Scorpion in the Sea

by P. T. Deutermann

  “Well,” observed Mike. “That’s what happens when you lose an ASW action; one or the other of you gets to spend eternity in a drowned ship.”

  The officers at the table shifted uncomfortably at this reference to death at sea.

  “There’s some tin cans out there along the coast along with those U-boats,” Mike continued, “not to mention a lot of dead merchies who were deep fried in burning oil when the U-boats got lucky. A torpedo hit on a destroyer is usually the end of the world; our training battle problems, where the script reader calls out, Torpedo hit, forward, does not begin to convey what it would be really like. We have to train for it, of course, but in most cases we’d have a minute or so to collect our hat, ass and overcoats and step into the sea.”

  “Well,” interjected the XO, “if you got hit on the bow or stern, you could do some damage control and probably keep her afloat. But for a torpedo amidships, I agree, we’d be wasting our time trying.”

  “Kinda like this little witch hunt we’re on, XO?” asked Ops.

  He had apparently remembered the Captain’s initial comments about the fishing boat incident. Mike glanced at the Exec before answering.

  “Well, it’s true we haven’t found any submarines; on the other hand, let’s review the facts: we’ve had a fishing boat Skipper sight what he thought was a submarine, and then we’ve had another fishing boat, skippered by a very experienced guy, go down for no apparent reason with no survivors or even a trace of the people onboard. Both of these events are unusual, and maybe, remotely connected. Some of what we’re doing is window dressing, of course; make the Navy look like it’s at least a little concerned. But, if nothing else, it’s been some good training, as well as producing some very unique knowledge about the local operating areas. If we ever had to fight our way out of Mayport in wartime, this stuff Linc’s team has put together would be invaluable, especially for shallow water ASW.”

  The sound powered phone under the table at the Captain’s chair buzzed twice. Mike picked it up, as the table went quiet.

  “Captain.”

  “Yes, Sir, Cap’n, Evaluator in Combat here; Linc’s guys think they have something worth looking into.”

  “Like?”

  “Yes, Sir. Sorry. An active sonar contact they’re classifying as possible, confidence low to medium, definition metallic. The guys got onto it about five minutes ago, and were about to drop it when it appeared to take off. Doppler went from no to audible down. Linc wants us to head back east, 110, to take a better look.”

  “OK, I concur. Don’t change the keying interval or make any other indication that we might have detected something. And make no reports to the beach yet; if this is another false alarm, I don’t want to interfere with the come-back-home message we expect any time now.”

  “Roger that, Cap’n.”

  Mike replaced the phone under the table. He looked up at the officers.

  “Line thinks they have something,” he announced to the table. “We’re gonna go take a look.”

  He turned to the Exec as he pushed back from the table.

  “XO, let me know when we hear from the Group. I’m going up to Combat.”

  TWENTY-FOUR

  The Al Akrab, Jacksonville Operating Areas, Friday, 25 April; 1215 “Idiot!” hissed the Captain, bursting into the control room. “Reduce speed to four knots! At once!”

  The alarmed watch officer relayed the order swiftly, and the boat quickly began to decelerate from the sudden burst of speed ordered only two minutes ago.

  “Make your depth 120 meters; flood negative—we must get some more layers above us.”

  The control room watch was tense, every man sitting upright in his chair. The Musaid, his face drawn and haggard, loomed over the planesman, coaching him softly as they worked to get the boat deeper without making any telltale noises. Any further telltale noises. The distant destroyer had changed its search pattern suddenly, and headed directly towards them. The Watch Officer had reacted by ordering a burst of speed to get away, followed by a depth change. Only then had he called the Captain, who was already on his way to the control room when he sensed the boat surging forward on the electric motors.

  The Captain scanned the gauges swiftly. “Sonar, report.”

  “Sir, the enemy destroyer is closing from the west; I hold him on the port quarter, but he’s drifting in and out of my baffles. His speed appears to be unchanged. He’s still in omni transmission mode, no frequency change. No new keying rate.”

  The Deputy looked up from the sound plot at the back of the control room. “Bearings indicate he has altered his pattern of search; bearings have steadied.”

  The Captain cursed again. They were on the battery, so engine noises were not the problem. Doppler was the problem. If the enemy sonar operator had suspected he had a real contact, and focused on it at the same time the Al Akrab increased speed, the audio on the destroyer’s sonar would have shown down doppler, and thereby, motion away from the destroyer. Doppler was one of the crucial classification cues; marine life rarely showed doppler. As soon as he had entered the control room, the Captain had taken the speed off, and dived deeper to get more acoustic layers of water between the boat and the destroyer.

  “Range?”

  “Estimate the range to be 12,000 yards; there is no way to tell if he is closing or not,” said the Deputy from the plotting table.

  “Bearing 280. Steady bearing.”

  The destroyer was coming their way. Something had attracted his attention. Much would depend on what the destroyer did with his sonar. The next clue would be if he went to directional keying, pumping out all the acoustic energy in the direction of where he thought he might have a contact, rather than his present mode of banging out the ping in all directions.

  “Sir, depth is passing through 70 meters. Negative tank is flooded.”

  “Make your heading 110; speed five. Level off at 120 meters.”

  “Planes, aye, 120 meters.”

  The Musaid was trying to get the Captain’s attention. There was a distinct note of apprehension in the planesman’s voice. Three hundred and sixty feet was approaching the submarine’s extreme operational depth capability limit. The boat’s hull was already beginning to make small groaning and popping sounds as the steel hull compressed under the increasing pressure of the sea.

  The Captain cursed again, silently. This was partly his own fault: he had ordered the watch officer to stay within five to ten miles of this destroyer ever since they had returned from the mothership and heard the steady pinging of a searching sonar. He glanced over at the Musaid, who looked swiftly at the rate of descent dial.

  “100 meters; preparing to blow negative,” he said.

  “No!” interjected the Captain. “Pump negative; increase speed if you must to hold her, but no noise. No air.”

  The men controlling the dive scrambled to line up the valve manifolds. The negative tank, a large seawater ballast tank with oversized water-admission valves, sat astride the submarine’s center of gravity, and was used to make quick changes in the submarine’s buoyancy. Flooding the negative tank made the submarine immediately heavy, thus rapidly accelerating a diving maneuver. When the boat approached its ordered depth, the normal procedure was to force compressed air back into the tank and thus blow the seawater out, thereby quickly restoring the submarine’s neutral buoyancy. Depth was then maintained with careful use of the trim tanks, much like an airplane is trimmed up to stabilize flight once the climb to altitude has been completed.

  The Captain was aware that the blast of compressed air from the flasks would send out a transmission of broadband noise. His order to pump out the negative tank with relatively silent electric pumps rather than using a blast of high pressure air was driven by the tactical necessity for silence. The price for silence was delay: pumping took much longer, especially against the pressure of almost 400 feet of depth. The delay, in turn, meant that the boat would settle past its ordered depth unless speed was increased so that she
could be held at depth by the force of the water flowing over the forward and after planes.

  “120 meters,” sang out the diving officer, his forehead glistening with sweat.

  The hull was complaining audibly now, creaking and groaning throughout the boat. A fine mist had appeared in the air ventilating system, casting a thin aurora around the lights. The men in the control room tried hard to ignore the signs and sounds of the implacable grip of the deep.

  “123 meters; I’m having trouble holding her. Request eight knots!”

  “Eight knots,” replied the Captain.

  His eyes, like those of every man in the control room, were fixed on the depth gauge. The black needle was inching around clockwise, past 125, 126, as the diving officer manipulated the bow and stern planes to put a shallow up angle on the boat, using the increased speed. The needle went to 127, and then to 128, as the boat mushed down into the depths. The boat inclined more sharply, and then levelled slightly. The diving officer had to take great care. He could put too large an up angle on the boat and cause it to stall like an airplane and even slip backwards. The key was to get the negative tank pumped out.

  “We cannot hold her,” declared the Musaid softly. “You will have to blow negative.”

  “No. Continue pumping. Ten knots.”

  “Ten knots, aye.”

  The depth gauge now indicated 130 meters, over four hundred feet of depth. The temperature was rising in the boat. At the back of the control room, a sailor surreptitiously closed the watertight hatch. The mist effect was more pronounced.

  “Steady yourselves,” growled the Captain. “We have taken this boat to 170 meters before.”

  He continued to watch the depth gauge; the needle was holding at 131 meters, as the extra speed took effect. His mind raced. The problem was now, once again, doppler. He could not maneuver the boat off the destroyer’s search axis until he had depth control back in hand, and the boat was now driving away from the enemy’s sonar at a speed which was definitely not typical of marine life. He desperately needed to make a turn.

  TWENTY-FIVE

  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.”