One of the large German U-boats fitted with deck guns hailing a Spanish merchantman which they have held up.
RUSSIAN-LAKE TYPE
These vessels are powerfully armed, fitted with four torpedo tubes firing fore and aft, also Dzrewiecke apparatus for firing torpedoes to either broadside.
The above articles having been published previous to our country entering the war, and being thus of public knowledge, it is permissible to republish them as a method which might be used to advantage in preventing the German submarines from coming out from their bases. It is admitted that the allied fleets are overwhelmingly superior to the German fleet, yet they are impotent to attack the German battle fleet or to make reprisals on Germany for the constant depletion of their merchant fleet, because Germany's fleet of battleships, cruisers, and merchantmen will not come out in the open, but lies safe behind nets and mine fields as their inner defence, using her submarines on her outer line of defence. As mentioned, Winston Churchill said we must "dig them out like rats out of a hole." That was over three years ago, but not one has been dug out as yet, and, although it would be a very expensive process to do so, it might be possible, by the coöperation of submarines, surface ships, trawlers, and aeroplanes, to move forward gradually and expansively a double or treble line of nets and to defend such a line of nets just outside of the range of the most powerful shore-defence guns. The battleships should be protected by operating between the line of nets to prevent attack upon them by submarines in the rear. Bottom-working submarines would be needed to clear away the mines and nets of the enemy as the mines and nets were moved forward. Constant patrol and repair of the nets would be maintained under the guns of the net-protected fleet, and allied submarines must be on constant attendance in advance of the first line of nets to meet the concerted attack of a portion of the German fleet in "rushing" the line—which must be expected in the attempt to break the same—in order to let out a fleet of their submarines into the open sea to continue their attacks on the allied and neutral commerce of the world. This seems to me the only practical way of stopping up the hole or holes through which the German submarines come out, and to make it effective it would require a double line of nets and patrol fleets extending from Norway to Scotland, and across the English Channel, and across the entrance to the Dardanelles from Brindisi, Italy, to the Albanian coast. Also, battleships which should be unsinkable and provided with longer-range guns than those of the enemy would be required. Perhaps the combined navies of the world as arrayed against the Central Powers could accomplish it, but unless their guns were more powerful and far-reaching than the shore guns, even then they could not land an invading army.
Submarines vs. Submarines.—Submarines to search for and sink other submarines have been proposed in all sorts of forms and advocated in the press under various titles, such as the "Bloodhounds of the Sea" and other fantastic and sensational captions. Submarines cannot fight submarines, because they cannot see each other, and if they are fitted with noiseless machinery they cannot hear each other. Therefore one might put thousands of submarines in the great ocean, and so long as they kept submerged the chance of their ever finding or colliding with one another would probably be not once in a year.
Derelicts have been known to keep afloat on the ocean for years, although constantly searched for as a menace to navigation. Here the searchers have had sight to aid them, and the object of their search has floated on one plane, the surface of the water, while submarines may navigate or remain at rest at various planes up to a depth of about two hundred feet, which is equivalent to multiplying the area of the ocean to be searched several times, and that in darkness, without the aid of sight to assist. It is ridiculous to think that anything can be accomplished except by the merest chance by one submarine searching for another.
Our attention will now turn to consideration of devices of the second class; namely, those which have been offered as a means of defence against the submarine.
Blinding Searchlight; Blinding Apparatus.—Blinding devices have been proposed which aim to direct powerful searchlights against the periscope so as to blind the commander. These are schemes based on very false notions. Submarine commanders frequently have to con their ship against the sun's rays, and have colored glasses to enable them to withstand the intensity of the sun's rays, so that it would be impossible to blind them this way. Further, I cannot imagine a more desirable target for a commander to direct his torpedoes against than a bright spot, either on the surface or submerged, as he knows the searchlight is probably on what he wants to hit; it becomes an illuminated bull's-eye for his target. Again, it has been proposed to blind the periscope by putting a film of oil on the surface to obscure the object glass of the periscope when it emerges through this oil, and a member of one of the British commissions told me he knew of shiploads of oil being pumped overboard, possibly for this purpose, or to show the course of a periscope through its "slick." Some periscopes have been built with means for squirting alcohol, gasoline, or other substances to clear the object glass if ice or salt forms on it. A device of this kind would clear off the oil.
Nets; Plates.—There have been many devices proposed for warding off the torpedoes, the usual weapon of the submarine. The most common of these schemes designate the use of nets or plates suspended from booms carried out from the sides of the ship and extending down into the water. Any device of this kind seriously handicaps the ship's speed, and, if she is once sighted by a submarine, is almost sure to be come up with and attacked. Plates, to be effective against a broadside attack, would need to be the full length and extend to the full depth of the ship. Now, skin friction of a ship's plating is the principal resistance to be overcome in forcing a ship through the water up to speeds of about ten knots, the average speed of the cargo-carrying ship. If you increase the speed beyond ten knots, other resistances come more prominently into effect, such as wave-making resistance, etc. Now a ship afloat has two sides, while a plate suspended in the water equal to the length and depth of the ship also must have two sides, and thus presents nearly the same square feet of plate surface to the friction of the passing waters as the two sides of the ship, and two plates, one on each side, present nearly twice the area and thus very materially reduce the speed. This resistance is further augmented by the roll and pitch of the vessel, and in a severe storm the plates would be unmanageable and of great danger to the ship itself. The resistance of nets with its vertical members is much greater than that of plates. To get some idea of what the resistance of a vertical rod extending down into the water is, take a broom handle and attempt to hold it vertical when it is extended down into the water from a launch running at about ten knots; it is almost impossible to hold it. A net with a mesh fine enough to catch a torpedo would consist of thousands of vertical members as well as horizontal members extending down into the water.