Tidal Rip

askance, and freeing up the three-man officers’ stateroom that Ilse and Kathy had been using allowed three male officers to get their regular quarters back. Bell’s next administrative nightmare would be finding places for sixteen SEALs to sleep, with the torpedo room already completely crammed with weapons and part of Challenger’s junior enlisted crew hot-racking — sharing bunks — as it was.

Milgrom’s laptop was wired to the big flat-screen TV on the wall of the wardroom, on the opposite bulkhead from Jeffrey’s chair. She touched her keyboard, and a briefing slide came up on the screen.

“Lord,” Jeffrey said, “it looks like all the veins on someone’s retina.” A retina the size of the Atlantic Ocean.

“In a sense,” Milgrom said, “that’s precisely the point. Orpheus lets us see out to vast distances, like a gigantic eye.”

“And in the middle, where all the veins come together like where the optic nerve would be, that’s us?”

“Precisely, Captain. The Orpheus connections and consoles, set up with help from the SEALs.”

“Okay. Go on.” Jeffrey was being intentionally standoffish today, not to Milgrom in particular but to all his officers. By playing devil’s advocate, making them work to sell him on the idea of Orpheus, he’d make sure they got a better handle on it and did a better job with it in combat.

“That seeming ‘retinal scan’ was the map of the relevant portion of the network of transoceanic undersea telephone cables, the old electrical ones. Mostly abandoned, most of them cut near one shore or the other.” Milgrom brought another slide on the screen. “This diagram shows the basic concepts behind how Orpheus picks up signals.”

Jeffrey looked at the picture. The physics were familiar enough from all his technical training.

“Point one,” Milgrom said, “the earth’s magnetic field isn’t shielded by seawater. It penetrates the ocean’s deepest depths.”

Jeffrey nodded.

“Point two, an electrically conductive material, moving through the lines of force of any magnetic field, produces an electric current.”

“Which is exactly how a generator works,” Jeffrey threw in.

“Point three, seawater is highly conductive.”

“Yup.” That’s one more thing that makes being on a ship or sub so dangerous. The hazard of lethal electric shock, when you mix salt water and steel with heavy voltages, is high.

“Next,” Milgrom said, “a submarine’s hull form, moving through the sea, creates an internal wave in the water. The fluid around the bow of the hull is forced up and down in a characteristic, predictable manner.”

“I’m with you so far,” Jeffrey said, mostly to be polite and keep the briefing moving.

“These principles, brought together, are the basis of Orpheus. When a submerged submarine advances through the ocean, the seawater that the bow dome pushes out of the way moves up and down in the earth’s magnetic field. This creates electrical currents. There is no way to prevent or mask these telltale currents. The submarine’s quieting does it no good. Attempts at using sonar layers or terrain masking to hide from the SOSUS hydrophones do it no good.”

“That part isn’t new,” Jeffrey said rhetorically. “The idea was looked at during the Cold War as a way to localize and track enemy subs non-acoustically. The result, unless I missed something, was zilch.”

Milgrom went on, unfazed. “The Cold War era did not have ceramic-hulled nuclear submarines, Captain. The problem with this detection method in the first thousand feet or so of the water column is confusion by environmental noise — signal clutter, in other words — from waves, passing whales, and thermal downwashes and such. That, plus the problem of how to have a platform, to cast a net as it were, with a large and steady search area that an enemy submarine cannot intentionally maneuver to avoid.”

“Granted.” A platform meant a ship or plane or sub.

“A ceramic-hulled submarine, however, running at ten or fifteen thousand feet, is far enough away from surface waves and large biologics to avoid that problematic signal-to-noise ratio. At the same time, said deep-diving submarine is close to the fixed, preexisting network of undersea electrical cables stretching from continent to continent all along the ocean’s bed. When the submarine passes over such a cable, the electrical current caused by the hull pushing its way through the water will, by induction, generate a small and subtle sympathetic current in the cable. That sympathetic current, induced point-blank by the passing submarine, will flow along the entire length of the cable, at the speed of light…. The key to Orpheus is to harness this phenomenon.”

“By patching into the cables,” Jeffrey stated, “where a bunch of them crisscross.”

“That’s where my men and their equipment come in,” Felix said. “We create the crucial node, the observation post the enemy can’t sneak past or avoid.”

Milgrom brought up another slide. “Lieutenant Estabo?”

Felix stood. “This nice little artist’s conception gives you the layout. Because parts of the cable hookups involve some very fine manual work, our hardwired anchor station needs to be in shallow water, here.” He pointed at a place beside a craggy island on the slide. “Shallow because of limitations on humans making repeated dives with the scuba equipment we’ve got… The satellite dish needs to be high and dry and stable, to get a good continuous lock on the geosynchronous commo bird.” He pointed to the schematic picture again, where a big dish sat on the island, aimed at a satellite in space. “The minisub, here, brings the divers and equipment to the cable anchor point and to the islet, and strings the transducer line out to deep water. That line lets the ground station, and Challenger, and the mini all talk by covert acoustics.” Transducers were a type of underwater microphone.

Jeffrey nodded.

Felix continued. “Then the mini sits over the cable-hookup anchor station, which is now connected to all the old phone cables, all underwater. More new wires of our own run from the anchor station sitting on the bottom to the Orpheus consoles inside the mini. Other wires run from the mini up to the beach on the islet and the satellite dish that talks to Norfolk. And then there’s the transducer line, also from the mini.”

“So the minisub is like a spider in its web,” Jeffrey said.

“Or like a fly caught in the web. Depends on your point of view, sir.” Felix shrugged. “Anyway, all this gets us what we want, without Challenger or the mini needing to raise an antenna mast for hours on end and give themselves away. My team will be exposed on land, sure, but we earn our daily bread by taking such risks. If we could do everything from a rubber boat or raft instead, we would. But small boats are just too unstable. We need solid ground to emplace that satellite dish and supporting equipment…. Notice that Challenger herself is not tied down by any physical linkages, so she remains fully mobile and stealthy and tactically flexible.” Felix sat.

“How long will you and your men need?” Jeffrey asked. “To make the cable hookups and establish the ground relay station and everything?”

“Working in shifts around the clock,” Felix said, “once we get there, about twenty-four hours.”

“And the place we’re heading to is neutral territory.”

“Also correct,” Felix said. “Won’t be the first time, for me. If anyone asks, we’re Brazilian. Not that there’d be a soul there who would ask.”

“Okay, thanks,” Jeffrey said.

Milgrom cleared her throat and resumed. “Of course, powerful software is needed to sort out and interpret these subtle electrical clues to the enemy submarine’s passage. The Orpheus consoles have microchips optimally designed for the particular type of maths and signal-processing required. In theory, it will be possible to tell the von Scheer’s exact location along the cable, as well as her depth and course and speed, from the shape and the decay rate of the internal electrical waves induced, even if she’s many hundred miles away from the Orpheus station. This data would let us calculate an intercept course and sneak up on von Scheer with surprise.”

“In theory,” Jeffrey said.

“As Lieutenant Estabo already anticipated in his discussion of the hardware layout, sir, this is why we need the land-based portion of the equipment. A voice-and-data satellite relay to Norfolk, whose supercomputers may catch whiffs of signal our portable consoles miss, to feed such information back to us. And for Atlantic Fleet to pass us any other detections made on von Scheer, from elsewhere, to redirect