He was now about fifty feet down, and gaining speed as he dropped to the bottom. The flat, sandy seabed was just coming into sight, and for a moment Franklin had to fight the automatic impulse to press the button which would blow the torpedo’s tanks and take him up to the surface. That would be the worst thing to do, natural though it was to seek air and Sun when anything went wrong underwater. Once on the bottom, he could take his time to think matters out, whereas if he surfaced the current might sweep him miles away. It was true that the station would soon pick up his radio calls once he was above water — but he wanted to extricate himself from this predicament without any outside help.
The torp grounded, throwing up a cloud of sand which soon drifted away in the slight current. A small grouper appeared from nowhere, staring at the intruder with its characteristic popeyed expression. Franklin had no time to bother with spectators, but climbed carefully off his vehicle and pulled himself to the stern. Without flippers, he had little mobility under water, but fortunately there were sufficient handholds for him to move along the torpedo without difficulty.
As Franklin had feared — but was still unable to explain — the rudder and elevator were flopping around uselessly. There was no resistance when he moved the little vanes by hand, and he wondered if there was any way in which he could fix external control lines and steer the torpedo manually. He had some nylon line, and a knife, in the pouch on his harness, but there seemed no practical way in which he could fasten the line to the smooth, streamlined vanes.
It looked as if he would have to walk home. That should not be too difficult — he could set the motor running at low speed and let the torp pull him along the bottom while he aimed it in the right direction by brute force. It would be clumsy, but seemed possible in theory, and he could think of nothing better.
He glanced at his watch; it had been only a couple of minutes since he had tried to turn at the leg of the triangle, so he was no more than a minute late at his destination. Don would not be anxious yet, but before long he would start searching for his lost pupil. Perhaps the best thing to do would be to stay right here until Don turned up, as he would be bound to do sooner or later…
It was at this moment that suspicion dawned in Franklin’s mind, and almost instantly became a full-fledged conviction. He recalled certain rumors he had heard, and remembered that Don’s behavior before they set out had been — well, slightly skittish was the only expression for it, as if he had been cherishing some secret joke.
So that was it. The torpedo had been sabotaged. Probably at this very moment Don was hovering out there at the limits of visibility, waiting to see what he would do and ready to step in if he ran into real trouble. Franklin glanced quickly around his hemisphere of vision, to see if the other torp was lurking in the mist, but was not surprised that there was no sign of it. Burley would be too clever to be caught so easily. This, thought Franklin, changed the situation completely. He not only had to extricate himself from his dilemma, but, if possible, he had to get his own back on Don as well.
He walked back to the control position, and switched on the motor. A slight pressure on the throttle, and the torp began to stir restlessly while a flurry of sand was gouged out of the sea bed by the jet. A little experimenting showed that it was possible to “walk” the machine, though it required continual adjustments of trim to stop it from climbing up to the surface or burying itself in the sand. It was, thought Franklin, going to take him a long time to get home this way, but he could do it if there was no alternative.
He had walked no more than a dozen paces, and had acquired quite a retinue of astonished fish, when another idea struck him. It seemed too good to be true, but it would do no harm to try. Climbing onto the torpedo and lying in the normal prone position, he adjusted the trim as carefully as he could by moving his weight back and forth. Then he tilted the nose toward the surface, pushed his hands out into the slip stream on either side, and started the motor at quarter speed.
It was hard on his wrists, and his responses had to be almost instantaneous to check the weaving and bucking of the torpedo. But with a little experimenting, he found he could use his hands for steering, though it was as difficult as riding a bicycle with one’s arms crossed. At five knots, the area of his flattened palms was just sufficient to give control over the vehicle.
He wondered if anyone had ever ridden a torp this way before, and felt rather pleased with himself. Experimentally, he pushed the speed up to eight knots, but the pressure on his wrists and forearms was too great and he had to throttle back before he lost control.
There was no reason, Franklin told himself, why he should not now make his original rendezvous, just in case Don was waiting there for him. He would be about five minutes late, but at least it would prove that he could carry out his assignment in the face of obstacles which he was not quite sure were entirely man-made.
Don was nowhere in sight when he arrived, and Franklin guessed what had happened. His unexpected mobility had taken Burley by surprise, and the warden had lost him in the submarine haze. Well, he could keep on looking. Franklin made one radio call as a matter of principle, but there was no reply from his tutor. “I’m going home!” he shouted to the watery world around him; still there was silence. Don was probably a good quarter of a mile away, conducting an increasingly more anxious search for his lost pupil.
There was no point in remaining below the surface and adding to the difficulties of navigation and control. Franklin took his vehicle up to the top and found that he was less than a thousand yards from the Maintenance Section jetty. By keeping the torp tail heavy and nose up he was able to scorch along on the surface like a speedboat without the slightest trouble, and he was home in five minutes.
As soon as the torpedo had come out of the anticorrosion sprays which were used on all equipment after salt-water dives, Franklin got to work on it. When he pulled off the panel of the control compartment, he discovered that his was a very special model indeed. Without a circuit diagram, it was not possible to tell exactly what the radio-operated relay unit he had located could do, but he did not doubt that it had an interesting repertory. It could certainly cut off the motor, blow or flood the buoyancy tanks, and reverse the rudder and elevator controls. Franklin suspected that compass and depth gauge could also be sabotaged if required. Someone had obviously spent a great deal of loving care making this torpedo a suitable steed for overconfident pupils…
He replaced the panel and reported his safe return to the officer on duty. “Visibility’s very poor,” he said, truthfully enough. “Don and I lost each other out there, so I thought I’d better come in. I guess he’ll be along later.”
There was considerable surprise in the mess when Franklin turned up without his instructor and settled quietly down in a corner to read a magazine. Forty minutes later, a great slamming of doors announced Don’s arrival. The warden’s face was a study in relief and perplexity as he looked around the room and located his missing pupil, who stared back at him with his most innocent expression and said: “What kept you?”
Burley turned to his colleagues and held out his hand.
“Pay up, boys,” he ordered.
It had taken him long enough to make up his mind, but he realized that he was beginning to like Franklin.
CHAPTER V
The two men leaning on the rails around the main pool of the aquarium did not, thought Indra as she walked up the road to the lab, look like the usual run of visiting scientists. It was not until she had come closer and was able to get a good look at them that she realized who they were. The big fellow was First Warden Burley, so the other must be the famous mystery man he was taking through a high-pressure course. She had heard his name but couldn’t remember it, not being particularly interested in the activities of the training school. As a pure scientist, she tended to look down on the highly practical work of the Bureau of Whales — though had anyone accused her outright of such intellectual snobbery she would have denied it with indignation.