Terminal Run

Catardi nodded. Finally the verbal test portion of the qual board was complete, and normally that would be enough, but Captain Catardi had ordered that Pacino stand a casualty drill watch before he earned his diving officer qualification.

Although it was 2030 hours Zulu time, the military term for Greenwich Mean Time, the local time at that point in the sea was only 1730, and the sun had not yet set. The control room was rigged for white — the overhead lights were on bright-but would probably be rigged for red at the next periscope depth excursion. During an approach to periscope depth at night, the OOD would rig the control room for black, which was the submarine term for turning the lights completely out to keep from ruining his night vision for collision avoidance.

“Mr. Pacino, take the diving officer watch, please,” Schultz ordered him.

“Officer of the Deck,” Pacino called to the navigator, Wcs Crossfield, who stood behind the command console, wearing a wireless one-eared headset with a boom microphone and red goggles. “Request permission to relieve Chief Keating as diving officer of the watch to stand as dive under instruction.”

“Very well, Pacino, take the dive.”

“Take the dive, aye, sir. Chief Keating, request permission to take the port seat at the ship control panel.” Keating sat inside a cocoon of consoles resembling an aircraft cockpit, a cramped semi sphere of wraparound displays and instruments and toggle switches. A central console divided the ship-control console area in half, an empty seat on the port side. Keating wore a headset and visor arrangement, which piped the displays in front of him in virtual reality, the consoles and displays in physical space around him all backups.

“Take the port seat, Mr. Pacino.” Keating was on his best behavior, Pacino noticed, the older experienced man usually calling him “nonqual.”

Pacino climbed into the cramped cockpit and settled in the port seat, strapping himself in. He put his hands on the aircraft-style control yoke, which controlled the rudder and stern planes and put his feet into the straps of the pedals that controlled the bow planes

“I’m ready to relieve you, sir,” Pacino said to Keating as he strapped on a visor. The virtual display surrounded him, the ship animated from a side view, the surface high overhead, the bow planes and stern planes undulating slightly to keep her on depth. The display was a busy one, the animated ship transparent and complete with different-colored tanks and pipes and pumps, the animation able to show valves opening or shutting and water flowing from tank to tank. Other graphics addressed the status of the rig for dive and the ventilation lineup, the ship’s speed and course and depth order, the status of the engineering plant and a few manual entries, called PDL, or pass down-log. Pacino studied the display for a moment before Keating began to speak.

“As you can see, nonqual — I mean, sir — the ship is at seven hundred feet at all ahead standard, course two seven zero, making bells on both main engines, evaporator making water to the makeup feed tank. We’ve got decent one-third trim, or at least we did two hours ago. We could be heavy aft, but I and Cyclops have entered a compensation. We’re supposed to come to PD in two minutes. You’re just in time. Got it?”

“Got it, Chief. I relieve you, sir.”

“I stand relieved. Off’sa’deck, I’ve been relieved of the dive by Mr. Pacino.”

“Very well, Chief.” Crossfield spoke into his boom microphone. “Sonar, Conn, coming shallow to one five zero feet in preparation for coming to periscope depth.”

The phrase made Pacino’s stomach tense. Now came the trial, with the captain and the XO and Lieutenant Alameda all watching him. Crossfield was about to come shallow, above the thermal layer from the near-freezing waters of the deep Atlantic. Above the layer, the water was heated by the sun and stirred by the waves. Above the layer, things would be completely different, Pacino thought, his mind on the ship’s weight. She might be balanced — trimmed with neutral buoyancy — at seven hundred feet, but in the warmer water above the layer, the buoyancy would change. The hull, with less pressure on it, would expand, taking up more volume, with the same weight of water ballast aboard, making it more buoyant. Above the thermal layer the effect of the shallower water would make them light, and the ship could float up like a balloon. But then, the shallower water above the layer was warmer, and going from cold water to warm water made the ship heavy, countering the lightness of the lowered pressure. Pacino’s mind rushed, thinking. He called up the screens of the Cyclops control system and blinked his way through a complex buoyancy calculation. Catardi and Schultz must have seen what he was doing in the auxiliary display, because just then Schultz murmured something to Crossfield and Pacino’s virtual screen winked out. They were running a casualty drill on him, trying to see how he’d handle it.