want anyone sneaking up on them, and running slow was the best way to keep Cheyenne quiet.
When Cheyenne was twenty-five miles north-northeast of the Sprattys, Mack proceeded to the control room, looked at Cheyenne's position on the quartermaster's chart, and then ordered the OOD, 'Slow to ten knots.'
'Slow to ten knots, aye, sir.'
The change in the speed of the submarine, while sudden, was not overly drastic for the crew. They had gotten used to the rough riding of a submarine in close combat.
Hours before, Cheyenne had shifted from the TB-23 to the TB-16 towed array. The sonar operators were listening quietly, but heard nothing on the towed array or the spherical and conformal sonars, and the sonar supervisor soon reported that there were no contacts. Mack was pleased with that report. He knew that if they were to encounter an enemy submarine, they would be in for a dangerous, shallow water fight.
Cheyenne was not at home in coastal waters like these. The Los Angeles class submarines were designed for blue water operations. Cheyenne and her sister ships performed best in the open ocean. While they still performed well in areas like the South China Sea and, more specifically, the Spratly Islands, their superiority gap was narrowed markedly.
A Los Angeles class SSN was 360 feet in length- nearly 100 feet longer than an Alfa submarine, and the Chinese and Russian Kilo submarines were smaller still. The Kilo was a perfect weapon system for these dangerous waters. Measuring 229 feet, it could weave in and out of tight spots that Cheyenne would not even want to venture into.
As Cheyenne approached Discovery Great Reef, Mack decided to remain relatively shallow. That would allow Cheyenne to copy any radio traffic that might be broadcast to them. In addition, he didn't trust the water depths in this area. He figured he had a better chance of running aground than he did of being detected by the enemy.
When Cheyenne crossed the 100 fathom curve inbound for Discovery Great reef. Mack ordered, 'Come to periscope depth.'
Cheyenne had already been running shallow at 200 feet. Now, however, Mack would use the periscope to check out the notorious 'oil platforms.'
'Conn, sonar,' the sonar supervisor called a short time later. 'I think we've got a contact on the towed array. It sounds faint, but it may be a submarine? although the computers haven't been able to confirm a thing.'
The contact was currently too weak for Cheyenne's sonar operators to do much with. Mack made a mental note to keep checking on it, though. He was sure that if this was a submarine they were picking up, Cheyenne would be going after it soon.
Mack was also sure that whatever they were picking up had not yet detected their own presence in these waters. Cheyenne was currently running at only three knots to minimize the periscope 'feather,' the wake caused by the periscope barrel as it moved through the air-water interface, and she was nearly as quiet as she could be.
'Captain, we are currently seventeen miles northeast of the first oil rig,' the navigator reported.
'Sonar, Captain, do you have any additional information to report on that contact?' Mack asked.
'Conn, sonar, we classify Master 48 as a probable submarine contact to the southwest. It appears that it's on the other end of the abandoned oil rig from our position. It's barely making a sound, though.'
Mack acknowledged the report and ordered battle stations manned and the towed array housed. He still didn't know for sure what that contact was, but he had the feeling that Cheyenne was about to go into battle once more.
Southwest of Cheyenne, at the other end of the abandoned oil rig, a Chinese Kilo submarine was getting into position near Discovery Great Reef. The Kilo was running silently, and its captain was confident that they could not be detected. But then, based on estimates from Chinese intelligence, he did not expect any American SSNs to be near his position for at least another day.
The Chinese intelligence machine was very different from its American counterpart. The Chinese focused their intelligence on the human aspect, or HUMINT, while the Americans focused their intelligence on ELINT-electronic signals interception and satellite photography.
These differences made sense in terms of the backgrounds of the two countries. China had a massive population, with citizens and former citizens scattered around the world. America, on the other hand, had massive quantities of money that they could use to invest in their defense industry.
These differences came into play off the Spratlys. Cheyenne, with her advanced technology and sophisticated sonar equipment, was able to pick up traces of the Kilo. The Chinese boat, however, was relying more heavily on human observers-but Cheyenne's submerged transit of the Philippine Islands area had precluded any HUMINT by Chinese observers on the islands.
The captain of the Chinese Kilo finally arrived in his position slightly more than one nautical mile west of the oil platform. He planned to wait there in silence for passing American naval vessels, hoping for some to venture close enough for him to strike.
He didn't know it, but he was about to get his wish.
'Conn, sonar,' reported the sonar supervisor, 'we just. lost contact on Master 48.'
'What was the last position of Master 48?' Mack asked the fire-control coordinator.
The executive officer, who was acting as fire-control coordinator for this watch, said, 'Captain, Master 48 was about nineteen thousand yards west of the Discovery Great Reef oil rig. Do you think she heard us?'
The question was a good one.
Could they have heard us? Mack wondered. The most probable reason that they would lose contact with a submarine was either that the enemy submarine's noise was being shielded from Cheyenne's sonar, possibly by a thermal layer or the surf noise, or that the submarine had detected Cheyenne's presence and had either stopped or was running silently. The silence indicated that if there was a submarine out there, it was probably a Chinese diesel boat, running on its batteries.
Slowly, Cheyenne approached the oil rig, which lay within one mile of Discovery Great Reef. The water was extremely shallow in this area and the huge rocks surrounding the now dilapidated oil rig served to shield the diesel's sounds.
Cheyenne's passive sonar suite was severely degraded in the shallow environment of the littorals. In this environment, active sonar would work almost as well as passive, if they used MIDAS to discriminate between rocks and a submarine's longer hull, but Mack didn't seriously consider the idea. He knew that using his active sonar would give away Cheyenne's exact position. He'd rather have both submarines blind than give away his position to the enemy.
Through the periscope, Mack could see the Discovery Great Reef oil rig. At a glance, he could tell that it had been destroyed during the Chinese occupation of the island. But he needed to give it more than just a glance. He was supposed to get some accurate photographs of the rig for intelligence back in Washington. In addition, he needed to ensure that the rig was not being used as a Chinese submarine depot that could rearm or refuel Chinese SSKs.
He made another quick circle as he 'danced' Ihe periscope around the surface. He could find no evidence that the rig was being used for anything-or that it was even in the process of being repaired-but still he was cautious. This was a very dangerous place for Cheyenne to be running at periscope depth.
Six nautical miles away, or about 12,000 yards from Cheyenne's current position, the Chinese Kilo submarine was operating in its silent mode-running on its batteries. With no noise coming from their own ship, the Chinese sonar operators listened carefully to their low frequency sonar, searching the waters for the sound of any American vessels.
They heard nothing.
