Collapse Depth

“Don’t worry sir,” said Renfro as they descended. “I won’t let them start filling it up ‘til you’re half way up the ladder.”

“We appreciate it,” said Jabo.

Duggan climbed down the iron rungs, which were welded directly to the side of the tank. The side of the tank was also the concave side of the ship, making it tricky to reach the next slippery step as they curved outward, away in the darkness, most of his weight hanging from his hands rather than supported by his feet, until he was halfway down and the hull curved back.

The darkness of the tank and the geometry of the ladder made it impossible to see how far he had to go; it was deeper than he imagined. He felt himself growing tense as he went further, thought about the single valve handle and the listless watchstanders that were the only things standing between him and thousands of gallons of diesel fuel. As he got deeper, the air in the tank grew thicker, harder to breathe, the smell a combination of diesel fuel and the sea, a more concentrated version of what permeated the entire ship. He kept his eyes on the manway above him, his only escape. It got smaller as he descended, like a full moon in a black sky.

Jabo had navigated the steps deftly and waited at the bottom, swinging the flashlight on its lanyard, making the shiny walls of the tank seem to sway.

“Okay, you know why we’re here?” said Jabo. His voice echoed metallically. Duggan realized that he still clung on to the bottom rung, afraid to lose contact with it in case Jabo dropped his light, or the batteries died. He forced himself to let go.

“Duggan? Why are we here?”

“To close out the tank.”

“You know what that means?”

“Make sure there’s nothing left down here?”

“Like tools and stuff? Sure. Good answer. And?” He held up the mallet.

“Sound shorts?”

“Sound shorts, anything loose. We’ll bang on everything, make sure it’s all squared away. Because if there’s something rattlin’ around down here, it will be impossible to fix at sea. And remember, we’re a submarine…we don’t like making noise. Any time we empty a tank like this and do work, before we’re done, a qualified enlisted man closes it out, then an officer verifies. Do you know why this tank is empty?”

“We did some maintenance, right?”

Jabo nodded, and pointed his flashlight to a corner of the tank, where a pipe rose like a stalagmite, extending the full height of the space. The walls of the tank gleamed like glass in the beam, the steel preserved pristinely by the blanket of fuel that normally covered it. “We had to fix that: the level detector. You know how that works?”

Duggan nodded. “No…sorry.”

“That’s okay…hell, you just got here. The tank is always full. As we burn diesel fuel, we let in water. The fuel, being about fifteen percent less dense, floats atop the water. The sensor floats atop the water-fuel interface. So as the tank empties of fuel oil, the sensor actually rises. Keeps the tank full of something all the time, which helps shield the people tank from the reactor.” He knocked his flashlight against the aft wall of the tank.

“Cool,” said Duggan.

“Yeah, those fuckers think of everything. One more question: how much fuel does this tank hold?”

“Thirty-five thousand gallons,” said Duggan, proud of himself for knowing the answer. Right before coming down, he’d seen the tanker truck on the pier, the hoses already extended, ready to send the cargo gushing into the tank where he stood.

“Good job. You have any idea why we carry that much diesel fuel?”

The question surprised Duggan. He hadn’t thought it was based on anything…it was just how much the tank held. He was struck by how many things there were to know inside an empty tank…and they weren’t trivial, either, they were actually important, capacities and specs developed by some of the finest engineers in the world. He contemplated how many hours he would have to spend at sea before he knew everything he was supposed to know about this giant boat.

“I’ll give you a hint,” said Jabo. “It’s based on a theoretical casualty in which we lose all power except the diesel engine, and this much fuel would allow us to steam for a certain number of hours at a certain number of knots, enough hours to get us out of harm’s way. The theory goes.”

“I’ll look it up.”

“Then get back with me and I’ll sign your book. Will that be your first signature?”

Duggan nodded.

“Holy shit! What an honor. You owe me a beer when we get back.”

Far above them, Renfro stuck his head through the hatch and yelled down. “Hey, topside wants to know what’s taking so long. Are you guys blowing each other?”

“Yeah,” said Jabo. “But we’re almost done.”

He handed Duggan the mallet. “Here, start banging on shit.”

• • •

The navigator sat huddled over a chart in a darkened corner of the submarine’s control room, frantically making revisions during the last few hours of the USS Alabama’s refit. He was a small man burdened with many secrets.