Chapter Four
Tom is Imprisoned
"Well, I must say he's a cool one," remarked Tom, as the echoes of Mr.Berg's steps died away. "The idea of thinking his boat better thanours! I don't like that man, dad. I'm suspicious of him. Do you thinkhe came here to steal some of our ideas?"
"No, I hardly believe so, my son. But how did you discover him?"
"Just as you saw, dad. I heard a noise and went back there toinvestigate. I found him sneaking around, looking at the electricpropeller plates. I went to grab him just as he stumbled over a board.At first I thought it was one of the old gang. I'm almost sure he wastrying to discover something."
"No, Tom. The firm he works for are good business men, and they wouldnot countenance anything like that. They are heartless competitors,however, and if they saw a legitimate chance to get ahead of me andtake advantage, they would do it. But they would not sneak in to stealmy ideas. I feel sure of that. Besides, they have a certain type ofsubmarine which they think is the best ever invented, and they wouldhardly change at this late day. They feel sure of winning theGovernment prize, and I'm just as glad we're not going to have acontest."
"Do you think our boat is better than theirs?"
"Much better, in many respects."
"I don't like that man Berg, though," went on Tom.
"Nor do I," added his father. "There is something strange about him.He was very anxious that I should compete. Probably he thought hisfirm's boat would go so far ahead of ours that they would get an extrabonus. But I'm glad he didn't see our new method of propulsion. That isthe principal improvement in the Advance over other types ofsubmarines. Well, another week and we will be ready for the test."
"Have you known Mr. Berg long, dad?"
"Not very. I met him in Washington when I was in the patent office. Hewas taking out papers on a submarine for his firm at the same time Igot mine for the Advance. It is rather curious that he should come allthe way here from Philadelphia, merely to see if I was going tocompete. There is something strange about it, something that I can'tunderstand."
The time was to come when Mr. Swift and his son were to get at thebottom of Mr. Berg's reasons, and they learned to their sorrow that hehad penetrated some of their secrets.
Before going to bed that night Tom and Mr. Sharp paid a visit to theshed where the submarine was resting on the ways, ready for launching.They found Mr. Jackson on guard and the engineer said that no one hadbeen around. Nor was anything found disturbed.
"It certainly is a great machine," remarked the lad as he looked up atthe cigar-shaped bulk towering over his head. "Dad has outdone himselfthis trip."
"It looks all right," commented Mr. Sharp. "Whether it will work isanother question."
"Yes, we can't tell until it's in the water," conceded Tom. "But Ihope it does. Dad has spent much time and money on it."
The Advance was, as her name indicated, much in advance of previoussubmarines. There was not so much difference in outward construction asthere was in the means of propulsion and in the manner in which theinterior and the machinery were arranged.
The submarine planned by Mr. Swift and Tom jointly, and constructed bythem, with the aid of Mr. Sharp and Mr. Jackson, was shaped like aCigar, over one hundred feet long and twenty feet in diameter at thethickest part. It was divided into many compartments, all water-tight,so that if one or even three were flooded the ship would still beuseable.
Buoyancy was provided for by having several tanks for the introductionof compressed air, and there was an emergency arrangement so that acollapsible aluminum container could be distended and filled with apowerful gas. This was to be used if, by any means, the ship wasdisabled on the bottom of the ocean. The container could be expandedand filled, and would send the Advance to the surface.
Another peculiar feature was that the engine-room, dynamos and otherapparatus were all contained amidships. This gave stability to thecraft, and also enabled the same engine to operate both shafts andpropellers, as well as both the negative forward electrical plates, andthe positive rear ones.
These plates were a new idea in submarine construction, and were theoutcome of an idea of Mr. Swift, with some suggestions from his son.
The aged inventor did not want to depend on the usual screw propellersfor his craft, nor did he want to use a jet of compressed air, shootingout from a rear tube, nor yet a jet of water, by means of which thecreature called the squid shoots himself along. Mr. Swift planned tosend the Advance along under water by means of electricity.
Certain peculiar plates were built at the forward and aft blunt nosesof the submarine. Into the forward plate a negative charge ofelectricity 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 thenorth end of a compass needle, while the other pole of a magnet isnegative and will attract it. In electricity like repels like, whilenegative and positive have a mutual attraction for each other.
Mr. Swift figured out that if he could send a powerful current ofnegative electricity into the forward plate it would pull the boatalong, for water is a good conductor of electricity, while if apositive charge was sent into the rear plate it would serve to push thesubmarine 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 wereauxiliary forward and aft propellers of the regular type, so that ifthe electrical plates did not work, or got out of order, the screwswould 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 forair, and some for water. To sink the submarine below the surface largetanks 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, whichwas 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 asmall cooking galley, or kitchen, there. Back of the engine-room werethe sleeping quarters and the storerooms. The submarine was steeredfrom the forward compartment, and here were also levers, wheels andvalves that controlled all the machinery, while a number of dialsshowed in which direction they were going, how deep they were, and atwhat speed they were moving, as well as what the ocean pressure was.
On top, forward, was a small conning, or observation tower, withauxiliary and steering and controlling apparatus there. This was to beused when the ship was moving along on the surface of the ocean, ormerely with the deck awash. There was a small flat deck surroundingthe conning tower and this was available when the craft was on thesurface.
There was provision made for leaving the ship when it was on the bed ofthe ocean. When it was desired to do this the occupants put on divingsuits, which were provided with portable oxygen tanks. Then theyentered a chamber into which water was admitted until it was equal inpressure to that outside. Then a steel door was opened, and they couldstep out. To re-enter the ship the operation was reversed. This wasnot a new feature. In fact, many submarines to-day use it.
At certain places there were thick bull's-eye windows, by means ofwhich the under-water travelers could look out into the ocean throughwhich they were moving. As a defense against the attacks of submarinemonsters there was a steel, pointed ram, like a big harpoon. There werealso a bow and a stern electrical gun, of which more will be told later.
In addition to ample sleeping accommodations, there were manyconveniences aboard the Advance. Plenty of fresh water could becarried, and there was an apparatus for distilling more from the seawater that surrounded the travelers. Compressed air was carried inlarge tanks, and oxygen could be made as needed. In short, nothing thatcould add to the comfort or safety of the travelers had been omitted.There was a powerful crane and wi
ndlass, which had been installed whenMr. Swift thought his boat might be bought by the Government. This wasto be used for raising wrecks or recovering objects from the bottom ofthe ocean. Ample stores and provisions were to be carried and, once thetravelers were shut up in the Advance, they could exist for a monthbelow the surface, providing no accident occurred.
All these things Tom and Mr. Sharp thought of as they looked over theship before turning in for the night. The craft was made immenselystrong to withstand powerful pressure at the bottom of the ocean. Thesubmarine could penetrate to a depth of about three miles. Below thatit was dangerous to go, as the awful force would crush the plates,powerful as they were.
"Well, we'll rush things to-morrow and the next day," observed Tom ashe 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 strollalong 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 hehad so unexpectedly gotten a sight. But nothing seemed to follow fromhis 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 beenlet go, and the ship needed but a few adjustments to make it ready forthe sea.
"I think I'll just take another look at the water tank valves," saidTom to himself as he prepared to enter the big compartments whichreceived the water ballast. "I want to be sure they work properly andquickly. 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 gottime enough to look them over before dad and Mr. Sharp get back."
Tom entered the starboard tank by means of an emergency sliding doorbetween the big compartments and the main part of the ship. This wasclosed by a worm and screw gear, and once the ship was in the waterwould seldom be used.
The young inventor proceeded with his task, carefully inspecting thevalves by the light of a lantern he carried. The apparatus seemed tobe all right, and Tom was about to leave when a peculiar noiseattracted his attention. It was the sound of metal scraping on metal,and the lad's quick and well-trained ear told him it was somewhereabout the ship.
He turned to leave the tank, but as he wheeled around his light flashedon a solid wall of steel back of him. The emergency outlet had beenclosed! He was a prisoner in the water compartment, and he knew, frompast experience, that shout as he would, his voice could not be heardten feet away. His father and Mr. Sharp, as he was aware, had gone to anearby city for some tools, and Mr. Jackson, the engineer, wastemporarily away. Mrs. Baggert, in the house, could not hear his cries.
"I'm locked in!" cried Tom aloud. "The worm gear must have shut ofitself. But I don't see how that could be. I've got to get out mightysoon, though, or I'll smother. This tank is airtight, and it won't takeme long to breath up all the oxygen there is here. I must get thatslide open."
He sought to grasp the steel plate that closed the emergency opening.His fingers slipped over the smooth, polished surface. He washermetically sealed up--a captive! Blankly he set his lantern down andleaned 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 nexttime you won't take a reward away from me, and lick me into thebargain. I've got you shut up good and tight, and you'll stay thereuntil I get ready to let you out."
"Andy Foger!" gasped Tom. "Andy Foger sneaked in here and turned thegear. But how did he get to this part of the coast? Andy Foger, you letme out!" shouted the young inventor; and as Andy's mocking laugh cameto him faintly through the steel sides of the submarine, the imprisonedlad beat desperately with his hands on the smooth sides of the tank,vainly wondering how his enemy had discovered him.
Tom Swift and His Submarine Boat; Or, Under the Ocean for Sunken Treasure Page 4