceased and both torpedoes' propulsor whine got slightly sharper.

Van Gelder stared at his displays, the attack geometry. He did a hasty calculation on his console—since height-to-range was one to four, at this distance an aggregate delta-T of 40°C would—Oh my God. "Captain," Van Gelder shouted, "plane up! Recommend emergency blow while we still can!"

"What?"

"Sir, incoming torpedo depth! They've fooled us. We won't be able to intercept in time!

If we boost our units' yield, they'll just take us with them instead!"

"What the hell are you talking about?" ter Horst said. "Have you lost your mind?"

"Don't you see, Captain?" Van Gelder said. "The Americans, they're going for undersea nuclear Mach stems, like an airburst, only much worse! A hammer and anvil strike, two shock waves hitting us simultaneously from opposite sides, after they both redouble when each

merges through the heated water with its own bottom bounce!"

Ter Horst's face went white. "Plane up, do an EMBT blow!" Voortrekker's nose bucked and hydrazine began to roar. Then both U.S. torpedoes detonated.

"Units from tubes one and five have detonated!" Bell shouted. It would be precious seconds till Jeffrey knew what effect they'd had on Voortrekker, if any.

"Six torpedoes still incoming at high speed," Sessions said.

"And this deep they'll all camouflet," Jeffrey said. "The fireballs won't break the surface."

"Concur, sir," Sessions said.

"It's high time to get our backsides out of here," Jeffrey said. "Helm, ahead flank smartly. Hard left rudder, make a knuckle, make your course two nine zero, back toward Durban.

"

"Ahead flank smartly, aye," Meltzer said. "Hard left rudder, aye."

"That'll take us off the track of those torpedoes," Jeffrey said, "and help make sure we outrun their fuel supplies." He glanced at a depth gauge to double-check: still 12,000

feet. "Helm, fifteen degrees down bubble smartly. Chief of the Watch, don't compensate till we reach fifteen thousand. Let us dive with negative buoyancy to pick up extra speed."

"Fifteen degrees down bubble smartly, aye," Meltzer said. He pushed on his control wheel—the deck nosed downward quickly.

"Transient bearing one two zero!" Sessions shouted. "Sierra 1 is doing a main ballast blow!"

"They figured out my trick," Jeffrey said.

"Sir?" Bell said.

"Mach stems from opposite directions dead abeam," Jeffrey said.

"Clever lad," Morse said. "A nutcracker suite, and with the seawater preventing neutron warhead fratricide."

"Sonar," Jeffrey said, "shut down your equipment before the enemy torpedoes start to detonate. I don't want to take a chance our gear's overloaded when the blast fronts get here through the lensing."

"Understood," Sessions said. "Our own units' shock waves will reach us momentarily." The rumbling and shaking weren't as bad as Jeffrey expected, but those detonations had been tens of kilo-yards away.

"All six enemy torpedoes still incoming, sir," Sessions said.

"Will we be able to outrun?" Jeffrey said.

"If we stay at flank speed," Bell said, "and don't have a propulsion casualty, it's still touch and go, sir."

Jeffrey picked up the mike for the 7MC. "Maneuvering, this is the captain. Push the reactor to one hundred ten percent." Challenger began to vibrate like a subway car. Five atomic blasts went off at progressively shorter distances from Challenger, the last of them on the nearer side of the vent field.

"Sonar," Jeffrey said, "reactivate your hydrophones. We need the data to evade that final fish." "Acknowledged," Sessions said.

"Last incoming torpedo still narrowing the range," Bell said. "Twenty thousand yards now, sir."

"What's its overtaking speed?" Jeffrey said. "Twenty-five knots."

"What's its depth?"