by Larry Bond
“Pavel, I’m not talking about the Carter!” growled the intelligence officer. “The Americans have put five attack submarines, one cruise missile submarine, and two ballistic submarines to sea in the last twelve hours. Now, unless you know of a nationwide exercise that I’m not aware of, this sudden surge brings their deployed assets to over fifty percent of their strength—and that is on both the Atlantic and Pacific coasts!”
“Are you sure of this, Vasiliy?” asked Drugov hesitantly.
“I just looked at the recent imagery for both the east and west coast bases and compared them with the latest summary report, Pavel, I do know how to count!” Lavrov insisted firmly.
“All right. Bring the imagery and your notes up immediately. I’ll fit you into Admiral Komeyev’s schedule somehow before he leaves for Moscow.” The click on the receiver told Lavrov that Drugov hadn’t even waited for his acknowledgement.
Lavrov started printing out the latest imagery, then grabbed the intelligence summary and his notes. If he was correct, and the Americans were sortieing their submarine forces, then they had to have a very good reason for doing so. He feared he knew exactly what that reason was.
15
ROUGH NEIGHBORHOOD
4 August 2021
1200 Local Time
Prima Polar Station
Bolshevik Island, Russia
* * *
The helicopter detachment used the airfield office as their headquarters. It was the only properly built structure near the airstrip, and it had the all-important telephone. They tacked status boards and charts to the walls, and worked from laptops. They all slept in prefab huts that had been brought in along with the detachment’s equipment.
The four pilots, eight flight crew, the weather officer, and ten mechanics had all arrived a little over a week ago. A hurry-up order from the Northern Fleet headquarters had snatched personnel and machines from wherever they were handy and sent them to the Prima Polar Station on Bolshevik Island to defend … something. They weren’t quite sure what it was, but orders were orders.
The pilots passed the time in the office. They played cards or chess, received a weather briefing every six hours, and wondered who they’d angered to end up in such a desolate place. Talk alternated between guessing what they were supposed to be protecting and when they would get to go home.
Captain-Lieutenant Stepan Mirsky, the detachment commander, took the call, while the others waited, deducing what they could. After scribbling a few numbers, still holding the phone with one hand and listening, he gave a thumbs-up with the other. The two duty crews started zipping up their flight gear, while the enlisted men left at a run to prepare their aircraft.
Theoretically, the standard was to launch within five minutes, but drills since their arrival had shown six to eight was more feasible, especially since they didn’t have as much ground-handling equipment as they would at a regular base. The command pilots, Senior Lieutenants Sharov and Novikov, each grabbed a fresh printout from the weather officer. The two co-pilots and sensor operators didn’t wait, but immediately headed out, right after the mechanics, to warm up the helicopters’ mission systems.
After a short while, Mirsky, listening and writing, finally responded, “Understood. Logged at 1203,” and hung up. Senior Lieutenant Sharov was still scanning the weather report, while Senior Lieutenant Novikov tried to read what Mirsky had written upside down. The detachment leader announced, “Mission orders.”
Both pilots came to attention, and Mirsky said, “A Sever acoustic module has alerted, bearing three four two degrees, fifteen kilometers from Center. They confirm it’s not a drill. Standard rules of engagement apply. Sharov is the flight commander.” The captain-lieutenant handed them each a slip of paper with the information, and added, “If there’s something there, find it and kill it.”
Sharov could hear turbines spooling up outside, and left the office at just a little less than a run, Novikov sprinted to his own aircraft. Still carrying his helmet, Sharov pulled it on as he reached the left-hand cockpit door. Climbing in, he connected his comm leads in the same motion. Petty Officer First Class Lukin, sitting at the sensor operator’s station behind the cockpit, was already reaching for the mission data, and Sharov handed him the paper.
“Red 81 is ready to fly, Senior Lieutenant.” Copilot Lieutenant Migulov’s voice over the intercom was calm and businesslike. Sharov hadn’t flown with his copilot before being assigned here, but standard procedures and a few practice flights had gotten them used to each other. The younger officer was eager to prove himself, and Sharov was happy to have such an energetic second.
The helicopter’s engines sounded smooth, and Sharov scanned the instruments carefully before telling Migulov, “Go ahead and taxi; course after takeoff is north-northwest, max cruise.” That would get them headed in the right direction while Lukin worked out an exact vector. On the radio circuit, Sharov sent, “Red 81 taxiing,” and received two microphone clicks in acknowledgement.
There was a stiff wind, forty-two kilometers an hour, which would make for a very short takeoff run and an equally bumpy ride. Up on the concrete, away from the row of parked helicopters, Migulov turned the machine northwest, facing into the wind, and revved the engine. The helicopter almost jumped into the air.
Sharov barely noticed. The lieutenant would get them where they needed to go. As the mission commander, he was working with the tactical display. A red pip showed where Lukin had already entered the last reported contact, marked “Datum 1.”
“Center” was marked as a yellow box on the navigation display. It was a spot about thirteen kilometers offshore. As far as anyone could tell, it was empty water, although they’d seen ships anchored nearby. The helicopter detachment used it as a navigational reference point, although they were instructed to stay at least two kilometers away from the place. It would be nice to know what was there, but for Sharov and the others, it didn’t really matter.
A yellow moving symbol showed the position of the helicopter, and as Sharov watched, a second yellow symbol appeared and the course indicators swung right to the course he’d ordered. A symbol on the upper edge of the machine appeared, showing that his aircraft, Red 81, was now data linked to Novikov’s Red 50.
They were flying relatively new Kamov Ka-27M helicopters. The design first flew in the eighties, but these machines had been refitted with the Lira antisubmarine system. Normally the Kamovs operated from helicopter pads on the stern of Russian warships, but flying from a land base was also fine. In fact, taking off and landing from a land base was far simpler than the pitching and rolling stern of a ship that was also moving through the water.
“Recommend course three four zero degrees. Passing over Cape Baranova. Recommend first dip point at twenty-seven kilometers, seven minutes at this speed.”
“Go to full military,” Sharov ordered over both the radio and the intercom. That would increase their speed from 240 kilometers per hour to 270. They were very close; the increased fuel consumption was far less important than getting on top of the contact and beginning the search.
“At full speed, time to dip point is now six minutes.” Sharov watched the other aircraft match his speed, a kilometer behind.
The first real bump hit them, and Sharov tightened his harness and returned a few items to their proper places. The airframe rattled, but bulled through the turbulence. Flying this low would be a rough ride, but you can’t dip from thousands of meters up. And you had to be low to use MAD as well. They hadn’t even bothered to load sonobuoys. They were useful tools for finding subs, but the buoys needed open water. The loose ice around the island, combined with the waves’ action, would crush any sonobuoy within moments.
Even dipping would require a little open water. Drills after they arrived had allowed them to figure out just how big the gap in the ice had to be, although it had cost them one sonar finding out. Luckily, openings in the ice five meters square weren’t too rare. After all, it was high summer.
“Two minutes to the dip,” Lukin reported.
“Red 50, assume a contact will break off to the north.”
This time, Novikov answered with a short, “Concur, taking station.”
“Prepare for auto-attack.”
Novikov answered, “Ready,” and Sharov ordered, “Go to auto-attack” on both the intercom and radio circuits.
Lukin was faster, but his acknowledgement was only seconds ahead of Novikov’s.
Another symbol appeared at the top of Sharov’s mission screen. The helicopters’ autopilots were now flying both machines, and would automatically head to the proper dip point, transition to hover, and lower the sonar without any human intervention. Based on which search pattern Sharov chose, it would then calculate the next dip location for each machine and fly there.
The roar of the turbines decreased as the helicopter’s symbol slowed, merging with the symbol on Sharov’s screen marked “Dip 1.” They revved again as the helicopter went into a hover, using full power to hold it aloft and stationary. He watched as Migulov tapped a few keys, and the Kamov crept ahead and slid left a dozen meters to center itself over a patch of open water.
Sharov heard the winch start up at the same time he got Lukin’s report. The sonar winch was a big thing, filling half the helicopter’s cabin behind the pilots with one hundred fifty meters of stout cable and the one-hundred-and-eighty-kilogram sonar array on the end. An opening in the cabin floor allowed the array body to be lowered into the water, while the operator, Lukin, monitored the procedure.
The winch started and stopped automatically, the Lira system stepping through a standard procedure: Lower the sonar projector to a water depth of twenty-five meters, listen for thirty seconds, then lower it to fifty, listen again, then one hundred, and finally one hundred and fifty meters. The entire sequence took several minutes.
Sharov read the status indicators on the mission display while splitting his attention between the ice-covered horizon, the engine instruments, and Red 50’s position, loitering a little to the northeast. It was waiting for Red 81 to finish her search. The results would determine where she had to dip. It was very unlikely that the first dip would be right over a contact, but if Red 81’s sonar picked up anything, then Red 50 would do its best to dip closer to the contact. Working as a team, the helicopters would use leapfrog tactics to first detect, then localize, and finally attack any submarine in the area. Assuming there was anything to find.
“Passive search completed, no contacts,” Lukin reported. “Request permission to go active.” If their sonar didn’t hear anything, then they could send out active pulses to look for a very quiet contact.
“Yes, go to active search.”
1215 Local Time
USS Jimmy Carter
* * *
The intercom report was expected, but it still startled everyone in UCC. “Conn, Sonar. Active sonar, bears one seven one degrees.” While Cavanaugh was still trying to figure out where that was in relation to everything else, LT Ben Ford immediately ordered, “Walter, José, all stop, and hug the bottom.” Behind Ford, the commodore gave a small nod of approval.
As Petty Officer Alvarez typed on José’s console, Petty Officer Frederick sang out, “Walter holds the active sonar at one eight six degrees.” Alvarez gave the bearing from José seconds later. Jerry pointed to the fire control technician at the geoplot, instructing him to plot the bearings and get a position on the helicopter that was pinging away.
Sonar came back on to announce, “Conn, Sonar. Active sonar is classified as a Lamb Tail. It’s unlikely that they detected José. No chance of seeing Walter, and own ship is well out of range.”
A moment after that Jerry reported over the intercom, “Control, UCC, we’ve got a three-point fix on the Lamb Tail. It’s two thousand one hundred yards to the south of José. Recommend sending José northwest before bringing him back. Own ship should also head west.”
Weiss’s voice came up on the circuit and responded “Concur, changing course to the west.”
Cavanaugh felt the deck shift slightly. Carter had started turning.
“Commodore, what kind of sonar is a Lamb Tail?” he asked, breaking his long silence.
“It’s a NATO code name for a dipping sonar. It’s a high-frequency set, and relatively short-ranged, but putting it on a helicopter makes it very mobile, and of course we usually can’t hear the helicopter until it puts the sonar in the water and starts pinging.”
“And it didn’t detect the UUV,” Cavanaugh stated hopefully.
“No, or his partner would already be dipping on top of José, and we would be in a very different situation,” Mitchell explained.
“His partner?”
“ASW helicopters operate in pairs, usually from ships, but these were probably flying from the island.”
“Why didn’t the active sonar detect the UUV?”
“Like Carter, the UUVs have anechoic coating that absorbs active sonar pings, reducing the amount of energy that is reflected. That can cut the detection range by roughly half. And since the UUV is very small, was moving slowly, and was close to the bottom, the acoustic processor would have a hard time telling José from a rock. Just to be sure, LT Ford had them put José on the bottom and stationary until the sonar stopped transmitting. Right now, the two helicopters are positioning for another dip. They’ll listen first, and then if they don’t hear anything, they’ll ping.”
“Then shouldn’t the UUV shut down its own sonar?”
“No, it doesn’t need to. José and Walter use really short-range, very high frequency sonars. They operate at several hundred kilohertz, but the Lamb Tail is transmitting and listening at twelve to fourteen kilohertz. It simply can’t hear the UUVs’ sonar, the same way we can’t hear a dog whistle.
“Same thing goes for the acoustic modems that allow us to communicate with the UUVs. They don’t operate anywhere near as high as the imaging sonar, but the modem frequency is still up there and is outside the frequency range of the dipping sonar. That and the transmissions use pseudo-random noise sequencing to hide the signal.”
“And the sensor can’t change the frequency it listens to?”
“Nope,” Jerry announced confidently. “They’d have to have a separate receiver. And it’s hard to passively search for sounds at such high frequency. Remember, Doctor, the higher the frequency, the greater the attenuation loss. The UUVs use it for close-range navigation and imaging, so range doesn’t matter as much. Its best range is just over a hundred yards. The Lamb Tail is a dedicated search sonar. It can see and listen to contacts several thousand yards away…”
“And Carter’s sonar is even lower-frequency, for greater range,” Cavanaugh concluded. The physics made sense, once he remembered to apply it properly.
“Lower frequency means larger size, too. The UUV’s sonar transducer is the size of a microwave oven. The Lamb Tail’s sonar is the size of a mini refrigerator. And Carter’s active bow array is like a big hot tub by comparison.”
During their discussion, José had been motoring west at a brisk four knots, but still just off the bottom.
The intercom chirped “UCC, Control. Report status of comms with Walter?”
Jerry relayed the request to team Walter, and Petty Officer Frederick checked the display. “We’re good, sir. Signal strength is still strong, but I’d recommend limiting any transmissions. At least for now.”
“Very well, have Walter head west at slow speed and secure communications.” Clicking his mike, Jerry replied, “Control, UCC. Comms are good, however, we are securing them for the time being. Walter has been ordered to head west.”
1225 Local Time
Red 81
Northwest of Bolshevik Island
* * *
Sharov put in a search axis of three five zero, based on nothing more than a guess. Standard tactics was to dip on each side of the axis, with an interval just slightly less than twice the sonar’s detection range.
The sonar contact had been nor
thwest of Center. While there was more open water straight north, the intruder might zig west instead of zagging north. The Lira combat system calculated the two next dip points, based on the sonar conditions and the contact’s estimated speed, which Sharov believed was slow. Both helicopters would go active simultaneously this time, but Sharov had biased the dip points so that the sonars’ detection ranges just barely overlapped.
The air was still rough, and he kept one eye on the engine instruments. He’d heard stories of turbulence shaking things loose, and considering how low they were to the water, there would be little time to correct, or even autorotate down if the engines failed. They wore immersion suits, which would give them a little time in the water before they died of hypothermia, but hopefully long enough for Red 50 to fish them out.
Sharov shook off those thoughts. That was one problem with the new Lira system. There was time to think now, while the computer ran the search. Focus on the hunt, he thought to himself.
Looking out his left cabin window, he saw Red 50 in the distance mimicking his own helicopter’s motions, smoothly slowing and settling into a hover, then the transducer array appeared under the fuselage. It took about ten seconds for it to disappear below the water’s surface.
1230 Local Time
USS Jimmy Carter
* * *
“Two separate Lamb Tail signals this time,” Sonar announced over the intercom. Petty officers Alvarez and Frederick fed the bearings from their UUVs in turn to the geoplot.
“Control, UCC. We’ve got two three-point fixes. The eastern helo doesn’t have a chance of picking up José, so you can angle him toward us as soon as they stop pinging. Walter’s course is good.”
Jerry paused to study the tactical display, and jumped out of his seat to inspect the paper plot. Then keying the switch, he said, “Control, UCC, the other helo to the northwest is not close to either UUV, but it’s closer to own ship. I recommend increasing speed on both UUVs to eight knots so we can get some sea room.”