Straits of Power

his mark.

Bell acknowledged, then said that Ohio acknowledged receipt of warning of the turn.

“Mark.”

Challenger turned and Ohio followed. The formation turn was executed smoothly, no easy maneuver since Ohio handled differently from Challenger.

I have to give Parcelli his due. His people learn well from even the slightest practice.

The Malta Channel area teemed with fish, and with fishing boats and their nets. The shoals and banks of the channel also teemed with offshore natural-gas drilling platforms, which made all sorts of machinery noise — and undersea pipes, which gave off flow noise.

Challenger and Ohio continued on course for the channel. They adjusted their depth for the rising local topography.

As the water became more and more shallow, the background-noise level rose. The highlight, in Jeffrey’s mind, was Mount Etna, a live volcano on Sicily 11,000 feet tall. Magma shifted constantly in widespread underground chambers, and vibrations too subtle for people on land to notice threw valuable extra decibels into the sea. The channel’s current made even more noise, as its lower portions flowed over jagged protrusions from what the chart indicated as “Numerous Wrecks,” or it gushed past platform pylons. The magma displacements created magnetic anomalies.

Merchant shipping continued to churn the waters overhead.

Jeffrey went through the whole series of orders and responses with Bell and Meltzer, to command the task group to slow to five knots. The reduced speed was necessary for several reasons. In shallower water, as the outside pressure lessened, to go much faster would make Ohio’s screw begin to cavitate. This was the submarine equivalent of a car burning rubber from too much torque to the tires and not enough road traction. Cavitation threw off a characteristic hissing, a dead giveaway to the vessel’s presence; Challenger’s cowled pump jet was much less prone to this than Ohio’s huge bronze screw. And too shallow, if they didn’t slow, both subs would create a moving hump on the surface above their hulls, with a subtle propulsor wake that trailed behind. Even in choppy water in a busy shipping channel, enemy forces processing special radar bounced off the surface could eke out the truth that something submerged was there.

The blend of these factors robbed Jeffrey of an important option for the next several hours: They dared not put on a burst of speed to avoid a potential problem. To do so would tell the Axis exactly where to zero in.

Everyone in the control room knew it too. People hunched tensely over their consoles. Whenever a fresh, unidentified sonar contact was listed, some of the newer men cringed.

Challenger and Ohio entered the thirty-mile-long channel. The clearance between the surface and the bottom became even narrower. This impaired sonar performance, because sound paths bouncing repeatedly between the waves and the seafloor muck lost signal strength before they could spread very far. A double-edged sword. The same bad propagation that muffled the task group’s signature also made both vessels partly blind.

We won’t have much advance notice of ships on a possible collision course. A supertanker’s keel is still as dangerous to us as the unseen part of an iceberg would be to that tanker.

Jeffrey’s primary worry remained optical detection — including LIDAR and LASH. LIDAR, at least, was active, and photonic sensors on Challenger’s and Ohio’s hulls could warn if a laser emitter was near. The water in the channel was turbid — cloudy — from biologic waste, erosion silt, particles from undersea volcanoes, dust blown from the deserts of North Africa, and human pollution. So a laser would scatter light in all directions, tipping off the task group to move to one side before the hostile emitter could get a measurable return.

LASH, on the other hand, was completely passive. The sunlight of Sicily this time of year was infamously strong. No storm had brewed up to give fortuitous cover. The weather, confirmed acoustically and photonically by Challenger, was fine.

About LASH, Jeffrey could do nothing but sweat and continue to pray. He did both, in deadly earnest. He patted his forehead with his handkerchief unashamedly; when it became too soggy, he used the cloth to squeegee further perspiration down the sides of his temples, away from his eyes.

“Sir,” Bell reported as evenly as he could, “Ohio signals, deploying three off-board Seahorse Mod Five probes.”

It was time to implement the next part of the plan.

“Very well, Fire Control,” Jeffrey said very formally. “Signal Ohio, ‘Commander Task Group acknowledges. Challenger now deploying two LMRS probes.’ ”

“Ohio acknowledges, sir.”

The LMRS probes were launched through torpedo tubes, and controlled by fiber-optic wire or via acoustic digital link. The Seahorses were larger, because they could be carried in triplets in one of Ohio’s big old missile tubes. They were fully autonomous, had much longer range and endurance, and their sensors were much more capable than the smaller ones on an LMRS; with a minisub in its in- hull hangar, Challenger couldn’t accommodate even one Seahorse probe — another reason Ohio was so vital as an escort.

By using acoustic links, both ships could see the data from all five probes. The off-board unmanned vehicles moved on ahead, searching stealthily for obstructions or hazards, like five fingers feeling their way for items lost under a dresser. The probes’ low-probability-of-intercept super-high-frequency active sonars, and passive image- intensification cameras, did most of their work. Transiting the Malta Channel, these feeds were indispensable.

Fishing nets could extend for miles from a trawler, Jeffrey knew. An uncharted wreck could lie on the bottom, with the top of its mast or superstructure rising many feet up from the floor. Loose or misplaced mines, or even unexploded ones left from World War II, could also be anywhere.

In conditions like these, an Axis U-boat might be anywhere.

Jeffrey watched his console as all the data kept pouring in. Murky black-and-white pictures showed him trash strewn on the channel floor — liquor and beer bottles, big tin cans with their opened lids bent back, and empty oil drums were common.

Then some probes found the edges of debris fields leading to wrecks. The control-room mood became grim, fatalistic. A shiver went up Jeffrey’s spine as his task group passed each drowned graveyard. He got an all-too- explicit tour of a World War II cargo ship, lying on its side with a huge hole punched below the waterline. The styling of the ship looked Italian or German, not British.

Probably hit by a Royal Navy sub, in the era of the battles for Tobruk and El Alamein.

Now and then Jeffrey needed to change course, coordinating with Ohio, to avoid one danger or another in their path. He asked Milgrom to turn on the sonar speakers.

The racket he could hear was reassuring. These waters were noisy indeed.

Milgrom reported aircraft overflights. These included military helos — identified by their engine power and transmission-gear ratio — and fixed-wing maritime patrol planes — also identified by their engine and prop sounds.

Jeffrey did what he could to steer away from the projected path of each aircraft. The formation’s own plotted path on his chart became a confusing zigzag, headed vaguely east. It was nearing local noon; the sunshine would aim straight down at them.

Milgrom announced another patrol plane.

Too close. “Hard left rudder! Due north!”

Bell typed frantically and Meltzer yanked his wheel. The task group made a panic turn to clear the zone beneath the aircraft.

“Natural-gas platform dead ahead,” Sessions stated between clenched teeth.

Jeffrey ordered another sharp turn, back on course, just as the aircraft flew by.

Two dozen people collectively held their breaths and waited forever.