Ice Station Zebra

‘We’ll surface now,’ Swanson nodded. He turned away from the chart table we’d been standing beside and headed for the diving stand. As he passed the plotting table he said to the navigator: ‘What was it you wanted, Will?’

Lieutenant Raeburn turned his back on me and lowered his voice, but my hearing has always been a little abnormal. He whispered: ‘Did you see his face, Captain? I thought he was going to haul off and clobber you one.’

‘I thought the same thing myself,’ Swanson murmured. ‘For a moment. But I think I just happened to be in his line of vision, that’s all.’

I went forward to my cabin and lay down in the cot.

THREE

‘There it is, then,’ said Swanson. ‘That’s the Barrier.’

The Dolphin, heading due north, her great cylindrical bulk at one moment completely submerged, the next showing clear as she rolled heavily through the steep quartering seas, was making less than three knots through the water, the great nuclear-powered engines providing just enough thrust to the big twin eight-foot propellers to provide steerage way and no more: thirty feet below where we stood on the bridge the finest sonar equipment in the world was ceaselessly probing the waters all around us but even so Swanson was taking no chances on the effects of collision with a drifting ice-block. The noonday Arctic sky was so overcast that the light was no better than that of late dusk. The bridge thermometer showed the sea temperature as 28° F., the air temperature as –16° F. The gale-force wind from the north-east was snatching the tops off the rolling steel-grey waves and subjecting the steep-walled sides of the great conning-tower – sail, the crew called it – to the ceaseless battering of a bullet-driven spray that turned to solid ice even as it struck. The cold was intense.

Shivering uncontrollably, wrapped in heavy duffel-coat and oilskins and huddled against the illusory shelter of the canvas wind-dodger, I followed the line of Swanson’s pointing arm: even above the high thin shrill whine of the wind and the drum-fire of the flying spray against the sail, I could hear the violent chattering of his teeth. Less than two miles away a long, thin, greyish-white line, at that distance apparently smooth and regular, seemed to stretch the entire width of the northern horizon. I’d seen it before and it wasn’t much to look at but it was a sight a man never got used to, not because of itself but because of what it represented, the beginning of the polar ice-cap that covered the top of the world, at this time of year a solid compacted mass of ice that stretched clear from where we lay right across to Alaska on the other side of the world. And we had to go under that mass. We had to go under it to find men hundreds of miles away, men who might be already dying, men who might be already dead. Who probably were dead. Men, dying or dead, whom we had to seek out by guess and by God in that great wasteland of ice stretching out endlessly before us, for we did not know where they were.

The relayed radio message we had received just forty-nine hours previously had been the last. Since then, there had been only silence. The trawler Morning Star had been sending almost continuously in the intervening two days, trying to raise Drift Station Zebra, but out of that bleak desert of ice to the north had come nothing but silence. No word, no signal, no faintest whisper of sound had come out of that desolation.

Eighteen hours previously the Russian atomic-engined Dvina had reached the Barrier and had started on an all-out and desperate attempt to smash its way into the heart of the ice-cap. In this early stage of winter the ice was neither so thick nor so compacted as it would be at the time of its maximum density, in March, and the very heavily armoured and powerfully engined Dvina was reputed to be able to break through ice up to a thickness of eighteen feet: given fair conditions, the Dvina was widely believed to be capable of battering its way to the North Pole. But the conditions of the rafted ice had proved abnormal to a degree and the attempt a hopeless one. The Dvina had managed to crash its way over forty miles into the ice-cap before being permanently stopped by a thick wall of rafted ice over twenty feet in height and probably more than a hundred deep. The Dvina, according to reports, had sustained heavy damage to its bows and was still in the process of extricating itself, with the greatest difficulty, from the pack. A very gallant effort that had achieved nothing except an improvement in East-West relations to an extent undreamed of for many years.

Nor had the Russian efforts stopped there. Both they and the Americans had made several flights over the area with front-line long-range bombers. Through the deep overcast and driving ice- and snow-filled winds those planes had criss-crossed the suspected area a hundred times, searching with their fantastically accurate radar. But not one single radar sighting had been reported. Various reasons had been put forward to explain the failure, especially the failure of the Strategic Air Command’s B52 bomber whose radar was known to be easily capable of picking out a hut against contrasting background from ten thousand feet and in pitch darkness. It had been suggested that the huts were no longer there: that the radar’s eye was unable to distinguish between an ice-sheathed hut and the thousands of ice-hummocks which dot the polar cap in winter; and that they had been searching in the wrong area in the first place. The most probable explanation was that the radar waves had been blurred and deflated by the dense clouds of ice-spicules blowing over the area. Whatever the reason, Drift Ice Station Zebra remained as silent as if no life had ever been there, as lost as if it had never existed.

‘There’s no percentage in staying up here and getting frozen to death.’ Commander Swanson’s voice was a half-shout, it had to be to make him heard. ‘If we’re going under that ice, we might as well go now.’ He turned his back to the wind and stared out to the west where a big broad-beamed trawler was rolling heavily and sluggishly in the seas less than a quarter of a mile away. The Morning Star, which had closed right up to the edge of the ice-pack over the last two days, listening, waiting, and all in vain, was about to return to Hull: her fuel reserves were running low.

‘Make a signal,’ Swanson said to the seaman by his side. ‘“We are about to dive and proceed under the ice. We do not expect to emerge for minimum four days, are prepared to remain maximum fourteen.”’ He turned to me and said: ‘If we can’t find them in that time …’ and left the sentence unfinished.

I nodded, and he went on: ‘“Many thanks for your splendid co-operation. Good luck and a safe trip home.”’ As the signalman’s lamp started chattering out its message, he said wonderingly: ‘Do those fishermen trawl up in the Arctic the entire winter?’

‘They do.’

‘The whole winter. Fifteen minutes and I’m about dead. Just a bunch of decadent Limeys, that’s what they are.’ A lamp aboard the Morning Star flickered for some seconds and Swanson said: ‘What reply?’

‘“Mind your heads under that ice. Good luck and goodbye.”’

‘Everybody below,’ Swanson said. As the signalman began to strip the canvas dodger I dropped down a ladder into a small compartment beneath, wriggled through a hatch and down a second ladder to the pressure hull of the submarine, another hatch, a third ladder and then I was on the control deck of the Dolphin. Swanson and the signalman followed, then last of all Hansen, who had to close the two heavy watertight doors above.

Commander Swanson’s diving technique would have proved a vast disappointment to those brought up on a diet of movie submarines. No frenzied activity, no tense steely-eyed men hovering over controls, no Tannoy calls of ‘Dive, dive, dive,’ no blaring of klaxons. Swanson reached down a steel-spring microphone, said quietly: ‘This is the captain. We are about to move under the ice. Diving now,’ hung up and said: ‘Three hundred feet.’

The chief electronics technician leisurely checked the rows of lights indicating all hatches, surface openings and valves closed to the sea. The disc lights were out: the slot lights burned brightly. Just as leisurely he re-checked them, glanced at Swanson and said: ‘Straight line shut, sir.’ Swanson nodded. Air hissed loudly out of the ballast tanks, and that was it. We were on our way. It was about as wildly exciting as watching a man push a wheelbarrow. And there was something oddly reassuring about it all.

Ten minutes later Swanson came up to me. In the past two days I’d come to know Commander Swanson fairly well, like him a lot and respect him tremendously. The crew had complete and implicit faith in him. I was beginning to have the same thing. He was a kindly genial man with a vast knowledge of every aspect of submarining, a remarkable eye for detail, an even more remarkably acute mind and an imperturbability that remained absolute under all conditions. Hansen, his executive officer and clearly no respecter of persons, had said flatly that Swanson was the best submarine officer in the Navy. I hoped he was right, that was the kind of man I wanted around in conditions like those.

‘We’re about to move under the ice now, Dr Carpenter,’ he said. ‘How do you feel about it?’

‘I’d feel better if I could see where we were going.’

‘We can see,’ he said. ‘We’ve the best eyes in the world aboard the Dolphin. We’ve got eyes that look down, around, ahead and straight up. Our downward eye is the fathometer or echo-sounder that tells us just how deep the water below our keel is – and as we have about five thousand feet of water below our keel at this particular spot we’re hardly likely to bump into underwater projections and its use right now is purely a formality. But no responsible navigation officer would ever think of switching it off. We have two sonar eyes for looking around and ahead, one sweeping the ship, another searching out a fifteen-degree path on either side of the bow. Sees everything, hears everything. You drop a spanner on a warship twenty miles away and we know all about it. Fact. Again it seems purely a formality. The sonar is searching for underwater ice stalactites forced down by the pressure of rafted ice above, but in five trips under the ice and two to the Pole I’ve never seen underwater stalactites or ridges deeper than 200 feet, and we’re at 300 feet now. But we still keep them on.’

‘You might bump into a whale?’ I suggested.

‘We might bump into another submarine.’ He wasn’t smiling. ‘And that would be the end of both of us. What with the Russian and our own nuclear submarines busy criss-crossing to and fro across the top of the world the underside of the polar ice-cap is getting more like Times Square every day.’

‘But surely the chances –’

‘What are the chances of mid-air collision to the only two aircraft occupying ten thousand square miles of sky? On paper, they don’t exist. There have been three such collisions this year already. So we keep the sonar pinging. But the really important eye, when you’re under the ice, is the one that looks up. Come and have a squint at it.’

He led the way to the after starboard end of the control room where Dr Benson and another man were busy studying a glassed-in eye-level machine which outwardly consisted of a seven-inch-wide moving ribbon of paper and an inked stylus that was tracing a narrow straight black line along it. Benson was engrossed in adjusting some of the calibrated controls.

‘The surface fathometer,’ Swanson said. ‘Better known as the ice-machine. It’s not really Dr Benson’s machine at all, we have two trained operators aboard, but as we see no way of separating him from it without actually court-martialling him, we take the easy way out and let him be.’ Benson grinned, but his eye didn’t leave the line traced by the stylus. ‘Same principle as the echo-sounding machine, it just bounces an echo back from the ice – when there is any. That thin black line you see means open water above. When we move under the ice the stylus has an added vertical motion which not only indicates the presence of ice but also gives us its thickness.’

‘Ingenious,’ I said.

‘It’s more than that. Under the ice it can be life or death for the Dolphin. It certainly means life or death for Drift Station Zebra. If we ever get its position we can’t get at it until we break through the ice and this is the only machine that can tell us where the ice is thinnest.’

‘No open water at this time of year? No leads?’

‘Polynyas, we call them. None. Mind you, the ice-pack is never static, not even in winter, and surface pressure changes can very occasionally tear the ice apart and expose open water. With air temperatures such as you get in winter you can guess how long the open water stays in a liquid condition. There’s a skin of ice on it in five minutes, an inch in an hour and a foot inside two days. If we get to one of those frozen over polynyas inside, say, three days, we’ve a fair chance of breaking through.’

‘With the conning-tower?’

‘That’s it. The sail. All new nuclear subs have specially strengthened sails designed for one purpose only – breaking through Arctic ice. Even so we have to go pretty gently as the shock, of course, is transmitted to the pressure hull.’

I thought about this a bit then said: ‘What happens to the pressure hull if you come up too fast – as I understand may happen with a sudden change in salinity and sea temperature – and you find out at the last minute that you’ve drifted away from the indicated area of thin ice and have ten solid feet of the stuff above you?’

‘That’s it,’ he said. ‘Like you say, it’s the last minute. Don’t even think about such things, far less talk about them: I can’t afford to have nightmares on this job.’ I looked at him closely, but he wasn’t smiling any more. He lowered his voice. ‘I don’t honestly think that there is one member of the crew of the Dolphin who doesn’t get a little bit scared when we move in under the ice. I know I do. I think this is the finest ship in the world, Dr Carpenter, but there are still a hundred things that can go wrong with it and if anything happens to the reactor or the steam turbines or the electrical generators – then we’re already in our coffin and the lid screwed down. The ice-pack above is the coffin lid. In the open sea most of those things don’t matter a damn – we just surface or go to snorkel depth and proceed on our diesels. But for diesels you need air – and there’s no air under the ice-pack. So if anything happens we either find a polynya to surface in, one chance in ten thousand at this time of year, before our standby battery packs up or – well, that’s it.’

‘This is all very encouraging,’ I said.

‘Isn’t it?’ He smiled, none too soon for me. ‘It’ll never happen. What’s the worthy Benson making all the racket about?’

‘Here it is,’ Benson called. ‘The first drift-block. And another. And another! Come and have a look, Doctor.’

I had a look. The stylus, making a faint soft hissing sound, was no longer tracing out a continuously horizontal line but was moving rapidly up and down across the paper, tracing out the outline of the block of ice passing astern above us. Another thin straight line, more agitated vertical movements of the stylus, and again another block of ice had gone. Even as I watched the number of thin horizontal lines became fewer and fewer and shorter and shorter until eventually they disappeared altogether.

‘That’s it, then,’ Swanson nodded. ‘We’ll take her deep now, real deep, and open up all the stops.’

When Commander Swanson had said he was going to hurry, he’d meant every word of it. In the early hours of the following morning I was awakened from a deep sleep by a heavy hand on my shoulder. I opened my eyes, blinked against the glare of the overhead light then saw Lieutenant Hansen.

‘Sorry about the beauty sleep, Doc,’ he said cheerfully. ‘But this is it.’

‘This is what?’ I said irritably.

‘85° 35′ north, 21° 20′ east – the last estimated position of Drift Station Zebra. At least, the last estimated position with estimated correction for polar drift.’

‘Already?’ I glanced at my watch, not believing it. ‘We’re there already?’

‘We have not,’ Hansen said modestly, ‘been idling. The skipper suggests you come along and watch us at work.’

‘I’ll be right with you.’ When and if the Dolphin managed to break through the ice and began to try her one in a million chance of contacting Drift Station Zebra, I wanted to be there.

We left Hansen’s cabin and had almost reached the control room when I lurched, staggered and would have fallen but for a quick grab at a handrail that ran along one side of the passageway. I hung on grimly as the Dolphin banked violently sideways and round like a fighter plane in a tight turn. No submarine in my experience had ever been able to begin to behave even remotely in that fashion. I understood now the reasons for the safety belts on the diving control seats.

‘What the hell’s up?’ I said to Hansen. ‘Avoiding some underwater obstruction ahead?’

‘Must be a possible polynya. Some place where the ice is thin, anyway. As soon as we spot a possible like that we come around like a chicken chasing its own tail just so we don’t miss it. It makes us very popular with the crew, especially when they’re drinking coffee or soup.’

We passed into the control room. Commander Swanson, flanked by the navigator and another man, was bent over the plotting table, examining something intently. Farther aft a man at the surface fathometer was reading out ice thickness figures in a quiet unemotional voice. Commander Swanson looked up from the chart.

‘Morning, Doctor. John, I think we may have something here.’

Hansen crossed to the plot and peered at it. There didn’t seem to be much to peer at – a tiny pin-point of light shining through the glass top of the plot and a squared sheet of chart paper marked by a most unseamanlike series of wavering black lines traced out by a man with a pencil following the track of the tiny moving light. There were three red crosses superimposed on the paper, two very close together, and just as Hansen was examining the paper the crewman manning the ice-machine – Dr Benson’s enthusiasm for his toy did not, it appeared, extend to the middle of the night – called out ‘Mark!’ Immediately the black pencil was exchanged for a red and a fourth cross made.

‘“Think” and “may” are just about right, Captain,’ Hansen said. ‘It looks awfully narrow to me.’

‘It looks the same way to me, too,’ Swanson admitted. ‘But it’s the first break in the heavy ice that we’ve had in an hour, almost. And the farther north we go, the poorer our chances. Let’s give it a go. Speed?’

‘One knot,’ Raeburn said.

‘All back one-third,’ Swanson said. No sharp imperatives, not ever, in the way Swanson gave his orders, more a quiet and conversational suggestion, but there was no mistaking the speed with which one of the crewmen strapped into the diving-stand bucket seat leaned forward to telegraph the order to the engine-room. ‘Left full rudder.’

Swanson bent over to check the plot, closely watching the tiny pin-point of light and tracing pencil move back towards the approximate centre of the elongated quadrangle formed by the four red crosses. ‘All stop,’ he went on. ‘Rudder amidships.’ A pause then: ‘All ahead one-third. So. All stop.’

‘Speed zero,’ Raeburn said.

‘120 feet,’ Swanson said to the diving officer. ‘But gently, gently.’

A strong steady hum echoed in the control centre. I asked Hansen: ‘Blowing ballast?’

He shook his head. ‘Just pumping the stuff out. Gives a far more precise control of rising speed and makes it easier to keep the sub on an even keel. Bringing a stopped sub up on a dead even keel is no trick for beginners. Conventional subs never try this sort of thing.’

The pumps stopped. There came the sound of water flooding back into the tanks as the diving officer slowed up the rate of ascent. The sound faded.

‘Secure flooding,’ the diving officer said. ‘Steady on 120 feet.’

‘Up periscope,’ Swanson said to the crewman by his side. An overhead lever was engaged and we could hear the hiss of high-pressure oil as the hydraulic piston began to lift the starboard periscope off its seating. The gleaming cylinder rose slowly against the pressure of the water outside until finally the foot of the periscope cleared its well. Swanson opened the hinged handgrips and peered through the eyepiece.

‘What does he expect to see in the middle of the night at this depth?’ I asked Hansen.

‘Never can tell. It’s rarely completely dark, as you know. Maybe a moon, maybe only stars – but even starlight will show as a faint glow through the ice – if the ice is thin enough.’

‘What’s the thickness of the ice above, in this rectangle?’

‘The sixty-four thousand dollar question,’ Hansen admitted, ‘and the answer is that we don’t know. To keep that ice-machine to a reasonable size the graph scale has to be very small. Anything between four and forty inches. Four inches we go through like the icing on a wedding cake: forty inches and we get a very sore head indeed.’ He nodded across to Swanson. ‘Doesn’t look so good. That grip he’s twisting is to tilt the periscope lens upwards and that button is for focusing. Means he’s having trouble in finding anything.’

Swanson straightened. ‘Black as the Earl of Hell’s waistcoat,’ he said conversationally. ‘Switch on hull and sail floodlights.’

He stooped and looked again. For a few seconds only. ‘Pea-soup. Thick and yellow and strong. Can’t see a thing. Let’s have the camera, shall we?’

I looked at Hansen, who nodded to a white screen that had just been unshuttered on the opposite bulkhead. ‘All mod cons, Doc. Closed circuit TV. Camera is deck mounted under toughened glass and can be remotely controlled to look up or round.’

‘You could do with a new camera, couldn’t you?’ The TV screen was grey, fuzzy, featureless.

‘Best that money can buy,’ Hansen said. ‘It’s the water. Under certain conditions of temperature and salinity it becomes almost completely opaque when floodlit. Like driving into a heavy fog with your headlights full on.’

‘Floodlights off,’ Swanson said. The screen became quite blank. ‘Floodlights on.’ The same drifting misty grey as before. Swanson sighed and turned to Hansen. ‘Well, John?’

‘If I were paid for imagining things,’ Hansen said carefully, ‘I could imagine I see the top of the sail in that left corner. Pretty murky out there, Captain. Heigh-ho for the old blind man’s buff, is that it?’

‘Russian roulette, I prefer to call it.’ Swanson had the clear unworried face of a man contemplating a Sunday afternoon in a deck-chair. ‘Are we holding position?’

‘I don’t know.’ Raeburn looked up from the plot. ‘It’s difficult to be sure.’

‘Sanders?’ This to the man at the ice-machine.

‘Thin ice, sir. Still thin ice.’

‘Keep calling. Down periscope.’ He folded the handles up and turned to the diving officer. ‘Take her up like we were carrying a crate of eggs atop the sail and didn’t want to crack even one of them.’

The pumps started again. I looked around the control room. Swanson excepted, everyone was quiet and still and keyed-up. Raeburn’s face was beaded with sweat and Sanders’s voice was too calm and impersonal by half as he kept repeating: ‘Thin ice, thin ice,’ in a low monotone. You could reach out and touch the tension in the air. I said quietly to Hansen:

‘Nobody seems very happy. There’s still a hundred feet to go.’

‘There’s forty feet,’ Hansen said shortly. ‘Readings are taken from keel level and there’s sixty feet between the keel and the top of the sail. Forty feet minus the thickness of the ice – and maybe a razor-sharp or needle-pointed stalactite sticking down ready to skewer the Dolphin through the middle. You know what that means?’

‘That it’s time I started getting worried too?’

Hansen smiled, but he wasn’t feeling like smiling. Neither was I, not any more.