Scorpion in the Sea

THIRTY-ONE

The assembled group of officers and chief petty officers rose in unison as Mike came into the wardroom. There were more people present than he had expected. Besides the Exec, the Weapons and Operations officers, the Combat Information Center Officer, Linc Howard, and the principal chiefs in CIC and Sonar Control were gathered around the green, felt-covered table. Mike greeted everyone and sat down, turning his coffee cup over in its saucer to allow the mess attendant to pour coffee. The others resumed their seats. The Exec opened the meeting as the mess attendant withdrew.

“Captain, the combined CIC and Sonar control officers are present this morning to brief the contact we had in the opareas last week. Our focus is on evidence which would indicate that it was a submarine and not something else, as you directed. The Senior Chief Operations Specialist, Chief Marnane, will present Combat’s material, which consists of a recapitulation of the track charts from the first three days of operations, our findings during that period, and then the track charts during the contacts of interest. The Chief Sonarman, Chief Mackensie, will present a set of audio tapes which have been edited to show the contrast between the general garbage contacts gained in the first three days and the contacts we’re interested in. Petty Officer First Class Magruder, the leading sonarman, will present the sonar video tapes, again contrasting the general, run of the mill contacts with the two contacts of interest. I’ll present a wrap-up and conclusions, if that’s acceptable, Sir.”

“Sounds fine, XO. Before you proceed, I want to apologize to everyone for your having to come in on Saturday morning. I’m going to see the Commodore first thing Monday morning, so there’s no other time to do this. Go ahead, please.”

The faces ringing the table were serious; some of the petty officers looked as if they were uncomfortable being in the wardroom.

Senior Chief Marnane, a slender and balding man whose face looked older than his forty-one years of age, rose and went to the briefing easel at the end of the table. He carried a stained and chipped coffee mug held loosely in his left hand; he was never without it. He folded back the cover sheet.

“Cap’n, XO, this first chart shows the whole operating area that we laid out from day one, with the planned tracks. You can’t see it from that end, but we also highlighted the major bottom topography features — seamounts, holes, wrecks, pinnacles — that we expected to see on the search and survey. We made detections on all of the expected features, and some we didn’t know about, and we entered all of them into Mr. Howard’s PC program that correlates bottom contours and features to the sonar picture. We spent Monday here, Tuesday in this area, here, Wednesday going along here, and Thursday, up to noon, in this sector, here.”

Mike nodded his acknowledgment.

“At around 1230 on Thursday, we gained contact on Goblin Alfa Three,” the Chief continued. “Initial contact was gained at this position here on the overall track. I’m now gonna shift to my second chart, which expands the contact of interest area.” He flipped the easel paper to the next chart.

“We picked up Alfa Three here, that’s the red line, and held him for six minutes. He initially displayed no doppler, and then he displayed down doppler, which correlated with both his track away from us and his computed speed. We lost him right here, at a last bearing of 137 and range of 8200 yards. We reacquired Goblin Alfa Three, or at least we thought we had, four minutes later at bearing 110 and range 8900 yards. After a minute or so, we recategorized the reacquisition as a new contact, Goblin Alfa Four, because it came up too far away from the tracking probability lines of Alfa Three. It also was showing up doppler, indicating a track towards us, and some features which we’ll talk about in the audio part of this pitch that caused both us in CIC and the guys in Sonar Control to call this contact a decoy. Any questions so far, Sir?”

Mike leaned forward. “Yeah, Senior Chief: what were the nearest bottom topographical features to the contact area of both goblins?”

The senior Chief pointed to the area of the chart where the background area changed from light blue to dark blue.

“The nearest plotted feature was a wreck, bearing 080 at a distance of 14,000 yards from us. We had plotted that wreck once before, and it was in our PC survey data base system.”

He shuffled the charts around.

“It’s right here on the big area chart. Directly east of the contact area, which is under the inshore margin of the Gulf Stream, is the edge of the continental shelf. This area has a series of submarine canyons, oriented east-west, where the edge of the shelf fractures and drops off from an average of 500 to 600 foot depth to about 10,000 feet.”

“Is it possible, Senior Chief,” asked Mike, “that either of these contacts could be vortices spinning off the Gulf Stream in the area of those canyons? You know what I’m talking about?”

“Yes, Sir, we’ve looked at that, and the area handbooks talk about them, sorta undersea versions of a dust devil. But Chief Mackensie is gonna show you why we don’t think that’s what these guys were.”

“OK, continue.”

“Yes, Sir. I gotta say we got a lot of useful data on the PC project — Mr. Howard’s program to correlate the visual image on the sonar stack with the feature that’s plotted on the bottom contour charts. In some cases, we had to correct the chart because the feature, a pinnacle, a wreck, whatever, wasn’t where the chart said it would be. But the unique stuff we got is the comparison between what the contact looked like on the sonar display, from a couple of different directions, too, and what the feature was. The mine hunting people already use this technique; they call it bottom conditioning, but they’re working with very precise, high definition, and short range sonars, not an SQS-23 like we got. So, anyways, we got some video images to go with specific features on the bottom. We didn’t cover every feature out here in the opareas, of course, but we got quite a few. And we got some on the contacts of interest, only because we had the video cameras running for the PC project when we made the contacts.”

“Very good, Chief. I want to have this project written up for the tactical improvement program, regardless of what comes of these two contacts.”

“Yes, Sir, Cap’n,” said the Operations officer. “We’ve got that project underway.”

The Chief continued his briefing.

“Yes, Sir. OK. I’ve shown you the overalls and the local tracks. Chief Mackensie will now run through the audio stuff; I’m gonna help him with the PC side of it, and we’ll leave the track charts up, because we need to show where it was we heard what, if you follow me …”

Chief Mackensie got up, as did Linc. Linc had a portable PC set up on the wardroom table, and the sonar chief had two bulky reel to reel tape recorders sitting on the serving counter next to the wardroom table. A tangle of wires led from each recorder to one of the wardroom’s hi-fi speakers in a corner. The sonar chief, an intense technical specialist who was ten years younger than the Chief Operations Specialist, began his presentation.

“Captain, XO, I’m gonna let you listen to a series of contacts we got during the first three days of the operation. Mr. Howard, here, will run the PC display in parallel with what we hear, and Chief Marnane will show you on the overall track charts where we recorded each of the contacts we’re gonna listen to. We’ve selected a sample of contacts so we can show you a wide variety of things: disassociated marine life, a whale, a surface contact, a wreck, marine life around a bottom feature, and the turbulence of the Stream itself. I’ll let you hear active and passive takes on these kinds of sounds, and I can let you compare the two. Then I’ve edited a tape which will let you compare the sound of Alfa Three and Four with the contacts from the spectrum which would most likely be confused with a real contact. OK. This first contact is what we call disassociated marine life: a school of fish, a swarm of shrimp, even a cloud of plankton. The first segment is passive: audio in the range of the human ear that this kind of sound source makes over an open speaker in sonar.”

The Chief turned on the tape, and the eerie, reverberating sussuration of life under the seas boomed out into the wardroom. Mike was startled, as were the other listeners, by the scale of it. He had heard sounds like this in ASW training as a junior officer, and on National Geographic television specials, but the incredible diversity of the individual noises was impressive. The Chief let it run for about thirty seconds, and then shut it off.

“OK,” he continued, “that was passive. Now we’re gonna hear that same sound source reacting to an active sonar pulse. And this is weird, because a swarm of shrimp, for instance, can feel the hydrodynamic pressure of the sonar pulse as it expands through the water, and they react to it. Scientists call it a biomass: a big gaggle of living things reacting as if the gaggle itself was the living thing, not the individuals. You’ll hear the ping as a click, ’cause, of course, the sonar receivers are blanked during the active transmission so’s to protect them from the outgoing power.”

He turned the tape back on, and a low hiss came up on the speakers. There was an instant of silence, and then a distinct click, followed by a washing sound, followed by the sound of thousands of different sized combs being stroked by human fingertips. The chirring sounds died out as the pulse travelled farther from the ship. There was another click, followed by the same response from the swarm.

The Chief took them through the rest of his underwater sound show, first with the passive audio, and then the response of the living organisms to the punishing pulse of acoustic energy generated by the ship’s sonar dome. In one case the Chief played the frenzied response of a pod of porpoises as they scrambled to get away from the painful sounds of the sonar, which was powerful enough to be a designated defense against underwater swimmer attack. The porpoises literally screamed and wailed as they darted frantically away from the ship and its deadly blast of noise. A trio of whales, audible at a great distance from the ship on the passive bands, stopped their unearthly singing after the first few pulses from the active sonar, as if to protest this alien acoustic intrusion.

Most interesting to Mike, however, was the sound of the echoes coming back from sunken ships. Every marine life target had a blurry characteristic to the echoes, a there-but-not-quite there quality to the sound. The wrecks, on the other hand, especially when caught side-on against a reasonably flat bottom topography, came back with a crisper sound. The Chief made a point of playing samples of this contrast, with the mushy echo of a reasonably good sized whale clearly different from the flat, metallic nature of the steel sides of sunken ships.

Linc Howard ran the video display of the sonar scopes, pictures of what the operators had been seeing during the collection of the audio segments. The display was amber in color, and circular, with the ship positioned in the center, and the sonar pulse represented by a ring of expanding light opening out from the ship. Contacts appeared as crescent-shaped smears of light, tiny croissants blooming on the bearing of the contact, persisting for a few seconds, and then fading out as the pulse travelled out beyond them at 1800 feet per second. Everyone could see what the problem was with the scope video: every contact looked like every other contact, except for the biomass swarms, which looked like cloud formations on the amber scope.

The Chief moved between the tape recorder and the video display, pointing out what each contact looked like. Mike and some of the other officers had to get up and stand in front of the television to see better, and, after a while, Mike could begin to see the difference between a school of fish and a bottom wreck. But it was very difficult. But there was no mistaking the crisp, metallic sound of the sonar hits on Alfa Three; even the video was brighter and stronger. The decoy was even better, too much better, than everything else.

The session in the wardroom was interrupted by the quarter-deck messenger, who told Mike the Commodore’s office had called in on the quarterdeck phone. The Commodore wanted him to call.

“Let’s break for coffee, guys,” said Mike. “I’ll be right back.” He left the wardroom and went to his cabin to place the call.

“Morning, Mike,” said the Commodore. “My duty officer tells me you wanted to talk to me last night. Whatcha got?”

“I need to come see you first thing Monday morning if that’s OK, Commodore: I need to talk to you about—”

“No can do, Michael,” interrupted the Commodore. “I’m outa here for Norfolk tomorrow for the Fleet Commander’s conference. The Admiral, the Chief of Staff, and the other two squad dogs — we’ve all got to go to this thing. Can’t it wait?”

Mike thought fast. From what he had seen already, Linc and his people had indeed found something out there. But he had not yet seen their entire presentation, nor had time to think about it, nor to make a full appraisal of the entire problem.

“Mike?” asked the Commodore impatiently.

“Yes, Sir: is there any chance you can come over here, say in about an hour? There’s something I need to show you, and I can’t really bring it over there.”

“What the hell, Mike: what’s this all about?”

“That mystery submarine, Commodore.”

“What?! Are you telling me you think it’s real? That there’s some sewerpipe screwing around in our opareas?”

“Commodore, I’m not positive, myself. But I think you should see what we’ve got before I do anything further with it.”

“Well, you got that part right,” said the Commodore. “What’d you tell Group last night?”

“Nothing, Sir. Besides, they were focused on the collision. Goldy and the submarine were down in the noise level.”

“Right. Good. OK — I’ll be over at 1130. I’ve got a tee time at 1315, so let’s keep it succinct. Jesus Christ, Mike.”

“I know, Commodore, I know. But I need some more experienced eyes to see this. I’m no ASW expert.”

“Everybody’s an ASW expert,” snorted the Commodore. “That’s why there are so many opinions about it. I’ll see you at 1130.”

“Thank you, Sir.” Mike hung up, and took a deep breath. This was going to be interesting. He headed back down to the wardroom.