by Joe Buff
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.
Chapter 5
Jeffrey 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 waterf
all 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.