“I got it a half hour ago on the lateral array,” Jones said. He referred to a subsystem of the BQQ-5 multifunction submarine sonar. Its main component was an eighteen-foot-diameter dome located in the bow. The dome was used for both active and passive operations. A new part of the system was a gang of passive sensors which extended two hundred feet down both sides of the hull. This was a mechanical analog to the sensory organs on the body of a shark. “Lost it, got it back, lost it, got it back,” Jones went on. “It’s not screw sounds, not whales or fish. More like water going through a pipe, except for that funny rumble that comes and goes. Anyway, the bearing is about two-five-zero. That puts it between us and Iceland, so it can’t be too far away.”
“Let’s see what it looks like. Maybe that’ll tell us something.”
Jones took a double-plugged wire from a hook. One plug went into a socket on his sonar panel, the other into the jack on a nearby oscilloscope. The two men spent several minutes working with the sonar controls to isolate the signal. They ended up with an irregular sine wave which they were only able to hold a few seconds at a time.
“Irregular,” Thompson said.
“Yeah, it’s funny. It sounds regular, but it doesn’t look regular. Know what I mean, Mr. Thompson?”
“No, you’ve got better ears.”
“That’s cause I listen to better music, sir. That rock stuff’ll kill your ears.”
Thompson knew he was right, but an Annapolis graduate doesn’t need to hear that from an enlisted man. His vintage Janis Joplin tapes were his own business. “Next step.”
“Yessir.” Jones took the plug from the oscilloscope and moved it into a panel to the left of the sonar board, next to a computer terminal.
During her last overhaul, the Dallas had received a very special toy to go along with her BQQ-5 sonar system. Called the BC-10, it was the most powerful computer yet installed aboard a submarine. Though only about the size of a business desk, it cost over five million dollars and ran at eighty million operations per second. It used newly developed sixty-four-bit chips and made use of the latest processing architecture. Its bubble memory could easily accommodate the computing needs of a whole squadron of submarines. In five years every attack sub in the fleet would have one. Its purpose, much like that of the far larger SOSUS system, was to process and analyze sonar signals; the BC-10 stripped away ambient noise and other naturally produced sea sounds to classify and identify man-made noise. It could identify ships by name from their individual acoustical signatures, much as one could identify the finger or voice prints of a human.
As important as the computer was its programming software. Four years before, a PhD candidate in geophysics who was working at Cal Tech’s geophysical laboratory had completed a program of six hundred thousand steps designed to predict earthquakes. The problem the program addressed was one of signal versus noise. It overcame the difficulty seismologists had discriminating between random noise that is constantly monitored on seismographs and genuinely unusual signals that foretell a seismic event.
The first Defense Department use of the program was in the Air Force Technical Applications Command (AFTAC), which found it entirely satisfactory for its mission of monitoring nuclear events throughout the world in accordance with arms control treaties. The Navy Research Laboratory also redrafted it for its own purposes. Though inadequate for seismic predictions, it worked very well indeed in analyzing sonar signals. The program was known in the navy as the signal algorithmic processing system (SAPS).
“SAPS SIGNAL INPUT,” Jones typed into the video display terminal (VDT).
“READY,” the BC-10 responded at once.
“RUN.”
“WORKING.”
For all the fantastic speed of the BC-10, the six hundred thousand steps of the program, punctuated by numerous GOTO loops, took time to run as the machine eliminated natural sounds with its random profile criteria and then locked into the anomalous signal. It took twenty seconds, an eternity in computer time. The answer came up on the VDT. Jones pressed a key to generate a copy on the adjacent matrix printer.
“Hmph.” Jones tore off the page. ‘“ANOMALOUS SIGNAL EVALUATED AS MAGMA DISPLACEMENT.’ That’s SAPS’ way of saying take two aspirin and call me at end of the watch.”
Thompson chuckled. For all the ballyhoo that had accompanied the new system, it was not all that popular in the fleet. “Remember what the papers said when we were in England? Something about seismic activity around Iceland, like when that island poked up back in the sixties.”
Jones lit another cigarette. He knew the student who had originally drafted this abortion they called SAPS. One problem was that it had a nasty habit of analyzing the wrong signal — and you couldn’t tell it was wrong from the results. Besides, since it had been originally designed to look for seismic events, Jones suspected it of a tendency to interpret anomalies as seismic events. He didn’t like the built-in bias, which he felt the research laboratory had not entirely removed. It was one thing to use computers as a tool, quite another to let them do your thinking for you. Besides, they were always discovering new sea sounds that nobody had ever heard before, much less classified.
“Sir, the frequency is all wrong for one thing — nowhere near low enough. How ‘bout I try an’ track in on this signal with the R-15?” Jones referred to the towed array of passive sensors the Dallas was trailing behind her at low speed.
Commander Mancuso came in just then, the usual mug of coffee in his hand. If there was one frightening thing about the captain, Thompson thought, it was his talent for showing up when something was going on. Did he have the whole boat wired?
“Just wandering by,” he said casually. “What’s happening this fine day?” The captain leaned against the bulkhead. He was a small man, only five eight, who had fought a battle against his waistline all his life and was now losing because of the good food and lack of exercise on a submarine. His dark eyes were surrounded by laugh lines that were always deeper when he was playing a trick on another ship.
Was it day, Thompson wondered? The six-hour one-in-three rotating watch cycle made for a convenient work schedule, but after a few changes you had to press the button on your watch to figure out what day it was, else you couldn’t make the proper entry in the log.
“Skipper, Jones picked up a funny signal on the lateral. The computer says it’s magma displacement.”
“And Jonesy doesn’t agree with that.” Mancuso didn’t have to make it a question.
“No, sir, Captain, I don’t. I don’t know what it is, but for sure it ain’t that.”
“You against the machine again?”
“Skipper, SAPS works pretty well most of the time, but ‘sometimes it’s a real kludge.” Jones’ epithet was the most perjorative curse of electronics people. “For one thing the frequency is all wrong.”
“Okay, what do you think?”
“I don’t know, Captain. It isn’t screw sounds, and it isn’t any naturally produced sound that I’ve heard. Beyond that…” Jones was struck by the informality of the discussion with his commanding officer, even after three years on nuclear subs. The crew of the Dallas was like one big family, albeit one of the old frontier families, since everybody worked pretty damned hard. The captain was the father. The executive officer, everyone would readily agree, was the mother. The officers were the older kids, and the enlisted men were the younger kids. The important thing was, if you had something to say, the captain would listen to you. To Jones, this counted for a lot.
Mancuso nodded thoughtfully. “Well, keep at it. No sense letting all this expensive gear go to waste.”
Jones grinned. Once he had told the captain in precise detail how he could convert this equipment into the world’s finest stereo rig. Mancuso had pointed out that it would not be a major feat, since the sonar gear in this room alone cost over twenty million dollars.
“Christ!” The junior technician bolted upright in his chair. “Somebody just stomped on the gas.”
Jones was the sonar watch supervisor. The other two watch-standers noted the new signal, and Jones switched his phones to the towed array jack while the two officers kept out of the way. He took a scratch pad and noted the time before working on his individual controls. The BQR-15 was the most sensitive sonar rig on the boat, but its sensitivity was not needed for this contact.
“Damn,” Jones muttered quietly.
“Charlie,” said the junior technician.
Jones shook his head. “Victor. Victor class for sure. Doing turns for thirty knots — big burst of cavitation noise, he’s digging big holes in the water, and he doesn’t care who knows it. Bearing zero-five-zero. Skipper, we got good water around us, and the signal is real faint. He’s not close.” It was the closest thing to a range estimate Jones could come up with. Not close meant anything over ten miles. He went back to working his controls. “I think we know this guy. This is the one with a bent blade on his screw, sounds like he’s got a chain wrapped around it.”