They continued on this course for twenty minutes when Erwin, who was at the back of the control room, began to cough. Mercer looked over his shoulder and saw a sickly green mist rising from the engine room behind him. Chlorine gas. The first tendrils seemed to wrap around Erwin’s stooped form like tentacles of some wrathful creature.
“Hold out for as long as you can before using the air tanks I rigged,” Ira reminded.
Mercer got his first stinging taste of the chlorine. His eyes burned. They had another fifty minutes before they reached the open. It was going to be close. In order to protect their vision, everyone donned the protective goggles they’d used to combat the arctic weather.
“The tunnel floor’s about to rise,” Mercer said. “Prepare to blow tanks to bring us to fifty-five meters, ten degrees up on the plane. Marty, we’ve got a quick series of turns coming up, port, starboard, port. You just turn the wheel when I tell you. Increase to one hundred and thirty RPMs again when we level out.”
They went into the turns at the increased speed, the old sub tilting first one way and then the other on Mercer’s commands. He didn’t tell them that the channel through the S-turn was just wide enough to allow the maneuver.
The tail slammed into a rocky pinnacle coming out of the first curve, slewing the boat like it had been torpedoed. Mercer’s call for a quick correction wasn’t fast enough. They went into the second turn and the bows veered into the rock face, reverberations booming like the inside of a church bell. Erwin shrieked and Anika’s knuckles whitened on the plane control wheel.
“We’re doing fine,” Mercer said, choking when he took a lungful of gas. “Marty, bring us to port, bearing ninety degrees.”
Marty nodded, unable to speak around the accordion tube from his air cylinder. The hull creaked.
Mercer didn’t understand what had happened. The chart said that they shouldn’t have hit anything that second time. The pipe was supposed to have widened. The next turn was in five minutes, and he wasn’t sure if they were traveling in the middle of the passage or along one side. They didn’t have the luck to consider they were in the middle, so Mercer had two choices. Were they far left or far right?
The control room was filled up to their knees in heavy chlorine gas, wisps rising up like fog from a haunted moor.
“Marty, are you right- or left-handed?” Mercer asked and finally started drawing breath from his own cylinder. Marty held up his left hand. “Bring us two points to starboard for a minute and on my command crank us to port.”
If Mercer’s guess was wrong, they would plow straight into the far side of the turn at roughly six knots. That kind of blow would crumple the bow like aluminum foil. “Helm, steer us to one hundred and thirty degrees.” Everyone felt the tension in his voice.
Angled over so they had to brace themselves, the sub went through the turn, gas pooling against the bulkheads like a liquid. Mercer held his breath. They all did. The beat of the propellers through the water sounded like a distant drumroll. By Mercer’s watch they were halfway through the turn. He checked the chart and lurched. The bottom of the tunnel had dropped away and the ceiling had lowered. They were supposed to be at seventy meters!
“Dive!”
Ira twisted open valves to flood the bow ballast tanks at the same time Anika and Hilda cranked the dive planes as far as they could go. The sub seemed to stand on its nose, loose articles crashing to the deck all along the length of the vessel. Mercer’s feet came out from under him and he swung free, dangling from a steel pipe.
They didn’t quite make it. The top of the conning tower crashed into the underside of the subterranean channel, ripping away both periscopes in a wrenching squeal of torn metal. Water flooded the attack center located in the sail and would have filled the ship if it weren’t for one more watertight hatch. A wall of chlorine gas as dense as smoke raced down the boat, cutting visibility to almost zero until Anika brought the bow back up, leveling her out at eighty meters just as her keel began to scrape the bottom. The noxious cloud settled again, reaching up to Mercer’s waist.
“Bring us to seventy meters. Ira, neutral buoyancy again.” Mercer checked the compass and saw that Marty had them perfectly on course. “Good job. That was my fault. Sorry.”
Mercer paid for complimenting them. Seared by gas, his lungs went into convulsions and vomit shot from his mouth. He sucked great drafts from his air bottle, cleansing the tortured tissue. They had only one more change of depth to clear a peak in the channel and fifteen more minutes to go.
He knew they wouldn’t last that long. Marty had been on his bottle much longer than he had, and Mercer could imagine poor Erwin had been hyperventilating since they’d left the cavern. He changed the figures on the chart, making a quick guess rather than an accurate calculation. “Maximum revolutions!”
The tachometer peaked at two hundred twenty RPMs. “Bring us to thirty meters on my mark.” Mercer could feel the sub racing along the bottom of the tunnel, careening toward a bump on the seafloor that rose nearly a hundred feet. Come up too soon and they slammed into the ceiling of the passage. Too late and they would barrel into the mount. “Ten degrees up on the planes. Mark!”
Mercer made up for his earlier mistake. His timing was perfect. Like a crop duster swooping over a field, the two-hundred-fifty-foot-long submarine rose off the bottom of the tunnel and climbed the sloped side of the hill, her keel never more than ten feet from its irregular surface. At thirty meters, the U-boat cleared the top of the mound with the ceiling of the tunnel now only forty feet above her ruined conning tower. Level once again and her screws churned with every remaining amp in her batteries. From here it was a race to the open sea. Mercer’s gamble had saved them nearly eight minutes.
“When we surface,” Ira said and took another draw from his breathing tube, “I’m going to blow compressed air through the boat to vent the gas. Be prepared for a pressure change.”
Once he was satisfied they had cleared the tunnel and entered the fjord, Mercer ordered Ira to blow the tanks. The climb from a hundred feet seemed to take forever. His air supply was about exhausted, and each breath was a supreme effort that left his chest aching. Anika and Ira were in even worse shape.
Somehow, Erwin found the strength to climb the ladder to the escape hatch. He wasn’t going to remain on the U-boat one second longer than necessary, pushed more by fear of confinement than of the gas.
The sub emerged from the sea bow first, lifting forty feet from the water before slamming back again, blowing off sheets of frothing water. Protected from the waves of the Denmark Strait by the fjord’s towering mountains, the cauldron of turgid water around the sub was the only mark on the otherwise calm bay. She rolled for a moment as Ira pumped up the air pressure in an effort to vent the poison gas.
As soon as the ex-Navy man nodded to Erwin, he undogged the hatch. Air pressure blew the hatch outward, sucking out a majority of the gas. Icy water from the flooded attack room rained into the control space, showering the crew. Erwin scrambled up the ladder, twisting around the bent remains of the two scopes to reach the next ladder. The outer hatch spun freely and he threw it open, reveling in their first sight of daylight in a week, Hilda and Anika at his heels. He clambered the rest of the way out of the sub and stood fully upright, facing eastward to the open end of the fjord several miles away.
No one heard the shots hammering the conning tower, but the metallic twang of ricochets sounded clearly, lead and fractured steel exploding in all directions.
Erwin felt a twin sting as his brain registered what was happening and he went limp, allowing himself to fall back into the attack center. His blood stained the pooled water pink. Hilda screamed. Even as the barrage continued against the U-boat’s steel hull, Anika began to check his injuries.
Like her, Mercer didn’t hesitate. It was as if he’d expected such an ending to this hellish trek. He raced back to his cabin and reemerged with a machine pistol in each fist, spare clips tucked into the pocket of his snow pants. Wordlessly, he tossed one MP-40 to Ira, racked back the cocking handle on his own, and climbed for the bridge.
