Collapse Depth

by Todd Tucker

  “Shit, we’re not slowing down,” said Kincaid.

  The captain looked where Kincaid was looking, the red digital numbers of the bearing repeater where speed wasn’t budging from Ahead Flank.

  “We’re not moving,” he said.

  “What…?”

  “We’re motionless,” said the captain. “The pitometers are probably sheered off.” It had happened to him once before, when he took the Tecumseh through the Panama Canal on his JO tour.

  “Fuck,” said Kincaid. Loss of forward motion was a catastrophe in almost any casualty.

  The captain took just a second to look out over the control room and take it all in: the alarms, the odd down angle of the ship, the wailing of the alarms, the reports of injuries that were starting to trickle in, and, above all else, the roar of rushing water below their feet. Within seconds he knew that, before it was all over, they would perform an emergency blow.

  But he also knew that the emergency blow was not a “get out of jail free” card, not a reset button that would put them up on the roof, basking in the sunshine, allowing them to start writing the incident reports and cleaning up the mess. Performing an emergency blow was the damage control equivalent of launching all their ballistic missiles. You had better make sure you do it right, because the consequences are pretty fucking dramatic. And you only get to do it once.

  “Back two-thirds,” ordered Kincaid, and maneuvering quickly answered. It was another non-conventional reaction that was laden with common sense. If a forward bell would drive the ship deeper, then a backing bell should pull it up. The captain could feel the rumble in his feet as the screw began turning backwards. The BRI still indicated a huge forward speed; the digital indicator was officially useless to them now. He stepped down to look at the bubble in the glass that indicated the ship’s angle; as he watched it went from thirty-one degrees to thirty-three. It was what he feared.

  “Take it off,” he said. “It’s pulling the angle more.” The water that had entered the forward compartment was acting like an anchor, pulling the front of the ship down. Pulling the rear of the ship up with a backing bell only exaggerated the angle.

  “All stop!” said Kincaid, and the bell was quickly answered. “Captain, the ship is rigged for flooding and general emergency.” Kincaid was collected, remarkably so, thought the captain, and he was glad that an experienced hand was on watch when the shit hit the fan. “Depth is continuing to increase,” said Kincaid, and the captain’s eyes followed his to the bearing repeater above the conn: while the speed indication appeared fucked, depth was accurate. He was certain that while they weren’t moving forward at all, they were deep, and getting deeper.

  “All the auxiliary tanks are emptied,” said the chief of the watch. He’d been furiously pumping them with the trim pumps, emptying the tanks in an attempt to make the ship lighter and rise. But a submarine is more like an airplane than it is a hot air balloon; its motion through the water, more than any other factor, makes it rise or fall, as water flows across it’s control surfaces like air across a wing. And at the moment, in their motionlessness, their submarine was just an 18,000 ton object drifting slowly downward, slowly tracing the downward slope on the other side of the guyot that had nearly killed them.

  “Sounding!” said the captain. The quartermaster jumped toward the console.

  “Sixty fathoms beneath the keel,” he reported. Whatever they’d hit was sloping away beneath them. Which was good news, because it meant they wouldn’t bottom out again. And bad news: because there was nothing to stop their descent.

  “We could flood the aft tanks,” said Kincaid. “Bring the angle down…”

  “No,” said the captain. In this case, Kincaid’s common sense response wasn’t the right one. “It would bring the angle down, but it would reduce our reserve buoyancy that much more…we can’t afford it.” There were calculations they could run to determine exactly what reserve buoyancy they had at this depth, with the tanks at these levels, but the captain knew intuitively that they were too close to the edge of that envelope to bring any water onboard that they didn’t have to. He was almost certain they’d lost the forward MBTs, which massively reduced their potential buoyancy. And with every second, with water pouring into the front of the boat, the situation got worse.

  “Captain…” Kincaid was looking toward the emergency blow valves above the COW panel, the chicken switches.

  “Not yet,” said the captain. “Not with this angle. We’ll end up with our tail out of the water, unable to move, water still coming in forward and pulling us down. At this depth…the blow might not even get us all the way upstairs. We need to stop the flooding. And we need to get this angle off.”

  “All the aux tanks are empty,” said the COW again.

  “Use the trim pump to move water aft,” said the captain. The diving officer gave the order.

  The forward trim pump took a suction on the forward variable ballast tanks and moved that water the length of the ship, to the aft tanks. This was water that was already on board, not new water, so it had no net effect on the ship’s buoyancy. But it moved the ship’s center of buoyancy aft. The rear of the ship slowly began to descend and the angle of the ship decreased.

  “Is that working?” said the Captain.

  The diving officer scanned his indications, finishing with a look at the bubble indicator that was the old fashioned, but most accurate way to look at the ship’s angle. He stared at that for a full minute.

  “Angle is coming down,” he said. “Slowly.”

  The captain glanced at Kincaid. In a normal situation, the trim pump moving water from all the way forward to all the way aft like that, for that long, would have an immediate and noticeable affect on ship’s trim. But now…it indicated that the trim pump could barely keep up with the flooding in the torpedo room. And as the flooding continued and the ship remained nearly motionless, it continued to descend, backwards, its nose pointing at gradual slope, following it down.

  “We have to slow down the flooding,” said the captain, to the entire control room. “What the fuck is going on down there?”

  • • •

  There was only noise. Not a wall of noise, but a solid impenetrable mass of noise. Stepping into the torpedo room was like walking into a furnace with flames of pure, roaring sound.

  Only after overcoming that sound did Jabo notice the sheer amount of water in the space: dark, frigid water that was roaring in from the port side, deflected by one of the torpedoes in storage, crashing against the port bulkhead. The water had long since filled up the bilge and was up over the deckplates, sloshing around his feet. He saw Juoni’s body laying face down in the water, another death. And he saw another enlisted man, alone, the canvas bag of a DC kit across his shoulder, lugging a submersible pump.

  “Any one try this yet?” yelled the XO. He had his hands on the flood control switches at the back of the space. They controlled hydraulic valves that shut every opening to the sea in the space. He threw them forward; nothing happened.

  Jabo ran over to him. “I didn’t hear it, but it’s so loud…”

  The XO shook his head. “Nothing happened…I was watching the panel…” he pointed to the torpedo room control panel. A number of valves were represented by green “Os” indicating they were open. The flood control system should have shut everything tight.

  “Problem with hydraulics?” shouted Jabo.

  The XO shook his head. “Problem with something.”

  Two men jumped down the ladder. The looked around briefly, wide eyed, stunned as Jabo had been by the violence of the noise. The XO grabbed each by the shoulder to get their attention. “Set up a hand pump!” he shouted, pointing to the flood control station. “See what that can do.”

  They nodded and started back up the ladder to go the Crew’s Mess to get the necessary equipment. “While you’re up there, get an officer down here to be phone talker.”

  They nodded again.

  “Who’s that?” said the XO,
noticing for the first time the lone enlisted man in the space who had set down the submersible pump and was attempting to rig it by himself. He was soaking wet, but his head was down, completely focused on the task.

  “Not sure,” said Jabo. “I think it might be that new kid.”

  “Help him out.”

  Jabo waded toward him.

  • • •

  “Sir, ship is at 900 feet,” said the diving officer.

  “Aye,” said the captain. Reports were steadily coming into control, all the spaces reporting their rigs, and from the EOOW, who reported he was ready to answer any bell that they ordered. All over the control room, alarms sounded from virtually every system on the boat. But their focus had gone entirely to the number that was most fundamental measure of a submarine’s peril: depth.

  “Nine-fifty,” said the Dive.

  “Aye,” said the captain again. He was running a dozen calculations in his head. To completely emergency blow now, he was certain, to expend all their high pressure air, would be a catastrophic error. With all the water they’d taken aboard, it might not even get them to the top. And even if it did, the ass end of the ship would be sticking out, the screw turning hopelessly in the air. The flooding would continue, and without propulsion to aid them, they would certainly sink again. If they were lucky they’d have enough time to transmit an SOS so a salvage ship could find their wreckage. He computed the ship’s reserve buoyancy in his head, the capacity of the emergency high pressure air banks, a rough estimate of the rate of flooding based on the rate at which it competed with the trim pump.

  “Ship is at test depth, sir,” said the dive. No one reacted, but everyone stared at the depth indicator to watch something they’d never seen before. They drifted down another foot, and the ship had exceeded its test depth.

  “Captain…” said Kincaid.

  “Blow the forward tanks for three seconds,” interrupted the captain. “That’s it…not another second.”

  “Emergency blow the forward tanks, three seconds.”

  “Emergency blow the forward tanks three seconds, aye sir,” said the chief of the watch. He stood and put his hands on forward switch only. It was an unusual posture; they were trained to completely blow the tanks dry if they ever needed too. To blow only one tank for a limited time was like trying to use half your parachute. The COW hesitated, then threw the single valve forward.

  High pressure air flowed roared through the valve, rushing into the forward main ballast tanks and the valves that sat atop them. Those valves turned, and for three seconds they admitted the ship’s highest pressure air, the air that had nearly ruptured Hallorann’s ear drums on his first day in the engine room. Released into the forward tanks, the air expanded. While the tanks were destroyed at the bottom, enough of the tank remained intact at the top that the air expanded and pooled there, forcing seawater out through the bottom. After three seconds at that sea pressure, a bubble of air roughly the size of a car developed in each of the front three main ballast tanks. It expelled from the ship an equivalent volume of water, and they almost instantly became buoyant again. The action also shifted the center of buoyancy aft, which pushed the front of the ship up.

  After three seconds, the COW pulled back the valve. The indicator lights for all three tanks turned amber again.

  “Angle is coming up!” said the Dive, confirming what the captain felt in his feet.

  Beneath them, thousands of gallons of seawater that had flooded into the torpedo room rolled aft. One positive effect of this was that it further shifted the ship’s center of buoyancy, accentuating the angle that the captain wanted to generate. But it also covered everything in its path in a rolling wall of cold, salty seawater. A great many of the things it touched had electricity coursing through them. Some of them, like the battery well, were designed to be watertight. Many of the machines, however, were designed only to be “splash proof,” and could not be submerged long without consequences.

  “We’re still going down,” said the Kincaid, quietly, straining to mask the worry in his voice. The angle was coming up but the ship was still sinking.

  “Give it time,” said the captain. He’d pictured it in his mind like one of those computer animations the shipyard engineers used, a graph of the ship’s depth versus time as air flowed into the front tanks, lifting the front of the ship up, the ship’s overall buoyancy turning positive. But there was downward momentum to overcome, and the captain knew it would take a few long seconds for the ship to rise. He’d tried to calculate the bare minimum amount of air he could expend and achieve positive buoyancy, and he hoped he was right. He had two bold, horizontal lines in the diagram he was constructing in his mind. The higher one was test depth, which they’d already exceeded. Beneath that line was crush depth, which if they exceeded they would never again rise above. But between those lines was a third line, a third important depth limit. And the Captain knew that before their momentum changed, they would cross it.

  “Still deeper,” said the Dive. “But the rate is slowing…”

  “We caught it,” said the captain. “We’re going to come up.”

  Suddenly, a new alarm rang through control, one no one had heard before, a primitive buzzing sound that came from the corner of control by the main ladder. On each side of control came a dull pop, one that made Kincaid jump. Something bumped against both sides of the hull. All but the captain were startled.

  “What the fuck was that?” asked Kincaid.

  “The BST buoys,” said the captain. “We’re going to be famous.”

  • • •

  Once the ship exceeded its test depth by a predetermined percentage, the explosive bolts that held the BST buoys to the outside of the hull detonated, and the buoys were released. Like so many key systems on the boat, there were two of them, redundant and identical, and both functioned flawlessly. Highly buoyant, they shot upward, untethered to the ship, until after twenty-one seconds they popped to the surface. A mechanical accelerometer sensed their stoppage, and the transmitters of both buoys began broadcasting a powerful, repetitive distress signal along a frequency that had been reserved by the Navy for just that purpose. The recorded message consisted of an SOS, a sequence of numbers that identified the Alabama, and the message SUBSUNK.

  Three radio rooms placed on three different continents were manned around the clock by radiomen whose only job was to await a signal that, much like the message ordering the launch of nuclear missiles, they all hoped would never come. Like the buoys themselves, the listening posts were designed with redundancy in mind: one was at the Marine Corps base in Okinawa, Japan. The second was in Holy Loch, Scotland. And the third was deep within the United State’s Strategic Command, in Omaha, Nebraska. All three listening posts began alarming simultaneously, even the one in Holy Loch, which was half a world away. Quickly the message was decoded and handed to a duty officer at each station, who in turn notified his commanding officer, who in turn notified the Chief of Naval Operations. The CNO made a call to the president’s chief of staff, and the president of the United States was then awoken with the news that a United States Submarine was in distress. From the time the buoys were launched until the president was awoken took a total of sixteen minutes.

  • • •

  Throughout the history of the submarine fleet, there has always been a degree of fatalism inherent in the various theories of submarine rescue. Alabama, like all ships in her class, was fitted with three Logistics Escape Trunks, or LETs, designed to mate with a Deep Submergence Rescue Vehicle and allow the egress of crewmen. Assuming total disaster and loss of power, each LET had affixed to it a steel plate describing a series of hammer signals men in and outside the trunk could use to communicate with each other. It read:

  ONE TAP means TANK IS FLOODED

  TWO TAPS means TANKS IS PRESSURIZED

  THREE TAPS means TANKS IS DRAINED

  On the plate outside of each trunk of Alabama, someone had long ago scratched “ZERO TAPS means I’M DEAD.�
�

  For several decades the submarine force relied on a fleet of submarine rescue ships, each with the hull designator ASR. These vessels were of World War II vintage, and were in effect modified salvage ships who could hover over a sunken boat and release divers. Submarine rescue theory of that era was startlingly crude, and revolved around “free ascent”—the process of having men egress a sunken boat and swim to the surface, arms crossed, and exhaling in concentrated, forced gasps to minimize the effects of decompression and the formation of lethal nitrogen bubbles in the blood. Every old submarine base had as its central landmark a tall, cylindrical “dive tower” where recruits could practice this procedure, a rite of passage for generations of submariners. It was officially estimated, and universally doubted, that a man might actually survive free ascent from a depth of up to 300 feet.

  The Navy lost two nuclear-powered submarines in the 1960s. First was Thresher, lost at sea in 1963, followed by Scorpion, lost in 1968. This led the Navy to seriously reevaluate its rescue capabilities, given the depths at which modern nuclear submarines operated, and the DSRV, or Deep Submergence Rescue Vehicle, was born. The Navy built two of these ships, Mystic (commissioned in 1970) and Avalon (1971), and positioned them both at the North Island Naval Air Station in San Diego. They were, in effect, deep-diving miniature submarines that could fit inside the belly of an Air Force C-5 cargo plane, to be flown within hours of a submarine disaster to its last reported location. Once on the scene, they had to operate with a mother vessel, either an ASR, or another submarine. They were not perfect, but their capabilities vastly exceeded that of the old ASRs operating by themselves. The DSRVs could operate at depths up to 5,000 feet, and rescue up to 24 men at a time.

  The DSRV program lasted until Mystic was decommissioned in 2008. The program was officially replaced by the SRDRS program, Submarine Rescue Diving and Recompression System. The very title of the program addressed one of the DSRV program’s greatest weakness: the fact that another vessel was needed to rescue submariners at pressure. The main vehicle of the SRDRS program, named Falcon, was self-contained, and not reliant on another vessel. But in some ways the program was a step backwards. Falcon could only conduct rescue operations in water up to 2,000 feet. And it could only rescue 16 men at a time. Finally, the old DSRV program was abolished before the cornerstone of the SRDRS program was even completed: the decompression system. For years, during the Cold War, some had believed deep water submarine rescue to be so unlikely that they deemed the DSRV program a cover operation, and claimed that Mystic and Avalon were actually spy ships. With the last hope of a sunken submarine being the Falcon and its half-complete support systems, it seemed the Navy had almost given up on the concept as well.