by Joe Buff
At the digital-navigation plotting table, Lieutenant Sessions and his team were standing, bent over their main horizontal display. They swayed clumsily as the deck pitched and rolled, with no predictable rhythm they could use to anticipate which way the ship would act next.
As Challenger made an especially violent sudden drop, and then rose like an elevator, Jeffrey gave thanks for this turbulence. His task group was following their entry plan for the Med; its keystone was to do the last thing the Axis expected. This was why Jeffrey was fighting the outgoing tide.
Most of the Mediterranean Sea had very little tidal range; from low to high was only a foot—almost nothing. But the Strait of Gibraltar was different. The tides through the narrow gap ran very strong.
The wind-driven prevailing surface current flowed into the Med from the Atlantic. The surface current was offset by another one underneath. This balancing countercurrent flowed steadily outward, from the Med toward the Atlantic.
When the tide flowed into the Med, it intensified the inward prevailing surface current’s speed. This is what any sailor would expect; it’s common sense.
But when the tide flowed out of the Med, peculiar things happened. At shallower depth, the outflow would be strong along both shorelines of the Strait. Yet in the middle of the Strait, contradicting the outgoing tide, the water down to about 150 feet still flowed inward. All these different currents and tides could run as powerfully as four knots.
When water at one temperature and with one salinity level flowed one way, and adjacent water at a different temperature and salinity flowed the opposite way, extremely chaotic eddies and gyres resulted. This badly garbled local sound propagation. And the outward tide ran at a different speed from the deep, outgoing current; where they touched, one sliding over the other, fluid shear and friction made acoustic conditions even worse.
The sonar speakers confirmed what Jeffrey knew. The gurgling, swishing sounds picked up from all around were uneven, jagged, unsettling. They were much louder than Challenger’s or Ohio’s flow noise would ever be at this speed.
Jeffrey’s task group was using this. Instead of riding an incoming tide—with the ship’s propulsion very slow for total quieting, an old submariner trick—Challenger and Ohio followed a route through the maximum turbulence ever available here. They hugged the southern boundary between the outgoing tide and the incoming shallow current, at the depth where the outgoing deep countercurrent began. Water to port ran westward. Water to starboard ran east. Colder, saltier water beneath the keel ran westward too, but not as fast.
Jeffrey was depending on this turbulence for acoustic concealment. It gave him and Parcelli a fighting chance to be missed by Axis hydrophones of many different varieties, on guard for movement through the Strait by Allied subs.
And staying relatively shallow, but not too shallow, provides several other benefits—though the effect on our odds of survival is rather mixed.
Both subs were below the keels of all but the deepest-draft surface ships; laden supertankers could reach down over 100 feet. Supertankers inbound here should be empty except for ballast, and riding high. It was the outbound ones full of oil, heading from the Middle East to neutral countries like Sweden or Finland, that were accidental submarine killers. By keeping to the south in the Strait, Jeffrey intentionally stayed at the edge of the inbound lane of the shipping traffic-separation scheme. But merchant mariners were notorious for sloppy navigation and for ignoring the rules of the road. Anything could happen.
Then there was the problem of mines. There weren’t supposed to be any in the Strait itself, and the surface traffic in front of the task group served willy-nilly as minesweepers. But a moored mine somewhere in the Med—or protecting the Axis fortress at Gibraltar—might have broken loose and drifted into their path, without being set off for them by some unfortunate merchie. Challenger and Ohio had off-board probes designed to hunt for mines, but these couldn’t be deployed. They were too slow to keep up with their parent subs at thirteen knots, and their active sonars wouldn’t work well in such acoustic turbulence—while any pings from them could betray the task group’s presence.
It occurred to Jeffrey that the Axis had probes and military ocean rovers too. Ohio or Challenger might crash into one and suffer serious damage. The noise of the crash could be loud enough to get noticed. The loss of signals from their probe would surely alert the enemy to investigate more closely—that was the whole point of using rovers for ASW patrols, and of cultivating an ASW commander’s mind-set of vigilant paranoia.
And while cruising at only 150 feet with their sonars underperforming, an enemy helo with dipping LIDAR might see Challenger’s or Ohio’s hull before they had any chance to react and defend themselves.
Milgrom announced another surface contact on the bow sphere. Since this new contact was ahead of them, it was slow: Challenger was overtaking.
Jeffrey watched the contact icon pop onto the tactical plot. The icon indicated an unknown vessel type and nationality. Jeffrey didn’t like this.
Milgrom’s people identified the vessel as a merchant ship.
The icon was updated. Jeffrey began to hear the ship on the speakers. Her screws swished and churned in a manner different from the current-boundary turbulence. She hissed and pounded as her hull cut through the water and met each swell. Then Jeffrey could hear mechanical growling and throbbing from the big diesel engines that modern merchants used instead of steam, and he listened to the humming of her auxiliary machinery. The sounds died abruptly in Challenger’s baffles.
The way that ship’s noise stopped so suddenly reminded Jeffrey of one of his other tactical problems. Because of the close proximity of Jeffrey’s and Parcelli’s subs, plus the bad sonar conditions and the vicious eddies and gyres, only Ohio, aft of Challenger, trailed a towed array. To avoid leaving the area of highest water disturbance—and thus become more exposed—neither sub would circle to do a baffles check in the Strait.
Challenger was blind to her stern, with Ohio acting as Jeffrey’s seeing-eye dog. They would learn soon the hard way if he’d made a wrong decision on this. Ohio’s towed array wouldn’t work well in such troubled waters, and might even snap or be cut at its root by her screw as Ohio dipped and bucked. Plus, when she did make a detection, she needed to send Jeffrey a report via the acoustic link—which could go out at any time.
Long minutes passed. A German destroyer went by from behind, heading inward, then another, presumably returning from the engagement with Dreadnought and Texas. Their hull-mounted active sonars pinged, setting Jeffrey’s every nerve on fire. The Germans acted as if they didn’t notice him, but that might be a trick, to lure his task group farther in to be bottled up and clobbered. Military aircraft overflights were detected faintly; no incoming weapons materialized, at least not yet.
“Enemy’s Gibraltar base off our port bow,” Sessions announced. “Closest point of approach in ten minutes.”
Jeffrey and his crew hunkered down. Gibraltar sat on the north side at the inner end of the Strait, its famous Rock on a long peninsula enclosing the massively defended harbor within a bay. Parcelli’s weapons officer would have his giant battery of Tomahawks pretargeted at Gibraltar now. In an emergency, the task group might wreak enough havoc to battle their way back to the Atlantic—or go down in a blaze of useless glory. The air in the control room kept getting stuffier and stuffier.
Chapter 27
Fresh from a full meal and a catnap, Egon Schneider exercised his privilege as captain of Grand Admiral Doenitz and took a long, hot shower. So far, he was satisfied with the performance of his new ship and his crew.
He dressed in a black jumpsuit and seaboots, and strode into his control room. A junior officer had the conn. Schneider’s einzvo, Manfred Knipp, kept an eye on things. Schneider read different displays, to update himself on the overall situation.
“I have the conn,” he announced. Acknowledgments were duly made, the junior officer vacated his seat, and Schneider sat down at th
e command console. The control-room lighting was red; it was nighttime on the surface.
Schneider’s trip through the whole South Atlantic Ocean at sixty knots had gone well. Doenitz’s sonar men performed repeated self-noise checks using the arrays mounted along the hull. The special superquiet cladding materials layered around the propulsion system’s various components suppressed the flank-speed tonals beautifully. To slow once he reached his station outside Durban, Schneider ordered all machinery to suddenly be turned off. He kept the temperature in both reactors just high enough to prevent the liquid-metal coolant from solidifying.
Nice to not have to worry about any signature from the coolant pumps. With no moving parts, the electromagnetic pumps emitted no decibels at all. Schneider drew electricity temporarily from Doenitz’s massive battery banks. The ship glided to a halt making nothing but flow noise. Then he ordered a patrol speed of three knots, with the turbogenerators back on line. This was enough to let his crew maintain control on the planes and the rudder, and was also enough to let him trail a towed array and recharge his batteries.
Schneider glanced again at his gravimeter display. He liked this setup a lot. The continental shelf by Durban, facing the Indian Ocean on South Africa’s east coast, was very narrow. Only fifty sea miles offshore, the bottom dropped to two thousand meters and then kept going deeper. Before reaching the rises of the Agulhas Plateau to the south, or the Mozambique Plateau to the east, the depth reached three thousand meters—ten thousand feet—and then four thousand plus.
Genuine blue water. Ideal for antisubmarine work.
Manfred Knipp came over. “Respectfully, Captain. Your intentions?”
“No change, Einzvo.” Schneider had taken the conn merely to keep his hand in. He felt no need to justify himself.
“Jawohl.”
Schneider eyed the tactical plot. “I see those two Los Angeles–class boats are still keeping their close blockade on the port.”
Ernst Beck’s damaged von Scheer was being repaired in the hardened underground sub pens dug into the bluff that formed one side of Durban Bay. The whole top of the bluff was crammed with internment camps for American and British businesspeople and tourist families—including hundreds of children—to discourage attack before the von Scheer put to sea. The human shields had all been corralled from South Africa and the countries to her north when the war broke out.
“No indication either Los Angeles unit detected us, sir.”
“Not surprising,” Schneider said dryly.
He had ordered Doenitz into a racetrack search pattern, a long oval, moving back and forth along the coast farther out than the two old American subs. He expected that the high-value targets the Allies would use in this blockade, Seawolf or her sister ship Connecticut, and Challenger or even Dreadnought, would also establish a more distant blockade. The Seawolfs had very strong and thick steel hulls, which let them dive much deeper than a Los Angeles or a Virginia class. They also had more torpedo tubes, and a substantially higher flank speed.
My advantage is, I can move slowly, since I’m already in position where the American vessels will want to be. To get here with reasonable promptness, they need to move much faster than three knots. . . . I’ll be quieter and my hydrophones will have better sensitivity. Sonar superiority, that’s the key to victory in any sub-on-sub battle.
Now it was just a question of continuing to patrol, and waiting—and pretending to be a snooping Russian submarine if a low-value Allied unit somehow came within its own detection range of Doenitz before Schneider’s sonar men heard it, so he could evade. The Boers had been warned that a Russian nuclear sub was in the area, doing espionage on the U.S./UK blockade of von Scheer. This prevented a friendly fire accident, and maintained the subterfuge that Schneider’s ship was a Russian 868U, not a German one.
At the moment, Doenitz was heading southwest, paralleling the coastline on the inshore leg of the racetrack search pattern. The Agulhas Current ran at this depth, one thousand meters, at about three knots. Combined with Schneider’s speed, this let him cover more ground over the seafloor every hour. He’d chosen to make the offshore leg of the oval be the one that went back northeast, because well away from the coast the current was weaker, and worked against his progress less.
Schneider’s intercom light blinked. It was the communications officer, a junior lieutenant in charge in the radio room: Doenitz received a code block through her on-hull ELF antenna, saying Schneider had to prepare to receive a message through the secure undersea acoustic transmitter the Boers had installed in the deep Transkei Basin with help from Imperial Germany.
“Navigator, give me a course to aim our starboard wide-aperture array at the Transkei Basin.”
“One-one-five, Captain.”
“Pilot, rudder starboard five degrees, steer one-one-five.”
The pilot acknowledged. Doenitz turned.
This is irregular. Why are the Boers sending me a message?
The bottom-emplaced transmitter system had much greater range than the sub-to-sub covert acoustic link that Schneider was more familiar with using. He waited for the message to be received.
Eventually, the communications officer decoded the header. It said the rest of the text was in Schneider’s personal captain-only code.
So the Boers relayed it, without being able to read it.
Good.
“Pass the message to my cabin.”
Schneider next addressed the junior officer who’d had the conn before. He’d remained in the control room, standing in the aisle, because he still was officer of the deck for this watch. Schneider told the young man to take the conn, and get back on course for the racetrack patrol.
Schneider went into his cabin and locked the door. He used his private passwords and top-secret software to decode the message. After he read it, he used the intercom to summon Knipp.
The einzvo knocked on his door in a moment—both men’s cabins were only a few paces aft of the control room.
“Sit.”
Knipp did what he was told.
“It seems the high command’s priorities are changing.”
“Sir?”
“They plan a new offensive soon, eastward, by the Afrika Korps. That’s all the message indicates, nothing about its objectives, but I assume it’s been planned for a while.”
“After the battle for the Central Africa pocket?”
This struck a raw nerve in Schneider. That battle was the one where Beck had commanded von Scheer and had not done well.
“The relevant thing for us is that Berlin suspects the Allies have seen the logistic movements preparatory to this offensive, and they might intend a spoiling attack.”
“To break up the offensive before it builds any momentum? Does the message say how?”
“Allied carrier groups, with their escorting submarines, are expected to stop protecting the shipping lanes from the Persian Gulf to the Pacific, and make a sudden lunge toward the Arabian Sea instead. This would get their aircraft and cruise missiles within striking range of our army’s line of advance through Egypt and Israel. We’re ordered to break off our patrol here and proceed at once to the Arabian Sea, and be ready to engage those submarines and carriers. At our discretion, we can enter the Red Sea as well. Further information on enemy naval movements, and permission for us to open fire, will be sent by ELF.”
“Understood, sir.”
“Since time is of the essence, we’ll need to head north at flank speed. This means we need to find terrain that’s shallow enough to mask us as we accelerate.”
“Jawohl.”
Schneider grabbed his laptop angrily. He called up a nautical chart. “We’ll head through the Mozambique Channel.” Between the huge island of Madagascar, and Africa. “Plenty of seamounts and shoals there to hide us while we’re noisy.”
“Understood, sir.”
“Tell the navigator to work out a course.”
“Speed, sir?”
“Twenty knots. We’ll be s
tealthy enough, and that should put us at the start of the Mozambique Channel in one day.”
“Understood.”
“Dismissed.”
Knipp left Schneider’s cabin.
Schneider called up a larger-scale nautical chart. This one showed the whole east coast of Africa, and the western part of the Indian Ocean, as far north as the Arabian Sea.
Once we achieve flank speed, it’s a few thousand miles to my new destination. Another three or four days. Enough time to think up good tactics. But not enough time to get back here before Challenger arrives and von Scheer sails. Whichever way that rematch goes, I’ll never gain command of von Scheer now.
Schneider stared at the nautical chart and cursed.
Chapter 28
Late Tuesday morning, toward the end of his regular office hours as a trade attaché, Klaus Mohr hung up from a puzzling phone call. He sat at his desk and brooded. Traffic noise coming through the open window broke in on his thoughts. A muezzin called the faithful to noon prayer from loudspeakers on the minaret of a nearby mosque. As if in counterpoint, radios and disk players outside blared as each passed by, in cars or held by pedestrians, an ever-changing mix of Western and Turkish and Arabic music that ebbed and flowed in exotic dissonance.
The musical dissonance, and the tug-of-war between theological and secular, seemed to Mohr to reflect his own mental state.
The phone call had left him concerned and confused. The voice was pleasant, female, young, and spoke German with a Pakistani accent. She’d told Mohr she was a secretary at Awais Iqbal’s company. Mr. Iqbal sent apologies that he wouldn’t be able to make the party Friday night; an export-import deal abroad had hit some snags. Instead, one of his local friends would pick Mohr up, with the same arrangements as before. The new person would be Turkish, and unlike Iqbal, he spoke fluent German. Mr. Iqbal hoped Herr Mohr would have a better time than ever.