Ssn (1996)

by Clancy, Tom

  When the data transfer was complete, Cheyenne detached from the Independence Battle Group without report and proceeded on her own. Mack had enjoyed having the carrier nearby for backup and air defense, but now Cheyenne was going back to doing what she did best: operating on her own, sneaking up on the enemy, and blowing them to hell.

  Three hundred fifty miles southwest of Cuarteron Reef, running at four hundred twenty-five feet, Cheyenne picked up her first contact. Mack was in the sonar room.

  “Captain,” the sonar supervisor reported, “we have a sonar contact bearing 020 on the spherical array. The contact’s intermittent, so I think we’re receiving the sound source via a convergence zone. We pick her up loud and clear, then we lose her and don’t hear anything for a while.”

  While normal sound traveled through water in waves that gave at least some predictability, there were some areas in which sound waves were turned up toward the surface and then often bounced back into the sea. These were called convergence zones, and they could allow sonar to detect these sound waves at far greater ranges than would otherwise be possible. If the water was deep enough and the sound velocity excess was present at depth, these zones commonly occurred about every thirty miles. In a way, the ray paths of the acoustic energy were much like AM radio transmissions, which could travel in a straight line, then bounce off the ground and up into the atmosphere, and then come back to earth. This allowed AM frequencies to broadcast much farther than FM, though beyond their immediate range they could be picked up only in pockets and were more affected by weather.

  “My guess,” the sonar supervisor added, “is that it’s in the second convergence zone from us.” That would put the signal’s source at a range of more than sixty nautical miles, or 120,000 yards.

  “Keep an eye on that contact,” Mack said. If the sonar supervisor was right and Cheyenne‘s operators had indeed heard their sonar contact through a convergence zone, then the signal’s source was far out of Cheyenne’s weapons range. It also meant that the thermal gradients in the deeper waters of the South China Sea had not been eroded by the storms. But if the sonar supervisor was wrong, Cheyenne could be in for some very dangerous close combat.

  Sixty-three miles away, 200 feet below the surface of the South China Sea, crept one of the newest additions to the Chinese fleet, and one of China’s best submarine captains. The Chinese Kilo submarine had been in service for less than two years and had made its crew very proud.

  The first Chinese Kilo submarines had been bought from Russia in 1993 and delivered in February 1995. The Chinese had planned to buy up to fifteen of these powerful diesel submarines and had hoped that they would be able to build five more themselves, under license from Russia.

  This particular submarine had excellent equipment, with the exception of her passive sonar outfit. That was the problem with all Russian submarines, as its captain knew. The Russians could not make a decent passive submarine sonar—at least not one that his country would be allowed to buy.

  And that was a problem. At any given moment, there might be an American Los Angeles class submarine sneaking up on his position, and he would never know it until it was too late.

  The captain of the Chinese submarine wasn’t too worried about it, though. His was the lead ship of three. Below the waves, his Kilo was working in tandem with an older Romeo class diesel submarine. Above them, Jinan, a Luda class destroyer, patrolled the surface. Their mission was to hunt down and destroy any American ships and submarines. In addition, there was another Kilo well off to the side—not part of his task force, but it could provide assistance if he needed it.

  The captain of the Kilo welcomed Jinan more than he did the Romeo. For one thing, the destroyer’s two turbines were loud, which would hopefully distract any enemy’s sonar from any noises his Kilo might make. Even more important, however, Jinan, like all Luda type II destroyers, carried two French ASW helicopters. Those would be very useful if the Kilo needed help while engaging an American submarine.

  As pleased as the Kilo’s captain was with the surface ship, he was equally displeased with the Romeo. It was an old attack submarine that had been reactivated from the naval reserve, and, in his opinion, it was more of a threat to his own submarine than it was to the enemy. It was too noisy, for one thing. That could be desirable when the noise came from the surface, but down below it would only serve to alert the Americans to the presence of one or more Chinese submarines in the area.

  Worse, the farther he tried to get from the Romeo, the more it tried to stay close to him. The Romeo captain was no fool. He knew he stood a better chance under the protection of the Kilo than he did on his own.

  Assuming, that is, that the Kilo captain didn’t sink the Romeo himself.

  Back on board Cheyenne, sonar was trying to reacquire contact. Mack had gone back to 247 feet to continue the search, while at the same time maintaining copy over the floating wire.

  In the control room, Mack was looking at the BSY-1 fire-control console, which he liked to keep online for himself. “Sonar, conn, have you regained contact on Master 24?”

  “Conn, sonar, we’re working on a possible contact,” the sonar supervisor said, “but I’m not sure it’s the same convergence zone one. This one may be a surface ship. Master 24 was tentatively classified as a submerged submarine.”

  Several minutes later, the sonar supervisor reported that he had not one contact, but two, one Romeo submarine and one Luda destroyer, both bearing 020. They were both given new Master Numbers, designated Masters 25 and 26 respectively, since the sonar supervisor was not sure if either one was Master 24. Reconstruction would have to sort it out later. Without hesitating, the OOD ordered his section fire-control tracking party manned. Mack went to the sonar room.

  “Good job,” Mack said, unaware that they had failed to detect the Kilo that was in the area of Masters 25 and 26. “Anything else out there?”

  “Not that we can tell yet, Captain,” the sonar supervisor said, “but those two contacts are loud. We can hear them aurally, so there could be more ships operating in the area.”

  Mack left the sonar room and went back to the control room. The BSY-1 operators had a rough solution on range, about 30,000 yards.

  At Cheyenne’s current speed of ten knots, Mack would soon be within range to launch his Mk 48 ADCAPs at the Chinese contacts. When he got closer, he would slow. No need as yet for long-range shots. Cheyenne was currently running with the TB-23 towed-array fully deployed and, with the OOD’s maneuvers, the section fire-control tracking party at the BSY-1 computers was getting better and better solutions on the Chinese destroyer and submarine.

  “Conn, sonar, the TB-23 just picked up a helicopter overhead,” the sonar supervisor announced. “Probably flying from the Chinese destroyer.”

  “Take her down fast, to five hundred feet!” Mack ordered the OOD. This was another helo “Sierra” addition to his patrol report.

  Throughout Cheyenne, sailors grabbed for whatever they could as the submarine headed down at standard speed with a twenty-degree down angle. The diving officer, helmsman, and planesman had all buckled their seat belts as soon as they heard “take her down fast.”

  Above them, the Chinese Z-9A helo hovered and began to lower its powerful French HS-12 dipping sonar via the hydraulic winch. The winch was touted to be “high speed,” but it didn’t seem fast enough for the helo pilot as it slowly lowered the HS-12 toward the water.

  “Conn, sonar, we just received a sonar pulse from the helicopter’s dipping sonar. It’s a French type, HS-12-the same kind they sold to China. The transmission came from the opposite direction of the Romeo. I don’t think they could have detected us, sir. Signal level of the pulse was low.” Which probably meant the helo was quite a ways off or else it hadn’t dipped its sonar beneath the layer.

  Mack acknowledged for the OOD. “Very well, sonar, we have it out here on the WLR-9 as well,” he said. “Were we able to pick up any other information from the transmission?”

&nb
sp; “Sonar, conn, negative,” the sonar supervisor answered. “It wasn’t a very strong pulse. Let’s hope she ran out of batteries.”

  Mack smiled at the joke. Unlike the communicator’s earlier gaffe, this comment was well timed, and helped to ease the tension slightly.

  One hour and fifteen minutes later Cheyenne had closed to within 20,000 yards of her targets, Masters 25 and 26. Mack ordered battle stations manned.

  A few minutes later the helo was active again. The WLR-9’s acoustic intercept receiver at the conn picked that one up also, even though it was near the baffles.

  “Conn, sonar, that was a loud one, sir,” the sonar supervisor said.

  Mack smiled. “She must have recharged,” he said, in a deadpan voice. “Designate the helo Master 27.”

  “Conn, sonar, she got us on that one, sir—but that’s not all she painted! Captain, we’ve got another submarine out there, a Kilo class, one six-bladed screw, making turns for ten knots. It’s bearing 025, near the same bearing as the Romeo. It’s been hiding from us all this time.”

  All humor was gone from the conn. Considering their situation, Mack was pleased with how well his officers and crew were handling the sudden tension. Not aware they had regained old Master 24, the Kilo was designated Master 28.

  Cheyenne had just been pinged on by a directly overhead Chinese ASW helicopter, which had undoubtedly received an exact fix on their present location five hundred feet below the surface. The helo would now probably be making an MAD (magnetic anomaly detection) pass to confirm Cheyenne’s position. Mack was concerned that they would follow that up by dropping a torpedo directly on top of Cheyenne.

  “Conn, sonar, the Kilo, Master 28, just picked up speed. It’s heading directly at us, making turns for seventeen knots. It must suspect that the helo gave their position away.”

  “What’s the range to the Kilo?” Mack asked the fire-control coordinator.

  “Twenty-four thousand yards, Captain. We’re within ADCAP range for the Kilo—it’s making lots of noise at seventeen knots. Recommend making tubes one and two ready.”

  Mack nodded and initiated Firing Point Procedures on Master 28. “Torpedo room, fire control, make tubes one and two ready in all respects. Open the outer doors.”

  The order was acknowledged. One minute later it was confirmed. “Tubes one and two are ready in all respects, sir. Outer doors have been opened.”

  “Sonar, conn, stand by.”

  “Conn, sonar, standing by.”

  “Match sonar bearings and shoot tube one, Master 28.”

  “Match sonar bearings and shoot tube one, Master 28, aye, sir.”

  Mack then came right to clear the datum.

  “Tube one fired electrically,” the combat system officer reported. That was as far as he got. Before he could report on the torpedo’s status, the sonar supervisor spoke up.

  “Conn, sonar, torpedo in the water bearing 180! It’s a Chinese Mk 46 copy, Mod 2.” Mack had been correct in assigning the helo a Master number, which were usually reserved for potential threats to Cheyenne herself, or to targets of significant intelligence value.

  “Cut the wire and shut the outer door,” ordered the captain. “Reload tube one.” Mack was throwing away his torpedo, and he knew it. The Kilo was too far away and maneuvering. The Mk 48 would probably not be able to acquire on its own, but right now Mack had a different torpedo to worry about.

  “Left full rudder, all ahead flank, steady course 305,” Mack ordered. “Cavitate. Make your depth 750 feet.” He waited for acknowledgment and then added, “Rig ship for depth charge.”

  Cheyenne’s power plant was now running at peak capacity in an attempt to get away from the deadly torpedo racing their way.

  “Conn, sonar, another torpedo in the water. Master 27 just dropped a second Mk 46 on us, bearing 245.”

  “Release a noisemaker,” Mack ordered.

  Confirmation was quick. “Noisemaker away.”

  Cheyenne’s top speed was nearly forty knots. The two torpedoes chasing her were knifing through the water at forty knots, but Mack wasn’t worried. Not yet, anyway. Sonar reported the Chinese torpedoes bearing 268 and bearing 187. If Mack maintained his course and speed, the torpedoes would both run out of fuel before they closed the distance.

  The problem was that, at flank speed, Cheyenne was making more noise. She was announcing her exact location to every nearby sonar device. On top of that, she was making enough noise that she could barely hear anything around her.

  Mack knew that in order to outrun the torpedoes, they would need to keep running at this speed, blind to anything but the noisy torpedoes, for at least another five thousand yards.

  That was when Cheyenne caught her first break. “Conn, sonar,” the sonar supervisor reported, “the first torpedo just fell for the noisemaker. It’s off our tail.”

  “Sonar, conn, what about torpedo number two?” Mack asked.

  “Conn, sonar, it’s at the edge of our port baffle.” There was a brief pause and then the sonar supervisor added, “It just went active, Captain.”

  “Release another noisemaker.”

  “Releasing noisemaker, aye, sir.”

  The tension level slowly mounted. “Conn, sonar,” the sonar supervisor announced, “the Mk 46 just latched on to the noisemaker decoy ... lost the torpedo in our baffles!”

  Mack nodded. The Mk 46s were fast, but they were easily fooled.

  “I guess those noisemakers really do work,” one of the sonar operators said to the operator sitting beside him.

  “Ahead one third,” Mack ordered. He wanted to run slower until he knew what was going on around him.

  It took several moments for Cheyenne to slow down enough to start listening once more. Mack slowly turned to the northeast to clear his baffles.

  “Sonar, conn, report all contacts,” Mack said, once they had slowed enough. He wanted to know who was out there and exactly where they were.

  “Conn, sonar, report all contacts, aye, sir,” the sonar supervisor acknowledged.

  Less than five minutes had passed since the first Chinese Mk 46 had been fired at them, but to the officers and crew on board Cheyenne it seemed like only five seconds. It was ironic, Mack thought. The minutes it took for their own torpedoes to acquire and complete their runs seemed to stretch into hours, but when hostile torpedoes were coming toward Cheyenne, time passed much faster.

  “Conn, sonar, we’ve got three contacts, Captain,” said the sonar supervisor. “One Kilo class submarine bearing 278, making turns for fifteen knots. One Romeo class submarine bearing 020, making turns for about six and a half knots. The third contact is a Chinese Luda class destroyer, which is probably where that helo came from, bearing 350. The destroyer is also heading in our direction. The TB-23 doesn’t hold the helicopter above us, which may be because we’re too deep, but my guess is that it’s rearming on board the destroyer.” Mack would be sure to mention his battle stations sonar supervisor in his patrol report.

  The BSY-1 operators confirmed the sonar supervisor’s expert calls. The Romeo was previous Master 25 and the Luda was previously Master 26. However, the Kilo’s bearing was too far to the left for it to be the previous Master 28, which Cheyenne shot at earlier. Master 28 was added to the kill list and the new Kilo was designated Master 29.

  “We’ll take out the Kilo, Master 29, first,” Mack said. It was the closest target, and potentially the quietest, and Mack wanted it out of the picture. He gave the orders to prepare tube two in all respects, including opening the outer door. As soon as his orders were acknowledged and confirmed, he gave the command to match sonar bearings and shoot tube two, Master 29.

  Seconds later, the combat systems officer reported, “Tube two fired electrically, sir.”

  “Conn, sonar, unit from tube two running hot, straight, and normal.”

  The Kilo knew the moment the torpedo entered the water. It tried to turn and to run in the opposite direction, but the Chinese submarine had little chance. The Kilo had
been closing on Cheyenne at top speed, and with a torpedo heading its way, it didn’t have much room to maneuver.

  The Kilo zigged and zagged, tossing its crew about as the Chinese captain tried to confuse the torpedo at the same time that he tried to reverse his heading. The Chinese submarine released a noisemaker decoy to buy time, but Mack, listening to the reports from sonar, didn’t think it would work this time.

  He was right.

  “Conn, sonar, the Mk 48 passed right by their noisemaker. It’s still on course, bearing 275.”

  Several minutes later sonar reported hearing the explosion. The 650-pound explosive warhead literally peeled open the Kilo’s back end, beginning with its screw. The Chinese Kilo roamed the sea no more.

  “Reload tube two with a Harpoon,” Mack ordered. There was no time to relish the victory. He wanted the destroyer, Master 26, next. With luck, the helo would still be on board. “Diving officer, make your depth one hundred feet.” Mack needed to get closer to the surface so that they could launch the missile.

  “Reload tube two with a Harpoon,” acknowledged the fire-control coordinator.

  “Make my depth one hundred feet, aye, sir,” the helmsman finished the round of repeat backs, acknowledging the diving officer’s order.

  The Luda II class destroyer was a fairly large target, so Mack was going to fire two weapons at it. He would have preferred to make them both Harpoons, but Cheyenne had already fired three of her four antishipping missiles in previous actions. He would have to attack the Luda with only one Harpoon and one Mk 48. The torpedo had a bigger warhead, but it also had a much shorter range.

  “What’s the current range to the destroyer?”

  “Range to Master 26 is 30,500 yards, bearing 354,” the fire-control coordinator answered.

  “And what’s the range on the Romeo?”

  “BSY-1 computes 28,000 yards, sir. Master 25 is not moving. I think they figure that if they move, we’ll hear them and kill them.”

  Mack ran through the situation in his mind and quickly made his decision. “Make tubes one and two ready in all respects, including opening the outer doors,” he said. “Firing point procedures, tube two, Master 26; tube one, Master 25.”