There had been a pause in the conversation between the two officers. Both felt their senses acutely tuned to the limitless medium through which their ship was passing. Above them, not far away, was the nearly impervious ice cover; below, very far below, the rock basaltic plates of two of those slowly drifting crusts on the earth’s mantle which, in the Arctic Ocean, had by their confluence ages past created two huge basins, thousands of fathoms deep. Between the two limits, and further limited by the maximum depth to which Manta’s strong shell could descend, there was complete freedom to move in any direction her masters willed, as fast as they willed, up to the top power her nuclear reactor could deliver and her turbines receive.
Except that Manta was not free. She was a prisoner of the towline, constricted to move only slowly, steadily, constantly, in a single direction. Slight, and only very gradual, changes could be made in speed; changes in depth and direction could be made only very slowly, with the greatest of care. Violation of any of these rules would inexorably rupture the thin, weak thread that held out hope to Keith and his crew of 126 men.
“I think I’ll go start Jerry on that plot we want,” said Buck. “Back in a minute. We’ll have to use the UQC to get the information we need from Keith. Okay?”
“Got to,” said Rich.
When he returned, rather more than a minute later, for he had made a quick head call, Buck found Richardson and Schultz huddled over the sonar display. “He’s begun echo-ranging again,” said Rich. “And he’s begun to move out ahead of us. He’s up to something!”
“If he shoots a torpedo, I’ll have to maneuver to avoid. The towline will break.”
“I know, Buck. We’ll have the other one to hook up again with, if we get the chance.” Then a thought struck Richardson. “Don’t you have a couple of decoys up forward?”
“Yes.”
“Have them get one ready for firing. Quick, man!”
Buck did not even answer. He picked up the telephone handset, spoke directly into it, gave the order. “They’ll have to haul out one of the fish and load the decoy into the tube. They’re pretty fast, especially with all the extra men up there on battle stations. Three minutes, they told me.”
“God, we should have thought of this before,” muttered Rich. “That’s one string to our bow we should have had ready!”
“I should have thought of it,” said Buck. “After all, I’m skipper of this craft.” He was silent for a long, thoughtful minute. “What kind of fish do you think he’s likely to have?”
“Some straight running, for sure. The question is whether he can set them to run this deep. Besides that, probably some kind of target-seeking torpedo. Since they’re antisubmarine, most of them can be set for any depth a sub’s likely to be, and when they detect a sub they’ll go after it, whatever the depth. If he shoots one of those, we’ve got to make it think the decoy is us.”
“That’s what the decoy’s for, all right. But where do we go after we shoot it? There’s not much maneuvering we can do.”
“If you stop your screws, put her in full dive and flood negative, the Cushing will coast overhead. You could even back a little, when you’re deep enough. If you’re lucky, you might not even break the towline.”
“We should warn Keith, shouldn’t we?”
“We should; but if that sub’s really up to something, he’s monitoring us with every resource he’s got. We’d better not take the chance. Keith will know something serious is going on, and will cope.”
The telephone gave its characteristic squeak. Buck snatched it, listened. “Four and a half knots,” he said.
“Forward room wanting to know what speed to set on the decoy, eh?”
“Yep. They’re about to shove it in the tube.”
“Good. That was quick work.”
“Thanks.” Buck picked up the telephone again, said, “Tubes forward, you got that loose fish secured for angles? Good! Good work up there!” Hanging up the phone he said to Rich, “We’re always supposed to be ready for steep angles, but that torpedo was hanging in midair while they hauled it out of the tube, so I thought I’d check to make sure it was secured. It’s secure, all right. The chief even pretended I hurt his feelings by asking.”
“His feelings weren’t hurt. He’s proud of his work, and he’s pleased with you for giving him a chance to show it.”
Buck felt an elbow in his middle. Schultz was pointing to the illuminated spot on his dial where the enemy submarine was indicated. It had drawn well ahead, and echo-ranging spokes were no longer coming from it. Simultaneously, both officers noted the unexpected lengthening of the silence since the last ping.
“What’s he doing?” said Rich. “Could he be getting ready to shoot?”
“Echo-range, Schultz! Full power and short scale!” Buck ordered. There was savagery in his voice. Grabbing the phone, he said, “Tubes forward, set the decoy for short-scale pinging. Then flood the tube and shoot it! Let me know when it’s away!”
“Good for you, Buck,” said Rich quietly. “If he shoots now, it’s likely a quiet, fairly slow torpedo, programmed to finish its run by homing on noise. That must be why he shut off his pinging. So as not to confuse it. If he plans to shoot he’ll do it now while we’re pinging, so that his fish can home on it.”
Buck still held the phone to his ear, did not answer. Suddenly he said sharply, “Secure pinging!” Schultz flipped a switch on his console as Buck thrust past Richardson, stepped into the passageway outside the sonar room. “All stop!” he called peremptorily. “Tom! Flood negative! Twenty degrees down angle! Make your depth seven hundred feet!”
There was a clank of mechanism beneath their feet, the sound of water rushing through a large orifice, a huge whoosh of air and an increase in pressure on the eardrums. Manta began to incline downward with an ever increasing angle.
Buck had run across the control room, was talking to Tom Clancy. “Start blowing negative and zeroing the bubble at seven hundred feet, Tom,” he said rapidly. “I’m going to have to back then, and you’ll have your hands full keeping control. Use a bubble in bow buoyancy or main ballast if you need to. When the Cushing’s about overhead we’ll go ahead again. You’ll have trouble with your weights aft, too.”
“Maybe you’d better let her drift down an extra hundred fifty feet, Skipper, seeing this looks like an emergency. Cushing’s got her anchor at seventy fathoms, and she’s at three hundred feet right now. So that’s four hundred twenty feet added to whatever depth she winds up at when she starts feeling that extra weight. We don’t want to bump into that big iron mushroom of hers down there!”
“Right, Tom! Make your depth eight hundred fifty!”
“Also, you know there’s going to be a hell of a lot of pressure in the boat when we vent off all that air we’ll be using in negative tank!”
“Can’t be helped, Tom. Do it slowly. When we get a chance to, we’ll pump it back down with the air compressors.”
The deck had begun to incline quite steeply. The depth gauge was already registering five hundred fifty feet as Buck struggled across the control room to the sonar room. Three hundred feet to go! And, of course, he would have to allow for the angle in calculating where Manta’s stern was.
Schultz was saying, “Looks like there’s another submarine out ahead of us! It’s pinging just like we were, and I can even hear machinery noises.”