USS Key West (SSN-722) International waters outside Yulin Naval Base, Hainan, People’s Republic of China
Lieutenant Commander Gordon Cremer spun the periscope barrel and dialed the handle to increase magnification.
“New contact, designated Sierra five-nine, a surfaced Chinese Shang-class submarine on this bearing. Mark.” The quartermaster called out the bearing.
“Conn, Sonar, confirm contact,” came the reply from the sonar shack, a few steps away.
Cremer cleared his throat. “Attention in Control, my intention is to trail our Chinese friend and see what they’re up to. Diving Officer, make your depth one-five-zero feet. Set the tracking party.”
The periscope optics submerged, and he activated the hydraulics to lower the scope back into the submarine. The smooth greased periscope barrel glistened as it slid into the well underneath the control room.
He turned his attention to the sonar “waterfall” display, a measure of the overall noise in the ocean around them. So named because of the snowy picture that scrolled down the monitor, the device provided a visual representation of broadband noise. Short spurts of noise, such as a whale sounding, might appear as a bright blip that traveled down the screen. Loud continuous noises, like the surfaced submarine they were seeking, showed up as a bright trace, and signals with movement relative to the Key West showed up as diagonal lines across the screen. It was a crude but effective way to gain a passive assessment of the world outside the submarine pressure hull.
Right now, the surfaced Chinese submarine showed up as a thick, bright trace that cut across the screen at a shallow angle.
“Conn, Sonar, Sierra five-nine is slowing. She’s submerging, sir.”
“Very well, Sonar. Let’s establish her narrowband signature quickly so we have something to track out here.”
When the Chinese submarine submerged, all the broadband prop noise on the waterfall display would disappear. The Key West would look for “tonals,” narrow frequencies of sound from individual elements on board the sub, such as a pump whose casing was touching the hull, radiating noise into the ocean.
“Conn, Sonar, we’re seeing additional ships getting under way from Yulin Naval Base.”
Cremer studied the waterfall display as the new contacts registered on the screen. At this distance from the multiple contacts, all he could make out was a froth of noise that showed up as a thick white band. He stepped into the sonar shack, a cramped room filled with floor-to-ceiling displays and young sailors wearing headphones. “How many, Supe?” he asked the first-class petty officer supervising his team. He also wore headphones and routinely switched between different audio feeds as he monitored his operators.
The young man handed him a spare set of headphones. “More than two, sir. Might be as many as six.”
Cremer slipped on the headphones and closed his eyes. The noise created by massive propellers thrashing seawater into foam sounded like a fleet of distant washing machines. He could make out at least two distinct platforms.
“All right,” he said, handing back the headphones. “I’m calling the captain to recommend we break trail and head up top for a look-see.”
Cremer strode into control and snatched a telephone handset from the rack. A few moments later, the captain entered the control room.
Captain Langford was a tall man whose features looked as if they might have been carved out of ebony. The CO’s eyes flitted around control, taking in details. Cremer tried to keep up with his gaze and failed.
“Report, XO.”
“Captain, we were establishing trail on a Shang-class submarine when we picked up indications of as many as six ships departing Yulin.”
Langford’s eyebrows ticked up a few millimeters, the equivalent of a shout for this reserved man. “Six? That would be unusual.”
“I agree, sir. I recommend we break trail and investigate.”
Langford rubbed his jaw. The Key West’s mission was to track Chinese submarines, and the best time to establish trail on a modern submarine was when it left port. Finding the ultraquiet Shang-class sub again in the open ocean would be like looking for a needle in a field of haystacks. The captain called for headphones and jacked into the sonar feed. He closed his eyes and slowed his breathing while Cremer fretted. He should have said two, not six. If he said six and they went to periscope depth and found two ships, he’d look like an idiot. If he said two and they found six, he’d be vindicated.
Langford opened his eyes. “Take us up, XO.”
The scope optics broke the surface and Cremer spun in a quick circle to ensure there were no ships about to hit them. “No close contacts!”
He turned in the direction of the port and dialed up the magnification on the scope. “I have one, two, three … seven contacts in view. Two Kilo-class submarines, two destroyers, and three Yuhai-class landing ships.”
He took his eyes off the scope. The captain was studying the TV monitor that mirrored the image on the periscope. “Did we receive any notice of Chinese naval exercises, XO?” Langford asked without taking his eyes off the monitor.
“No, sir.”
Langford nodded. “I don’t like the look of this. Let’s get a flash message off to Pac Fleet while we’re still at PD. Then, find that Shang-class sub again.”
“Aye, aye, sir.”