Authors: Todd Tucker
For a second, they all stared at each other. Then Frank stormed out of control without a word, while Hana continued to glare at the chart.
Frank pushed his way past the doctor on the ladder on the way out. He'd been standing there the whole time, listening.
Â
Commander Carlson kept waiting for the shot, but it became clear to her that the Alliance boat was trying to evade her, not willing to engage in any suicidal actions: smart. In the meantime, she would follow. She was proud of shooting that little plane down, and she would stick to that philosophy. Better to shoot the enemy ship on her return trip from Eris Island.
Polaris
was a good, quiet ship, with a skilled captain, she could tell. Acoustically, they had two things she could hold on to. At very close ranges, inside of one thousand meters, they could hear a 60 Hz tonal. It could be anything electrical that was sonically sorted to the hull, broadcasting that slight electric whine into the sea. It traveled a very short distance, its high, narrow frequency attenuating quickly in the ocean. But it was distinctively man-made and therefore invaluable, a sound they could pluck from the cloud of natural noises that surrounded them: the roar of the ocean, the tides, the shifting of the ocean floor, and the mournful cries of whales a hundred miles away. Moreover, it was distinctively Alliance, as the Typhon boat operated on a 50 Hz electrical system, so they could quickly distinguish any of their own noise from the enemy's.
Secondly, they had discovered a sound made from the ship's reduction gear, a slight chirp. It could have been a chipped tooth along one of the many gears, and it clicked reliably with every full rotation of the screw. This sound had the added advantage of being directly related to the speed of the reduction gear, and therefore, the speed of the ship. Over many days of tracking
Polaris,
they had even constructed a formula to convert the frequency of the chirping to the speed of the ship.
Both noises disappeared entirely outside of about two thousand meters, so they worked hard to stay inside that range. It was difficult because the
Polaris
tried all the standard evasion techniques, changing speed and course often.
Polaris
was hampered here by the fact that Carlson knew their destination: Eris Island. Still, sometimes they drifted out of range. When they did, Carlson had a third sound she could count on to reel the
Polaris
back in: the voice of their spy. It almost felt unsporting to rely on it, but there you go. War is hell.
Carlson was in control with Banach and two of her officers whom she trusted only slightly less. They were staring at the small-scale plot in the corner, looking at their estimate of the
Polaris
's course and speed. Suddenly a starburst of noise lit up their sonar display. Banach quickly put headphones to one ear.
“They're launching countermeasures,” he said, quickly putting down a red X on the chart at the position of the launch. “And another,” he said, making another red X.
“They're up to something,” said Carlson. The Alliance had basically two categories of countermeasures, things that spun in the water, and things that fizzed; they looked to be using both. The goal for both was to create a large acoustic cloud that the
Polaris
could escape behind, the same way infantry used smoke grenades on the battlefield. Carlson wasn't too worried; she had too many good cards in her hand. But she was curious.
“Target zig,” said Reese, her youngest officer, on the phones with sonar. “Target has turned to the south,” he said, taking the information from the display in front of him.
Carlson looked at the plot. Over days, the ship, despite all its maneuvering and attempts to evade them, had steadily made its way toward Eris. Maneuvers like this weren't unusual as they tried to shake her. But the countermeasures were a new twist; the large amount of ambient noise they were creating was weakening the acoustic grip they held on their prey.
She walked over to the sonar display, the narrow band readout stacking dots on top of each other. The dots represented the actual data from sonar. If they stacked in a perfectly straight line, it indicated that they had a good-quality solution: they knew the
Polaris
's course and speed. But the newest dots were starting to stray, bending toward the right.
“Target is speeding up, too, no?” she asked.
“Yes, Captain,” said Reese. “Turned to starboard and sped up.”
She clicked on the screen and looked at the data. The 60 Hz tonal was loud and clear. But the clicking of the reduction gear had disappeared entirely.
*Â Â Â *Â Â Â *
“Ship is rigged for silent running,” said Moody. She was looking at an electronic status console in front of her. All unnecessary machinery had been stopped to make the ship even quieter. This included fans and air conditioners, so the temperature was steadily climbing in control. They were all at their battle stations. The doctor was in sick bay, “counting Band-Aids,” as he said. Frank was in the torpedo room, while Ramirez was in the engine room. The captain, Pete, and Moody were in the control room. Pete was in the dive chair, directing the rudder and the stern planes. “Countermeasures are in the water and activated.”
“Very well,” said McCallister. “Launch the MOSS.”
They felt nothing in their feet, no rush of water or change in pressureâit wasn't like when a torpedo was ejected from the ship. They had pumped open the outer doors of the torpedo tube, and the MOSS simply swam out.
“The MOSS is launched,” reported Moody.
“Very well,” said the captain. “All stop.”
Pete rang it up, and the engine room answered immediately.
“Left five degrees rudder,” said the captain. Pete turned the yoke in front of him. “Sir, the engine room has answered all stop. My rudder is left five degrees.”
“Very well,” said McCallister. “We're turning away. How long until the MOSS broadcasts?”
“Five minutes,” said Moody.
Everyone in the control room looked at their watches.
*Â Â Â *Â Â Â *
The MOSS swam from its torpedo tube powered by a small electric engine. Unlike the ship it was born to imitate, its propulsion machinery was almost silent, the energy flowing from a chemical battery rather than the spinning of turbines and the pumping of water through a nuclear reactor. Five minutes into its journey, it began broadcasting a recording from a transponder in its nose. The sound was carefully designed to sound like a
Polaris
submarine, with a 60 Hz tonal and a broadband signature in the back of that like the
whooshing
of steam through pipes. While the MOSS was tiny, it was noisy, purposefully so, creating an acoustic profile that was slightly louder than the ship it was leaving behind. It was a decoy, and like a hunter's wooden duck floating on a lake, it had to attract attention without being obvious.
After five minutes of broadcasting, the MOSS turned on its programmed course. It turned right and sped up slightly, to 8 knots. Its acoustic twin, the real submarine, turned left at this same time, and the distance between the two grew.
After forty-five minutes, its battery exhausted, the MOSS died. A small valve slid open, filling a center chamber with seawater. Its mission complete, the MOSS sank to the ocean floor.
*Â Â Â *Â Â Â *
“The MOSS is broadcasting,” said Moody. The
Polaris
was now just drifting, its screw not turning, as silent as the big ship could be.
“I see it,” said the captain, tapping the screen in front of him. He looked at the narrowband profile that had suddenly appeared on his console, the 60 Hz tonal a bright line that was peeling away from them. He switched displays to see broadband sound, and watched the line tracing away from them that marked the “steam ring,” the signature of a very nearby submarine, the actual sound of high-pressure steam moving through pipes. It was a faithful duplication of their own noise being broadcast by the MOSS. “So that's what we look like,” he said, almost to himself.
Moody came to his side. Despite her lack of faith in the plan to evade, she was excited, and determined, as always, to succeed. “Look!” she said excitedly, pointing at the display of the enemy boat. “They're turning! They're following the MOSS!”
“Make turns for three knots,” said the captain. “Let's drive slowly away before they figure it out.”
*Â Â Â *Â Â Â *
Carlson allowed them to swing right to follow the sound, but the hair was standing up on the back of her neck. Something wasn't right.
“Captain?”
Banach was standing beside her. Just as she had finely tuned instincts about enemy submarines, like any good XO, he had developed good instincts about his commander.
“I don't know about this⦔ she said.
“Why? We can hear them clearly. If anything, it's louder.”
“Exactly,” she said. “And faster. So why no noise from the reduction gear?”
He furrowed his brow at that.
“We're following that sixty hertz because it's all we've got.”
“Correct,” said Banach. “It's all we've got. We haven't always held both signals.”
“It's going completely straight now, at a higher speed.”
“Maybe they've given up,” said Banach. “Perhaps they are abandoning their mission. Because of us.”
She snorted at that. “No,” she said. “You poor thing. It's been so long since we've been in port, you've forgotten what it feels like to be seduced.” She swept through the sonar display, looking on all bearings for another sound, anything. But there was only silence, except for the 60 Hz beacon in front of them, the clearest they'd heard their target since they first acquired it.
Then, after forty-five minutes, it disappeared entirely.
“Shit!” said Carlson.
“I don't understand,” said Banach, sweeping the cursor on the display through the ocean. “It just disappeared!”
“A drone of some kind,” said Carlson, already heading for the main plot. “We've been duped.”
She tapped her finger on a spot on the chart precisely between their current position and the spot where the fake
Polaris
had first turned and sped up. “Here!” she said. “Drive us here!”
“Left full rudder!” said Banach. The big ship turned to port.
“We've been driving away from them for almost forty minutes,” she said. “Assuming they are going very slow⦔
“Maybe a mile or two?”
“If they were driving directly away from us,” she said.
“Have we lost them?” said Banach.
“We lost them,” she said. “They outsmarted us, fair and square.”
“We're almost in position,” said Banach.
“All stop!” she ordered. “Rudder amidships!”
As her big ship coasted silently through the ocean, she closed her eyes and pictured the drone submarine to her north, and her prey somewhere to the south, an entire ocean to hide in.
Banach started to talk, but she stopped him with a finger to her lips, her eyes still shut.
Suddenly, a bright blip appeared on the sonar screen.
“Transient!” said Banach. “Bearing two-zero-zero.”
“Drive to it,” said Carlson, relief flooding through her even as she felt a slight sense of shame. Just as she told Banach, the
Polaris
had outsmarted them fair and square. The only reason they were able to find them again was because at this critical juncture they had a friend onboard. A friend who helpfully dropped a heavy wrench into a dry bilge, sending a pulse of sound into the sea that traveled for miles and miles.
*Â Â Â *Â Â Â *
“I think we did it!” said Moody.
The captain nodded grimly. “Ahead one-third,” he said. They were three miles away from the enemy boat, the farthest they'd been since they first spotted her. At this distance, they would be invisible, even at the slightly higher speed.
“Engine room answers ahead one-third,” said Pete.
Frank appeared in control. “Did it work?” he said.
“Maybe,” said the captain. He fought the urge to speed up even more, the desire to open distance faster balanced by the greater noise the ship would create.
“No sonar contacts!” said Moody as the enemy disappeared entirely from their screen. The captain checked his watch.
“The MOSS will die soon. Then they'll know.”
They drove a few minutes more at five knots, seemingly alone according to the blank display in front of them. Then the enemy reappeared.
“She's there!” said Moody. “And faster, by the look of it.”
“She figured it out,” said the captain, “when the MOSS died. Doesn't surprise me. Sped up and backtracked. I would have done the same thing. She still doesn't see us.”
“Speed up?”
“No,” said the captain. “Let's just try to slip away.”
They watched the Typhon sub move on sonar, created a solution that showed her moving, just as the captain had predicted, right down her old track. Not pointing directly at them as she had for days. The bright dots stacked up neatly.
And then suddenly the enemy veered.
Moody sat down and quickly worked out a new solution.
“Target zig.” She looked up. “She's turned toward us.”
“Dammit,” said the captain.
“Speed zig,” said Moody. “Speeding up.”
“Ahead two-thirds,” said the captain. “Make turns for eight knots.”
“Too late,” said Moody, fine-tuning her solution on the display. In minutes, the Typhon boat was again following them so closely and so tightly that on sonar it looked almost like they were towing her. “They've got us.”
“Goddammit!” shouted Frank. Pete winced. He realized they'd all been whispering everything since they went to battle stations.
“How?” said Moody. “How did that happen?”