by Hal Clement
Even here, however, chaos reigned. A patch of ocean would grow just slightly warmer than its surroundings, either from sunlight or from biological effects. Ammonia would become correspondingly less soluble and escape into the atmosphere, which would drop accordingly in density and start a strong updraft. The water would of course grow denser and settle. Wind and surface flows would race toward the spot with essentially no inertial deflection until the final moments and even then in an unpredictable direction. There might be a waterspout, a whirlpool, or both; neighboring spouts or eddies might attract or repel each other; whatever happened, no wind or waves got very far undisturbed in this region. Regularity in either was unknown. Farther away from the evaporation center, of course, there was an effective long reach. Long, high waves did build up across The Pupil, focusing on The Cataract, and found their way into the chaotic mass of rocking, swirling local storm centers where even the winged Habras didn’t try to fly. Once there, though, they merely complicated the local chop.
Janice began to doubt that the surface was for her. Not just now. Not just in a suit, or even riding the massive Thrasher. The raft was bad enough.
She tried valiantly to concentrate on the Cephallonians’ conversation, but with less and less success as they neared the heaving surface.
She shouldn’t have thought of that participle.
“Thrasher,” she buzzed, “I’ll have to go back down. I can’t take the motion—I’ll explain why later, or you can ask Hugh. I’ll be swimming toward the raft; you two can catch me when you’ve eaten.” Without waiting for an answer she opened the carrier in which she had been riding, emerged, and headed downward. It was rather hard work, but not impossible. The temptation to reduce buoyancy was easy to resist when one knew that the darkness extended five hundred kilometers that way before anything except perhaps a wandering iceberg on the verge of explosive shattering would stop a sinking body. She had no intention of sleeping, and expected no accidents that might knock her out, but common sense insisted on positive lift.
Waves or no waves, she would be easier to find and possible to reach on the surface.
She keyed a brief message to Hugh, telling her plans.
“Why?” came his reasonable question. “Thrasher can bring you here in a few minutes.”
“Surface rough. Stomach.”
“Oh. All right. The Box will keep track of you, and I’ll have the two pick you up when Thrasher’s eaten. I hope—” He fell silent.
“What?” There was still a long wait for his answer.
“The raft isn’t exactly steady, either. Maybe when you get here you’d better get rid of the diving juice and let me take over the deep work. I don’t get queasy.”
“We’ll see.” Janice had no intention of giving up what promised to be the interesting part of the trip, but arguing by code was far too much nuisance.
Having Hugh come with her into the depths, as he had before during the Sclera investigation, would of course be different. In fact, it seemed a very good idea, and there was enough reserve diving fluid to allow it. Maybe the need for a surface monitor could be ducked somehow. If not, however, Janice Wind Cedar would not be filling that job. It would be her beloved husband Hugh who stayed on deck watching instruments, regardless of how protective he might feel.
She was still firmly of this opinion, tired as she was getting, when the Cephallonians caught up with her. She resumed her place in Thrasher’s carrier without comment, and in half an hour they were at the raft.
This was simply a resting tank for the swimmers and support deck for equipment. A large framework outlined a volume of water shallow enough so that they could keep their blow-slits near the surface and breathe occasionally with minimum effort. Some sort of streamlining was achieved by covering the sides with polymer sheeting. From below the surface, the main body of the structure looked a little like a canoe submerged to the gunwales and with the open stern cut off flat. Decks of stiffer polymer formed the tank’s bottom and a rim some five meters wide all around at the waterline. A low shelter stood on this for the convenience of the Erthumoi. Between this cabin and the nearest edge of the tank was a roughly cubical structure some three-quarters of a meter on each edge; why this was called The Box was obvious. Near this was a compressor and filter system to charge oxygen tanks, and inside the resting place near it, mostly under water, a rack of high-pressure gas cylinders. Half a dozen smaller structures, sheltered like The Box from rain and spray, were scattered around the edge of the tank, accessible to both Erthumoi and Cephallonians, to house the research equipment and fermenters.
Floats of polymer foam were attached at scores of seemingly random points all over the structure—under the deck, at its edges, and around and under the tank. No one of these was highly buoyant, since the designers did not want wind to have much of a grip on the craft, but there were enough of them to satisfy the firmest believer in the value of redundance. A dozen hydro-jets were mounted on as many of the floats, allowing the whole unit to be maneuvered rather clumsily. No one had studied the currents closely enough to foresee the need for more. The winged Habranhans had reported that the aerial storms in The Cataract were violent, but no one seemed to know much about the sea.
Someone had made a casual estimate of centripetal currents based on calculated evaporation rates, and powered the raft to move at twice their speed. This was why the Pupil Study Group was in trouble. Evaporation had been calculated simply from cloud observations made from space. No one had computed the amount of ocean that sank from ammonia loss and thus created more inbound current. In fact, the surface flow toward the planet’s sunward pole reached a speed much greater than the raft’s thrusters could override. None of the four living explorers had paid enough attention to the trackers to notice this on the inward trip, and no one had told The Box to watch out for such matters. Winds feeding into the same zone reached speeds five or six times as great as the ocean currents, resulting in spectacular waves; but the raft had very little structure above the surface and no one had really worried about air motion until they reached the really chaotic region almost under the sun.
One does not use or even carry radio transmitters on Habranha, since they interfere with native speech. There was no neutrino set on the raft, so they could reach nothing off the surface. It was wildly unlikely that they could be spotted optically from orbit against a stormy ocean background even if The Cataract’s cloud cover should happen to open briefly, and even more unlikely that a flying native would pass anywhere near. Habranhan researchers concentrated on the Sclera region, the low-sun rim of their small world, where grew the icebergs making up for the ever-melting warm edge of The Iris. The stormy hot pole was not only a dangerous flying area, but promised little useful knowledge. The net result was four explorers entirely on their own.
Hugh was summarizing. His wife would have been better at it, but code was too slow.
“As far as food goes, the fermenters will keep us alive indefinitely, or until we let something into them that poisons their pseudolife. Statistically, somewhere between a hundred hours and old age. We Erthumoi have partial recycling units in our suits which would take a thousand hours or so to run down if we lived on nothing else. You swimmers don’t have any recycling, and need the fusers to concentrate oxygen for you, so there’s a limit to the power we can commit to getting out of here.”
“We can’t get the raft out. We know that already,” Splasher pointed out, “and without the raft we can’t carry the fermenters. If we try to build something smaller, it’s an all-or-nothing project.”
Janice made a negative gesture, and the others paused to listen to her code.
“One can go for help.”
Hugh pursed his lips thoughtfully.
“I suppose so. Thrasher or Splasher couldn’t swim all the way with supplies they can carry, though, and you or I would have to use some sort of jerried boat, either surface or sub. I suppose if we mounted several jets on something small enough it might make it. Would it be bet
ter to ride the surface and keep the oxygen problem down, or stay below and use diving juice? And if it doesn’t work, what happens? One person at some unknown spot on or in the ocean, out of touch with both the raft here and the rest of the world, lost or out of power or both?”
“The Job.” The woman’s code remark was terse but adequate. She paused a moment, then added, “Submerged. Navigation.”
“You mean it’ll be easier to hold heading below storm level? I suppose that’s right, though from what you and Thrasher say about the test dive it’s pretty turbulent down below, too.”
“Low speed.”
Hugh was silent for some time. He knew his wife was slanting the arguments in favor of letting her make the trip. He’d have done the same if he’d been quick-witted enough, he realized; he couldn’t blame her. He still didn’t like the idea, though. He was not particularly protective as husbands went, but knew her tendency to overdemonstrate her already obvious competence, and even after four years of marriage couldn’t help worrying just a little when they were apart. He curbed his thoughts firmly after a minute or so, since all three of the others were clearly waiting for him to speak.
“All right. We’ll have to do some designing and building, though, and we don’t have much of a machine shop with us.”
“Basics,” keyed Janice.
“I know. The inclined plane. We have a knife apiece, and there are a lot of nuts and bolts in the thruster mounts. We’ll have to scrounge material from what’s around us, though, and make sure it’s chemically stable.”
“You dry land and flying types have a violent idea of what makes the basic tool,” Thrasher remarked. “Every one of you seems to regard the cutting edge as primary.”
“Well, what would you offer, and did you bring it along?” asked Hugh.
“The rope, of course. Yes, we have several kilometers of high-tensile cord, though it’s so thin we may have to pad it to keep it from cutting through other material. That’s the real fundamental. Support for the helpless, towing burdens, nets and nooses for capturing food—the fiber started civilization, with glue and the lens next.”
Hugh was about to respond when Janice and Splasher interrupted together in almost identical phrases, though translator and coder didn’t sound much alike. “Design now. Philosophy later.” The males looked at each other, read what each was sure must be sympathy in the other’s expression, and got back to the real subject.
“How many thrusters should we risk? Will two be enough?”
“I’d advise more,” replied the Cephallonian. “There’s a time question, and while Janice apparently can’t travel very fast through turbulence, power is still relevant. It may be well to have drive force in reserve even if she doesn’t want to use all of it.”
“All right. You two look over the local seaweed supply. I hope you know what’s explosive by sight; with pieces the size we’ll need, finding out the hard way is risky.”
“We know what furnishes safe cordage—which might be wise to use instead of our own reserves, when we can. Thicker samples of the same growths should make adequate frame members. We won’t need too much if the rider is to be an Erthuma. Let’s go collecting, Splasher.”
The seaweed that the swimmers selected was extremely tough and springy, but the knives of the human workers were able to deal with it. As much as possible was done aboard the raft, since a knife dropped over the abyss would be hard to retrieve. The Cephallonians might recover it before reaching their depth limit, but there were already enough problems. More of the high-tech cord was used than the swimmers had wanted, since the natural material they had hoped to employ was inconveniently thick when strong enough. In any case, the skeleton submarine produced in twenty hours or so of labor seemed sturdy enough. It was an open framework like those of the natives, partly to save time and material, partly to help the pilot’s visibility. Four of the thruster-fuser units were lashed securely to it slightly ahead of what the group hoped would turn out to be its center of drag pressure. The hull diameter held opposite members of the thruster pairs nearly two meters apart; there had been some argument about making the craft so large, but the thought of having to lie prone for the whole trip was not merely unpleasant. Janice knew she would sometimes need to move around and her husband agreed that this was not just a whim.
Lines of Cephallonian cord were gathered at a “panel” in front of the pilot station and led to the thrusters, where they were wrapped around the control potentiometers a dozen times to provide friction and let the pilot handle all four from one point.
She would have to rely mostly on her own recycling equipment for food, and hope to reach the ring continent before it zeroed. Taking one of the fermenters along would have required an even larger craft, more thrusters, and divided attention for the pilot—selecting the right vegetation to feed the device was time-consuming.
Hugh found no adequate excuse for changing the female pronoun of the pilot up to launch time, and unhappily watched his wife disappear into the depths. “If something goes wrong,” he called after her, “just shut off the power and call for us. We put enough floats into that thing so the thrusters won’t sink it!”
“In the right places, I hope,” muttered Splasher.
Janice did call, very quickly. She was back in ten minutes, towed by the swimmers, and for once did not allow herself to be gagged by the code equipment.
“It’s lucky we spaced the drivers equally around this thing,” she keyed, “and if we do get back, let’s not report this whole episode in detail. I could only steer by changing thrust. The jets were far enough apart to have fair torque, but it was too awkward to manage for more than a few minutes. We’d better install some kind of rudders, lateral and vertical.”
Her husband raised his eyebrows. “A thought. It didn’t occur to me, either, I admit.”
“I took for granted you planned to steer that way,” said Splasher. “I thought of suggesting we mount them so they could be swiveled, but decided the control system would be too hard to rig and doubted that we could attach them firmly enough under such conditions. I agree about rudders.”
Making control surfaces was a fairly quick job: frames were easy, sheeting was cannibalized from the raft, and while the Cephallonians did not regard adhesive as quite so fundamental as rope, they did have plenty in their basic kits. More time was required to rig an additional system of control lines that Hugh could hope would neither tangle nor kink; and he was more uneasy than before when he saw the skeleton hull slide off once more into the weedy darkness, though his wife had spent some minutes in test maneuvers this time before actually starting.
The moment she was out of sight he made his way to The Box. The artificial intelligence was still producing an almost real-time hologram of the surrounding ocean, a picture growing slowly in size and shrinking in scale as more and more sense was made of the chaotic ocean currents. The model depth, Hugh saw, was now nearly five kilometers at the center, the radius over forty. The image of Janice’s craft showed clearly enough, and her husband cringed. Unlike The Box and the Cephallonians she had no sonar, and could not detect vertical currents until she was close enough to see the bits of luminous plankton whose motion would sometimes reveal them. After a few moments of watching, Hugh realized that she had accepted this; she wasn’t trying to dodge but merely maintain depth, correcting the brief up or down accelerations as they came. Her attention must have been mostly on her inertial tracker, the man judged; he hoped she was sparing a little for really large explosive plants.
He resisted the urge to call warnings as she nosed toward the bigger verticals. The Box could have produced sounds audible to her transducer easily enough, but she was already far enough away for signal delay to make warnings useless. She’d just have to take the jolts.
Which meant she’d better not eat for—how long? He hadn’t thought of that in detail. If Janice had, she hadn’t mentioned it. And she had eaten before departure—stuffed herself as foil as she could to give her recycler as
long a run as possible! And she was out there, soaked with diving fluid, with a stomach sensitive to motion, no real way to dodge those awful up-and-down currents, and no reflexes to keep vomit out of her trachea if she lost control!
“Jan! Come back! You can’t make it through those currents! We should have thought!”
Dragging seconds passed before the code came back—long enough to make him wonder whether she had failed to hear or was actually ignoring him, and tempt him to call out again.
“I did think. It’s all right. I’m driving.”
He didn’t get her point. “But Jan! How—?” he fell silent, not knowing what to say, but realizing his wife was not going to be argued out of her mission. Even before the partial sentence could have reached her, another message arrived. “Please don’t worry, dear. I know what I’m doing.”
Hugh always wondered, but never asked, whether the attention she had given to the second message had anything to do with what followed. He couldn’t see how, even after they finally figured out the cause, but there might have been something—
Usually her code calls were extremely terse; this time she had used extra words, and therefore extra time. The coder must have distracted her, at least a little. He never asked, because he knew she’d never tell.
The Box could spot currents, but there must have been something else. The submarine’s image nosed into an unusually complex set of vertical patterns, and suddenly Hugh realized that it was no longer countering them but following, going down with the descending ones, rising with the ascending. For some reason Janice seemed no longer trying to maintain depth. Had she lost her tracker? Unlikely; it was part of her suit, and she was holding direction well enough.
Explosive plant? The Box would have seen, heard, and presumably reported. An electrical encounter? Probable enough, but what could that have done? The submarine frame was of wood, which on Habranha did not necessarily or even probably mean a nonconductor, but her armor should be protection from any charge source they had seen or heard of so far.
