USS Goldsborough, Jacksonville Operating Areas, Friday, 25 April; 1230
“Captain’s in Combat!”
Mike entered the darkened central control area of the CIC and went directly to the plotting table, where a small crowd of officers and enlisted operations specialists were staring hard at the plot.
“What’ve we got, John?”
The CIC officer scooted his stool forward and pointed down to the plotting paper, where the NC-2 plotter was marking a small dot in red pencil on the tracing paper. The dot was the most recent in a trail of red dots which began about five miles east of the Goldsborough, and which was now tracking southeast. The spacing between the dots was supposed to be proportional to the target’s speed, but sonar was notorious for offering up ambiguous velocity data. The plot showed that the distance between the Goldsborough and the underwater contact was slowly closing, after remaining steady for five minutes. Mike stared down at the plot, and then reached over and keyed the intercom squawk box to sonar.
“Sonar, Captain, tell me again why you think this contact is any more valid that all the other ghosts we’ve stirred up out here this week.”
Linc’s voice came back over the box. He had been in
sonar control for six hours, and had stayed past his watch time when this contact was detected. His voice was husky with fatigue.
“Captain, this one’s got substance. I’ve got Chief Mac on the stack and the audio on the wall speaker, and this goblin’s got some meat on him. We hold him in a stern aspect, going deep, with varying doppler—marked down doppler when we first turned to look at him, then much less, and then again down doppler, like someone’s trying to peel off the clues while we’re sniffing around.”
Mike felt the first stirring of apprehension as he listened to the ASW officer. The classification of a sonar contact was an art; one added up the cues and clues and made the call, and even then, the guy could get away while you were still trying to decide what you had. A new thought intruded: if this turned out to be a hostile submarine, how prepared was Goldsborough for a surprise attack?
“OK. If he’s going deep, you want to go to directional? It might be worth it to get a solid ping on this thing before the layers bury it.”
Mike noted that he was speaking about the contact as if he had already decided that it was a submarine.
“Yes, Sir, I think we better. We’ve followed doctrine so far—no changes which might alert the target that we’re on to him, but this is the Stream—”
“Right, OK: go to long pulse on the bearing and knock on his door; make sure you’re taping all of this, too.”
“Oh, yes, Sir, we have been. Video and audio. Sonar shifting to directional transmission.”
Mike released the squawk box key, and turned to the Evaluator.
“Evaluator, set up condition 1AS; if we do have a live one out here, I want the underwater weapons ready. Tell Damage Control Central to set modified condition zebra below the main deck.”
“Aye, aye, Sir.”
The Evaluator picked up the ship’s announcing system microphone, and passed the word to set Condition 1AS throughout the ship. Moments later, the Exec and the
Weapons officer came hustling through the door to CIC, followed by the rest of the CIC team.
“We actually have something?” asked the XO.
“Don’t really know, XO,” replied the Captain. “But if we do I don’t want to be sitting out here in condition Sunday drive.”
The XO nodded, and went out to the bridge to check the setting of condition 1AS. Men continued to come into CIC as the increased manning of weapons and sensor systems was implemented.
Condition 1AS was a variant of general quarters, wherein all of the anti-submarine warfare stations were manned up, and certain watertight doors were closed below decks in case a contact turned into a fight. In Goldsborough, 1AS meant that CIC and Sonar control were fully manned instead of having just enough men to operate the basic equipment. The anti-submarine torpedo tubes were manned, and all the air flasks which propelled the torpedoes over the side were charged up with high pressure air. The depth charge rack station was also manned on the stern, where the men removed the covers on the ten 500 pound depth bombs and inserted arming plugs and hydrostatic fuzes. In the Sonar Control room down on the 3rd deck, well below the waterline, senior sonarmen took over the sensor consoles and the attack director. In CIC, the plotting team was doubled and augmented with more experienced and senior technicians. The three principal officers in the ASW tactical team put on sound powered telephones and established a control circuit, where ship maneuvers, contact information, and weapons control could be coordinated directly by the tactical team.
“Shifting to long pulse, directional mode,” called Sonar control on the squawk box.
Mike walked over to his Captain’s chair, which was set up at one end of the plotting table, and climbed in. The tactical team members closed in around the plot, and waited for the sonarmen below to report.
Mike thought about the contact. Young Linc had spent almost his every waking hour down in sonar, watching the
watch teams as they probed the turbulent waters of the operating areas along the Gulf Stream for signs of something besides marine life and seamounts. They had mapped large portions of the bottom, refreshing charts and recording any larger underwater objects which might confuse a submarine search.
Mike was still convinced that this whole submarine thing was an enormous waste of time. He was also very disappointed about missing the fleet exercise, and now the maintenance world wanted him shut down for an entire week in order to work the main feed pumps. This meant another week alongside the pier coping with all the shoreside “help.”
He recalled the Commodore’s words of advice about command, and still had half a mind to ask for a short tour. He was probably going to have to retire just like his ship. He thought about where he might go after the command tour, and drew a complete blank. Most Commanders were promoted to Captain at the end of their ship command tours; those who were not usually went to dead end jobs, or retired as soon as they had accumulated their twenty years. He would reach the end of his command tour and his twenty at about the same time. He shook his head mentally to get himself back to the current ASW problem.
“Sonar contact!” announced the squawk box. “Definition sharp and clear, doppler is down, bearing 112, range 10,500 yards; echoes intermittent due to layers.”
The Operations officer, who was the Evaluator for Condition 1AS, spoke rapidly into his sound powered phones.
“Bridge, Combat, increase speed to fourteen knots, come right to 112.”
He looked over at the Captain. “Bearing’s clear, Captain. I’m going to close him a little; Linc thinks he’s going deep.”
“He really got doppler on this thing?”
“Yes, Sir. Good down doppler.”
“Evaluate possible submarine, confidence medium,” reported the squawk box. “Bearing 110, range 10,000 yards.”
Mike leaned forward.
“Change keying frequency, down one band,” he ordered.
The Evaluator relayed the message to sonar. The plotters bent over the table, keeping up the marks with the red light from the NC2 plotter. Now that the sonar had contact, the plotting table’s circuits were tracking the contact automatically. The other watchstanders in CIC were eavesdropping hard on what was going on at the plotting table in the center.
“Keying frequency changed one band; contact remains strong; echoes still intermittent due to layering. Bearing 108, range 9700 yards.”
“Is this an area we’ve mapped with the bottom recording system?” asked the Weapons Officer.
“Yes, Sir,” replied the CIC Officer.
“What’s on the bottom around here?”
The CIC Officer tapped in some search codes on the PC. “We’re on the edge of the inner Gulf Stream boundary; we have the beginnings of several parallel, shallow canyons that run east west about ten miles out to the shelf. According to the PC, there is only one significant wreck, a tanker that went down in 1946.”
“Can we get the bearing and range of the wreck from our present position?”
“Yes, Sir, I think so. Surface Supervisor, give me a lat-lon!”
A young operations specialist read the dials on the dead-reckoning tracer table, and called out the current latitude and longitude. The CIC Officer keyed in the geographic coordinates, and then rolled the cursor over to the charted position of the tanker.
“Sir, it’s 130, eight miles from our current position.”
The Weapons officer turned around in his chair to look at Mike in his Captain’s chair.
“Right where this contact is headed, Captain,” he said.
“If it is a submarine,” mused Mike aloud. The squawk box erupted again.
“Sonar has no echoes, last bearing was 122, last range was 8500 yards. Attack director is in PK.”
Mike acknowledged this report with a sigh. It figured;
they had been lucky to hold on to this contact for as long as they had, given the water conditions. He had not had much faith in it to begin with, and now the contact had disappeared just like all the others. Linc had put the underwater weapons fire control computer in the Position Keeping mode, which assumed that the contact would keep going on the last computed course and speed. The computer kept the sonar’s display cursor pointed at the predicted position of the contact, in case the echoes emerged again. Mike leaned forward.
“OK, guys, I think we’ve locked on to another hydrospook. Weps, ask Linc if he wants to keep playing with this anymore.”
The Weapons Officer picked up a handset and held a brief conversation with the ASW Officer, nodding as he listened. Mike heard the words “wreck” and ranges and bearings being exchanged.
“OK, Linc. I’ll tell him.”
He hung up the phone and turned to the Captain.
“Sir, Linc wants to go silent on the sonar and continue down this last bearing at twelve knots, below cavitation speed. He wants to drive in for about four miles, and then light off again, see what we turn up. He really thinks this was a valid contact.”
Mike thought for a minute. The ASW Officer always thought that the last contact was a good contact, a possible submarine. This was normal; the ASW officer was supposed to be aggressive. But Mike thought he knew what would happen next: they would pursue the matter for another twenty minutes or so, light off the sonar again, and gain contact on the wreck on the bottom. The whole 1AS team was waiting for his decision.
“And what do you recommend, Weps?”
Mike had learned this ploy at the Navy’s surface command school: if you can’t make up your mind on what to do, ask your subordinates for a recommendation. One of them might know or illuminate the right answer, and it gave you time to think some more.
“We’re out here, and this is the strongest contact we’ve
had,” said the Weapons Officer. “It doesn’t cost us anything to keep screwing around with it. Linc thinks this guy is headed for the wreck, either to hide or to throw us off the scent. He wants to go ping around the wreck.”
“OK, OK, you guys do what you want to. I’ll sit here and watch.”
The Weapons officer grinned. “Yes, Sir!”
Mike watched as the Weapons and Operations officers used the PC to refine a course that would allow the ship to pass over the wreck, some 500 feet below the surface. The Exec came back into Combat to see what was going on, and Mike brought him up to speed.
“Gonna let the guys screw around with it for a while; there’s nobody else out here, they like to do it, and it builds up their self confidence,” he explained in a low voice, as the officers crowded back around the plotting table, and the Weapons officer sent new course and speed orders out to the bridge.
“They thought about how they’ll distinguish between a wreck on the bottom and a submarine hiding nearby?”
“Presumably with Linc’s PC magic, but they haven’t thought that far ahead, XO. One thing at a time,” smiled the Captain.
Mike knew that it was going to be hard enough to pass over or even near the wreck, given the vagaries of navigation when beyond radar range of land. If there were a submarine here, it would probably drive by the wreck, presuming the sub knew it was there, and then slip down into one of the canyons and disappear over the shelf into the deep ocean abyss while the destroyer went around in circles. He called for coffee, and settled back into his chair to watch his young ASW team work. It was one of the few remaining joys of being in a destroyer as opposed to a larger ship—the junior officers could be allowed to run an ASW search by themselves, or almost so, and he could observe without having to direct every detail. The Exec would go out to the bridge to make sure they didn’t run over a fishing boat in their enthusiasm. And then hopefully they could go back into port for the weekend.
The Al Akrab, submerged, Jacksonville Operating Areas, Friday, 25 April; 1240
“Eight knots,” ordered the Captain. His forehead was damp with perspiration, and his uniform was getting sticky.
The depth gauge continued to hold steady; the whine of the pumps beneath the deckplates of the control room competed with the creaking and crackling noises coming from the pressure hull. The needle backed off to 129, and then 128.
“Get her level. Now. We need to turn.”
The Musaid continued to coach the planesman as he adjusted bow and stern planes to bring the boat level. As the water was forced out of the negative tank, the boat became more responsive.
“Come port to 040, small rudder angles,” ordered the Captain.
He knew that if he could bring the submarine’s heading around to a course perpendicular to the oncoming destroyer’s search axis, the net effect would be to nullify the doppler on any returning echoes, regardless of his speed. The tradeoff was that he would now present the whole length of the submarine to the probing sound rays, but he counted on depth and the swirling acoustic layers of the Stream to mask the larger target he presented.
“Depth unstable,” called the Musaid urgently, putting his hand on the helmsman’s shoulder to stay the turn order.
Turning without depth control could spell disaster because the planes would induce rolling moments. The Captain looked at the depth gauge needle; as it cycled between 128 and 130. The submarine was porpoising, creating a shallow roller coaster ride as her buoyancy changed. The pumps continued to mill and grind.
“Commence the turn! Now! I need to show him null doppler,” shouted the Captain.
The Musaid removed his hand, his face stiff.
“Helm, Aye. Commencing the turn,” responded the
helmsman, his voice cracking. The other men in the control room were frozen in position, afraid to look at one another.
“Sonar, what is the destroyer doing?” demanded the Captain, his voice more under control.
“Sir, he continues to ping in omnidirectional mode; the bearing is beginning to draw right; I don’t think he—”
The sonar operator suddenly opened his headset away from his ears, and then reached forward to the console to make an adjustment on the audio volume. He did not have to tell the Captain or anyone else in the control room why: the drawn out, ringing sound of a powerful directional sound pulse was reverberating in the control room. The men looked nervously at one another, and swallowed. A second long ping. The men had to hold on as the submarine rolled to one side, and then the other, as the rudder took effect. The Captain’s face tightened.
“Prepare to release a decoy. Quickly.”
The Deputy jumped from his station at the plotting table, and opened an air valve to arm the starboard decoy tube. There was a small hiss of air as the firing chamber filled to 3000 psi.
“Decoy tube is armed, Sir.”
“Very well.”
Now, thought the Captain, they would have to wait. It all depended on how determined this enemy was. He did not know how long this destroyer had been out looking around the operating areas. They had returned from the mothership in the early hours of Thursday morning and detected the pinging as they closed in submerged from the Gulf Stream. He had to know if this destroyer was actually conducting a search or just out testing his sonar. When his sonar officer had run back through his tapes and determined that this was a sonar they had encountered before, the Captain became suspicious. This destroyer’s presence was no accident. He had determined to shadow it, staying outside the predicted sonar range but near enough to record the enemy destroyer’s search patterns on the passive plot, to learn his tactics, and to appraise his vigilance.
The Captain’s mind raced. Somehow this destroyer may
have detected the Al Akrab. And he was sure enough that he had something other than a school of fish to switch to directional keying. The turn would nullify the doppler, but now the Al Akrab would present her full beam to the enemy sonar. Going deep and the swirling layers above them should take care of that. Should.
“Passing 070.”
“Depth is stable; we can slow,” declared the Musaid, straightening up.
“Slow to five knots; continue the turn to 040.”
“040, Aye. Passing 060.”
The Captain considered the timing of the decoy launch. The decoy was a miniature transponder. It was shaped like a tiny torpedo, three feet long and about four inches in diameter. It had an air driven propeller that would run for about three minutes. In the body of the decoy was a sonar receiver and an amplifier. At its nose was a miniature sonar transmitter. The decoy could detect the incoming sonar pulse from the destroyer’s sonar, match its frequency, introduce some slight doppler shift, and ping back at the destroyer. The destroyer’s sonar would see a solid echo since the decoy’s response, however muted, was always stronger than the faint, real echo from the submarine. The destroyer’s sonar tracking circuits would then lock on to the decoy, while the submarine stole away into the depths.
The key to success was the timing of the decoy launch: if the enemy was in firm contact, the decoy would show up as a second contact and be exposed as a decoy, thereby confirming the presence of a submarine. If the enemy sonar had lost contact, the decoy could trick the enemy operator into thinking he had regained contact. The Captain listened carefully to the directional ping.
“Passing 045; steadying on 040.”
His new course was almost seventy degrees off the original course, enough to strip off most of the doppler effect, but not so far north that he would emerge back out of the protective thermal layers of the Gulf Stream. The long pings were not so loud now. The Captain made his decision.
“Release the decoy!”
There was a relatively loud thump as the decoy was expelled into the depths, pointed behind and below them. They could not know precisely which way the decoy would go, only that it would begin to transpond after thirty seconds. The Captain stared at his watch.
“Speed ten knots,” he ordered when the thirty seconds was up.
He would make a dash to the northeast, while hopefully the destroyer would lock onto the decoy as it careened along to the southwest at random depths.
“Ten knots, aye.”
The boat surged forward perceptibly. The long pinging was still audible, but its frequency had changed. Everyone in the control room listened and waited. Then the pinging suddenly stopped.