Crush Depth cjf-3

by Joe Buff

  On the photonics displays, Challenger passed a group of what looked like huge ice steps or platforms or slabs, attached to and projecting down from the roof — that was what Jeffrey called the bottom of the ice shelf now, the roof Jeffrey eyed the steps and slabs. "What made those things?"

  "I'm guessing, but I suspect they're fragments left when big chunks of the shelf calved off. There'd be secondary projectiles, and some would be shoved back under the shelf by a backwash when the main bergs tumbled away… Older pieces would be frozen solid into the roof. Newer ones might still be loose."

  "Loose ones we could try to shove aside, if we had to?" "I think so."

  "What's that?" There was a giant boulder, scratched and with its edges rounded, sticking partway down from the roof.

  "Glacial origin, I think, carried out this far as the shelf advanced. It must have been stuck there for millennia." "Think there'll be more like that?"

  "Probably. The whole underside of the shelf may be studded with them."

  "Could they be shaken loose by torpedo blasts?" "Probably."

  "Terrific." One more thing to worry about.

  "They may fall on their own, from time to time, as their weight makes them slowly ease down through the ice. Some of the boulders on the sea floor here look glacial, not volcanic."

  Jeffrey studied the imagery. He saw what Ilse meant. "Sonar? Your assessment?"

  "These conditions are extremely unfavorable, sir," Kathy said. "We're getting multiple reflections off all the ice and boulder surfaces. Even our own minimal self-noise seems to be coming back at us from everywhere at once… And the water temperature is so steady and constant with depth, Captain, we won't be making direct-path sonar contact at any distance. The sound-speed profile makes all sound rays bend up, so the paths will curve and bounce off the bottom of the shelf repeatedly."

  Jeffrey nodded.

  "They'll reflect back toward the sea floor," Kathy continued, "and bounce even more.

  Each bounce distorts and weakens any coherent sound waves badly, both as to direction and signal intensity, sir. The pressure ridges and ice slabs and crevasses we're seeing, the boulders of different shapes and composition, this bottom mud from erosion silt combined with volcanic ash, they're almost impossible for us to model and adjust for.

  With respect, Captain, Voortrekker chose a good place to hide."

  "Very well, Sonar."

  "Enemy visual contact!" Bell hissed urgently.

  "Helm, all stop!" Jeffrey studied the imagery. His heart pounded, and he hoped it didn't show. He realized he'd been taken in by the alien beauty of this strange seascape, and almost forgot ter Horst could be lurking for him anywhere.

  "What is it? An Axis minisub?" Something long and big was hugging the underside of the ice, half concealed by the ridges and steps.

  "No incoming fire," Kathy reported. "No tonals or mechanical transients."

  "Oh, God," Ilse said.

  "Give me a proper report," Jeffrey snapped.

  "It's a dead whale, Captain."

  "Helm, get closer."

  The whale floated upside down, with its belly against the ice.

  "I can't believe it," Ilse said. "It's a right whale."

  Jeffrey couldn't tell if Ilse was delighted or horrified.

  "They're endangered," Ilse said. "They were almost hunted to extinction, but they'd started to come back. Most of them are in the North Atlantic. I had no idea they came anywhere near here!"

  "Why is it so far in under the shelf?"

  "Deafened, or brain damage, I think. Too close to a nuclear battle in the Atlantic somewhere. It must've wandered through the Drake Passage, disoriented. It ended up under the shelf, too far in to get back out again in time. It suffocated."

  "You mean like when a sick whale beaches and dies?" "I think so. It's awful."

  Challenger moved on. Close above them, everywhere for miles around, loomed the impenetrable thickness of the dark and massive ice shelf. Jeffrey almost felt its great bulk pressing on him personally. Close beneath, everywhere under the shelf, the sea floor seemed to press from the other direction. In most places the distance between was less than the length of a football field — a headroom shorter than Challenger was long. Ice bummock and protruding boulders made things even tighter.

  "Sir," Bell said to break the uncomfortable silence, "I feel the need to advise that our weapon effectiveness will in different ways be both degraded and enhanced by these conditions." Bell's reports, like Kathy's, became formal recitations using standard phraseology — which might seem regimented, but was needed for the good of the ship.

  "Talk to me, Fire Control."

  "The sonar seekers in our fish will be just as confused as our hull arrays, or more so. But with the roof and the floor in close proximity, the usual spherical attenuation model for warhead power in deep water won't apply. Any weapon blasts, either high explosive or nuclear, will have much more effective force, much greater lethal range, than we're used to."

  "Understood, Fire Control. We need to plan for that. Very well."

  "Sir, I also want to reemphasize that we are no longer expendable. A double-kill in this situation would be a serious disadvantage for the Allies. Unless we survive and get out and confirm Voortrekker's destruction, the boomers launch."

  "Captain, I concur," Kathy said. "A tactical atomic duel far in under the shelf will be impossible for friendly forces to follow and interpret, either from out at sea or from atop the shelf. Even if we sink Voortrekker and do survive the action, there'll be no way for the outside world to know it unless we escape to tell them so in time."

  "Sir," Ilse said, "I also have to concur. The blizzard will make the ice shelf shift and flex.

  Compacted ice is strong, but it flows, just like a glacier. Any boreholes cut through the shelf, old ones or new, will pinch off rapidly. And up on the surface, in winds of maybe seventy knots and a wind chill of eighty below, our troops will have a battle just to survive. Forget about them doing useful work establishing listening posts or relay stations to monitor us and give us any aid."

  "Understood, everybody," Jeffrey said. "So let me throw in- my two cents. We're just like that dead whale. If we get — in trouble, or lose propulsion power, we're stuck down here.

  We do an emergency blow, we simply bob against the bottom of the shelf and wait to die."

  Jeffrey knew there was no way they could go shallow to ease the outside pressure if there was flooding. There was no way to snorkel and get fresh air to vent the boat, if they had a fire or toxic-substance spill.

  "That ice is much too thick for our weapons even on highest yield to make much of a dent in it. And there's no way to launch a radio buoy, or trail a floating wire antenna, either… So we have to stop being pessimists, people, and all make sure we get things right the first time."

  Jeffrey's officers acknowledged. None of them seemed sheepish — they'd been doing their jobs.

  "Sir," Sessions said, "as navigator, given what the strict conditions are for mission success, I recommend we establish the concept of a bingo point."

  "You mean like with an aircraft," Jeffrey asked, "the time when half your fuel's gone so you better head home?"

  "Yes, sir. Given the physical obstacles we're encountering, and the unknown track we'll have to follow pursuing our target, there will come a point when we need to turn back or we'll be caught under the shelf ourselves, and die when Voortrekker dies, when the hydrogen bombs come raining down."

  "You put that all too aptly, Navigator… I didn't mean that as a put-down. It's a very good idea. Establish an estimate of time till bingo point."

  "Captain, I'd need a lot more data to come up with a meaningful figure, and the figure will change depending on what course we steer and what terrain conditions we encounter."

  Jeffrey reluctantly saw Sessions's point. "Well, what's your initial best guess, for starters?"

  "Right now? Let's use half the hours remaining until the boomers launch."

  "Co
ncur. Pass the time-to-bingo-point to the vertical display. We'll put it under the time-to-boomer-launch number, in green below the red. When the green runs out, we know we better turn back."

  Sessions acknowledged.

  "If Antarctica has to perish," Jeffrey said, "at least we can make good our own escape.

  And that's not a selfish statement, people. If those boomers launch, the world is gonna be in a really big mess, and our navy will need us bad."

  Everyone nodded somberly.

  Jeffrey began to plan ahead, and felt somber indeed.

  This place may be a wonderland of strange, chaotic ice and rock formations, but to a submariner it's a navigational and tactical nightmare. It's like ter Horst and I are two half-blind, half-deaf enemies, fighting with blunt knives and twelve-gauge shotguns in a maze in a house of mirrors. Besides that, the house is on fire and we're not even sure where the exits are.

  "Pressure ridge dead ahead," Meltzer reported. "Volcanic ridge below it on the bottom.

  Clearance is inadequate, Captain."

  "Very well, Helm. Turn left as needed and find a way through."

  On Challenger, one hour later

  Jeffrey's first major decision had been for Challenger to go under the Ross Ice Shelf a bit to the east of Ilse's former listening post. This was partly for better stealth and concealment, since to go precisely under her abandoned ice bunker would be too obvious. Also, given IIse's datum as Voortrekker neared the shelf, this maneuver put Voortrekker almost certainly east of Challenger — and that told Jeffrey which way to search for ter Horst.

  Again Jeffrey felt the incredible weight of the ice shelf pressing down, and the different drastic pressure of the running of the clock. He straightened his posture, as if to fight back — and also because he knew every person in the control room would take their mental and physical cues from his body language.

  Jeffrey drew a deep breath. At times of such supreme tension, like most people, his senses were always heightened. The normal odors around him seemed strangely enhanced. The traces of ozone from electronic equipment made Jeffrey's nose tingle.

  The nontoxic cleansers, and lubricants and paint, always left a smell in the air in a submarine, but now that smell was particularly pungent and metallic. It seemed to leave an aftertaste as it went down Jeffrey's throat when he breathed. The ripeness of unwashed clothes and unbathed people all around him seemed even more ripe than only minutes before.

  Jeffrey's vision was heightened, too. Objects he looked directly at appeared harder and sharper than normal. Colors — like a red fire ax, or a yellow battle lantern — were so vivid they almost throbbed. Sometimes there was a barely perceptible halo effect around things in Jeffrey's peripheral vision.

  "Fire Control," Jeffrey said to Bell. "From here our lives are very simple. We have to solve two tactical problems."

  "How do we find ter Horst, and then how do we kill him and get away?'

  "Well and succinctly put. Oceanographer, Sonar, Navigator, we need a pregame huddle.

  Fire Control, take the conn."

  Bell acknowledged. Ilse and Kathy joined Jeffrey and Sessions around the navigation plot. The main display on the digital table showed the Ross Sea and the shelf.

  "Throw things in the stew pot, people," Jeffrey said. "Let's stir them around and see what we get."

  Kathy Milgrom spoke first. "We know passive sonar doesn't work well here, and pinging could give our position away disastrously."

  "That leaves nonacoustic means," Jeffrey said. He'd been thinking about exactly this already, but he wanted his officers to participate and make contributions. He knew they' d do a better job of implementing a plan if they had a share in forming it.

  Sessions brightened. "Temperature gradients, Captain, from the heat in Voortrekker's steam-condenser cooling-loop seawater discharges."

  "Good," Jeffrey said. "That ought to work well here, since the natural water temperature is so constant and cold."

  "I concur," Ilse said. "And chemical sniffers. We already know the water under the shelf is very clean and pure. No manmade pollution, or nearby passing ships, or wrecks, to confuse the issue."

  Kathy nodded. "There's always some leakage of lubricants and hydraulic fluids in any submarine's wake, no matter how thorough the seals. Propulsion shafts and torpedo-tube doors, rudder and stemplane and bowplane fittings, and antennas and periscope masts.

  From the seams around moving parts, fluids seep and mix with the seawater?'

  "So Voortrekker ought to be leaving a trail." Jeffrey made this a firm statement, not a question.

  Ilse thought for a moment. "The trail should be fairly stable. No wave mixing down here, and gentle currents if any."

  Bell, who couldn't help listening since the others were standing only a few feet aft of the command console, added something. "We pounded Voortrekker good in our last encounter, Captain, near the Bounty Platform. They'll probably have even more chemical leakage than usual."

  Jeffrey nodded curtly. Then he noticed he was holding himself more aloof from the crew.

  With Wilson gone, Jeffrey was for the first time the ultimate command authority present on the ship. He found himself already becoming more demanding and less collegial. He understood Wilson's behavior better, and began to see him as a role model, not an antagonist. Jeffrey was pleased with this, and felt good.

  Now, speaking of antagonists, just where do we pick up ter Horst's nonacoustic trail?

  "Nav," Jeffrey ordered, "show me the bottom terrain under this part of the shelf."

  Session turned to his assistant. The senior chief typed on his keyboard. A different digital chart came up, and as Jeffrey watched the display zoomed in.

  Jeffrey studied the chart. He eyed the contour lines. "So the Antarctic continental shelf is more like a doughnut than a plateau."

  "That's right," Ilse said. "The shelf doesn't just rise gradually to the shoreline, like on other continents. There's so much ice all over Antarctica, eons of snow building up and compacting, it forms a layer in many places ten thousand feet thick. All that added mass pushes the whole tectonic plate down. It presses furthest in the middle, over dry land and the pole." Ilse ran her fingers along the nautical chart. "You get this shallow ring along the edge of the continental shelf, but then the water gets deeper again toward shore, before the bottom rises at the actual coast."

  Jeffrey pointed at a place on the chart. "Here." A shallow spot, the high part of that outer tectonic ring, where the clearance between the sea floor and the ice-shelf roof was tightest. "We go here, we narrow our search for Voortrekker's trail from three dimensions to two. Navigator, plot a course to this way point."

  "Aye aye, sir," Sessions said. He and his senior chief went to work.

  Jeffrey strode decisively back to the command console. "I have the conn."

  "Aye aye, sir," Bell acknowledged. "You have the conn." "This is the captain. I have the conn."

  The watch-standers all crisply said, "Aye aye."

  "Fire Control, when we reach my chosen way point, we turn east. When our temperature and chemical sensor readings spike, we know we're hot on Voortrekker's tail."

  "Understood," Bell said. "But our opponent can mimic our thinking, Captain, and Voortrekker has temperature and chemo sensors too."

  FORTY-FOUR

  On Voortrekker, one hour later

  Van Gelder watched his displays, fascinated by the weird conditions under the Ross Ice Shelf.

  "Gunther:' ter Horst said, "now that we see what it's like down here, I want your recommendation on what to put in our working torpedo tubes. I intend the melee to be fast and savage once contact is made, and we can't count on having time to reload."

  Van Gelder was sure that Fuller and his executive officer were holding just such a discussion. Van Gelder thought very carefully: The choice of first-use weapons could make all the difference. "One tube for an off-board probe, sir, for better scouting into areas with narrow clearance."

  "Agreed. Reconnaissanc
e must be the prelude to attack."

  "One nuclear torpedo, and one high-explosive torpedo, to keep our options open, Captain. The engagement range could be very short once we find Challenger; possibly too short for a nuclear warhead."

  "I concur:' ter Horst said. "That leaves us one more tube in our crucial first salvo. What do we put in it? Not a decoy, we can't kill Challenger with decoys. So, a second nuclear Sea Lion, or a second Series Sixty-five?" Voortrekker's high-explosive torpedoes were Russian exports, Series 65s, wide-body weapons with three times the warhead thaw of the American Mark 48 Improved ADCAPs.

  "I think it's a question of balancing offense and defense, sir. We can use our antitorpedo rockets against an inbound conventional weapon." The antitorpedo rockets were mounted in nonreloadable recesses on the outside of the ship. They homed on an inbound weapon and fired a blast of depleted-uranium buckshot, to destroy a high-explosive warhead, but their rocket motors burned out at only one kilometer — far short of the lethal range of an Allied atomic torpedo. "Sir, I recommend the last tube have another Sea Lion. That increases our offensive power. Or instead, it lets us use one Sea Lion against Challenger and one for self-defense, in case Fuller shoots at us with nuclear Mark 88s instead of high-explosive ADCAPs."

  "Hmmm. I disagree. I want two Series Sixty-fives, not two Sea Lions. It gives us more flexibility."

  Van Gelder wondered what decisions they'd make on Challenger.

  "Load the tubes," ter Horst ordered.

  Van Gelder passed commands. He and ter Horst armed the one Sea Lion's nuclear warhead.

  "Sir," the sonar chief called out, "contact on acoustic intercept!"

  Van Gelder turned. "What is it?" -

  Ter Horst glanced up eagerly from his console. "Challenger? Her under-ice sonar?"

  "Er, no, Captain," the chief said. "It's an acoustic message burst. The format shows it's friendly."

  "What's the message source?" Van Gelder asked, surprised.

  "Range and bearing indicate it's a microphone, sir, lowered through a bore in the ice shelf a number of miles away."

  "Pass the data to the communications room," Van Gelder ordered.