Deep Sound Channel cjf-1

by Joe Buff

  "Aye aye," the watch standers said.

  "Ilse, Commodore," Jeffrey said, "join me at the navigation plotting table, please." Jeffrey hobbled over. Ilse rose and followed him.

  She and Morse and Jeffrey conferred with the assistant navigator. The local nautical chart was already up on the main horizontal flat screen. The assistant navigator brought a copy onto the smaller working screen.

  "Overlay the locations of the nuclear blasts," Jeffrey said, bending over the table, using it to help support his weight. The assistant navigator worked the keyboard and three red Xs popped onto the working screen.

  "Okay Chief," Jeffrey said, "now add the torpedo tracks." Three lines appeared, leading back from the Xs toward an area nearer the shore.

  "Hmm," Jeffrey said. "If I were ter Horst, I'd search the arc along the Xs, on the inner edge of the sonar whiteout zone. Use my HF gear to look for Challenger's debris."

  "Makes sense," Morse said.

  "Whichever end he starts at," Jeffrey said, "north or south, he'll have to go slow. Sonar conditions are still pretty awful. There'll be high attenuation loss from bubbles and stirred-up particles. Right, Ilse?"

  "Absolutely."

  "And high-frequency sound sheds its energy the fastest," Jeffrey said, "so his search will cover fairly narrow swaths."

  Morse smiled. "Are you thinking what I'm thinking … Captain?"

  Ilse looked up. "You're going to shoot at him."

  "Does that bother you?" Jeffrey said. "If you're emotionally involved, I need to know it now."

  Damn you, Jeffrey Fuller, Ilse thought. After everything we've been through together on this mission. "My whole family's dead or disappeared because of him."

  "Sorry," Jeffrey said. He sounded like he meant it. "Here's my plan," he said. "We have four Mark 88s left. It's time to use one. We'll program it to run along the arc through all the Xs, starting near our end, the south. We preset it to move just over the bottom, using slow speed, twenty knots, until it locks on Voortrekker."

  Morse nodded. "That'll give it plenty of cruising range to turn back and try again if needed."

  "Affirmative," Jeffrey said. "We'll make the unit ping on active at low intensity so it won't be blind, and at the same time Voortrekker won't hear it coming till too late."

  "They may think its pings are their own garbled side-scan echoes," Morse said, "or stray signals from a friendly. Doppler will be chaotic out there now."

  "All the better," Jeffrey said. "We'll preset the frequency to forty-five kilohertz, since some of their frigates use that for mine avoidance. We'll have the weapon do a wigwag search, to help disguise its base approach course. We'll preset the warhead for maximum yield."

  "Decimal one KT?" Morse said.

  "Best we can do," Jeffrey said. "Ilse, you know these waters. Am I missing something?"

  "No," she said. "We have to strike back quickly. But why not use two fish? Send one to search down from the north end of the arc."

  "We're awful low on ammo," Jeffrey said quietly, "and awfully far from home. The Mark 88s are the only weapons we can operate at depth. ADCAPs and ISLMMs will fail much past three thousand feet, and that's on a good day. And to launch our Tomahawks we'd have to be much shallower than that."

  "Okay," Ilse said. "I was just curious." She noticed Jeffrey's eyes were strangely hooded for a moment. Is he concerned I challenged his authority, or is this some personal quirk?

  I noticed it when we first met, he's the sensitive type outside of purely military circles.

  Could it be he has trouble making shop talk with a woman … or that he likes it? Still single at his age, and so damned good-looking too, I wonder what's the deal.

  "Fire Control," Jeffrey said, "I aver that ROEs apply for hot pursuit in enemy territory, authorizing use of tactical nuclear weapons undersea."

  "I concur," Bell said.

  "Assistant Navigator, make a record," Jeffrey said. "Fire Control, get a nuclear Mark 88 loaded and enabled in tube seven."

  "Aye aye," Bell said. "Tube seven, load an 88."

  "Also prep the other three Mark 88s," Jeffrey said. "Use tubes one, three, and five. I've a feeling we may need them in a hurry."

  "Make tube seven ready in all respects," Jeffrey said, "including opening outer door. Firing point procedures on tube seven, programmed area search."

  "Solution ready," Bell said. "Ship ready. Weapon ready."

  "Match generated bearings and shoot," Jeffrey said.

  "Tube seven fired electrically," Bell said. "Unit swimming out."

  "Unit is running normally," Sessions said.

  "Time to make some tracks," Jeffrey said, "and here comes the really dangerous part. Chief of the Watch, disengage shallow water valves and pumping hardware, line up abyssal suite."

  "Line up abyssal pump and valve suite, aye," COB said.

  "Helm, all stop," Jeffrey ordered. Meltzer acknowledged.

  "Phone Talker," Jeffrey said, "relay to all hands. Now transiting the deep sound channel under combat conditions. Rig for superquiet." Jeffrey knew the deep sound channel was formed by sound wave bending, in the region where seawater stopped getting colder with depth and then hovered just above freezing. The deep sound channel acted like an acoustic superconductor, and the slightest noise would propagate for countless miles.

  Morse raised an eyebrow at Jeffrey. "Superquiet?"

  "Aye, sir," Jeffrey said, abashed. "I'm making a lot of this up as we go along … Chief of the Watch, give us five tons negative buoyancy and let us drift on down."

  "Five tons of negative buoyancy, aye," COB said.

  "The thing that makes me really nervous," Jeffrey whispered, "is that the upslope toward the continental margin will tend to focus sound energy right at their SOSUS nets."

  "Too true," Morse whispered back. "With all the pinging going on up there, someone may get an echo despite your active masking."

  Jeffrey glanced apprehensively at a depth gauge — passing through 6,000 feet. "With the beating Challenger's taken, the hull might start popping shallower than normal."

  "They'll sound like shotgun blasts on enemy passive sonar," Morse said quietly. "Let's hope nobody's trailing a hydrophone down here."

  "Keep your fingers crossed," Jeffrey mouthed.

  * * *

  "Still no sign of anything," Van Gelder said.

  "We've got lots more ground to cover," ter Horst said.

  "Sir, I've been thinking."

  "That can be dangerous in today's world, Gunther."

  Van Gelder hesitated. "Understood, Captain. But hear me out, sir, with respect. I'm looking at what that Q-ship did to us in the Antarctic. If you adjust for warhead yield and range, I'm not sure how badly we hurt Challenger."

  "Go on."

  "She may have used the same tactic we did when those British planes came after us, staying well inside the limiting circle of possible egress distance covered."

  "You mean you think we missed?"

  "Sir!" the sonar chief called out. "New passive sonar contact on starboard wide-aperture array. Sounds like a mine-avoidance sonar but it's at our depth … Incoming torpedo bearing one zero zero! Range three thousand meters, approach speed twenty knots!"

  "Verdammt," ter Horst snapped. "Helm, ahead flank maximum revs!"

  "Ahead flank maximum revs, aye aye," the helmsman said. "Turbine room answers steam throttles are wide open, sir."

  "Range-gating active lock," the sonar chief said, "too close to cancel it, torpedo accelerating to end-game speed!"

  "What type is it, Number One?" ter Horst said.

  "Closed-cycle liquid-metal fuel," Van Gelder said, "geared turbine and pump-jet propulsor. An American Mark 88, Captain."

  "Torpedo gaining on us!" the chief shouted.

  "Firing jammers and noisemakers now," Van Gelder said.

  "No time to launch a decoy," ter Horst said, "and the things don't always work. Prepare to fire tube seven, deep-capable nuclear torpedo. Tube seven snap shot on course one zero zero,
minimum yield, our depth."

  Van Gelder reached for his special weapons key at the same time ter Horst pulled his own out. "Weapon enabled!" Van Gelder shouted.

  "Open the door and shoot!"

  "Tube seven fired!" Van Gelder said. "I have control of the weapon."

  "Helm," ter Horst said, "port thirty rudder smartly, make a knuckle, minimize our profile."

  "Port thirty rudder smartly, aye aye, no course specified, sir."

  "Get that incoming torpedo, Number One," ter Horst said between clenched teeth. " Intercept and smash it."

  Van Gelder read his screens, then checked the trigonometry. "Detonation in three seconds."

  He flipped up the plastic cover and pressed ARM. The light went green. He held his breath and then pressed FIRE. The status screen said DETONATED.

  * * *

  Jeffrey, Ilse, Morse, and the assistant navigator were still gathered round the digital nav display. Challenger was right over the bottom at 7,800 feet, and Jeffrey considered it okay to talk in normal tones again. Apparently they'd made the trip down through the deep sound channel safely, given the lack of enemy fire. The hardest part right now was restoring neutral buoyancy, since COB had to pump those five tons from the negative tank against the outside pressure, plus an extra gallon of water for each ten feet of depth they'd added simply to adjust for hull compression — and he had to do it quietly. There was a sudden roar in the distance, building into an ear-splitting crescendo that died off slowly, seeming to spasm as surface and bottom reflections hit.

  "What was that, XO?" Jeffrey said.

  "Captain," Bell said, "unit from tube seven has detonated."

  "Weapon effect?" Jeffrey said.

  "Impossible to tell."

  * * *

  A half second after the signal came back through the fiber-optic wire, a gigantic kaboom kicked Voortrekker in the stern, jarring Van Gelder forcefully against his seat back, rolling the boat to port, and surrounding him in sound that was more felt than heard, a physical sensation of ungodly Armageddon that made him want to curl up in a ball. Instead Van Gelder gripped his console with both hands, watching the damage control enunciators, dreading what he'd see. The blast was simply too powerful — the enemy warhead must have gone off an instant before the weapon did, subjecting the boat to both A-bombs at once.

  * * *

  "Very well, Fire Control," Jeffrey said. "Assistant Navigator, give me the 30-by-30degree square centered at 40 south, 25 east."

  The senior chief brought the large-scale chart onto the screen.

  "At this point," Jeffrey said, "I think discretion is the better part of valor. If we try a battle damage assessment on Voortrekker and they're still alive, they'll pull the same trick we just used."

  "I concur, sir," Bell said. "Conditions are poor now for a reattack. We're low on ammo and there's too much ground for us to cover. The priority should be our egress." Jeffrey nodded. "Now we've disengaged from enemy forces, it's time to make our getaway."

  "I agree," Morse said. "Remember our objectives. At this stage survival equals mission success, a strategic win for us."

  "We have this whole area to get through, people," Jeffrey said, gesturing at the map, "this whole area for hide-and-seek inside Axis territory"

  "Where do you want to aim for?" Morse said.

  "Hmm," Jeffrey said, studying the chart. "Our best bet is to insert somewhere in the Mid-Ocean Ridge. I'm guessing that's what Captain Wilson and Monaghan planned. Hundreds of miles of rifts and faults on both sides of the endless central spreading valley. No one would ever find us till we wanted to be found."

  "That's what I'd do too," Morse said.

  "So just how do we get there?" Jeffrey said.

  "Hmmmm … We need to bypass areas that are too deep for us. We'd stand out much too well against the bottom. Assistant Navigator, shade in red everything below our crush depth."

  "Which estimate of our crush depth do you want to use, sir?"

  "NAVSEA's latest work's the most refined I know about," Jeffrey said. "Based on their tests and calculations, let's go with fifteen thousand feet."

  The assistant navigator hit some keys. Large areas of the map turned red.

  "Okay," Jeffrey said. "We also need to stay down low, not just for stealthy nap-ofseafloor routing away from the shallows but also to avoid the deep sound channel. It's our glass ceiling, folks — we break it we get cut. Assistant Navigator, shade everything less than seven thousand feet in blue."

  The assistant navigator hit more keys.

  "What we see is what we get," Jeffrey said. "We need to avoid the continental shelf off Cape Town and Port Elizabeth, and the huge Agulhas Basin south of that is way too deep, well over twenty thousand feet."

  "Northeast of us," Ilse said, "we'd hit the Mozambique Plateau and then the Almirante Leite Bank, also too constricted and too shallow"

  Jeffrey stared at the map. "That leaves southeast, this neck of less-deep ground between the south edge of the Mozambique Basin and the northeast edge of the Agulhas Basin, a kind of hump where the bottom's at our crush depth. That route would take us straight to the Prince Edward Fracture, the closest point of insertion to the ideal topography along the spreading ridges. The final approach has lots of seamounts too, good hiding places that cut off long-range sonars."

  "The seamount flanks are moonscapes," Ilse said. "There's no erosion underwater."

  Jeffrey nodded. "The deep bowls of the basins on either side of this hump-neck make me really nervous, though. They're too wide open and we'd be too far off the bottom. Enemy ships could easily drop temporary ambient-look-up SOSUS grids, then make short work of us with twenty-KT depth bombs."

  "And what about the Axis air groups based on the Prince Edward Islands?" Morse said. " They'll be right in our face as we get to the fracture."

  "If we stay deep and run quiet," Jeffrey said, "we give them a huge area to search under adverse terrain and acoustic conditions, except for right at the choke point at the hump between the basins. It's also the route they may think we'd be least likely to follow for exactly that reason, Commodore, their heavy air support."

  "Go where we hope they don't expect us?" Morse said. "That's basic doctrine, sir," Jeffrey said.

  "I'm not disagreeing," Morse said.

  "Ilse," Jeffrey said, "what kind of bottom would we find along this hump?"

  "Well," Ilse said, "it's part of a divergent boundary between lithospheric plates. The hump itself is caused by molten rock upwellings deep within the mantle, called diapirs, that lead to magma chambers."

  "What's that mean in English?" Jeffrey said. He smiled.

  "Sorry," Ilse said. "It means the bottom is bare rock and uneven. There are some shield volcanoes, the low-lying multiterraced kind."

  "We're trained to usually avoid such areas," Jeffrey said. "How live are these volcanoes?"

  "Sometimes very," Ilse said. "The hump-neck at the Prince Edward choke point does have active hydrothermal vents."

  "Okay," Jeffrey said. "One more reason they won't think to look for us right there."

  "There's another item we need to cover," Morse interjected. "What will Voortrekker do if they're still alive?"

  "Aye," Jeffrey said, "that's the puzzlement."

  "No it's not," Ilse said. "They'll try again to sink us."

  "Concur with that," Jeffrey said. "Hmmmm … Well … I think if I were them I'd think this through the same way we just did, and aim for the same place. The choke point's like a gateway to the Fracture Zone. It's only forty nautical miles from side to side, eighty thousand yards, very easy for one SSN to set up a barrier patrol."

  "Sure you don't want to use a different route, then," Morse asked, "on further consideration?"

  "No," Jeffrey said. "I'd rather take on ter Horst there, on sort-of-equal terms, deep down and one-on-one, even if his boat is faster and quieter than us, as it appears to be. We lose contact with Voortrekker at this point, God knows how many ships and lives will be destroyed. My ever
y instinct, banged up as we are, is to get this damn thing over with now."

  "Good," Morse said. "That was a trick question. I was testing you."

  "Jan will feel exactly the same way," Ilse said. "Get this damned thing over with … If he's still alive."

  "Very well," Jeffrey said. "Helm and Chief of the Watch, make your base course one six five, commence nap-of-seafloor cruising mode. Ahead two thirds, make turns for twenty-six knots." Meltzer and COB acknowledged.

  "We'll try to stay above twelve thousand feet when possible," Jeffrey said. "Less strain on the hull and sea pipes."

  "Understood," COB and Meltzer said.

  "Fire Control and Sonar," Jeffrey said, "we'll stop occasionally to keep our ears peeled, especially in our baffles."

  "Understood," Bell and Sessions said.

  "Good plan," Morse said. "Ter Horst could be waiting out there anywhere … The pressing question is, how do we find him before he finds us?"

  "I don't know," Jeffrey said, "and we don't have very long to think about it. The quiet transit to the choke point should take just about a day."

  * * *

  Van Gelder watched his screens in disbelief. Was this true death, entering a fantasy where life went on impossibly? Was this the hell he'd earned?

  Someone farted, probably from fear. Van Gelder had to bite his cheek to keep from giggling madly. That detail wasn't fake — he was alive.

  Van Gelder read his data. The incoming torpedo had gone off barely outside lethal range. Maybe it mistook Voortrekker's weapon, rushing to make the intercept, for Voortrekker herself.

  Some boxes on Van Gelder's damage control panel showed yellow and others red, but nothing that couldn't be dealt with, nothing that would slow the vessel or hurt her battleworthiness. Yet this punishment must have taken years off the hull's service life — dry-dock tests would show.

  "Son of a blery kaffir," ter Horst said, his cursing another reminder that Van Gelder was alive. "They actually got a shot off at us!"

  "Yes, sir," Van Gelder said.

  "What does it take to kill these bloody people?"

  * * *

  Jeffrey got up from the command workstation and stretched. He craved sleep very badly, but that was out of the question for now. He glanced around the control room for the umpteenth time in the last half hour. Imagery flickered on all the consoles, watched intently by Challenger's crew. His crew, he reminded himself, at least till they were out of immediate danger, or captured or dead.