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