Authors: Joe Buff
Out of curiosity, and to audit the proper preparedness of
Challenger
’s brand-new command team, Jeffrey called up a copy of the main weapons status page. He saw that Bell had four tubes loaded with high-explosive Mark 48 Improved ADCAP torpedoes, the standard heavyweight fish of the U.S. submarine fleet. The other four tubes held Mark II brilliant decoys, which could be programmed to imitate
Challenger,
or another sub, by giving off an acoustic signature meant to be noticed by the enemy.
He typed a message to Bell: “Why no off-board probes to scout ahead?” Remote-controlled probes could be deployed through the torpedo tubes, too. Similar in size and shape to an ADCAP, they were fitted with a mix of active and passive sonars, passive photonic imagers, and active laser line-scan cameras.
Bell answered right away, typing, “Path here known clear of shipwrecks.” A pause. “You’re welcome to stand by my console.”
Jeffrey got up and eased forward through the compartment’s cramped left aisle. He stopped next to Bell’s console, with his back touching the sonar supervisor’s chair. Bell turned from his horizontal screens and looked up at Jeffrey. He responded to the query more, his voice lowered to be barely audible. Bell spoke softly mainly to not break his crew’s concentration on their console displays, since a threat could appear out of nowhere at any time. But some of it was purely mental: at ultraquiet people walked and talked and even thought on pins and needles.
“Because probes might be detected, Commodore, and Russian subs wouldn’t use them in their own safe corridor. It would show right away we’re not friendlies. Besides, in these conditions our own probe sensors in passive-only won’t give us much we can’t get better on
Challenger
herself.”
Sessions joined in from the seat next to Bell, his soft features softened further in the dim red lighting. “The Captain and I discussed it, Commodore.” While Jeffrey had been in the wardroom, apparently. “Since we can’t afford to radiate, we can’t use the acoustic link to control any probes. If we use a fiber-optic tether instead, and it breaks, we can’t recover the probe and then we’ve left a clue we were here. . . . Plus, to send a probe on ahead of us slowly and quietly, by far enough to make a difference in tactically useful data, would take too long when we want to minimize our dwell time by the strait.”
“What about antisubmarine mines, if this path you picked isn’t in their safe corridor of the day? The whole channel’s fifteen miles wide. What if we’re too far right or left of where Russian subs know they should go?”
“No notices to mariners, sir,” Sessions reminded Jeffrey politely. “No minefield.”
The reminder was unnecessary—Jeffrey had been quizzing him. By international law, all naval minefields had to be publicly announced, with all mines moored or otherwise held stationary. Modern mines could be programmed to ignore surface shipping, and to go off only when a submerged submarine went by. They could also be armed and later switched off via remote control, altering safe pathways through a solid field of mines.
Jeffrey nodded sourly. “If there’s one good thing we can say about Moscow, they’re sticklers for the outward letter of international law. . . . Axis subs using the strait?”
“Intel says our forces have them too well bottled up on the other side of the world, sir.”
These were good answers. “Okay.” Jeffrey eyed the tactical plot vertical display on the forward bulkhead. Something genuinely puzzled him. “Why do you think the U.S. doesn’t have any surface ships or aircraft patrolling the American channel?”
He felt the sonar supervisor sliding sideways in his seat. Jeffrey glanced at O’Hanlon, a self-assured expert who liked to go clean-shaven, and almost bald with a razor cut, accentuating the way his small ears stuck far out from the side of his head. Senior Chief O’Hanlon, in his mid-thirties, was a battle-hardened sailor, and Jeffrey could see the very top of a chest tattoo above the collar of his undershirt, worn beneath his jumpsuit. He had a pair of sonar headphones draped around his neck, so he could don them in a jiffy if he wanted to. A small lip mike was positioned to one side of his very square jaw.
Jeffrey stepped back to not block his view of the captain and XO. “If I may?” O’Hanlon asked. Bell nodded.
“Sir,” the chief told Jeffrey, “we conjecture it’s to minimize signal-to-noise ratio for U.S. bottom sensors and our own subs sneaking through or doing barrier patrols.”
“Makes sense,” Jeffrey said. By flying around and charging all over, engine and machinery sounds from aircraft and ships created underwater interference. This would make it harder for bottom hydrophones, or the sonar arrays of a lurking American submarine, to pick out a hostile sub’s giveaway broadband and tonals from amid the extra background clutter.
But . . .
“That would be true for Russian bottom sensors, too.”
“Of course, sir,” O’Hanlon said.
“Then why are they making things harder for themselves?”
“We conjecture that with the water so shallow, and no pronounced sonar layer, they use a completely different approach from us, relying mainly on surveillance from above instead.”
“Which is why you’re keeping the ship as deep as you can,” Jeffrey stated to Bell, who nodded.
“There’s another factor in these waters, Commodore,” Sessions murmured. “The entire strait’s bottom is just within reach of divers using compressed air rigs. If they work out of a seabed habitat, they can spend long hours inspecting the bottom, day in, day out, and map or even disable a bottom sensor grid.”
“You mean, SEALs deploying out of a SeaLab type of contraption, saturation divers, sneaking to the Russky side and jiggering with their security measures?”
“Something like that, sir,” Sessions said.
“Suppose so. Then what prevents Russian divers from doing the same thing to us?”
“Presumably the SEALs would be standing guard against that, or they could have sensors specifically meant to watch for human intruders crossing the treaty line.”
“So saturation diver SEALs defend our channel’s hydrophones, and can sabotage any Russian ones? The Russians don’t even try to compete for the low ground, they just use surface and airborne surveillance platforms instead? That didn’t even occur to me.”
Bell summoned up a different type of display. The spikes and jiggles showed a graph of sound intensity versus frequency, which Bell had set to focus in on the relative bearings near one-eight-zero—rearward.
Challenger
hadn’t deployed a towed array, because it could drag or snag on the bottom, creating giveaway noise. He was using the sonar sphere at the bow, with its all-around coverage, to check on his own ship’s signature.
Bell turned to Sessions and pointed to spikes on the display. “We need to quell our self-noise more.”
“Concur, sir.”
“Chief of the Watch,” Bell ordered in a stage whisper. “Stop portside auxiliary turbogenerator. On the sound-powered phones, rig ship for reduced electrical.”
This would turn off more unnecessary equipment, large and small, making
Challenger
as silent as a church mouse.
Jeffrey shimmied back to his console and sat. He cringed as his backside rubbed against the vinyl, squeaking. His brain told him this couldn’t possibly get through
Challenger
’s state-of-the-art quieting technology, to be heard outside the ship. The sudden tightness in his gut showed that the rest of his body didn’t believe his brain.
Bell ordered one more course change. Patel acknowledged, and Jeffrey’s displays shifted their pictures leftward. The maw of the strait was dead ahead. Bell had Patel reduce speed to three knots, about 3.5 miles per hour—a brisk pace for a person on a sidewalk. The current coming from behind, of about a half-knot, gave them a small extra push with no noise penalty.
“Helm, rig for nap-of-sea-floor cruising mode.”
Jeffrey’s repeat of the helm displays now showed a different type of information, with steering cues and warnings of gradual dips and rises in the bottom in front of the ship, as revealed by the gravimeter’s sharp resolution at very short range.
“Helm, maintain clearance beneath the keel of one-five feet. Engage autopilot but be prepared to override.” Jeffrey knew Bell well enough to hear a subtle quiver in his voice; what he’d ordered was no easy task, with a ship as long as a football field including both end zones.
Even with computer assistance from the ship control station’s autopilot, depth management by Patel and buoyancy and trim control by COB were critical now. The slightest mistake and the bow or stern would hit the sea floor. But
Challenger
needed every foot of distance from the surface that she could get: LASH worked best at the peak of daylight, and outside the ship it was noon. Every soul aboard was aware, based on horrible experience, of how deadly an antisubmarine weapon LASH was.
Tension in the control room thickened palpably, becoming almost suffocating. Crewmen pulled off sweaters, or unzipped the tops of their jumpsuits. Others rolled up their sleeves, to stay fresh as the air grew increasingly stale. This was only the beginning of the ordeal of making it through the strait.
Jeffrey shuffled his windowed displays, to give more room to the pictures from the hull’s photonic sensors. In passive image-intensification mode, he caught glimpses of fish swimming by, and watched the soft, silty bottom receding behind the ship as she moved forward. He saw rocks, transported over the centuries in icebergs calved off glaciers along the coast; as the bergs melted, their burden, released, fell through the sea.
The tactical plot showed two Russian surface ships just past the northern end of the strait. One was a destroyer, of the type NATO gave the code name Udaloy. Though they tended to be plagued by onboard fires, when they worked right they were formidable. The Russians called the Udaloy class a “Large Antisubmarine Ship,” and to Jeffrey this said it all. The other was a Grisha-V antisubmarine corvette, much smaller than the Udaloy.
At low altitude, on a racetrack-oval course that ran east-west beyond the strait, the plot also showed sonar holding intermittent contact on an Ilyushin-38 four-engine turboprop plane, NATO code name May. The Mays had been modernized since their introduction in 1969. Finally due for retirement just when the war broke out, Russia kept them in service. Each one could carry a dangerous mix of air-dropped torpedoes, sonobuoys, and depth charges. They also bore a magnetic anomaly detector—MAD—on a boom behind their tail, which if properly calibrated could find
Challenger
in water this shallow. Though her hull was made of nonmagnetic ceramic composite, there was enough steel and iron inside to register at short enough range.
Challenger
could easily outrun an Udaloy or a Grisha, but not the Udaloy’s two antisubmarine helicopters. She might or might not manage to escape their lightweight torpedoes. The May maritime patrol bomber,
Challenger
could never outrun. If that aircraft was carrying APR-2 or APR-3 rocket-propelled torpedoes, and her crew drew a bead and chose to drop the weapons armed, in such confined waters
Challenger
was finished.
J
effrey was staring tensely at the pictures from outside.
“What’s that?”
COB hissed.
Through the murky water ahead, Jeffrey saw a long and thin object projecting high off the bottom.
“Helm left thirty rudder,” Bell snapped, the risk of collision too real. “Back one third.”
“Aye, sir!” Patel said, his voice cracking, too panicked to acknowledge properly. The ship swung left. In front of them were more of these towering objects.
Challenger
had too much momentum to be able to stop or turn out of their way.
“Helm maximum rise on autohover!” Bell kept his voice deep with great effort. The only thing remaining was to try to go up and over the obstacles.
“Autohover, aye, rise!”
“Chief of the Watch, pump all variable ballast!”
COB acknowledged crisply. His hands worked his console controls and keyboard like a concert organist giving the performance of his life. Bell was doing everything he could to get the ship going straight up on an even keel. To use the bow and stern planes would make her pivot about her center of buoyancy too much, especially with a jittery helmsman, and her rudder and pump-jet propulsor would smash into the bottom’s muck and stones. The autopilot computer assists could aid Patel only so far.
Challenger
’s depth began to decrease. The unexpected spires were still there.
They must be forty or fifty feet high,
Jeffrey thought
. What the hell are they? . . . We’re going to hit them.
“Helm back two thirds!” Bell’s order came out at a higher pitch this time. “Chief of the Watch, on the sound-powered phones, rig for depth charge.” As a modern expression, this meant to prepare for possible shock and damage from enemy weaponry, including not just depth charges but mines, torpedoes, cruise missiles, or bombs. No one knew what might happen next.
“Propulsor is cavitating,” O’Hanlon announced, his Boston Irish accent especially thick. The power Bell had demanded, with the comparatively low sea pressure at such mild depth, meant that the pump-jet turbine blades, thrown hard into reverse, began to suck vacuum, fighting
Challenger
’s nine thousand tons of inertia.
“Chief of the Watch, on the sound-powered phones, silent collision alarm.”
COB acknowledged. Phone talkers in each compartment, monitoring the circuit, would pass the word to all hands.
The ship’s rise began to accelerate, even as her forward speed slowly came off. Everyone braced themselves and watched the photonics imagery, and prayed. A crash would be disastrous for stealth, and could seriously damage the bow dome or bowplanes—or worse.
As the pump-jet propulsor strained, and internal pumps emptied the variable ballast tanks’ water into the sea,
Challenger
moved upward past the tips of the spires.
Jeffrey caught glimpses of their profiles: each had a slim, teardrop-shaped cross-section, with the razor-thin edge pointing at him, into the current. They showed no sea-growth fouling. He realized they bore a slippery, echo-suppressing outer sheath.
This configuration would minimize their water drag and flow noise, and make it very hard to get a return with any obstacle-avoidance sonar ping—which Bell dared not use for fear of destroying their stealth.
No wonder we didn’t hear them on passive sonar.
Jeffrey’s heart was racing, his breathing ragged and short. The spires’ tops bore rounded fairings that probably housed hydrophones, or sensors to measure unusual turbulence or vibrations, or all three. He badly wanted to bark out instructions, but this was Bell’s battle, not his.
“Sir,” Patel called to his captain, “my depth is one hundred feet and decreasing rapidly.”
Reported ship’s depth always meant at the keel.
Challenger
’s hull was forty feet in diameter, and her sail projected twenty feet higher than that. The top of the sail was barely forty feet under the surface now, less so by the second.
Bell needed to make some very fast decisions.
“Helm, maintain depth one hundred feet on autohover. Chief of the Watch, flood variable ballast to restore neutral buoyancy. Helm, all stop. On auxiliary maneuvering thrusters, rotate our heading to westward, then translate the ship sideways north.”
Patel acknowledged, his words slurred. COB leaned over to give him help with one hand while he did things on his own console with the other.
Jeffrey watched his displays. The ship’s depth had risen dangerously to eighty-four feet before her upward motion came off. The small thrusters at bow and stern were swinging the ship parallel to the line of spires, and those thrusters and the current were moving
Challenger
over and past the spires.
An antisubmarine booby trap. Simple and fiendishly clever. We barely missed hitting it . . . but these movements, cavitation noise, and mechanical transients can’t go unnoticed.
Now Jeffrey understood with horrible clarity how the Russians intended to block their channel to foreign submerged submarines: they
wanted
unfriendly captains to think it was safest to stay deep. Who’d built this peculiar snare of a fence? Jeffrey answered his own question. Russian saturation divers. It had to be recent, since its surfaces were so clean. Why wasn’t this in the intel reports he’d been given? He definitely had a need to know. The U.S. must not be aware of it. Construction could have been achieved unobserved, given how short the acoustic detection ranges were locally, especially with Big Diomede totally blocking any hydrophones near Little Diomede.
Challenger
was past the fence, slowly moving sideways further north into the strait; Bell was making the most of the current to drift quietly out of the area.
“Aspect change on Masters Nine-Five, Nine-Six, and Nine-Seven,” O’Hanlon stated. The Udaloy, the Grisha-V, and the May bomber. “Blade rate increase on Masters Nine-Five and Nine-Six. Bearings to contacts now constant, range decreasing.” The destroyer and the corvette were steering toward
Challenger
and speeding up. The bomber was headed their way, too.
“Helm,” Bell ordered, “on autohover, make your depth one-five feet from the bottom. On auxiliary thrusters, maintain distance four-zero feet upcurrent from bases of spires.”
Patel acknowledged more calmly. The pictures from outside showed no end to the line of spires to east or west. They were spaced evenly, twelve or fifteen feet apart, the gaps too narrow for even a small diesel boat to slip through.
Challenger
began to descend. Soon she hugged the sea floor, and hugged the backs of the spires from inside the strait, as closely as Bell dared.
“Overflight, north to south!” a sonarman shouted.
“Quiet in Control,” Bell snapped. People were too agitated.
“Master Nine-Seven passed almost directly overhead,” the same sonarman stated with a mix of sheepishness and fright.
The whole control room became deathly quiet. If Jeffrey had miscalculated about Russian attitudes, then an air-dropped torpedo—impact with the sea cushioned by a parachute—might have already left the Il-38’s bomb bay. An eternity passed, but Sonar announced no noise of a weapon hitting the water.
“Let’s hope these spires have some steel in their cores,” Jeffrey said. “It might confuse their MAD.”
The Grisha-V was charging toward
Challenger
at thirty knots, her top speed. The Udaloy, further off when
Challenger
hit the booby trap, was coming their way just as quickly.
“New passive sonar contacts on the bow sphere,” O’Hanlon reported. “Airborne, bearing three-five-five, range is short, closing rapidly. . . . Turbine engines and helicopter rotor noise. Assess as two Helix-As, scrambled from the Udaloy.”
“Very well,” Bell responded. “Activate sonar speakers.” The noise of the helos filled the control room, in surround-sound quadraphonic, giving a three-dimensional sense of the location of the contacts. Engine turbines roared and whined, the helicopters’ transmissions screamed, and their twin counterrotating main rotors, mounted one above the other on each aircraft, made steady throbbing, thudding beats. “Stand by to suppress active sonars with out-of-phase return emissions.”
Challenger
’s sonar arrays, mounted in different places at her bow and along her sides and on her sail, could actively cancel enemy pinging—if the enemy systems weren’t too powerful or too sophisticated.
Jeffrey heard sharp smacking sounds. He almost jumped out of his seat.
“Surface impacts!” O’Hanlon continued his running commentary.
People ducked, as if cowering from a depth charge.
“Assess as sonobuoys!”
The sonobuoys went active, making musical bleeps, taunting, high-pitched, nerve-shattering. They used small hydrophones to pick up echoes, relayed back to the Helix-As by radio. The helicopters in turn might be relaying the data to the Udaloy’s computers for thorough analysis. The only good thing Jeffrey could say about them was that because they had to be small and battery-powered, sonobuoys were not the most dangerous threat.
A deeper tone sounded. “Contact on acoustic intercept!” a different sonarman called out. “Grisha-V hull-mounted Bull Horn system.” Bull Horn was another NATO code name.
“Helicopters departing,” Sessions, as Fire Control Coordinator, said to Bell, sounding hopeful.
“Too easy,” Bell retorted.
A new bright line appeared on Jeffrey’s waterfall display, streaking across it diagonally like a comet.
“Overflight!” came from O’Hanlon. “South to north!”
This time, on the sonar speakers, the droning rumble and roar of a four-engine turboprop fixed-wing aircraft punished everyone’s ears, then receded.
Sonar made formal reports, belaboring the obvious.
“The helos backed off so the May could get a better MAD fix,” Bell said. Jeffrey knew he was right.
“Helos returning!” Sessions was too overwrought not to shout.
Turbines, transmissions, and rotor noises increased in intensity, almost drowning out the
plop
and
bleep
as more active sonobuoys fell and switched themselves on.
“They’re keeping us pinned until the ships get here.” Now Bell was giving his own running commentary. “Sonar, are they getting solid echoes off us?”
“Negative,” O’Hanlon said. “Am able to suppress.”
So far.
The control room had begun to feel roasting hot, like an oven. Sweat dripped from Jeffrey’s chin, and his underarms were drenched with it. The atmosphere tasted foul, and smelled rancid—the stench of two dozen men’s fear.
Challenger
had Polyphem antiaircraft missiles, which could knock down helicopters and maritime patrol planes. They were loaded and fired four at a time through a torpedo tube. Using them now was entirely forbidden by U.S. ROEs—and they’d merely prove
Challenger
’s exact location to the corvette and destroyer getting closer by the minute. Torpedoing those ships was absolutely not an option, and useless besides since the Russians would only send more.
Another deep tone filled the air, followed by a weaker, higher-pitched one.
“Bull Horn from the Grisha-V again. Udaloy has gone active with hull-mounted Horse Jaw.” The Udaloy’s sonar was more powerful than the Grisha-V’s, but the Udaloy was further away.
Jeffrey watched the tactical plot and listened to the sonar speakers. The helicopters began to circle, sometimes coming very close to
Challenger
.
The Grisha-V announced its arrival on scene with a louder blast from its Bull Horn system. The tactical plot showed her slowing, reducing her self-noise to get clearer sonar returns.
“Sit tight, people,” Bell said. “We can’t sneak further into the strait or they’ll track us for sure, by a Doppler shift in whatever fragmented echoes they’re hearing. Just sit tight.” An object in motion toward or away from an active sonar caused the returning ping to be higher or lower in frequency, enough to register on the active sonar’s signal processors—a dead giveaway of a genuine target.
Everyone waited for the Russians to make their next move.
People were jolted by three loud
bangs
in quick succession.
“Signal grenades,” Bell said before Sonar could.
Three grenades dropped one after another was the international signal meaning, “Unidentified submarine in my territorial waters, surface and indicate your intentions.”
“Sit tight,” Bell repeated. Three more grenades went off, much closer. “Commodore, any directives?”
Jeffrey stood and eased gingerly past the sonar officer, Finch, over to Bell. “Whatever we do, don’t surface,” he whispered. A junior enlisted man let out a yelp as three more grenades went off, closer still. “We don’t know for sure that they know that we’re here.”
“You do like to gamble, Commodore.”
“Get inside their minds. They don’t have a solid sonar return off our hull, with our out-of-phase suppression. They might think what they’re getting are garbled bounces off the backs of the spires. Whatever sensor data zeroed them in on this location could just be dismissed as a false alarm, or a whale.”
“Maybe.” Bell was starting to sound sarcastic.
Jeffrey brought his face a few inches from Bell’s. “They can’t be positive of an MAD contact because of these spires.”
“Only if they do have steel in them.”
“Yes, there is that.”
“The bomber might have gotten a lock on us, twice, by LASH.”
“I think the water’s too opaque.”
“And
I
think we should sneak away on auxiliary maneuvering thrusters. The longer we stay here, the better their chance to be certain they have a non-Russian sub in their sights.”
“We can’t move away from the spires. You said so yourself.”
“Not
away,
Commodore.
Along.”
“You mean follow the fence east or west?”
“Yes.”
“No. If we move at all, their readings at this spot on sonar and MAD and even LASH will alter. They’ll grow more suspicious, instead of doubting they’ve got a real contact.”