Seen from a distance, the ice looked like a heavily demarcated horizon, a solid white line between the gray of the sea and the leaden blue of the sky. As the Cushing drew cautiously nearer it was evident that it was not solid, for what appeared to be the edge was a mass of broken blocks, crumbled off the solid ice behind by the combined action of sea movement and the weakening effect of melting. Most of the pieces nevertheless were of quite respectable size, several tons in weight and many feet across; and when Keith decided he had approached as close as was prudent he turned to a course parallel to the putative frontal edge for a close and leisurely inspection, all the while maintaining a continuous and careful watch ahead. It would not do to damage valuable periscopes by ramming them against a miniature iceberg during a quixotic rubberneck tour for crew members!
The coloration of the ice and ice blocks was fascinating, even though he had been prepared by his reading. White on top, of course, and white on the broken-off edges, down to the waterline. But where the ice entered the water it assumed a greenish tinge. Some of the blocks were wallowing gently in the nearly motionless sea, enough that he could see a foot or more below their normal waterlines, far enough to note that the light green shaded swiftly to almost black. Some of the pamphlets he had read had explained it: This was the norm for much of the Arctic, though not for all of it. The discoloration was the combined result of normal sea growth and water action on tiny organisms frozen into the ice when it was formed. These organisms, and growth on the ice under surface, formed much of the food for the wildlife — the seals, porpoises, whales and fish — and through them for the bears and man himself. The white mass was essentially snowfall over the frozen sea ice, built up during the years it had slowly circulated around the Arctic basin.
Ice, to Keith, should be white; or at least clear, like frozen water. But he had learned it could be a number of other colors, the slimy blue-green of the undersides of these blocks being only one of several manifestations. It was also hard, both from the cold and from the compression to which it was so often subjected, and deserving of respect. Cushing had been built with an ice suit, one of the reasons she had been chosen for this mission. Her sail was specially strengthened, as were her propeller, hull and control surfaces. In addition, her sailplanes were designed so that they could be put on ninety degrees rise, straight up and down, to facilitate breaking through the ice if necessary. She could cope with the ice, if handled intelligently, but she could not ignore the facts of physics, either. For the next few weeks he and his ship would be spending all their time in intimate relation with this common, yet most unusual, substance. It behooved him to learn what he could of it at first hand.
Sunlight was waning when Keith decided that his crew and he had had enough opportunity to inspect the ice under which they would henceforth be operating. He housed the periscopes, retracted the radio antenna masts, ordered deep submergence and set the course due north. Jim Hanson had obtained several Loran fixes, and the next thing would be to detect the nearest part of Spitsbergen, Prins Karls Forland, on sonar and Fathometer, in the place where it was supposed to be. This would confirm the practicability of avoiding unwanted shallow water should there be difficulty with other navigational equipment. From this time onward, except for occasional tests of missiles, Cushing would be divorced even from periscope view of the surface of the sea, confined — except for thinner ice in a rare winter polynya — beneath a virtually impenetrable layer of ice twenty feet thick.
In obedience to his operation order, Keith set a slower speed of advance than before, and when the upward-beamed fathometer showed that block and brash ice had given way to solid cover he doubled the sonar watch. As the Cushing drove ever northward, her echo-ranging sonar probed ahead, on a secure and varying frequency, listening for the somewhat mushy return which would spell danger. If there were a return echo, any attempt to halt Cushing’s forward progress would be useless. Like all nuclear submarines, however, especially the whale-shaped ones, she turned on a dime, far more sharply than any surface ship could possibly hope to match. Here lay her safety. Keith’s orders to his officer of the deck and helmsman were simple and direct. “If deep ice is contacted ahead, immediately put the rudder hard over away from it, and then call me.”
It was not, however, Keith’s intent to proceed directly to the North Pole. If there were time, he might do it later. Likewise, the slow counterclockwise rotation of the ice pack had long been plotted by explorers and scientists. This was a factor of interest, not of immediate concern. Cushing’s mission was to proceed to several specified geographical positions and determine if she could depend upon being able to fire her missiles within a given radius of each as the ice slowly drifted overhead. The operation order said she was to be the first of a number of submarines sent to determine whether the possibility of firing missiles in the Arctic Ocean could be guaranteed during all periods of the year.
Of all the navigation instruments with which ships have been fitted since the beginning, the most important has always been the compass. The early mariners had nothing else. But a compass in the Arctic Ocean is essentially valueless, a fact dramatically brought out when one contemplates that at the North Pole all directions are south. The rotation of the earth no longer gives any directive force, and the gyrocompass, that marvel of the industrial age, wanders at will. A magnetic compass might theoretically be able to point to the nearby north magnetic pole, which ever so slowly drifts around among the icebound islands of Canada’s northern archipelago, but at this close range the magnetic pole is very broad and very weak. Inside the steel hull of a submarine a magnetic compass, moreover, is not dependable.
This problem had presented itself with the voyage of the Nautilus across the top of the world, not quite three years before. It had been resolved by installation of the guidance system of an early missile, and by redrawing the map of the Arctic so that Nautilus’ northward course, as she headed toward the Pole, continued to be “north” after she had passed through it and was heading in a southerly direction — and remained so until normal functions of the gyrocompass could be restored. The grid system resulting made it at least possible to orient one’s location in relation to navigable water and land masses. Three years later, Cushing had a much more sophisticated system designed specifically for submarines and useful anywhere in the world. A good segment of Keith’s training and that of many of his officers and crew, before ever reporting to the Electric Boat Shipyard, had been devoted to learning the intricacies of the Submarine Inertial Navigation System, which, inevitably, became known as SINS.
Now they were using their SINS for real, in the trickiest of situations, the high northern latitudes, and applying it to the same old grid system. Even though he had been well prepared for it, both in briefings and in his studies of previous northern voyages, Keith felt a surge in his adrenaline when Cushing’s ice detector showed that the ice above was solid.
There was an underwater television transmitter mounted on the main deck several feet forward of the sail, controllable in train and elevation from a small console located near its receiver in the control room. Two strong searchlights had also been installed, synchronized in direction with the television head. It was hard to see far underwater in the best of conditions, but the water was at least clear, the lights powerful. Keith estimated that he could see for about a hundred feet in any direction. The only things visible, however, were Cushing’s rounded bow, if one trained the head down and forward, and bumpy ice overhead.