CHAPTER IV
THE TERRORS IN THE DARK ROOM OF AN UNDERSEA BOAT
Imagine yourself locked in a compartment, barely large enough to stretchyourself out straight, in a ship under the sea, in total darkness,knowing that should any one of the hundreds of things within that shipgo wrong, it would mean a plunge to the bottom of the sea, beyond thehelp of all human aid.
The danger to them was just as great while on the surface of the water,for the guns mounted on most vessels at this time, would make thesubmarine a legitimate prey. One shot would be sufficient, for ingenuityhas not yet found a way to quickly stop a leak in a submarine. Such avessel, when once struck, dare not dive, for that would quickly fill theinterior of the vessel with water.
It must, in that case, remain afloat, subject to the hail of shot whichmust follow, their only salvation in that event would be to hoist thewhite flag. Few, if any submarine commanders have done so, and evenshould that occur, it would not prevent the hull from being riddledbefore the fact could be made known. The three-inch guns mounted onmost of the merchantmen, with an effective range of three miles, couldtear the weak hull of a submarine to pieces at a single shot, and allwould be sure to go down before help could arrive from the attackingsteamer.
"The machinery seems to go very slow now," remarked Ralph.
"They may be cautiously coming to the top," replied the captain.
"Did you hear that peculiar noise?" said Alfred, as he laid his hand onthe captain's arm.
"That was plainly a shot from a ship," said the captain.
"Do you think we could hear firing through all this metal?" asked Ralph.
"Much easier than if we were on deck," answered the captain.
"Why do you think so?" asked Alfred.
"Because water is a better conductor of sound than air," was the reply.
"Do you mean that we can hear it better than if the sound came throughthe air?" queried Alfred.
"The sound can be heard not only much plainer, but also much sooner thanthrough the air," answered the captain.
"I think we are going down again," remarked Ralph.
"No doubt of it," answered the captain quietly.
"Do you think they have hit us?" eagerly inquired Ralph.
The captain did not reply. Alfred reached his hand forward and graspedthe captain's hand. "You needn't fear to tell us if you think we aregoing down for the last time."
"You are a brave boy!" said the captain. "I do not know what to answer.I have never been on a submarine when it was struck by a bullet; but itseemed to me as though something struck our shell, and if it did thereis no help for us, for the devils would gloat on our misery, and wouldnot think of liberating us, to give us a chance for our lives."
Fifteen minutes elapsed before the captain continued: "This gives mesome hope."
"What is it?" quickly inquired Ralph.
"We are still on an even keel," was the answer.
"Does that mean that we are safe?" asked Alfred.
"Yes, if the shell of the submarine had been pierced, and we were reallygoing down it would not be long before the hull would lose its equipoiseand turn around, or it might stand on end, due to the distribution ofwater throughout the interior," was the reply.
"I understand now," said Alfred. "You think we are still floating, butdo you think we are on the surface?"
"We are, undoubtedly, submerged, for it is evident that the smoothmotion of the propeller comes from the electric motors and not from theinternal combustion engines, which are used solely while running on thesurface," remarked the captain.
After hours more of interminable waiting, they heard a noise close athand. With something like a snap the door opened and a flood of lightstreamed into their compartment from the electric bulbs without, and,looking up, they saw, at the ceiling of their room, a small electricbulb.
"Why is it we didn't hunt for that?" whispered Ralph, looking up.
"But I can't see any way to turn it on," said Alfred.
"That lights only from the outside," said the attendant. "Here issomething to eat," he continued in English.
"What time is it?" asked the captain.
"Half past one o'clock," was the reply.
They had been in that cramped prison pen five hours.
"Did you torpedo another ship?" queried the captain.
"We tried to; but a torpedo boat destroyer came up too close," heanswered.
"How many shots did it fire?" asked Ralph.
"Two," was the laconic reply.
"How long have we been submerged?"
"Two hours," answered the man. "As I came down the report from theperiscope showed a clear sea, and we are now about to resume surfacetravel and repair one of the periscopes."
The boys glanced at each other and at the captain.
"Yes," remarked the captain, "that was a pretty close call."
The attendant left them without closing the door, and as the prisonersglanced about, nothing was to be seen of the stairway which led to theconning tower. Men were noticed at work, each being stationed at someparticular machine or set of machinery. Then, with a bang, somethinglike a trap door swung aside and the stairway was revealed, and apeculiar light streamed in through the hatch opening.
"It's the sun," said Ralph, in ecstacy.
"I never thought we'd see that again," said Alfred, almost overcome.
"May we walk around?" asked the captain, as he approached an underofficer.
"There isn't much chance for exercising here," was the reply, "but Ithink you will be given top liberty after awhile," replied the man.
"Will they let us go?" asked Ralph eagerly.
"No; he didn't say that; he meant they would give us liberty to walk onthe top deck for a short time," replied the captain.
Shortly thereafter the lieutenant in command of the submarine appearedat the foot of the hatchway and informed the captain that they were atliberty to ascend. Never did the sun appear to be more beautiful orinviting, although there was a perceptible chill in the atmosphere. Thesubmarine was moving along at a speed of twelve knots an hour. Four menwere engaged in taking down a bent and partially ruptured periscopetube.
The captain glanced at it and drew the attention of the boys to itsstructure. It was the tall periscope that received the shot, whichstruck it about four feet from the top.
"It must have been hit on the water line," said the captain, addressingthe lieutenant.
The latter merely nodded, but made no remarks in response.
They were permitted to walk to and fro for an hour, when the order cameto descend, and they again entered their prison. As before, they weresubjected to total darkness, but there was no necessity for thisdeprivation, and it is not clear why an enemy should treat prisoners inthis manner, for such actions necessarily leave only resentments and dono good whatever.
It was a long, long, dreary afternoon and night, which they tried towhile away in sleeping, for conversation, under the circumstances, soonbecame irksome. When they awoke, or, rather, when all were again alertand felt as though the night must have passed, the captain was the firstto break the silence, as he said:
"We have been resting quietly for more than an hour, I should say,probably lying in wait in one of the steamer lanes for new victims."
"Isn't it likely we are on the bottom of the ocean? Don't they go downsometimes and wait there?" asked Ralph.
"Yes; but not in deep water, such as is found in this bay. At no placeis it less than 150 fathoms, and in the central portion, where our shipwent down it is more than 2,000 fathoms."
"Why, that's two miles deep, or more," said Alfred.
"Yes, the Bay of Biscay is one of the deep holes in the Atlantic coastline of Europe. The average depth of the Irish Sea, St. George Channel,the English Channel and the North Sea is only about 250 feet, and thereare thousands of places in the North Sea, particularly, like the DoggerBanks, where the water is not more than a hundred feet deep," remarkedthe captain.
"Then the
submarines could easily rest on the bottom if the depth is notmore than one hundred feet?" asked Alfred.
"Submarines have, in several cases, gone down as far as 200 feet belowthe surface, but it is at a great risk," said the captain.
"You mean risk from the pressure of the water?" said Ralph.
"Yes," was the reply.
"What would be the pressure of the water on a submarine at that depth?"asked Alfred.
"Pressure is calculated on the square inch of surface; for everytwenty-eight inches the pressure is equal to one pound. If, therefore,200 is multiplied by 12 and then divided by 28, the quotient willrepresent the number of pounds on each square inch," answered thecaptain.
"Why multiply 200 by twelve?" asked Ralph.
"Because there are twelve inches in a foot," said the captain.
"Oh, yes; I didn't happen to think of it; well, 200 by 12,--that's2,400, and divided by 28, is----"
"Eighty-five," interrupted Alfred. "Well, that's not very much."
"Quite true," rejoined the captain; "but how many square inches arethere in a square foot?"
"One hundred and forty-four," replied Alfred.
"Then, eighty-five times one hundred and forty-four makes quite a sum,"continued the captain.
"Whew,----" said Ralph with a half whistle in his tone, "why, if I havemade it out right, it's over 12,000 pounds. No wonder it isn't safe tostay down very long, if at all, at that depth."
"I have often wondered how it is that the submarine could rest on thebottom or come up at will," said Alfred.
"All submarines are lighter than the water in which they float,"answered the captain. "They are provided with tanks holding compressedair. Now, in order to submerge, the only thing necessary is to permitenough water to flow into special tanks within the submarine, until thecombined weight of the water, hull and mechanism, is the same as theamount of water that the ship displaces. If an added quantity of wateris now added, it will go down, and remain under water until the air inthe compressed tanks is used to force out a quantity of water from thespecial tanks."
"But is that the only way they can go down?" asked Ralph.
"Oh, no; a submarine can submerge without doing that, but in such a casepower must be used," answered the captain.
"What! push it down by power?" asked Alfred.
"Exactly; these vessels have fins, the same as fish, so arranged that ifthey are properly turned and the ship moves forward, it will dive, andcontinue to go down at an angle as long as the fins are properly set. Ifthe vessel should stop moving the submarine would come to the top,because it is lighter than the water," responded the captain.