More interest in submarine warfare than ever before was aroused in this country when the German war submarine U-53 unexpectedly made its appearance in the harbour of Newport, R. I., during the afternoon of October 7, 1916. About three hours afterwards, without having taken on any supplies, and after explaining her presence by the desire of delivering a letter addressed to Count von Bernstorff, then German Amba.s.sador at Washington, the U-53 left as suddenly and mysteriously as she had appeared.

This was the first appearance of a foreign war submarine in an American port. It was claimed that the U-53 had made the trip from Wilhelmshaven in seventeen days. She was 213 feet long, equipped with two guns, four torpedo tubes, and an exceptionally strong wireless outfit. Besides her commander, Captain Rose, she was manned by three officers and thirty-three men.

Early the next morning, October 8, it became evident what had brought the U-53 to this side of the Atlantic. At the break of day, she made her re-appearance southeast of Nantucket. The American steamer _Kansan_ of the American Hawaiian Company bound from New York by way of Boston to Genoa was stopped by her, but, after proving her nationality and neutral ownership was allowed to proceed. Five other steamships, three of them British, one Dutch, and one Norwegian were less fortunate. The British freighter _Strathend_, of 4321 tons was the first victim. Her crew were taken aboard the Nantucket shoals light-ship. Two other British freighters, _West Point_ and _Stephano_, followed in short order to the bottom of the ocean. The crews of both were saved by United States torpedo boat destroyers who had come from Newport as soon as news of the U-53's activities had been received there. This was also the case with the crews of the Dutch _Bloomersdijk_ and the Norwegian tanker, _Christian Knudsen_.

Not often in recent years has there been put on American naval officers quite so disagreeable a restraint as duty enforced upon the commanders of the destroyers who watched the destruction of these friendly ships, almost within our own territorial waters, by an arrogant foreigner who gave himself no concern over the rescue of the crews of the sunken ships but seemed to think that the function of the American men of war. It was no secret at the time that sentiment in the Navy was strongly pro-Ally. Probably had it been wholly neutral the mind of any commander would have revolted at this spectacle of wanton destruction of property and callous indifference to human life. It is quite probable that had this event occurred before the invention of wireless telegraphy had robbed the navy commander at sea of all initiative, there might have happened off Nantucket something a.n.a.logous to the famous action of Commodore Tatnall when with the cry, "Blood is thicker than water" he took a part of his crew to the aid of British vessels sorely pressed by the fire of certain Chinese forts on the Yellow River. As it was it is an open secret that one commander appealed by wireless to Washington for authority to intervene. He did not get it of course. No possible construction of international law could give us rights beyond the three-mile limit. He had at least however the satisfaction when the German commander asked him to move his ship to a point at which it would not interfere with the submarine's fire upon one of the doomed vessels, of telling him to move his own ship and accompanying the suggestion with certain phrases of elaboration thoroughly American.

The rapid development of submarine warfare naturally made it necessary to find ways and means to combat this new weapon of naval warfare. Much difficulty was experienced, especially in the beginning, because there were no precedents and because for a considerable period everything that was tried had necessarily to be of an experimental nature.

To protect harbours and bays was found comparatively easy. Nets were spread across their entrances. They were made of strong wire cables and to judge from the total absence of submarines within the harbours thus guarded they proved a successful deterrent. In most cases they were supported by extensive minefields. The danger of these to submarines, however, is rather a matter of doubt, for submarines can dive successfully under them and by careful navigating escape unharmed.

The general idea of fighting submarines with nets was also adopted for areas of open water which were suspected of being infested with submarines. Recently, serious doubts have been raised concerning the future usefulness of nets. Reports have been published that German submarines have been fitted up with a wire and cable cutting appliance which would make it possible for them to break through nets at will, supposing, of course, that they had been caught by the nets in such a way that no vital parts of the underwater craft had been seriously damaged. A sketch of this wire cutting device was made by the captain of a merchantman, who, while in a small boat after his ship had been torpedoed, had come close enough to the attacking submarine to make the necessary observations. The sketch showed an arrangement consisting of a number of strands of heavy steel hawsers which were stretched from bow to stern, pa.s.sing through the conning tower and to which were attached a series of heavy circular knives a foot in diameter and placed about a yard apart. Even as early as January, 1915, Mr. Simon Lake, the famous American submarine engineer and inventor, published an article in the _Scientific American_ in which he dwelt at length on means by which a submarine could escape mines and nets. One of the ill.u.s.trations, accompanying this article, showed a device enabling submarines travelling on the bottom of the sea to lift a net with a pair of projecting arms and thus pa.s.s unharmed under it.

[Ill.u.s.tration: International Film Service, Inc.

_Submarine Built for Spain in the Cape Cod Ca.n.a.l._]

Many other devices to trap, sink or capture submarines have been invented. A large number of these, of course, have been found impracticable. Others, however, have been used with success. Few details of any of these have been allowed to become known.

The most dangerous power of submarines, is their ability to approach very closely to their object of attack without making their presence known to their prey. This naturally suggested that a way be found to detect the presence of submarines early enough to make it possible to stave off an attack or even to a.s.sume the offensive against the underwater boat. A recent invention, the perfection of which is due to the work of Mr. William Dubilier, an American electrical engineer, and of Professor Tissot, a member of the French Academy of Science, is the microphone. Few details are known about this instrument except that it records sound waves at as great a distance as fifty-five miles. This would permit in most cases the calling of patrol boats or the use of other defensive means before the submarine would be able to execute an attack.

At the present moment it would appear that the most dangerous enemy of the submarine yet discovered is the airplane or the dirigible.

Some figures as to the mortality among submarines due to the efforts of aircraft have been published in an earlier chapter. The chief value of aircraft in this work is due to the fact that objects under the water are readily discernible at a considerable depth when viewed from a point directly over them. An ill.u.s.tration familiar to every boy is to be found in the fact that he can see fish at the bottom of a clear stream from a bridge, while from the sh.o.r.e the refraction of the water is such that he can see nothing. From the air the aviator can readily see a submarine at a depth of fifty feet unless the water is unusually rough or turbid. The higher he rises the wider is his sphere of vision. With the lurking craft thus located the airman can either signal to watching destroyers or may bide his time and follow the submarine until it rises to the surface, when a well placed bomb will destroy it. Both of these methods have been adopted with success. For a time the submarines were immune from this form of attack because of the difficulty of finding a bomb which would not explode on striking the surface of the water, thus allowing its force to be dissipated before it reached the submarine, or else would not have its velocity so greatly checked by the water that on reaching the submarine the shock of its impact would not be great enough to explode it at all.

Both of these difficulties have been overcome. The new high explosives have such power, taken in connection with the fact that water transmits the force of an explosion undiminished to a great distance, that many of them exploding at the surface will put out of action a submarine at a considerable depth. Furthermore bombs have been invented, which being fired, not merely dropped from an airplane, will go through the water with almost undiminished momentum and explode on striking the target, or after a period fixed by the a.s.sailant. Other bombs known as "depth bombs" are fitted with f.l.a.n.g.es that revolve as they sink, causing an explosion at any desired depth.

About the actual achievements of the airplane as a foe to submarines there hangs a haze of mystery. It has been the policy of the Allied governments to keep secret the record of submarines destroyed and particularly the methods of destruction. But we know that a few have met their fate from bolts dropped from the blue. In _The Outlook_ Lawrence La Tourette Driggs, himself a flying man of no contemptible record, describes the method and result of such an attack. After recounting the steps by which a brother airman attained a position directly above a submerged submarine preparatory to dropping his bomb, he says:

Down shot his plummet of steel and neatly parted the waters ahead of the labouring submarine. But it did not explode. I could see a whirling metal propeller on the torpedo revolve as it sank. It must have missed the craft by twenty feet.

Suddenly a column of water higher than my position in the air stood straight up over the sea, then slipped noiselessly back. By all that is wonderful how did that happen?

As we covered the spot again and again in our circling machines, we were joined by two more pilots, and finally by a fast clipper steam yacht. The surface of the water was literally covered with oil, breaking up the ripple of the waves, and smoothing a huge area into gleaming bronze. Here and there floated a cork belt, odd bunches of cotton waste, a strip of carpet, and a wooden three-legged stool. These fragments alone remained to testify to the _corpus delicti_.

"Philip," I said half an hour later, as the hot coffee was thawing out our insides, "what kind of a civilized bomb do you call that?"

"That bears the simple little t.i.tle of trinitrotoluol; call it T.

N. T. for short," replied Sergeant Pieron.

"But what made it hang fire so long?" I demanded.

"It's made to work that way. When the bomb begins sinking the little propeller is turned as it is pulled down through the water. It continues turning until it screws to the end. There it touches the fuse-pin and that sets off the high explosive--at any depth you arrange it for."

I regarded him steadfastly. Then I remarked, "But it did not touch the submarine. I saw it miss."

"Yes, you can miss it fifty yards and still crush the submarine."

He took up an empty egg sh.e.l.l. "The submarine is hollow like this. She is held rigidly on all her sides by the water. Water is non-compressible like steel. Now when the T. N. T. explodes, even some distance away, the violent expending concussion is communicated to this hollow sh.e.l.l just as though a battering ram struck it. The submarine can't give any because the surrounding water holds her in place. So she crumples up--like this."

Pieron opened his hand and the flakes of egg sh.e.l.l fluttered down until they struck the floor.

Gunfire undoubtedly is still the most reliable preventive against submarine attacks. Comparatively small calibred guns can cause serious damage to submarines even by one well directed shot.

Submarines have been sunk both by warships and merchantmen in this way and many more have been forced to desist from attacks. Not every merchantman, of course, can be equipped with the necessary guns and gunners. Neither equipment nor men can be spared in sufficient quant.i.ties. But the efficiency of gun protection has been proved beyond all doubt by many authentic reports of successful encounters between armed merchantmen and submarines in which the latter were defeated.

Ramming, too, has been advocated and tried. It is, however, a procedure involving considerable danger to the attacking boat. For one thing all the submarine has to do is to dive quick and deep enough and it is out of harm's way. Then, too, the chances are that the submarine can launch a torpedo in time to reach the ramming vessel before the latter can do any damage.

[Ill.u.s.tration: _A Critical Moment._

_Painting by John E. Whiting._]

There have been reports of submarine duels between Austrian and Italian submarines in the Adriatic in which it was claimed that in each at least one submarine was destroyed, and, at least, in one instance both the duellists were sunk. Generally speaking the fact has been established, however, that submarines cannot fight submarines with any degree of success, except in exceptional cases and under exceptional conditions.

Since the outbreak of the war between the United States and Germany the question of combating the submarine has become more acute than ever. The latest development has been along negative rather than affirmative lines. It has apparently been decided that none of the devices, known at present and capable of destroying submarines, is sufficient either alone or in combinations to defeat the submarines decisively. The best means of balancing as much as possible the losses which German submarines are inflicting on the shipping facilities of the Allies at the present seems to be the unlimited and prompt building of large fleets of comparatively small ships. If this can be accomplished in time, the German submarines undoubtedly will find it impossible to destroy a tonnage sufficient to exert any great influence on the final outcome of the war.

CHAPTER XVII

THE FUTURE OF THE SUBMARINE

The world will not always be at war. Interminable as the conflict by which it is now racked seems, and endless as appear the resources of the nations partic.i.p.ating in it, the time must come when victory or sheer exhaustion shall compel peace. People talk of that peace being permanent. That is perhaps too sanguine a dream while human nature remains what it is, and nations can still be as covetous, ambitious, and heedless of others' rights as are individuals. But beyond doubt a prolonged period of peace awaits the world. What then is to be the future of the aircraft and the submarine which had to wait for war to secure any recognition from mankind of their prodigious possibilities?

Of the future of the aircraft there can be no doubt. Its uses in peace will be innumerable. Poor old Count Zeppelin, who thought of his invention only as a weapon of war, nevertheless showed how it might be successfully adapted to the needs of peace merely as a byproduct. As for the airplane both for sport and business its opportunities are endless. Easy and inexpensive to build, simple to operate with but little training on the part of the aviator, it will be made the common carrier of all nations. Already the United States is maintaining an aerial mail service in Alaska. Already too, bi- and triplanes are built capable of carrying twenty-five to thirty men besides guns and ammunition. It is easy to foresee the use that can be made of machines of this character in times of peace. Needing no tracks or right of way, requiring no expensive signalling or operative system, asking only that at each end of the route there shall be a huge level field for rising and for landing, these machines will in time take to themselves the pa.s.senger business of the world.

But the future of the submarine is more dubious. Always it will be a potent weapon of war. It may indeed force the relegation of dreadnoughts to the sc.r.a.p heap. But of its peaceful services there is more doubt. That it can be made a cargo carrier is unquestionably true. But to what good? There is no intelligent reason for carrying cargoes slowly under water which might just as well be carried swiftly on the surface unless war compels concealment. Underwater navigation must always be slower and more expensive than surface navigation, nor does it seem probable that the underwater boats can ever equal in size ordinary ships, though undoubtedly their present proportions are going to be greatly increased.

As a result of the German submarine campaign it is possible that the United States may develop a fleet of underwater merchantmen to circ.u.mvent the enemy while this war continues, though there has been but little discussion of it. But even so, commonsense would indicate that such a fleet would be abandoned on the restoration of peace. If anything is to be done toward making the submarine a vessel of ordinary everyday use the present double system of motors--the Diesels for surface navigation and the electric for submerged service--will have to be abandoned. Inventors however are diligently working on this problem to-day. Indeed so well known and successful a builder of submarines as Mr. Simon Lake seemed to have faith in their possibilities as merchant craft. As early as February, 1916, he announced that he had taken out a patent on a new form of cargo-carrying submarine which he described as made up of "nests of light-weight circular tanks of comparatively small diameter surrounded by a ship-shape form of hull." What advantage was to accrue from this type of vessel Mr. Lake has not explained. However the Germans who seemed to originate everything successfully demonstrated that the merchant submarine was a practicable and useful craft with which to beat the blockade.

This was proved by the two successful trips made by the unarmed German merchant submarine _Deutschland_ between Germany and the United States in 1916. Loaded with a cargo of dyestuffs and chemicals she left Bremen on June 14, 1916, and arrived in Baltimore early in July. After a short stay, during which she took on a full return cargo, consisting chiefly of rubber and metal, she started on August 1, 1916, for her return trip to Bremen where she arrived safely soon after August 15, 1916. Once more, in October of the same year she made a successful round trip, docking this time in New London. There was considerable talk about additional trips by other German merchant submarines, but none of them were ever carried out.

It has never become known whether this was due to the loss of these merchant submarines or to political relations between Germany and the United States which were then gradually a.s.suming a less friendly form.

[Ill.u.s.tration: Photo by International Film Service.

_A Submarine Built for Chili, Pa.s.sing through Cape Cod Ca.n.a.l._]

Of course, it is true that such boats are blockade runners and in a way, therefore, part and parcel of warfare. But they are unarmed merchantmen just the same and their exclusively mercantile character has been officially acknowledged by the United States Government.

Under conditions of peace, however, it is very doubtful whether submarine merchantmen would pay, nor does it seem as if they possessed any advantages at all over surface merchant vessels.

Nevertheless they represent an entirely new development of submarine navigation and, therefore, deserve attention.

During her stay in the United States, very few people were permitted to get more than a glance of the _Deutschland_. As a result, comparatively little became known regarding her mechanical details.

The _Scientific American_, however, in its issue of July 22, 1916, gives a fairly detailed description of this first merchant submarine.

From this account we learn that the _Deutschland_ conforms rather closely to the typical German naval U-boat. The hull proper consists of an internal cigar-shaped, cylindrical structure, which extends from stem to stern, and in its largest diameter measures about twenty feet. Enclosing this hull is a lighter false hull, which is perforated, to permit the entrance and exit of the sea-water, and is so shaped as to give the submarine a fairly good ship model for driving at high speed on the surface and at a much lesser speed submerged. The upper portion of the false hull does not present such a flat deck-like appearance as is noticeable in the naval U-boats.

In fact, the whole modelling of the _Deutschland_, as compared with the naval boats, suggests that she has been fulled out somewhat, with a view to obtaining the necessary displacement for cargo carrying.

The interior cylindrical hull is divided by four transverse bulkheads into five separate water-tight compartments.

Compartment No. 1, at the bow, contains the anchor cables and electric winches for handling the anchor; also general ship stores, and a certain amount of cargo. Compartment No. 2 is given up entirely to cargo. Compartment No. 3, which is considerably larger than any of the others, contains the living quarters of the officers and crew. At the after end of this compartment, and communicating with it, is the conning tower. Compartment No. 4 is given up entirely to cargo. Compartment No. 5 contains the propelling machinery, consisting of two heavy oil engines and two electric motors. The storage batteries are carried in the bottom of the boat, below the living compartment. For purposes of communication, a gangway, 2 feet 6 inches wide by 6 feet high, is built through each cargo compartment, thus rendering it possible for the crew to pa.s.s entirely from one end of the boat to the other.