Modern German Airplane Types.
In the United States Navy the submarine has never been popular. Indeed it is by no means certain that in comparison with other navies of the world the United States was not better off in underwater boats in 1911 than she was three years later when the warcloud broke. The bulk of our naval opinion has always been for the dreadnoughts. A change of political administration at Washington in 1912 gave a temporary setback to naval development, and the submarines, being still a matter of controversy, languished. Few were built and of those few many showed such structural weakness that the reports of their manœuvres were either suppressed, or issued in terms of such broad generality that the public could by no possibility suspect, what all the Navy knew to be the fact, that the submarine flotilla of the United States was weak to the point of impotence.
Happily we had nearly three years in which to observe the progress of the war before becoming ourselves embroiled in it. During this period our submarine fleet was somewhat increased, and upon our actual entrance upon the struggle a feverish race was begun to put us on an equality with other nations in underwater boats. It would have been too late had any emergency arisen. But Germany had no ships afloat to be attacked by our submarines had we possessed them. Her own warfare upon our merchant shipping could not be met in kind, for submarines cannot fight submarines. We have, therefore, up to the present time, not suffered from the perilous neglect with which we long treated this form of naval weapon.
Indeed the submarine fleet of the United States Navy at the beginning of the war was so inconsiderable that foreign writers on the subject ignored it. In 1900 we had purchased nine of the type of submarines then put out by the Holland Company. One of these, the first in actual service, known as the "Baby" Holland was kept in commission ten years and upon becoming obsolete was honoured by being taken in state to the Naval Academy at Annapolis and there mounted on a pedestal for the admiration of all comers. She was 59 feet long and would make a striking exhibit placed next to one of the new German submersible cruisers which exceed 300 feet and have a displacement of 5000 tons. These first Holland ships which long constituted the entire underwater force of the United States were but trivial affairs compared with the modern vessel. Their displacement was but 122 tons, their engines for surface navigation were of 160 horse-power, gasoline, and for underwater navigation 70 horse-power, electric. They carried but one torpedo tube and two extra torpedoes and had a radius of action of but 300 miles. At that time in fact the naval theory was that submarines were coast defence vessels altogether. After this war they are likely to form part of the first battle line of every navy. Yet these pioneer vessels established their seaworthiness well in 1911, when four of them accompanied by a parent ship to supply them with fresh stocks of fuel and to render assistance in case of need, crossed the Pacific Ocean under their own power to the Philippines. This exploit tended to popularize these craft in the Navy Department, and soon after larger vessels known as the "Viper" class were ordered. One of these was called the Octopus, the first submarine to be fitted with twin screws. In many ways she represented a distinct advance in the art of submarine construction. She was in fact the first vessel built with the distinct idea of being a cruising, as well as a harbour defence ship. Her type proved successful in this respect. The Octopus further established a record for deep sea submergence in 1907 when she descended to a depth of 205 feet off Boston, returning to the surface in entire safety.
The ability to withstand the pressure of the water at great depths is a vital quality of a successful submarine. One American submarine narrowly escaped destruction because of structural weakness in this respect. She had by accident descended a few feet below the normal depth at which such boats navigate. The water pressure affected the valves which refused to work and the vessel slowly sank deeper and deeper. At a recorded depth of 123 feet the sinking of the vessel became so much more rapid that the crew with frantic endeavours sought at once to stop the leaks and pump out the water which had entered. At that depth there was a pressure of 153-½ pounds upon every square inch of the surface of the submarine. This the workers at the one hand pump had to overcome. It was a savage and a desperate struggle but the men finally won and the vessel regained the surface. As a result of this experience every navy prescribed submergence tests for its submarines before putting them into commission. How to make these tests was perplexing at first. A government did not want to send men down in a steel casket to see just how far they could go before it collapsed. But if no observer accompanied the ship it would be impossible to tell at what depth leakage and other signs of weakness became apparent. An Italian naval architect, Major Laurenti, whose submarines are now found in every navy of the world, invented a dock in which these tests can be made up to any desired pressure while the observers inside the submarine are in communication with those without and the pressure can be instantly removed if signs of danger appear. In the United States Navy boats to be accepted must stand a pressure equivalent to that encountered at 200 feet. In the German navy the depth prescribed is 170 feet. Under normal conditions submarines seldom travel at a depth of more than 100 feet although the "F-1" of the United States Navy accomplished the remarkable feat of making a six-hour cruise in San Francisco Bay at a depth of 283 feet. At this depth the skin of the ship has to withstand a pressure of no less than 123 pounds per square inch.
Specific information as to the nature of submarine construction in the United States since the beginning of the war in 1914 is jealously guarded by the Navy Department. In broad general terms the number of ships under construction is revealed to the public, but all information as to the size of individual vessels, their armour or the qualities of novelty with which every one hopes and believes American inventive genius has invested them, are kept secret. The Navy Year Book of 1916 summarized our submarine strength at that time as follows:
| Displacement | ||||
| Submarines | fit for action | 42 | 15,722 | Tons |
| " | under construction | 33 | 21,093 | " |
| " | authorized and appropriated | |||
| for | 30 | 22,590 | " | |
| —— | —— | " | ||
| Total | 105 | 59,405 | " | |
In addition thirty-seven more had been authorized by Congress without the appropriation of money for them. By this time however these appropriations have been made together with further heavy ones. While figures are refused at the Navy Department, it is declared that while the United States in 1914 was the last of the great powers in respect to submarine strength provided for, it is now well up to the foremost, even to Germany.
Great Britain like the United States continued for many years to build submarines of the Holland type. Naturally all the recent improvements were incorporated in the British boats. Very little, however, is known concerning the details of the more recent additions to the British submarine flotilla because of the secrecy maintained by the British authorities in war time.
At the beginning of the present war, the British navy possessed 82 active submarines of 5 different classes. They were all of the Holland type, but in each class there were incorporated vast improvements over the preceding class. Displacement, size, motive power, speed, radius of action, and armament were gradually increased until the "E" class contained boats possessing the following features: Submerged displacement, 800 tons; length 176 feet; beam 22-½ feet; heavy oil engines of 2000 H.-P.; electric engines of 800 H.-P.; surface speed 16 knots; submerged speed 10 knots; cruising range 5000 miles; armament: 4 torpedo tubes, space for 6 torpedoes, and two 3-inch quick-firing, high-angle, disappearing guns; armoured conning-towers and decks; wireless equipment; 3 panoramic periscopes.