Scorpion in the Sea

THIRTY-SEVEN

Sonarman Third Class Francis McGonagle was trying hard to stay awake. It was always the same on a midwatch: the agony of getting up at 2330, the zombie-like walk through the messdecks for some coffee or, occasionally, hot soup, the climb through darkened passageways to the Combat Information Center, and then the turnover in sonar control, where he and his teammate, Petty Officer Paul Barney, went through the motions of assuming the watch, checking the display equipment, adjusting their console chairs and the ambient lights, and then, finally, having burned up a grand total of twenty minutes of their four hour midwatch, came the realization that they had another three and half hours to go. Another cup of coffee to keep the heart turning over; five more minutes used up.

“God, I hate this shit,” muttered Barney, blinking his eyes in the blue light of the CIC.

As usual the air conditioning worked especially well at one in the morning; both men wore jackets over their dungarees to ward off the chill. Barney sat the active sonar console, which contained three large black and white video screens and four panels of control equipment. The active console was side by side with the passive array console, where McGonagle sat, rubbing his eyes for the tenth time in the past ten minutes.

“Yeah, I hear that,” said McGonagle. “This coffee ain’t working, Man.”

“Well, at least you have something to do,” said Barney. “I’m shut down.”

McGonagle grunted. Recording the passive displays on surface diesel engines was not his idea of modern antisubmarine warfare. The night orders, passed on to them by the 20–24 watchstanders, were short and explicit: keep the active sonar in standby, and conduct a passive search in the acoustic frequency bands where marine diesel engines emitted. The night orders did not say what they were looking for, only that they were to cover the entire internal combustion engine frequency band, and record everything, from 2300 until 0600. The previous watch had focused the passive array into the correct frequency bands, and now there was nothing to do but watch the displays and ensure that recorders did not run out of paper.

Sonar control in the Deyo was located in one module of the Combat Information Center, which was four times the size of the CIC in Goldsborough. The CIC in Deyo was compartmentalized into modules, with sonar control and the ASW weapons control center located on the port side of the CIC, which itself was only one deck down from the bridge. At general quarters there would have been twelve men in the sonar section alone, but for an independent steaming situation, there were only two watchstanders. One could have managed with the big, active sonar shut down; there were two to ensure that they both stayed awake.

The active and the passive displays were all synthesized digital video which looked nothing like the older displays in Goldsborough. In place of the expanding ring of light that Goldsborough’s sonarmen studied, Deyo’s active sonar equipment produced what were called waterfall displays, dozens of parallel light lines streaming down a gray screen display that looked very much like a computer graphics depiction of a waterfall. The sonarmen were trained to pick out changes in the gradations and character of the lines which indicated the presence of a return echo. The passive displays were also waterfall screens, but the screen remained blank until the sensitive passive detection array computers actually picked up a sound in the underwater environment, and began drawing a line down the screen. Each line represented both a discrete frequency of sound and a bearing, or direction from which the sound was emanating.

Deyo’s sonarmen were trained to recognize certain frequencies, such as the unique line emitted by all Soviet Navy electrical equipment. Or the equally characteristic line generated by the Soviets’ older, six bladed submarine propellers. Unlike Goldsborough, Deyo’s main sonar armament was the passive array, which capitalized on the same principle that passive electronic warfare used: a signal could be heard well beyond the range at which that signal could tell its originator anything. Goldsborough’s sonar had to push a sound wave out into the water, and then wait for that wave, which was dissipating in power with every spherical meter it travelled from the sonar dome, to hit a contact, bounce off, and return to the sonar receiver. Since the return wave also dissipated with every meter it travelled back from the contact towards the ship, the initial hit had to be pretty strong to complete the cycle. Deyo, on the other hand, listened for the tiny sounds emitted into the water by a submarine’s own machinery or propellers. These sounds ranged in frequency from the very low frequency sound of a propeller beating in the water to the very high frequency, and inaudible to the human ear, squeal of a worn out bearing in a submarine’s pump. These sounds only had to go one way, dissipating in power as they went, of course, but detectable thereby at ranges many times that of active sonar. The target had to cooperate for this system to work, which meant that it had to make noise. Modern, nuclear submarines, with their steam plants and pumps and turbines, were ideal candidates for passive tracking. Diesel-electric submarines, running on DC motors powered by silent batteries, made almost no sound at all. Unless they ran their diesel engines.

“Well, we’ve got at least two of these suckers out there,” said McGonagle, looking up at his waterfall, yawning again.

There was a group of squiggly lines trailing down the paper on the recorder. The screen showed that the sounds being picked up were all similar in frequency, differing only in their bearing from the Deyo.

“Looks like they’re all to the south of us, and pretty close in bearing,” observed Barney.

“Yeah that’s probably the Mayport fishing fleet; one guy finds a school of fish or shrimp, and the others drift over to where he’s working and pretty soon you got a gaggle of ’em. There’s no way we’re going to break out individual contacts when they bunch up like that.”

“You ever go over to Mayport and get a bushel of shrimp and boil ’em up in the backyard? They’re cheap as hell that way.”

“Naw, I hate shrimp. I guess I’m allergic or something. Shellfish tear me up inside, Man.”

“That’s too bad; makes for a good excuse to drink a pony of beer.”

“I don’t need any excuses to drink beer; wouldn’t mind one right now.”

“That’s for damn sure,” said Barney. “Look at all that shit, would you—”

Barney slid his chair over on its tracks to study the passive display. The lines were more numerous now, drawing over one another now, creating a black smear on the recorder’s paper trace, and a confusing jumble of light lines on the video displays.

“I’m gonna have to expand this display,” McGonagle complained.

He made some adjustments, and shifted the frequency scale, which had the effect of separating each line being displayed into a quarter-inch of vertical space. Several new lines began to draw even as he opened up the display.

“Look, there’s another one,” he pointed. “A lot bigger engine, too. Maybe there’s a merch coming out of the St. Johns, and we’re seeing it on the same bearing.”

“What bearing is that?”

“From us, 170 to the centroid of the sound sources.” Barney flipped down an intercom switch.

“Surface, sonar, gimme a bearing to the mouth of the St. Johns.”

He waited for a minute while the surface plotter in the adjacent module ran the bearing, and then said, “Sonar, aye, thanks.”

“That ain’t the St. Johns, Man — river bears 195.”

McGonagle squirmed in his chair. All the coffee was beginning to accumulate. He watched the lines drawing down the plot, beginning to merge again as the sound sources overlapped. He shook his head.

“I can’t see anything useful in all that shit,” he said. He took off his intercom headset.

“I gotta go take a piss. We’ll let the recorder run; the Chief can make out of that whatever he wants. I don’t even know why we’re doing this shit.”

“You know how it is, Man; the officers gotta pretend we’re out here for some reason other than boring holes in the water.”

“Right. Well, tell ‘em we found the fishing fleet for ’em.”

“Roger that.”

McGonagle took off his intercom earphones and departed for the head. Barney watched the waterfall displays, and studied the last set of lines to begin drawing. Deeper tones in that stream, with some heavy harmonics in the low frequency bands. Bigger engine, he thought. Much bigger than the Jimmie V1271’s they usually heard out here. He stood up out of his chair and flipped back along the paper trace coming out of the recorder. There. It had started up right there, after the other two began to draw. Maybe a harmonic set adding from the sound lines of the first two. Naw. Too big. He extracted a red pen from his shirt pocket, and made a little tick mark next to the timeline on the left side of the paper trace. McGonagle would probably laugh at him, but he’d mark it anyway. That way if something came up, he could always say he did in fact see it. They had, after all, said to record any variations in the normal sound patterns. This one was fading in and out of the other two sound groups, like a deeper bass note thrumming in and out of an audience’s audible consciousness. He rolled the paper trace back up to the current drawing, and sat back down to watch the maze of light lines squiggling down the video display like the streams from a leaking paint can cover. It was going to be a long freaking watch.