Although its frequency was nearly twenty times that of die BSY-1 spherical active array, it was still detectable by the enemy. Mack wished even more that he had that FOR-MIDABOD sensor capability. R and D or not, the United States had shown during Desert Storm that the playing field of war was a better checkout of newly emerging systems than simulated targets and ranges. And its frequency, which was more than five times that of MIDAS, was not detectable by other than its own transducers.
All of which meant that Cheyenne would have to contend with quiet diesels and mines while attacking the quiet Akulas, and she'd have to do it with a shortage of torpedoes.
Shaking his head, Mack ordered Cheyenne to get under way before anything else could go wrong.
Cheyenne submerged to periscope depth at the fifty fathom curve and then altered her course to the south. In this direction the shallow waters of the Formosa Strait quickly gave way to the depths of the South China Sea. Within a few miles, the ledge would fall off to nearly 1,300 fathoms.
"Captain, officer of the deck. Sonar reports the sound of chains dead ahead of us. I can't see any mooring buoys, but with this sea state three, they could be bobbing up and down, hard to see."
Mack acknowledged the report and quickly left his stateroom, making a beeline for the sonar room. Putting on his own headset, which he had insisted be available for him whenever he wanted, Mack heard the sounds sonar had reported. But they were not the clunking noise of mooring buoys. They were clinking noises that he had heard once before in the Mediterranean, as the sonar officer during his first submarine assignment on a 637, when Egypt's Romeo submarines had laid mines in the Gulf of Sidra.
"Officer of the deck, come around to the west and get the combat systems officer and executive officer to the conn," Mack called from the sonar room.
A few minutes later, Mack explained to the officers gathered at the conn that they were up against moored mines. If it had not been for the sea state causing the mines to move up and down and the chain links to rattle against themselves, Cheyenne would have been close to being history. He also knew that Cheyenne could probably skirt the minefield using MIDAS, but that would not help other sea travelers, including the other 688s on their way to help. Instead, they would have to try to take out the mines with off-board sensors.
To do this, the warhead grain burn would not be incited, allowing the torpedo to be command-detonated in the minefield-assuming that the torpedo didn't merely set off the mines with its screw noise. If everything worked as planned, and the torpedo detonated in the proper position, the sympathetic concussions should set off a number of mines.
Mack did not want to expend more than two Mk 48s. That would leave eighteen for Cheyenne^ Taiwan-area sanitization duties. To eliminate the minefield with only two torpedoes, Cheyenne would have to rely on the high frequency of the torpedo's transducer, nearly twice that of MIDAS, to paint the scene well enough to ensure that the minefield was plotted prior to their attempting the kills.
Cheyenne didn't need to man battle stations for this evolution. The mines couldn't shoot back. Besides, Mack would stay at least five thousand yards away, standing back at a comfortable distance, far beyond the mine detection and destruction capability.
The combat systems officer alerted the TMOW (torpe-doman of the watch) of the plan to swim out tube three and then tube four if necessary. At the same time, Mack informed the crew over the 1MC of what would be happening. They would be able to hear the Mk 48 Otto fuel engines spinning up, which one could pick up through the hull while the torpedoes were still close, and Mack didn't want them to be alarmed and wonder what was going on. He also wanted to alert the personnel sleeping in the torpedo room, who would have to get up and move their portable skid bunks so that the tubes could be reloaded.
"Conn, sonar, we have diesel lines bearing 285. No screw blade information yet. But it's not a submarine's diesel. More like two old Chinese twelve-cylinders firing away, out of sync with each other. No bearing drift, either. He's closing."
Cheyenne had detected the Hainan. Mack was sure of it. Which meant the Romeo might be around.
Mack found himself wondering how accurate his intel was this time. Naval intelligence and the CIA had been wrong a bit too often lately, and it was especially important this time. If he could count on the report that the Romeo had replaced all its torpedoes with mines, he wouldn't have to worry about getting shot at. On the other hand, he couldn't just ignore the Chinese submarine, either. The last thing he wanted was a submerged collision at sea.