Ssn (1996) Page 3

  The officers took this news in stride, and while the meeting was not as rousing as the captain had hoped, it had gotten his point across. Word would soon be buzzing throughout Cheyenne that they would be on the lookout for a nuclear attack submarine, possibly Chinese, lingering far too close to United States waters for comfort—even if being in international waters was within the legal realm of international law.

  For her transit to Pearl Harbor, Cheyenne was given a small loadout of torpedoes. The full capability of her torpedo room was twenty-six weapons, including four in the torpedo tubes, consisting of a combination of Mk 48 torpedoes, Tomahawk cruise missiles (land-attack and antiship varieties), Harpoon antiship missiles, and sometimes, though rarely, Mk 67 submarine-launched mobile mines. However, for this transit, Cheyenne was given only 12 Mk 48 ADCAP torpedoes. With a top speed of over fifty knots while running deep, and a range in excess of 30,000 yards, the Mk 48 ADCAP was arguably the best heavy torpedo in existence. Its only real competition came from the British Spearfish, which was carried by the submarines of the Royal Navy.

  The Mk 48 ADCAP, which stood for Advanced Capability, was a heavy wire-guided torpedo weighing over 3,000 pounds. Nearly 20 percent of its weight, or 650 pounds, consisted of PBXN-103 high explosive. One of the advantages of the Mk 48 was that it could be used against both submarine and surface targets, which made it much easier on logistics. It also pleased many submarine captains who still preferred the thrill of launching a torpedo over the newer, vertical launch Tomahawks or encapsulated Harpoon missiles.

  Each Mk 48 was wire guided so that targeting data during the initial stages of the torpedo launch could be transmitted back and forth from the Mk 48 to the BSY-1 fire-control system on board the attack submarine. During the terminal stages of the attack, the Mk 48 would use its powerful active seeker to detect, home in on, and then destroy its target. As long as the wire was intact, information from the torpedo was constantly relayed to Cheyenne until detonation.

  After the meeting, Mack returned to the control room. Knowing that there might be a nuclear attack submarine in the area, he ordered that instead of running at twenty-six knots for much of the way to Pearl Harbor, as he had originally planned, Cheyenne would now slow more frequently in order to listen to her surroundings. This “sprint and drift” technique was one of the best methods of arriving at a destination quickly while also allowing the submarine’s passive sonar to search for any possible sonar contacts.

  Cheyenne was now at an ordered depth of four hundred feet. At this depth, she was in her own element, that of the depths of the ocean. If necessary, she could still be reached by the relatively new, albeit slow, ELF, or extremely low frequency, band of communications. If there were a dire emergency, or a change in her orders, Cheyenne would be instructed by a short, coded ELF message to come to communications depth in order to receive important message traffic.

  Running at twenty-six knots was not always quiet. The screw, known to those outside the Navy as a propeller, was working feverishly to propel the submarine at this speed. If too shallow, this created tiny air bubbles, which made a popping noise when they collapsed. This noise was known as cavitation and could give away a submarine’s presence in the area. At this moment, Mack did not care as much about his stealth capability as he did about two other concerns: locating the submarine that was lurking dangerously near the West Coast, and arriving at the Pearl Harbor Naval Submarine Base with Cheyenne intact.

  All aboard Cheyenne were aware that they were making slight cavitation noise and that anyone who was close enough and quiet enough could determine their location. The frequent slowing and so-called clearing of the baffles, the normally “sonar blind” area astern of submarines, evened the score somewhat.

  At 1100 on 12 August, just ten hours after leaving San Diego, the OOD ordered Cheyenne to slow to one-third. Exactly eleven minutes later the sonar room came alive as Cheyenne slowed and her course was changed toward the north.

  “Tonal contact, center bearing 187 on the end-fire beam,” called one of the young sonar operators. The consoles, which looked like computer screens with green lines running through them, were often the sonar operator’s most important ally.

  An instant later the sonar supervisor, who had been paying close attention to the goings-on in this important center of the submarine, called to the captain, “Conn, sonar, we have a possible submarine contact bearing 187. We’re only receiving blade rate information so far.”

  Mack entered the sonar room, joining the five other men already there—including the sonar supervisor and the sonar officer. Everyone in the room knew that there was the possibility of encountering a Chinese submarine, but also knew it was highly unlikely. Chinese naval vessels rarely ventured this far away from home waters. This was especially true of the Chinese submarine fleet, which consisted largely of older-model diesel boats with just a few very noisy nuclear-powered attack submarines of the Han class.

  If there was a Chinese submarine patrolling off the West Coast of the United States, however, Mack was fairly sure that it would have to be a Han class. Naval intelligence reports had repeatedly explained that only one type of submarine was capable of travelling this far from Chinese home waters and operating—without surfacing—for an extended period of time. That type was a nuclear submarine, and the only Chinese SSN currently in service was the Han class.

  Captain Mackey was, as were all experienced submariners, at least slightly familiar with the Han class of submarine. In addition, when word was passed of a possible war with China, the intelligence officer assigned to SubRon 11 from SubGroup 5 had quickly prepared a brief report of what was known of the Han class in the U.S. intelligence community. According to that report, construction of the Han class had stopped after only five submarines due to extremely high internal radiation levels, and all of those were currently in service with the Chinese navy. They carried the pennant numbers 401, 402, 403, 404, and 405 painted on their sail. One of the class had, of course, been destroyed earlier that month by a U.S. SSN. Naval intelligence was still unsure which number it was, but they reported that it was probably number 402, the second of the class. They were assuming this because it had been tracked since leaving Ningbo Naval Base in China’s East Sea Fleet four days prior to the actions involving Nimitz.

  The torpedo complement fitted to the Han class was reported to be a mix of the older straight-running types as well as some of the newer Russian homing varieties. According to the reports, numbers 401 and 402 carried only torpedoes, but the last three submarines of the class, numbers 403 to 405, carried the Ying Ji. Also known as the Eagle Strike, this antishipping missile was a sea skimmer and caused great concern in the eyes of naval commanders. The most recent intelligence reports stated that while these missiles could be a significant threat to warships, the submarine needed to surface in order to launch them. And submarine commanders knew all too well that a surfaced submarine was an easy target.

  Unlike the USS Seawolf, Cheyenne did not have a wide aperture array, or WAA, so she would have to triangulate the position of her passive sonar contacts in order to determine their exact bearing, speed, and range. The ship maneuvers to accomplish this would have to be done very quietly, especially if the contact, now designated Master 1, was a direct-path contact. But it was a painfully slow process.

  “Captain,” the sonar supervisor said, “it’s possible the submarine was tracking us but lost us when we slowed. With these convergence zones out here in deep water, it could be in excess of 75,000 yards away. My guess is that he thinks we passed him, and based on its blade rate, is running full speed in an attempt to catch up with us and regain contact.”

  That was a good guess, Mack thought, but it was still just a guess. He wanted something more than that. Proceeding to the conn, he ordered the OOD to station the section fire-control tracking party so the BSY-1 computers could be used to determine the solution on the target. The OOD would maneuver the submarine in order to change the bearings received by the tow
ed arrays.

  Mack also ordered the OOD to house the TB-16 towed array and deploy the TB-23 towed-array. Unlike the 240 feet of TB-16 hydrophones, the TB-23 towed-array sonar measured over 900 feet in length, mounted nearly 100 hydrophones, and was towed at the end of a 2,600-foot cable. Then he returned to the sonar room.

  “Captain, blade rate indicates Master 1’s speed is steady at eighteen knots,” reported the sonar supervisor. “We’re getting more tonals now, including one from the conformal array. She’s definitely not American. The tonals compare to those listed in the sonar intelligence manuals as unique to Chinese Han class, number 402.”

  That stopped Mack. “I thought 402 was sunk by the submarine escorting Nimitz,” he said.

  “So did naval intelligence,” the sonar supervisor replied. “I guess they got their numbers mixed up. Wouldn’t be the first time.”

  The captain called to the OOD, “Begin retrieving the TB-23. I don’t want to get tangled up in case we have a fight on our hands.” The towed-array sonar was valuable for quietly listening to passive sonar contacts, but Mack, like many submarine captains, preferred to retrieve it before engaging in close combat with an enemy submarine.

  Mack left the sonar room and went back to the conn to see how the fire-control solution was coming.

  “Conn, sonar, our contact, Master 1, just stopped his shaft.”

  Seven more minutes passed, Cheyenne’s sonar operators carefully monitoring the tonals from the Chinese submarine’s reactor coolant pumps. These had to be run constantly in order to avoid destroying the reactor, one of the few drawbacks of a nuclear-powered submarine. A conventional, or non-nuclear, submarine could stop dead in the water, running entirely on her battery power, and be completely silent. A nuclear submarine, however, such as Cheyenne or Han number 402, had to constantly pump reactor coolant in order to keep the reactor critical and prevent its overheating. That difference meant that it sometimes could be easier to hunt an SSN than a regular diesel boat—especially when the SSN was an old, 1970s-vintage Han with reactor plant problems.

  The silence ended when the sonar supervisor called, “Conn, sonar, single active pulse from Master 1.” Moments later there was a second sonar pulse.

  Mack ordered the chief of the watch to “Man battle stations torpedo,” then took the conn from the officer of the deck.

  With battle stations manned, the executive officer, in his role as the fire control coordinator, reported to the captain, “Master 1 is now bearing 169, BSY-1 range is 22,000 yards. He was not in a convergence zone.”

  Aboard Han 402, the Chinese commander felt as if he had little choice but to give his position away. His sonar had acquired only intermittent contact on the American submarine maneuvering in this area, and he needed to locate it in order to accomplish his mission: sink the submarine and then continue on against American merchant ships. He knew an American submarine was out there, but didn’t know where, and didn’t know it was Cheyenne. Unfortunately for him and his crew, however, he had thought that he was much closer to the Americans than his active sonar told him he was. 22,000 yards was out of torpedo range for his submarine, but not for Cheyenne’s Mk 48s.

  Those two active “pings” were a calculated risk on the Chinese captain’s part. He knew his submarine was as noisy as a bull in a china shop and he suspected the Americans had been tracking him. Once he’d figured out that the American submarine had passed him he knew they could not be far off. If he waited too long, he would miss his chance to attack.

  Aboard Cheyenne, Mack was trying to outguess the Chinese captain. He knew that Chinese submarines were notorious for having very poor sonar outfits, but he didn’t think they were bad enough that the captain of number 402 would have no choice but to use his active sonar, giving away his own exact location. No, Mack thought. This does make sense. If the Chinese captain knew we were tracking him, he probably had figured that we knew his location, so all he was really doing was leveling the playing field-giving away information we already had in order to learn our location as well.

  What this amounted to was that the Chinese submarine had gone active on the American submarine and both submarines now had an accurate firing solution. Mack didn’t expect the Chinese captain to let this opportunity slip away. The Han was currently outside its own torpedo range, but that could change rapidly.

  “Conn, sonar, the Han just started up again. It’s making turns for twenty-five knots, sounds like she’s really straining. They are closing quickly.”

  Captain Mackey reversed course to minimize the range closure while he ordered tubes one and two made ready in all respects.

  “Torpedo room, fire control, make tubes one and two ready in all respects and open the outer doors.”

  When the outer doors were open, Mack turned back toward the Han and increased speed to full. Both submarines were headed straight for one another in an underwater game of chicken that could potentially ignite a third world war.

  “Conn, sonar, we have a torpedo in the water! Type SET-53, bearing 163. It’s active, Captain.”

  “Range to Master 1 is 21,000 yards,” reported the fire control coordinator.

  Mack looked around his control room. There was a look of horror in the eyes of the young sailors who had not yet been in the Navy for six months.

  “All stop,” he ordered.

  “All stop, aye, sir,” the helmsman repeated. Seconds later he added, “Maneuvering answers all stop.”

  The normal procedure for countering a torpedo was turn and run, flank speed, in the opposite direction. This was not, however, a normal situation.

  The U.S. intelligence community had managed to secretly buy three of the Chinese type SET-53 homing torpedoes from the Russians in a not-so-friendly transfer of technology. From their various tests, they had determined that the maximum range of the SET-53 was five nautical miles, or 10,000 yards. Even building in a large margin of error by doubling that range to ten nautical miles, or about 20,000 yards, Mack knew that there was simply no way that the Chinese torpedo could hit Cheyenne.

  It did, however, make Captain Mackey furious, and not just because this was an act of war against the United States by a Chinese submarine. More than that, this was an aggressive action against him, his submarine, and his crew.

  Cheyenne was not in any immediate danger—not yet, at least. Just in case, however, the captain calmly ordered, “Rig ship for depth charge.”

  The Chinese captain had put his submarine in a very bad position. The Chinese leaders, wanting to demonstrate their power to the Americans, had given Han 402 orders to attack American submarines and surface ships operating in the area. The 402’s captain was following his orders faithfully ... but he didn’t believe those orders included suicide. And he knew all too well that attacking a Los Angeles class submarine was tantamount to suicide. If he could manage to get in close enough to attack Cheyenne, he would do so. If not, he would follow his orders and launch at whatever range he felt he could without getting himself killed, and then he would dive deep and hunt for American merchant ships.

  When the active “pings” revealed Cheyenne’s location, the Chinese captain realized that he had given away their location much too far away to effectively attack the Americans. With their own location revealed, closing with Cheyenne would put the Han at serious risk, which meant that his only real choice was either to simply turn and run or to first shoot at the Americans and then turn and run. The first option appealed to him the most, but the second option was what his orders demanded.

  The Han captain gave the command to release a single torpedo and then began turning to his right. His only plan was to make a turn to the east and get away from the now-angry American submarine.

  Mack thought about that torpedo in the water and what it meant. The Han had fired upon him without provocation, which meant that China had decided to escalate. They would be starting hostilities at any moment, and all submarines would by now have been tasked by the Chinese navy to sink any American warships,
merchant ships, or submarines as they exited their home ports.

  All around the world, wherever Chinese vessels came in contact with American ships, there would be blood-shed. Some of them would get lucky. Some would win, and some would lose. But this particular Chinese captain had gotten unlucky when he decided to attack Cheyenne rather than a defenseless merchant vessel.

  And it was too late to change his mind.

  Mack immediately saw what the Han was doing. It was turning and running—in the direction of San Diego, which could only mean one thing. China was at war with the United States.

  “Conn, sonar, the Chinese torpedo just settled dead in the water,” the sonar supervisor reported. “Based on run time, it didn’t even make it 6,000 yards.”

  Mack nodded. The Chinese had had their turn. Now it was Cheyenne’s.

  The Los Angeles class attack submarine began to pick up speed rapidly, rushing to get behind the Han. The Chinese submarine was running from them in an attempt to escape the American submarine and return to a safe haven, hiding somewhere off the West Coast, but Cheyenne wasn’t about to allow that.

  The Han’s top speed was twenty-five knots; Cheyenne was doing thirty-one knots, and the range to Master 1 closed rapidly. Both commanding officers knew it would only be a matter of time before the Americans were within firing range.

  Aboard the Han, the Chinese captain’s options were limited once again. He could continue to run, prolonging things for a short while longer, or he could turn and fight.

  His orders were clear, and so was his choice. At his command, his submarine came around in another slow turn and bore down on Cheyenne.

  It was a noble gesture, but a futile one. The Han captain was racing to get within torpedo range, knowing that the effective range of the American Mk 48 ADCAP was more than double that of his Chinese SET-53.