The frogmen (15 page)

He fitted the U of one wire into the U of the other and clamped the two wires together with the tips of the needle-nose pliers.

Then he clamped the top loop of the vertical wire to the crossbar, twisting it until the wire of the mine was held exactly where it had been and could not move up or down.

Finally he was able to turn loose with the round-nose pliers. And yet, when he decided to do it, he suddenly found that he was too afraid.

With the pliers in place around the wire, the mine had remained silent, motionless, safe.

His right hand was hurting badly now, his fingers feeling nothing except pains shooting along the nerves.

At last he withdrew the pliers slowly and was surprised to see them drop out of his hand, striking the edge of the can and falling onto the top of the mine.

He lifted his arms straight up from the area of

the horns, let go with his legs, and slid slowly down the cylindrical walls of the mine until he reached the bottom.

He stayed there for a long time, his face against the mine, his arms half around it. When he opened his eyes, he saw that the light had grown very dim, the colors around him slowly fading.

He pulled himself up the mine to the top and got the knife, feeling a little surge of pride as he saw how well he had fastened the lethal wire in place.

Somehow, it seemed that the stuff cut easily now, and he soon had the diaphragm completely free of the clamp at the edge of the can. He put it inside his wet suit.

There was a dark opening going down into the heart of the mine, and as Amos hung motionless above it, looking into it but unable to see anything in the darkness, he had a strange feeling.

He loved this mine. It was so honest, so straightforward. No secrets within secrets, just an honest mechanism, designed only to destroy ships.

Getting the flashlight, he beamed it down into the hole.

The wire in the diaphragm triggered a device almost like a rat trap. It was a spring-loaded release that tripped a plate when the tiny wire moved, letting the powerful spring jerk the bale shackle off.

The mine was armed.

He hurried now, putting the posts back in place, sliding the screens in and then laying the top plate down on the posts. His wires prevented the plate

from fitting exactly, but he bolted the two corners down firmly enough to hold it in place and provide some protection.

As he got the tool bag and put his fins on again, Amos felt good.

Then the truth hit him in the face.

All he knew was how the mine worked; he did not know what made it work.

Magnetism did not. A magnetic firing mechanism was a delicate device with magnetic bars finely balanced on a knife edge so that the slightest movement of a magnetic field around them would trigger the mine. There was nothing like that in this mine.

Acoustics did not. There was nothing down in that black hole that he could not account for. There was no microphone in there.

There was no physical thing, like an antenna brushing against a ship's hull. There were no wires from a shore control station.

There was nothing.

It was late now, the shadows very long on the bottom, the light growing dim, as Amos swam slowly toward the entrance to the cave.

He couldn't seem to keep his mind on the problem.

Instead he thought about his best blue uniform with the gold ensign stripes lying at the bottom of the Pacific Ocean near that beat-up island.

He had bought the suit when he'd been accepted in the NROTC. He'd been pretty proud of it.

Amos stopped swimming entirely.

Rotcy class. One day they had been taken to hear

a lecture at the Bureau of Ships testing-tank laboratory . . . huge tanks, like enormous swimming pools, with catwalks over them and beautiful ship models floating in them. . . .

They could do anything in those tanks, create any kind of wave form, varying them from the long, slow, crestless waves of a ground sea, to the furious waves of hurricanes.

They could create currents of any velocity, from the deep, slow current of the Gulf Stream to the fast tidal currents past some constriction.

Amos thought about that laboratory as he began to swim again toward the wall.

The lieutenant assigned to give the lecture was evidently irritated about the interruption of his work by civilian students pretending to be naval officers, and so made his lecture about as interesting as a dial tone.

He talked in a fast, monotonous, flat voice about wave action, tidal movements, ocean currents. Then he showed them models of ships and rattled on about hull design and skin friction and the signature ships made in the water.

He also told them about hydrostatic pressure, demonstrating that the pressure at any point in the ocean is fixed by its depth, and changes as the depth changes.

Amos remembered the shape of one graph the lieutenant had shown them, because, at the time, it had looked to him like the outline of a tongue hanging down from smiling lips.

He swam slowly through the tunnel and out into the dimly lit pool of the cave.

As he came to the surface, he saw Max sitting beside Tanaka, giving him water through the tube, while John unpeeled some of the K-rations. "When a ship passes over a definite point in the water, does the pressure on that point increase or decrease?" Amos almost yelled at them.

"Do who do what?" Max asked.

"Come on! Does it increase or decrease?"

"Now everybody's crazy," John said. "Tanaka's crazy, and you're crazy."

Amos stood waist deep in the water and stared at the diaphragm, its edges ragged where he had cut it. The light was dim in the cave, and he could hardly see the little hole.

He shoved the diaphragm at John. "This is what fires those mines. The . . ." His voice trailed off as he remembered the dangling tongue and smiling lips.

"I think it increases," Max said. "The weight of the ship would make it increase."

"John!" Amos said. "I've got it! I've got it all!"

"Is it catching?"

"Those mines are hot all the time. . . . Yeah! That's it!"

Amos came on out of the water. "How is he?" he asked, nodding at Tanaka.

"Bad. What is it, Amos?"

"Pressure," Amos said, unbuckling the harness. "Remember that lecture on hydrostatics? How the pressure on a point fixed in the ocean is the same at

that depth everywhere? The only way you can change the pressure is to change the depth of the water. The deeper, the more pressure."

Amos got the pack and belt off and unzipped his wet suit. As he struggled to peel it off, he said, "A ship passing over that point doesn't increase the pressure, it decreases it, because, no matter what the ship weighs, the hull displaces a certain amount of water." He grinned at John. "So simple. There's a diaphragm on the mine with a wire attached to it. When a ship passes over the mine, the pressure graph looks like this. . . ." He drew the lips and tongue in the wet pebbles. "At first, at the bow, the pressure goes up a little, but then it drops sharply down, like this tongue here, then goes up again at the stern. The faster the ship goes, the further this tongue hangs out—the greater the decrease in pressure. That's all there is to it!"

"To what?" Max asked.

"When the pressure on that diaphragm decreases, it is pushed upward by the higher pressure under it. That pulls a little wire up, which releases a sort of monster rat trap inside the mine. When that trips, it yanks a bale shackle off a pelican hook and the mine shoots straight up through the water, and wham it hits whatever is up there."

John took the piece of rubber and looked at it. "Just a decrease in pressure?" he asked, his voice vague.

"That's all."

"So do all the mines explode twice a day when the tide goes out?" John asked.

"That's what took me so long," Amos told them. "But you see that little hole in the rubber? Hold it up so you can see it. That hole is to equalize any slow change of pressure, like a wave or the tides. Water can flow through it, making the pressure equal on both sides. But the hole's too small to let it equalize for the fast change of pressure that a ship causes when it goes over. Unless the ship goes so slow that it gives the hole time to work. That's the whole secret. Speed."

"You smart," Max said.

"You wouldn't think so if you'd seen what I did to that mine, when all I really had to do was spot that little hole and sit down and figure it out."

John studied the diaphragm. "Very clever, these Japanese. Because if I was an admiral, I'd come in full speed ahead, four bells and a jingle, so I'd be a harder target to hit. And this little thing would blow me out of the water. They'd bust me back to radioman, sure."

"That's all we've got to tell Pearl Harbor," Amos said. " 'Go slow and you've got it made.'"

Tanaka's voice sounded as though it came from nowhere, a faint voice from space. "Write," he said.

Max moved over to him. "Yeah, Commander, you're okay."

"No," Tanaka said, "write it down."

They stared at him as he lay there with his eyes closed. "The key for the nineteenth is King Fox

George William Charlie. For the twentieth, Able Fox Baker Mike Victor. For the twenty-first ... for the twenty-first. . . Charlie . . . Charlie . . . No . . ." "Take it easy," Max said. "We've got it." "King Fox George William Charlie," Tanaka said. 'The nineteenth."

John got the coding board out of the case and sat down with it, slowly turning the knobs. "Go . . . slow . . . and . . . you . . . have . . . got ... it . . . made." Then he said in a mincing voice, "Please acknowledge receipt of this message." He looked up at them. "We can send it by tapping it out on the tomtoms of the natives."

BOOK THREE

The tide was high now, leaving them only a narrow strip of beach. They had moved Tanaka so that his back was against the rock wall and only his feet were in the water. For an hour he had been fading in and out, sometimes saying rational things, sometimes just words. At one point he had suddenly remembered the key code for the twenty-first, and John had written that down with the others.

It was pitch dark in the cave. The only light coming down through the hole was from the dim, early-evening stars, and most of that was blocked out by Amos' head and shoulders.

Amos was looking out of the hole in the roof. To

get him up that high, Max had to stand on the bottom with a scuba, his head a foot or so under the water. Amos was standing on his shoulders.

John sat beside Tanaka, feeding him bits of K-ration dipped in water.

As Amos waited for the moon to rise, he thought of the submarine that had been blown up in the channel. The explanation fitted his theory perfectly. The sub had gone into the lagoon at dead slow, feeling her way along, her pressure not disturbing the diaphragm. But on her way out, thinking that there were no mines, mission accomplished, she had been in a hurry. And her speed had killed her.

The moon was golden and enormous as it came up above a low, rolling mountain.

Looking shoreward, Amos saw a section of landscape about as bleak as he imagined the moon itself was. Just a wide band of lava, torn and twisted, where nothing grew.

Beyond that, the jungle started, tentatively at first along the edge of the lava, then growing thicker and higher—a black wall of trees.

To his left, Amos could make out the little village beside the beach. The native houses were built on stilts in a curve at the edge of what looked like a grove of coconut trees. There were several small fires going, and he could see the outlines of people moving between him and the fires.

Looking at the village, Amos remembered the excitement of Tanaka's crew when they had passed it that morning. It was their village. They were plan-

ning to go home that night, they had told Max, and had invited him to come along. It was going to be a good party.

Inland, there seemed to be nothing except jungle, but as Amos shifted his eyes, he was startled to see the glow of bright, electric light. Staring at it, he gradually made out the shape of a small, whitish-looking building, slits of light streaming out of it.

From inside the cave he heard John calling him.

"Tanaka's talking," John said, then leaned close to the man, listening.

Amos could hear only the weak, hesitant sound of his voice.

"He says look for a little building . . ." John relayed.

Amos looked out again, and this time saw more buildings, off to the right, they, too, all lit up.

"I see a lot of buildings," he told John.

". . . with a tall tree behind it . . ." John said.

"It's too dark to make out the trees."

"You're fading, Commander," John said. "What's in the building?"

John slumped down. "He's gone again. Just a little building, on a hill, with a tall tree."

"I see a building on a hill," Amos said, dropping down into the water.

On the beach he felt around until he found the .45 and then picked up a coil of life line and one of the extra strips of copra sack. "Let's go out and take a look."

"Will that gun shoot?" John asked.

"It's supposed to. The Marines shot theirs at Tarawa and they'd been under water a lot longer than this one."

Max surfaced and waded ashore. "What's out there?"

"Keep your gear on, Max; we're going out. I'll go up first, then John. When you feel him lift off, shuck the gear and come on out."

Max looked over at Tanaka. "What about him?"

"What can we do?"

"Nothing, I guess. Kind of lonely, though."

"I don't think he'll even know we're gone," John said.

As Amos started to wade into the water, Max stopped him. "You two guys look like something that ought to be preserved in a bottle. You wander around on this island where everybody is either yellow or brown and you'll attract a whole lot of attention."

Amos looked down at himself. What tan he'd had had been wiped out by the days spent in that sweltering cabin.

"We'd better wear wet suits," John said.

Amos started to pick up his jacket but then let it drop. "If anybody sees us in wet suits they'll know exacdy how we got here."