We eased off the clips on the for'ard collision bulkhead door, knocked them off cautiously as the pressures equalized. The water in the torpedo room was about two feet above the level of the sill, and as the door came ajar, the water boiled whitely through into the collision space while compressed air hissed out from behind us to equalize the lowering pressure of the air in the torpedo room. For about ten seconds we had to hang on grimly to hold the door and maintain our balance while water and air fought and jostled in a seething maelstrom to find their own natural levels. The door opened wide. The Water level now extended from about thirty inches up on the collision bulkhead to the for'ard deckhead of the torpedo room. We crossed the sill, switched on our waterproof flashlights, and ducked under.

The temperature of that water was about 28°F. — 4° below freezing. Those porous rubber suits were specially designed to cope with icy waters, but, even so, I gasped with the shock of it — as well as one can gasp when breathing pure oxygen under heavy pressure. But we didn't linger, for the longer we remained there, the longer we would have to spend decompressing afterward. We half walked, half swam toward the fore end of the compartment, located the rear door on number 4 tube, and closed it, but not before I had a quick look at the inside of the pressure cock. The door itself seemed undamaged: the body of the unfortunate Lieutenant Mills had absorbed its swinging impact and prevented it from being wrenched off its hinges. It didn't seem distorted in any way, and fitted snugly into place. We forced its retaining lever back into place and left.

Back in the collision compartment we gave the prearranged taps on the door. Almost at once we heard the subdued hum of a motor as the high-speed extraction pumps in the torpedo room got to work, forcing the water out through the hull. Slowly the water level dropped, and as it dropped, the air pressure as slowly decreased. Degree by degree the «Dolphin» began to come back on even keel. When the water was finally below the level of the for'ard sill, we gave another signal and the remaining over-pressure air was slowly bled out through the hose.

A few minutes later, as I was stripping off the rubber suit, Swanson asked, "Any trouble?"

"None. You picked a good man in Murphy."

"The best. Many thanks, Doctor." He lowered his voice. "You wouldn't by any chance — "

"You know damned well I would," I said. "I did. Not sealing wax, not chewing gum, not paint. Glue, Commander Swanson. That's how they blocked the test-cock inlet. The oldfashioned animal-hide stuff that comes out of a tube. Ideal for the job."

"I see," he said, and walked away.

The «Dolphin» shuddered along its entire length as the torpedo hissed out of its tube — number 3 tube, the only one in the submarine Swanson could safely rely upon.

"Count it down," Swanson said to Hansen. "Tell me when we should hit, when we should hear it hit."

Hansen looked at the stop watch in his bandaged hand and nodded. The seconds passed slowly. I could see Hansen's lips move silently. Then he said, "We should be hitting — now," and two or three seconds later, "We should be hearing — now."

Whoever had been responsible for the settings and time calculations on that torpedo had known what he was about. Just at Hansen's second "now" we felt as much as heard the clanging vibration along the «Dolphin's» hull as the shock waves from the exploding warhead reached us. The deck shook briefly beneath our feet, but the impact was nowhere nearly as powerful as I had expected. I was relieved. I didn't have to be a clairvoyant to know that everyone was relieved. No submarine bad ever before been in the vicinity of a torpedo detonating under the ice pack; no one had known to what extent the tamping effect of overhead ice might have increased the pressure and destructive effect of the lateral shock waves.

"Nicely," Swanson murmured. "Very nicely done indeed. Both ahead one third. I hope that bang had considerably more effect on the ice than it had on our ship." He said to Benson at the ice machine, "Let us know as soon as we reach that lead, will you?"

He moved to the plotting table. Raeburn looked up and said: "Five hundred yards gone, five hundred to go."

"All stop," Swanson said. The slight vibration of the engines died away. "We'll just mosey along very carefully. That explosion may have sent blocks of ice weighing a few tons apiece pretty far down into the sea. I don't want to be doing any speed at all if we meet any of them on the way up."

"Three hundred yards to go," Raeburn said.

"All clear. All clear all around," the sonar room reported.

"Still thick ice," Benson intoned. "Ah! That's it. We're under the lead. Thin ice. Well, five or six feet."

"Two hundred yards," Raeburn said. "It checks."

We drifted slowly onward. At Swanson's orders the propellers kicked over once or twice, then stopped again.

"Fifty yards," Raeburn said. "Close enough."

"Ice reading?"

"No change. Five feet, about."

"Speed?"

"One knot."

"Position?"

"One thousand yards exactly. Passing directly under target area." -

"And nothing on the ice machine? Nothing at all?"

"Not a thing." Benson shrugged and looked at Swanson. The captain walked across and watched the inked stylus draw its swiftly etched vertical lines on the paper.

"Peculiar, to say the least," Swanson murmured. "Seven hundred pounds of very high-grade amatol in that torpedo. Must be unusually tough ice in those parts. Again, to say the least. We'll go up to ninety feet and make a few passes under the area. Floodlights on, TV on."

So we went up to ninety feet and made a few passes and nothing came of it. The water was completely opaque, the floods and camera useless. The ice machine stubbornly registered four to six feet — it was impossible to be more accurate — all the time.

"Well, that seems to be it," Hansen said. "We back off and try again?"

"Well, I don't know," Swanson said pensively. "What do you say we just try to shoulder our way up?"

"'Shoulder our way up?'" Hansen wasn't with him; neither was I. "What kind of shoulder is going to heave five feet of ice to one side?"

"I'm not sure. The thing is, we've been working from unproved assumptions and that's always a dangerous basis. We've been assuming that if the torpedo didn't blow the ice to smithereens, it would at least blow a hole in it. Maybe it doesn't happen that way at all. Maybe there's just a big upward pressure of water distributed over a sizable area that heaves the ice up and breaks it into pretty big chunks that just settle back into the water again in their original position in the pattern of a dried-up mud hole with tiny cracks all around the isolated sections. But with cracks all around. Narrow cracks, but there. Cracks so narrow that the ice machine couldn't begin to register them even at the slow speed we were doing." He turned to Raeburn. "What's our position?"

"Still in the center of the target area, sir."

"Take her up till we touch the ice," Swanson said.

He didn't have to add any cautions about gentleness. The diving officer took her up like floating thistledown until we felt a gentle bump.

"Hold her there," Swanson said. He peered at the TV screen, but the water was so opaque that all definition vanished halfway up the sail. He nodded to the diving officer. "Kick her up — hard."

Compressed air roared into the ballast tanks. Seconds passed without anything happening; then all at once the «Dolphin» shuddered as something very heavy and very solid seemed to strike the hull. A moment's pause, another solid shock, and then we could see the edge of a giant segment of ice sliding down the face of the TV screen.

"Well, now, I believe I might have had a point there," Swanson remarked. "We seem to have hit a crack between two chunks of ice almost exactly in the middle. Depth?"