SSN

    As Mack had hoped, the McKee captain's gig turned out to be a useful target for active sonar tracking. In addition, it provided a source of sonar passive tonal information. In shallow water like this, the TB-16 towed array's entire 2,600-foot tow cable, with its 240 feet of hydrophones at the end, could not be totally deployed. Instead, it would be deployed at a "short stay," an optimum length for all hydrophones to be at some distance away from its own ship tonats, yet short enough to ensure that it remained off the bottom during maneuvers, its own "towed-array altitude."

    The longer TB-23 thin-line array, with its 960 feet of hydrophones, would remain stowed for these war patrol shallow water operations, thus ensuring its availability for deepwater tracking operations when-and if-the Chinese ventured into the deeper waters of the South China Sea. The depths northwest of the Spratly Islands, ranging to over 15,000 feet, were ideal for convergence zone tracking of the noisy Chinese submarines while they were running at high speeds.

    Cheyenne had nearly completed her exercises when Mack heard over the speaker at the periscope stand, "Captain, radio, incoming flash traffic!"

    Proceeding quickly to the radio room, he arrived in time to see the printer spitting out new orders. Cheyenne was to proceed at best speed to a location west of Cuarteron Reef. Overhead imagery had shown that the Chinese were stirring, probably preparing to deploy under cover of darkness, which was only hours away.

    Mack was ready. Before beginning the high speed, shallow water maneuvers, he had decided that Cheyenne should not dally inside the Sulu Sea. Instead, he had decided to continue west while conducting the proficiency training, and now he was doubly glad that he had made that decision.

    Cheyenne had earlier released the captain's gig to return to McKee. Now, having already cleared Balabac Strait, deep water was nearby, so the captain used the radiomen's microphone to pass the order, "Officer of the deck, Captain, shift main coolant pumps to fast speed and then proceed to flank speed. Make your depth four hundred feet."

    The OOD repeated the captain's order verbatim, then ordered maneuvering to shift the main coolant pumps to fast speed. The OOD could have accomplished the same thing by ordering flank on the engine order telegraph, a "jump bell," but that method, which was faster than ordering maneuvering to shift the coolant pumps, was saved for when speed was of the essence… as in torpedo evasion.

    Cheyenne arrived northwest of West Reef shortly after nightfall, remaining outside the 100 fathom curve for the time being. Upon receiving the report from the officer of the deck that they were on station, Mack proceeded to the control room.

    "Make preparations to come to periscope depth," he said.

    After acknowledging the captain's order, the OOD slowed to two thirds and brought Cheyenne up to 130 feet, above the layer, and cleared baffles. He then advised the captain that he had no sonar contacts and was ready to proceed to periscope depth.

    "Very well," Mack replied. "Come to periscope depth."

    "Come to periscope depth, aye, sir. Sonar, radio, conn, proceeding to periscope depth."

    "Conn, sonar, aye. No contacts," replied the sonar supervisor.

    "Conn, radio, aye… manned and ready." That acknowledgment came from the communicator.

    "Diving officer, make your depth six zero feet smartly," ordered the OOD as he raised the Type 18 periscope and started his underwater visual sweeps to make sure there were no dead-in-the-water underwater hulls for Cheyenne to run into during this last, most tenuous part of the trip to periscope depth.

    "Make my depth six zero feet, smartly," answered the diving officer. "Smartly" meant that the diving officer would maintain the two-thirds bell as he ordered the helmsman to fifteen rise on the bow planes and ordered the planesman to a fifteen degree up bubble. Using the stern planes to control Cheyenne's angle, the bubble would be eased as Cheyenne was nearing eighty feet for the final glide to sixty feet.

    "Seven zero, six five, six four, six three, six two," the diving officer said, counting down their depths.

    When the count hit six two, the OOD called out, "Braking," and quickly swung the periscope through a 360-degree arc. A moment later he said, "No visual contacts, Captain." There were a number of radar contacts chirping over the Type 18 ESM receiver, but the periscope wasn't picking up any visuals.

    "Ahead one third," Mack ordered quietly to the OOD, not wanting to be entered in the deck log as having assumed the conn.

    "Conn, ESM, I have five ESM contacts, one a Chinese radar, and four Russian radars. HULTEC indicates a Han class, three Kilo class, and one Alfa class. The closest is the Han at signal strength three and increasing."

    Captain Mackey and the OOD looked at each other with surprise.

    Mack turned to the microphone. "ESM, Captain," he said, "are you sure about that Alfa?"