The chief yawned and took a sip from her own coffee. “What have you got, sir?”
The ensign echoed her yawn. “Not a hell of a lot, Chief. We’re about two and a half hours into Passive Search Plan Delta. No luck so far.” He looked up at the clock. “We don’t roll over to a new Zulu-day until after your watch, so you don’t need to worry about updating call signs or loading new-day crypto.”
He yawned again and was about to start a rundown of all surface contacts being tracked by radar and sonar, when the Sonar Supervisor’s voice came over the net. “USWE — Sonar, request clear-or-foul, bearing three-zero-seven.”
Cooper slapped his palm on the CDRT’s trackball and slewed the cursor over to three-zero-seven. His heart skipped a beat. There were no surface symbols on the plot anywhere near that bearing; the SPY-1 radar had no contacts. But it might still be a small craft. Sometimes wooden boats, especially those with low profiles, didn’t show up very well. He keyed his mike. “Bridge — USWE, request a visual clear-or-foul, bearing three-zero-seven.”
The reply came back in less than ten seconds. “USWE — Bridge, your bearing is clear. Lookouts report no surface contacts to thirty degrees either side. Mast-mounted sight shows negative visual and negative infrared.”
Ensign Cooper swallowed. Instantly awake, his fatigue and boredom were forgotten. He keyed his mike. “Sonar — USWE, bearing three-zero-seven is clear. Tag it, bag it, send it to fire control, and then call it away.”
A few seconds later, speakers for the 29-MC announcing circuit crackled to life all over CIC. “All stations — Sonar has passive broadband contact off the port beam, bearing three-zero-seven. Initial classification: POSS-SUB, confidence level low.”
Even before the contact had popped up on the CDRT screen, Ensign Cooper was punching the button that patched his comm headset into Navy Red. The sync pulse warbled crazily in his ear for a second until the ship’s encryption system synchronized with the encryption system aboard Antietam. He cleared his throat before keying the mike. “SAU Commander, this is Towers. Contact report to follow. Time, seventeen fifty-one Zulu. My unit holds passive broadband contact, bearing three-zero-seven. Initial classification: POSS-SUB, confidence level low, over.”
Less than a second later, Captain Whiley’s voice came over the scrambled radio net. “SAU Commander, aye. Your contact designated Gremlin Zero One. My unit will launch Samurai Seven-Nine in approximately five mikes. Alert status of your aircraft, Firewalker Two-Six upgraded to Ready-Five, over.”
“SAU Commander, this is Towers, roger, out.” As soon as he punched out of the radio circuit, Ensign Cooper keyed back into the USW control net aboard Towers. “TAO — USWE, the SAU Commander has upgraded our helo alert status to Ready-Five.”
The TAO’s voice came back immediately. “TAO, aye. Break. ASTAC — TAO, set Helo Ready-Five.”
The current Ready-Five helicopter, Samurai Seven-Nine was sitting on Antietam’s flight deck, spinning its rotors up for launch at that very second. It would be in the air in five minutes or less — time the screening ships would use to build a firing solution and refine their classification of the contact.
Cooper shifted his attention to the CDRT. Now came the tough part.
The next four or five minutes would be crucial. He needed to know what the submarine, designated Gremlin Zero One, was up to — before Antietam’s helo was in the air.
The first piece of the USW puzzle was in place; they knew the contact’s bearing. Instead of a tidy NTDS symbol, the contact appeared on the CDRT display as a red line extending from the center of the symbol for USS Towers to the edge of the screen. The angle of the line was 307 degrees: the bearing of the contact from Towers. The contact could be anywhere along that line of bearing, at a range of anything from a couple of hundred yards, to hundreds of thousands of yards. To localize him further, they would need to know his range. For an effective firing solution, they would also need to know the target’s course and speed, but that could be estimated with a good degree of accuracy once they knew the contact’s range.
Cooper keyed his mike. “UB — USWE, got anything yet?”
The Underwater Battery Fire Control Operator keyed up. “USWE — UB. That’s a negative, sir. The sonar track is looking pretty good, but it’s going to take me a while to nail this guy down off passive broadband alone. If you want something quick, I’m going to need a turn.”
“USWE, aye.”
If they’d had passive narrowband frequency data on the contact, the fire control computer could have calculated the target’s range based on minute changes in Doppler as the submarine moved through the water. Without frequency information, they were restricted to Target Motion Analysis.
While it would eventually give them the information they needed, TMA could take twenty minutes or more and would require them to turn at least once (and maybe twice) to feed the computer enough changes in bearing rate to do its magic. But turning wasn’t an option right now. He couldn’t afford to open up a hole in the formation. If he did, the submarine could slip through it and get inside the screen’s defenses — which was exactly what had happened to Kitty Hawk.
The ensign stared at the colored symbols on the CDRT. Every thirty seconds, another red line appeared, each one tagged by a tiny set of digits that represented the Zulu time of that particular bearing update. The red lines accumulated slowly. Using only bearings, this was going to take a long time. Too long.
He exhaled fiercely. “Shit.” He keyed his mike. “Sonar — USWE, have you got any kind of narrowband on this contact at all?”
“No discrete tonals, sir. The target is showing a tightly packed cluster of frequencies up around 550 hertz, but it’s so garbled I can’t do anything with it. Everything else I’ve got is too broad and diffused to track or classify. We are definitely not getting anything we can use for Doppler. Request permission to go active, sir.”
Cooper’s answer was immediate. “Negative, Sonar. Remain passive. If we spook this guy, he’ll pop off a shot at us and run like hell.”
Chief McPherson nodded. “Good call, sir. No sense in tipping our hand this early in the fight.”
Cooper tapped his fingers on the face of the CDRT. “Thanks, Chief.
What do you think about having Sonar adjust the depth of the towed array, to see if we can get some useful narrowband?”
Chief McPherson shook her head. “Never violate the second rule of USW, sir: ‘If you’ve got contact, don’t screw with anything.’”
“We’re running out of time, Chief. Antietam’s helo is going to be airborne in …” he checked his watch—“about two minutes.”
“It’s your call, sir,” the chief said. “Until we finish our watch turnover, you’re still the USWE. But if it were me, I’d say screw the helo. That’s a LAMPS III bird, strictly re-detect and attack. They’re not set up for search. They’ve got no business launching until we have the contact localized.”
A hand squeezed Ensign Cooper’s shoulder. He looked around to find the captain standing behind him. “Listen to your chief, Pat. I can’t count the number of times I’ve seen somebody lose contact because they were futzing with equipment line-up, trying to get a better picture.”