Larry Bond - Shattered Trident

“Watch her.” Dave Covey was the OOD, and Jerry watched silently as he conned North Dakota, following Chakra through another turn. It was obvious the sonarmen were watching the Indian sub closely, but Covey’s imperative referred specifically to the size of her turn. He needed to know when she was going to stop turning, or if she wasn’t going to stop at all.

“Doppler has not changed, OOD, she’s still in a slow starboard turn.” The sonar operator’s report involved a lot of subjective judgment, but after several days in close company with Chakra, they had gotten used to the way she moved.

“Pilot, make turns for three knots,” Covey ordered. The more the other boat turned, the slower North Dakota had to go if she was going to stay in her trailing position. The U.S. sub was well astern and offset to starboard, on Chakra ’s “quarter.” The Indian’s hull-mounted sonars were blind at this angle, and at ten thousand yards back, her towed array would not detect the Virginia -class boat, mirroring her movements.

“Doppler shift is zero—she’s steadied up,” the sonar operator reported. A moment later, the fire control computer finished its analysis. “New course is zero two zero,” announced Ensign Andrews.

Covey checked the time, doing the math in his head for the fourth time on this watch… twenty seconds… and now . “Pilot, right fifteen degrees rudder, steady course zero two zero. Make turns for five knots.”

“Right fifteen degrees rudder, steady on course zero two zero, make turns for five knots, Pilot, aye.”

“Sonar, is there anything out there in front of Chakra ?”

“No, OOD, the nearest contacts are in the first convergence zone, thirty-plus miles out, and thirty degrees to port. And this is not even close to an intercept course.”

Sitting in one of the empty fire control console chairs, Jerry speculated aloud. “Heading north to close on the shipping lanes?”

“Except there’s not a lot of shipping traffic left, Skipper,” Covey replied.

“Valid point, OOD. But whatever the reason, where he goes, we go.”

“Aye, sir. UUV operator, how’s Minot doing?”

“Minot is on station, five thousand yards abaft the port beam, matching Chakra ’s new course.” Keeping the vehicle on station was trivial compared to North Dakota . Much smaller than any submarine, and quieter, she could turn on a dime. Software on the UUV actually calculated any course and speed changes, so the operator’s job was usually just making sure Minot was behaving itself.

“Watch the range, OOD. Make sure we don’t drift too far aft.”

“Aye, aye, Skipper. Sonar, keep an eye out for another maneuver. Pilot, make turns for six knots.”

Jerry watched his OOD and was more than satisfied with his performance. Covey had been busy like this since he’d taken over the conn, and had handled it well, but they were trailing a tiger on the hunt. This was a very different situation than when he’d trailed that Chinese Shang-class boat not so long ago.

Back then, Jerry had fought to keep his watchstanders alert, trailing a boat with the acoustic signature of a heavy metal band. The Russian-built sub was a different animal entirely. She was still noisier than North Dakota, but not by that much. And to make matters worse, he had to stay tucked in close. He could have trailed from twice this distance, or just let Minot track and report the Indian’s movements, but Jerry had to be ready to move in and spoil any attack Chakra attempted to make.

Jerry’s only hope was to use his smaller signature and better sonars to stay one step ahead of the Indian sub skipper—figure out what he was doing, and if it involved a potential target, get in his face. But it all depended on knowing what the other boat might do next.

INS Chakra

“There, sir. Do you see it?” The sonar operator pointed to a faint trace on the waterfall display, more a loose series of dots than a true line.

“I see something, but it’s not distinct enough to be a man-made source.” Captain Samant pointed to a different part of the screen. “This trace looks exactly the same. Probably a biologic.”

“But that one will drift aft. This one keeps a constant bearing. I’ve been watching it for some time now. When we made that starboard turn just now, it dropped aft, with a left drift, then drifted right again until it was at the same relative bearing.”

Samant didn’t appear convinced. At this point, Lieutenant Rajat, the sonar officer, added his opinion. “Sir, I compared this signal with the recording of the submerged contact two days ago. This type of trace was on that same bearing right before the torpedo appeared.”

“What’s your recommendation, then?” Samant was willing to let the sonar officer have his say. He certainly didn’t want to discourage this type of independent thinking, even if the boy was likely full of nonsense.

“There are no contacts nearby. Let’s attempt to close on it. Go and say hello. If we force it to maneuver or reduce the distance to the contact, we may get a decent acoustic signature.”

Samant considered the idea. The area was clear, and if there was indeed some extremely quiet platform out there, he wanted to know about it before it fired another torpedo.

“All right, Lieutenant, get your best people on the equipment.” Then, sticking his head out of the sonar room, Samant called to the deck officer. “Lieutenant Parul, sound action stations.”

USS North Dakota

“OOD, rapid left bearing drift, down Doppler… and now a speed increase! Chakra has turned sharply to port.”

“Pilot, make turns for seven, correction, eight knots. Make your depth two hundred fifty feet.” Covey’s response was immediate and correct. Jerry nodded his approval. If they were on the outside of the turn this time, they’d have to speed up to keep station.

Like everyone else in control, Jerry felt a jolt of adrenaline at the sonar supervisor’s report. Dave Covey was coping, but he looked worried.

“Skipper, he doesn’t normally increase speed when he clears his baffles.”

“Concur, OOD. Sonar, what’s the blade rate?”

“The rate jumped up quickly, sir, passing ten knots. Slight cavitation.”

This time both Jerry and the OOD frowned. “He’s not interested in staying quiet,” Jerry remarked. “What’s he up to?”

Covey looked at the port VLSD. “Skipper, new course is two seven zero, a one-hundred-ten-degree turn to port. Speed is thirteen knots.”

Jerry noted Chakra ’s new course, and he didn’t like what he was seeing. “UUV operator, what’s Minot see?”

“Minot’s information matches ours, it’s turned to two eight five and gone to maximum speed. The logic is trying to compensate for the maneuver, but Chakra ’s faster. Range is decreasing rapidly.”

INS Chakra

“There you are!” the sonar operator announced triumphantly. “Submerged contact, bearing two zero five, slow left drift, down Doppler!”

“Confirm down Doppler. It’s headed away from us?” Samant asked quickly.

“Yes, sir, it’s trying to open the distance, but we’re faster. Range is decreasing. It’s headed westerly.”

“Good, I’ll hold this course, then. What does it look like?”

“I can’t say, sir. Only a weak tone around forty hertz. Maybe an electric motor?” Lieutenant Rajat had put the senior sonar rating on the set. The captain trusted his ears.

“Nothing else?”

“It’s not like any submarine I’ve ever heard. It’s far too quiet. Forty hertz suggests a relatively high rotation rate if it’s a propulsion motor, but that’s all I can say. Contact is drifting slowly to the left.”