Seas of Crisis

depth was dropping. Sonar conditions deteriorated.

“Sir,” O’Hanlon called out, “intermittent contact on broadband, man-made, bearing is roughly zero-nine-zero, range ten thousand or twenty thousand yards.” East, five or ten miles.

“That’s near the rendezvous point,” Sessions told Bell.

“Any acoustic link contact, XO?”

“Negative, sir.” Sending messages back and forth to Carter, composed by Jeffrey or Bell, would be part of Sessions’s job.

O’Hanlon frowned. “What we’re hearing doesn’t make sense.”

“Explain,” Bell said. Finch moved in and peered over O’Hanlon’s shoulder, then moved down the aisle and looked at the different sonarmen’s screens.

“Broadband signal intensity is stronger than it should be,” O’Hanlon said. “Carter is supposed to hold her position, while we approach.”

“Maybe she’s running late,” Jeffrey said.

“If I didn’t know better,” O’Hanlon responded, “I’d say there were two distinct broadband signatures, overlaid.”

The ice gave off another loud crack, and again the noise reverberated like thunder.

“Sir, that was a torpedo warhead detonating.”

“What?”

“We’re getting… Rapid bearing rates on both broadband signatures, not consistent with any known under-ice sound propagation effects!… Assess signatures are a sub-on-sub dogfight!” Bearing rate meant the contact was turning through the water compared to Challenger’s steady course.

There was another sudden loud noise. This time, cued in, Jeffrey could tell that it had a rumbling, throaty quality, very unlike the natural sounds from the ice cap.

“Loud explosion bearing zero nine zero!” a sonarman called. “Range approximately fifteen thousand yards. Assess as a high-explosive torpedo warhead detonating!”

“This shouldn’t be happening,” Bell said. He hesitated, for only a moment. “Sonar, can you estimate the speed at which those submarines are moving?”

“Not yet,” Finch reported, “but from the intense broadband we’re getting they have to be doing flank speed.” All out, as fast as a vessel could go.

“Contact on acoustic intercept!” a different sonarman called. Acoustic intercept was used to warn of another submarine’s sonar going active. “Assess as melee pinging by one of the vessels involved in combat!” Melee pinging was used to find the adversary and get an accurate target range while both subs made wild maneuvers.

“Identify active sonar system,” Sessions ordered in his role as fire control coordinator.

“Impossible, sir,” Finch told him after O’Hanlon shook his head. “System frequency unknown due to unknown target speed and Doppler shift.”

“Very well, Sonar,” Sessions said. “Captain, we need a more reliable acoustic path to understand what’s going on.”

“Concur,” Bell said. “If they’re doing flank speed their passive sonars will be almost deaf from flow noise…. So… Chief of the Watch, rig ship for deep submergence.”

“Deep submergence, aye.”

“Helm, make your course zero nine zero. Ahead full, make turns for thirty-five knots. Thirty degrees down- bubble, make your depth eight thousand feet.”

Patel acknowledged, far more self-confident now.

Challenger’s bow nosed steeply down, so steeply that Jeffrey’s seat tilted back uncomfortably as he sat facing toward the stern. His inner ears’ sense of balance told him that straight up meant not the overhead but the top screen of his console.

“Nav,” Bell ordered, bracing himself against his console as it and he tilted forward, “tell me when we’ve covered five nautical miles along the bottom.”

“Aye-aye, Captain.” Meltzer was gripping a handhold on the overhead, standing sideways with his legs splayed wide, as the deck beneath his feet turned into a hillside.

Challenger went deeper and deeper. “Hull popping,” O’Hanlon called out. With Challenger’s ceramic-composite hull, it sounded more like a crunch. The ship was being squeezed inward by the pressure of the ocean, but this was what she’d been designed to do: achieve total waterspace dominance by seizing the low ground near the ocean floor and then exploit her tactical superiority.

She began to level off. “Sir,” Patel reported, “my depth is eight thousand feet.” The outside pressure was more than three and a half thousand pounds per square inch — almost two hundred fifty times atmospheric pressure at sea level.

“Sir,” Meltzer called out, “own ship has moved five miles.”

“Very well, Nav. Helm, all stop.”

“All stop, aye, sir…. Maneuvering answers, all stop.”

“Helm, back full until our way comes off.” Challenger still had considerable momentum; she’d halt much faster this way.

“Sonar and Fire Control Coordinator, tell me what’s happening up there.”

“Insufficient data,” Sessions responded.

“Request put ship on heading due north,” Finch said, “to present starboard wide-aperture array for optimal analysis.”

“Helm, on auxiliary maneuvering thrusters, rotate your heading to due north.”

Patel acknowledged and worked a joystick.

The wide-aperture arrays, one along each side of the ship, consisted of three widely spaced rectangular hydrophone complexes attached to the hull. Because they were big in two dimensions, and were held rigidly in three dimensions by the stiffness of Challenger’s hull, they could perform extremely detailed analyses of sounds to either side of the ship, in signal processing modes not possible with even the latest towed arrays.

“My heading is due north, sir.”

“V’r’well, Helm,” Bell said.

Sonarmen and fire-control technicians conferred and worked their keyboards. A tactical plot began to form on Sessions’s main console screen, repeated on other displays around Control.

“Two ships in combat, Captain,” Sessions stated. “Both appear to have flank speed of approximately twenty- five knots.”

Jeffrey was surprised. Slow by modern standards. Unless—

“Getting definite tonals,” O’Hanlon said. “Both ships nuclear-powered.” Sound was traveling directly down from the dogfight, immune to the confusing effects at shallower depth.

“What classes?” Bell demanded. Knowing this was essential. It would tell him who fought whom.

“Torpedoes in the water,” a sonarman called. “Engine noises indicate ADCAPs.” An electric-like screaming came over the sonar speakers. “Noisemakers and acoustic scramblers in the water!”

Hissing, gurgling, and undulating siren noises intensified — Jeffrey realized he’d been hearing them already, almost drowned out by the noise of twisting and turning submarines with their propulsion plants going at maximum power.

“Sonar, turning own-ship east,” Bell cued Finch and O’Hanlon. “Helm, make your course zero-nine-zero. Ahead one third, make turns for eighteen knots.” Bell wanted to sneak closer, get right underneath the other two subs.

Patel acknowledged, this time it seemed with true relish.

Bell ordered him to stop and rotate north again.

“One contact is an Amethyste-Two,” O’Hanlon stated. A modern, refurbished French sub, captured and crewed by Germans. The Amethystes were slow and small, but maneuverable and deadly.

She’s not supposed to be able to get here. So much for intel about the Allies’ North Atlantic anti-U-boat blockades.