Deep Sound Channel (01)

by Joe Buff

  "You'll be able to scan in azimuth by moving the whole ship," Morse said.

  Jeffrey nodded.

  "We've set our signal processors to isolate the fifty-hertz line and its harmonics,"

  Sessions said.

  "Good," Jeffrey said.

  "The Mark 88s in tubes one and five are nominal," Bell said. "Just give us a target, Captain."

  Jeffrey glanced at his weapons status screen. Tubes three and seven, the other working tubes, were empty. "Load tubes three and seven with ADCAPs," Jeffrey said.

  "They're useless this far down, sir," Bell said. "And they only have conventional warheads."

  "I know," Jeffrey said. "Just as a last resort."

  Van Gelder stared at the gravimeter screens. Two huge seamounts loomed to port and starboard some 10,000 yards ahead, back toward Durban. The hydrophone lines covered the extinct volcanoes' off-side flanks, out to past the 5,000-meter curve. If Challenger came down either side, she'd have to cross a group of hydrophones at point-blank range.

  Voortrekker was in perfect position for an intercept. If Challenger came down the middle, she'd be ideally backlit by the noise source in the distance: the scattered hydrothermal fields, each the size of several soccer stadiums, that straddled the narrowest part of the choke point.

  Van Gelder turned to look over the sonar chief's shoulder. They both watched the narrowband waterfalls for several minutes, scanning one bearing after another.

  "Still nothing, Captain," Van Gelder said.

  "Very well," ter Horst said. "They're out there. They're coming. I can feel it in my balls."

  "Still nothing, Captain," Sessions said.

  "We'll have to bring the boat up higher," Jeffrey said. "They must be further away than I expected, masked by ground shadowing."

  "Either that," Bell said, "or this telescope isn't working."

  "Helm," Jeffrey said, "on auto-hover, stationary rise, make your depth twelve thousand feet."

  "Sir," Bell said, "we'll be awfully exposed like that, three thousand feet off the bottom.

  The pumps will be very noisy getting us up there, and the hull will pop."

  "Those are chances we'll have to take," Jeffrey said.

  "Make my depth twelve thousand feet, aye," Meltzer said.

  "We also need to sneak our Mark 88s out there now," Jeffrey said, "so we can hit Voortrekker by surprise once we have a range and bearing. They'll be waiting somewhere between the hydrothermal field and those two 4,000-foot-high seamounts up ahead, staying within weapons range of the black smoker megaplumes."

  "Sir," Bell said, "I don't want to seem a naysayer, but our units have limited cruising endurance even on low speed. We'd be gambling we make a contact before their fuel runs out."

  "Understood," Jeffrey said. "But the ranges here are very large and sonar contact may be intermittent. If we use conventional tactics, a high-speed torpedo attack once we have a target, Voortrekker will hear and immediately get off a snap shot salvo. Once that happens, we can't count on hitting her with one 88 and stopping all incoming fire with the other."

  "Understood," Bell said. "The best we could hope for then would be a double kill, both ships sunk."

  "That's why we have to get our units out there now," Jeffrey said.

  "At slow speed they'll orbit a couple of hours," Morse said.

  "Understood," Bell said.

  "Very well, Fire Control," Jeffrey said, "and keep asking the tough questions. . . . Now, make tubes one and five ready in all respects, including opening outer doors. Preset the weapons for twenty knots running speed. We'll control through the wire and circle one off each

  flank of the hump. Run them in nap-of-seafloor mode, with tracks five hundred feet off the bottom for terrain-and sound-shadow masking. Disable active pinging, reenable only on my command."

  "Aye aye, sir," Bell said.

  "Once we launch, be real careful not to lose the wires," Jeffrey said. "Run them out with room to spare around these hot vents."

  "Understood," Bell said.

  "Very well," Jeffrey said, "here we go. Firing point procedures, tubes one and five.

  Manual control of the weapons."

  "Both units ready," Bell said.

  "Tube one shoot," Jeffrey said.

  "Set," Bell said. "Stand by. Fire. Tube one fired electrically. Unit is swimming out."

  "Unit is running normally," Sessions said.

  "Tube five shoot," Jeffrey said.

  "Set," Bell said. "Stand by. Fire. Tube five fired electrically. Unit is swimming out."

  "Unit is running normally," Sessions said.

  "Very well," Jeffrey said. "The clock is ticking, and the weapon fuel is burning."

  "Still nothing, Captain," Van Gelder said. "It's taking Challenger longer to get here than we thought." "Patience, Gunther, patience," ter Horst said.

  "Captain," Sessions said, "we're getting something now! Definite fifty-hertz tonals. I designate the contact Sierra 1. But we have a difficulty, sir. The indicated range is ninety thousand yards."

  "Forty-five nautical miles," Jeffrey said. "The other side of the seamounts, well beyond the maximum range of our Mark 88s."

  "Concur, sir," Sessions said. "This telescope works so well we're actually getting fifty-hertz bounces off both seamounts' inner flanks, letting us double-check the distance.

  Definitely ninety thousand yards."

  "Sir," Bell said, "our units are committed. We are unable to shut down or retrieve torpedoes—they're not like our LMRS probes."

  "I know," Jeffrey said. "I didn't think ter Horst would wait for us that far back. . . .

  Hmmm. The running ranges of our nuclear torpedoes are supposedly about the same as theirs, and at Voortrekker's current position both seamounts could block their shots. . . .

  less . . . I'm starting to think they must carry some kind of deployable weapon, deep-capable CAPTOR mines or some sort of expendable SOSUS gear."

  "You'll just have to make them come forward, then," Morse said.

  "Concur, sir," Bell said. "But how?"

  "We'll move forward briefly ourselves," Jeffrey said, and give them something to shoot at—us."

  Bell opened his mouth to object, but Jeffrey held up a hand. "Get ready to drop a wrench in the torpedo room, just to be sure."

  "Hydrophone line contact!" Voortrekker's sonar chief shouted. "Now passive contact on the bow sphere as well! Direct path, relative bearing zero zero two."

  "At last," ter Horst said.

  "Contact classification?" Van Gelder said.

  "Mechanical transient, sir. Some kind of machinery noise. Might have been a casualty in torpedo room equipment."

  "Indeed," ter Horst said. "So they've had some battle damage, or the crew's been worked past their endurance. Or both. What's contact range?"

  "Sir," Van Gelder said, "distortion from the hot vents is impairing our ability to triangulate using the deployed arrays."

  "Give me your best guess of depth and distance," ter Horst snapped.

  "Extreme range, sir," Van Gelder said, "about sixty-five kilometers. . . . For us to hear at all given ground masking effects, Challenger has to be above thirty-eight hundred meters. Conjecture that's her crush depth."

  "Or it's as far down as they want to push their luck today," ter Horst said. "Interesting. . .

  . Well, we'll just have to move in closer."

  "Sir," Van Gelder said, "that's risky and we'll lose the wires to the deployable hydrophones."

  "We must strike while we have the enemy localized, Number One. At nearly five thousand meters depth ourselves, if we simply wait here for much longer, the hydrophones might fail anyway."

  "Understood," Van Gelder said.

  "Don't worry, Gunther," ter Horst said. "As we get closer, we'll pick up Challenger on hole-in-ocean, long before they see us on their ambient sonar. Closing the range before we fire will cut the running time of our torpedoes, improve the odds of a kill even if the units get in a high-speed stern chase against the
target."

  "Concur, Captain," Van Gelder said.

  "Zero zero two relative is three two three true," ter Horst said. "Helm, steer three two three. Slow ahead, twelve knots."

  "Aye aye. . . . Turbine room answers slow ahead, making revs for twelve knots, sir."

  "Warm up the weapons, tubes one through eight," ter Horst said.

  "Warm up the weapons, tubes one through eight, aye aye," Van Gelder said.

  "Preset all weapons for maximum yield."

  "Maximum yield, aye aye."

  "Flood the tubes, equalize the pressure, and open the outer doors tubes one through eight."

  "Sierra 1 signal strength is increasing slightly," Sessions said.

  "That might just be from reduced particulate attenuation," Ilse said, "along our line of sight."

  "Or ter Horst might be coming closer," Jeffrey said. "We have to be sure. . . . We need to triangulate, try to get cross bearings from another hot vent eyepiece."

  "That one eight hundred yards north of us might work," Ilse said.

  Jeffrey studied the vent field map. "Concur. Helm,

  ahead one third, make turns for four knots." "Mechanical transients!" Sessions broke in. "

  Classification?" Jeffrey said.

  "Many torpedo tube doors being opened."

  "How many is many?" Jeffrey said.

  "Eight, I think," Sessions said.

  "All of them," Jeffrey said.

  1 HOUR LATER

  "Still no new contact on the target," Van Gelder said. "What's range to their last known position?" ter Horst said.

  "Now forty-five kilometers, Captain. Query going active for a precise range and bearing."

  "No," ter Horst said, "I think it's premature. They'd have a snap shot in the water before we even heard our ping come back."

  "Good," Morse said. "You've picked up Sierra 1 again. I'd suggest you shuttle back and forth, to keep updating the triangulated range and start a TMA. Now you've calibrated both eyepieces, the data reduction ought to go much faster."

  "I concur," Jeffrey said. "Helm, back one third, make turns for four knots. Return us to that other eyepiece vent location."

  "Back one third, make turns for four knots, aye," Meltzer said. "Maneuvering acknowledges back one third, making turns for four knots, sir."

  "Very well, Helm," Jeffrey said. "Now, people, listen up, we need to caucus. . . . We have a problem. Our lure to bring Voortrekker toward our weapons seems to have worked, but now that she's in motion, she'll be harder for us to track, and she's been alerted."

  "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 o
n 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."