Another peculiar feature was that the engine-room, dynamos and other apparatus were all contained amidships. This gave stability to the craft, and also enabled the same engine to operate both shafts and propellers, as well as both the negative forward electrical plates, and the positive rear ones.
These plates were a new idea in submarine construction, and were the outcome of an idea of Mr. Swift, with some suggestions from his son.
The aged inventor did not want to depend on the usual screw propellers for his craft, nor did he want to use a jet of compressed air, shooting out from a rear tube, nor yet a jet of water, by means of which the creature called the squid shoots himself along. Mr. Swift planned to send the Advance along under water by means of electricity.
Certain peculiar plates were built at the forward and aft blunt noses of the submarine. Into the forward plate a negative charge of electricity was sent, and into the one at the rear a positive charge, just as one end of a horseshoe magnet is positive and will repel the north end of a compass needle, while the other pole of a magnet is negative and will attract it. In electricity like repels like, while negative and positive have a mutual attraction for each other.
Mr. Swift figured out that if he could send a powerful current of negative electricity into the forward plate it would pull the boat along, for water is a good conductor of electricity, while if a positive charge was sent into the rear plate it would serve to push the submarine along, and he would thus get a pulling and pushing motion, just as a forward and aft propeller works on some ferry boats.
But the inventor did not depend on these plates alone. There were auxiliary forward and aft propellers of the regular type, so that if the electrical plates did not work, or got out of order, the screws would serve to send the Advance along.
There was much machinery in the submarine There were gasolene motors, since space was too cramped to allow the carrying of coal for boilers. There were dynamos, motors and powerful pumps. Some of these were for air, and some for water. To sink the submarine below the surface large tanks were filled with water. To insure a more sudden descent, deflecting rudders were also used, similar to those on an airship. There were also special air pumps, and one for the powerful gas, which was manufactured on board.
Forward from the engine-room was a cabin, where meals could be served, and where the travelers could remain in the daytime. There was also a small cooking galley, or kitchen, there. Back of the engine-room were the sleeping quarters and the storerooms. The submarine was steered from the forward compartment, and here were also levers, wheels and valves that controlled all the machinery, while a number of dials showed in which direction they were going, how deep they were, and at what speed they were moving, as well as what the ocean pressure was.
On top, forward, was a small conning, or observation tower, with auxiliary and steering and controlling apparatus there. This was to be used when the ship was moving along on the surface of the ocean, or merely with the deck awash. There was a small flat deck surrounding the conning tower and this was available when the craft was on the surface.
There was provision made for leaving the ship when it was on the bed of the ocean. When it was desired to do this the occupants put on diving suits, which were provided with portable oxygen tanks. Then they entered a chamber into which water was admitted until it was equal in pressure to that outside. Then a steel door was opened, and they could step out. To re-enter the ship the operation was reversed. This was not a new feature. In fact, many submarines today use it.
At certain places there were thick bull’s-eye windows, by means of which the underwater travelers could look out into the ocean through which they were moving. As a defense against the attacks of submarine monsters there was a steel, pointed ram, like a big harpoon. There were also a bow and a stern electrical gun, of which more will be told later.
In addition to ample sleeping accommodations, there were many conveniences aboard the Advance. Plenty of fresh water could be carried, and there was an apparatus for distilling more from the sea water that surrounded the travelers. Compressed air was carried in large tanks, and oxygen could be made as needed. In short, nothing that could add to the comfort or safety of the travelers had been omitted. There was a powerful crane and windlass, which had been installed when Mr. Swift thought his boat might be bought by the Government. This was to be used for raising wrecks or recovering objects from the bottom of the ocean. Ample stores and provisions were to be carried and, once the travelers were shut up in the Advance, they could exist for a month below the surface, providing no accident occurred.
All these things Tom and Mr. Sharp thought of as they looked over the ship before turning in for the night. The craft was made immensely strong to withstand powerful pressure at the bottom of the ocean. The submarine could penetrate to a depth of about three miles. Below that it was dangerous to go, as the awful force would crush the plates, powerful as they were.
“Well, we’ll rush things tomorrow and the next day,” observed Tom as he prepared to leave the building. “Then we’ll soon see if it works.”
For the next week there were busy times in the shop near the ocean. Great secrecy was maintained, and though curiosity seekers did stroll along now and then, they received little satisfaction. At first Mr. Swift thought that the visit of Mr. Berg would have unpleasant results, for he feared that the agent would talk about the craft, of which he had so unexpectedly gotten a sight. But nothing seemed to follow from his chance inspection, and it was forgotten.
It was one evening, about a week later, that Tom was alone in the shop. The two mechanics that had been hired to help out in the rush had been let go, and the ship needed but a few adjustments to make it ready for the sea.
“I think I’ll just take another look at the water tank valves,” said Tom to himself as he prepared to enter the big compartments which received the water ballast. “I want to be sure they work properly and quickly. We’ve got to depend on them to make us sink when we want to, and, what’s more important, to rise to the surface in a hurry. I’ve got time enough to look them over before dad and Mr. Sharp get back.”
Tom entered the starboard tank by means of an emergency sliding door between the big compartments and the main part of the ship. This was closed by a worm and screw gear, and once the ship was in the water would seldom be used.
The young inventor proceeded with his task, carefully inspecting the valves by the light of a lantern he carried. The apparatus seemed to be all right, and Tom was about to leave when a peculiar noise attracted his attention. It was the sound of metal scraping on metal, and the lad’s quick and well-trained ear told him it was somewhere about the ship.
He turned to leave the tank, but as he wheeled around his light flashed on a solid wall of steel back of him. The emergency outlet had been closed! He was a prisoner in the water compartment, and he knew, from past experience, that shout as he would, his voice could not be heard ten feet away. His father and Mr. Sharp, as he was aware, had gone to a nearby city for some tools, and Mr. Jackson, the engineer, was temporarily away. Mrs. Baggert, in the house, could not hear his cries.
“I’m locked in!” cried Tom aloud. “The worm gear must have shut of itself. But I don’t see how that could be. I’ve got to get out mighty soon, though, or I’ll smother. This tank is airtight, and it won’t take me long to breath up all the oxygen there is here. I must get that slide open.”
He sought to grasp the steel plate that closed the emergency opening. His fingers slipped over the smooth, polished surface. He was hermetically sealed up—a captive! Blankly he set his lantern down and leaned hopelessly against the wall of the tank.
“I’ve got to get out,” he murmured.
As if in answer to him he heard a voice on the outside, crying:
“There, Tom Swift! I guess I’ve gotten even with you now! Maybe next time you won’t take a reward away from me, and lick me into the bargain. I’ve got you shut up good and tight, and you’ll stay there until I ge
t ready to let you out.”
“Andy Foger!” gasped Tom. “Andy Foger sneaked in here and turned the gear. But how did he get to this part of the coast? Andy Foger, you let me out!” shouted the young inventor; and as Andy’s mocking laugh came to him faintly through the steel sides of the submarine, the imprisoned lad beat desperately with his hands on the smooth sides of the tank, vainly wondering how his enemy had discovered him.
CHAPTER FIVE
MR. BERG IS SUSPICIOUS
Not for long did the young inventor endeavor to break his way out of the water-ballast tank by striking the heavy sides of it. Tom realized that this was worse than useless. He listened intently, but could hear nothing. Even the retreating footsteps of Andy Foger were inaudible.
“This certainly is a pickle!” exclaimed Tom aloud. “I can’t understand how he ever got here. He must have traced us after we went to Shopton in the airship the last time. Then he sneaked in here. Probably he saw me enter, but how could he knew enough to work the worm gear and close the door? Andy has had some experience with machinery, though, and one of the vaults in the bank where his father is a director closed just like this tank. That’s very likely how he learned about it. But I’ve got to do something else besides thinking of that sneak, Andy. I’ve got to get out of here. Let’s see if I can work the gear from inside.”
Before he started, almost, Tom knew that it would be impossible. The tank was made to close from the interior of the submarine, and the heavy door, built to withstand the pressure of tons of water, could not be forced except by the proper means.
“No use trying that,” concluded the lad, after a tiring attempt to force back the sliding door with his hands. “I’ve got to call for help.”
He shouted until the vibrations in the confined space made his ears ring, and the mere exertion of raising his voice to the highest pitch made his heart beat quickly. Yet there came no response. He hardly expected that there would be any, for with his father and Mr. Sharp away, the engineer absent on an errand, and Mrs. Baggert in the house some distance off, there was no one to hear his calls for help, even if they had been capable of penetrating farther than the extent of the shed, where the underwater craft had been constructed.
“I’ve got to wait until some of them come out here,” thought Tom. “They’ll be sure to release me and make a search. Then it will be easy enough to call to them and tell them where I am, once they are inside the shed. But—” He paused, for a horrible fear came over him. “Suppose they should come—too late?” The tank was airtight. There was enough air in it to last for some time, but, sooner or later, it would no longer support life. Already, Tom thought, it seemed oppressive, though probably that was his imagination.
“I must get out!” he repeated frantically. “I’ll die in here soon.”
Again he tried to shove back the steel door. Then he repeated his cries until be was weary. No one answered him. He fancied once he could hear footsteps in the shed, and thought, perhaps, it was Andy, come back to gloat over him. Then Tom knew the red-haired coward would not dare venture back. We must do Andy the justice to say that he never realized that he was endangering Tom’s life. The bully had no idea the tank was airtight when he closed it. He had seen Tom enter and a sudden whim came to him to revenge himself.
But that did not help the young inventor any. There was no doubt about it now—the air was becoming close. Tom had been imprisoned nearly two hours, and as he was a healthy, strong lad, he required plenty of oxygen. There was certainly less than there had been in the tank. His head began to buzz, and there was a ringing in his ears.
Once more he fell upon his knees, and his fingers sought the small projections of the gear on the inside of the door He could no more budge the mechanism than a child could open a burglar-proof vault.
“It’s no use,” he moaned, and he sprawled at full length on the floor of the tank, for there the air was purer. As he did so his fingers touched something. He started as they closed around the handle of a big monkey wrench. It was one he had brought into the place with him. Imbued with new hope be struck a match and lighted his lantern, which he had allowed to go out as it burned up too much of the oxygen. By the gleam of it he looked to see if there were any bolts or nuts he could loosen with the wrench, in order to slide the door back. It needed but a glance to show him the futility of this.
“It’s no go,” he murmured, and he let the wrench fall to the floor. There was a ringing, clanging sound, and as it smote his ears Tom sprang up with an exclamation.
“That’s the thing!” he cried. “I wonder I didn’t think of it before. I can signal for help by pounding on the sides of the tank with the wrench. The blows will carry a good deal farther than my voice would.” Every one knows how far the noise of a boiler shop, with hammers falling on steel plates, can be heard; much farther than can a human voice.
Tom began a lusty tattoo on the metal sides of the tank. At first he merely rattled out blow after blow, and then, as another thought came to him, he adopted a certain plan. Some time previous, when he and Mr. Sharp had planned their trip in the air, the two had adopted a code of signals. As it was difficult in a high wind to shout from one end of the airship to the other, the young inventor would sometimes pound on the pipe which ran from the pilot house of the Red Cloud to the engine-room. By a combination of numbers, simple messages could be conveyed. The code included a call for help. Forty-seven was the number, but there had never been any occasion to use it.
Tom remembered this now. At once he ceased his indiscriminate hammering, and began to beat out regularly—one, two, three, four—then a pause, and seven blows would be given. Over and over again he rang out this number—forty seven—the call for help.
“If Mr. Sharp only comes back he will hear that, even in the house,” thought poor Tom “Maybe Garret or Mrs. Baggert will hear it, too, but they won’t know what it means. They’ll think I’m just working on the submarine.”
It seemed several hours to Tom that he pounded out that cry for aid, but, as he afterward learned, it was only a little over an hour. Signal after signal he sent vibrating from the steel sides of the tank. When one arm tired he would use the other. He grew weary, his head was aching, and there was a ringing in his ears; a ringing that seemed as if ten thousand bells were jangling out their peals, and he could barely distinguish his own pounding.
Signal after signal he sounded. It was becoming like a dream to him, when suddenly, as he paused for a rest, he heard his name called faintly, as if far away.
“Tom! Tom! Where are you?”
It was the voice of Mr. Sharp. Then followed the tones of the aged inventor.
“My poor boy! Tom, are you still alive?”
“Yes, dad! In the starboard tank!” the lad gasped out, and then he lost his senses. When he revived he was lying on a pile of bagging in the submarine shop, and his father and the aeronaut were bending over him.
“Are you all right, Tom?” asked Mr. Swift.
“Yes—I—I guess so,” was the hesitating answer. “Yes,” the lad added, as the fresh air cleared his head. “I’ll be all right pretty soon. Have you seen Andy Foger?”
“Did he shut you in there?” demanded Mr. Swift.
Tom nodded.
“I’ll have him arrested!” declared Mr. Swift “I’ll go to town as soon as you’re in good shape again and notify the police.”
“No, don’t,” pleaded Tom. “I’ll take care of Andy myself. I don’t really believe he knew how serious it was. I’ll settle with him later, though.”
“Well, it came mighty near being serious,” remarked Mr. Sharp grimly. “Your father and I came back a little sooner than we expected, and as soon as I got near the house I heard your signal. I knew what it was in a moment. There were Mrs. Baggert and Garret talking away, and when I asked them why they didn’t answer your call they said they thought you were merely tinkering with the machinery. But I knew better. It’s the first time we ever had a use for ‘forty-seven,’ Tom.”
Tom was soon himself again and able to go to the house, where he found Mrs. Baggert brewing a big basin of catnip tea, under the impression that it would in some way be good for his. She could not forgive herself for not having answered his signal, and as for Mr. Jackson, he had started for a doctor as soon as he learned that Tom was shut up in the tank. The services of the medical man were canceled by telephone, as there was no need for him, and the engineer came back to the house.
Tom was fully himself the next day, and aided his father and Mr. Sharp in putting the finishing touches to the Advance. It was found that some alteration was required in the auxiliary propellers, and this, much to the regret of the young inventor, would necessitate postponing the trial a few days.
“But we’ll have her in the water next Friday.” promised Mr. Swift.
“Aren’t you superstitious about Friday?” asked the balloonist.
“Not a bit of it,” replied the aged inventor. “Tom,” he added, “I wish you would go in the house and get me the roll of blueprints you’ll find on my desk.”
As the lad neared the cottage he saw, standing in front of the place, a small automobile. A man had just descended from it, and it needed but a glance to show that he was Mr. Addison Berg.
“Ah, good morning, Mr. Swift,” greeted Mr. Berg. “I wish to see your father, but as I don’t wish to lay myself open to suspicions by entering the shop, perhaps you will ask him to step here.”
“Certainly,” answered the lad, wondering why the agent had returned. Getting the blueprints, and asking Mr. Berg to sit down on the porch, Tom delivered the message.
“You come back with me, Tom,” said his father. “I want you to be a witness to what he says. I’m not going to get into trouble with these people.”
The Tom Swift Megapack Page 41
