If the torpedo-boat is a fiend that works mainly at night, its sister, the submarine, works only by day. If the submarine has not, as was at one time expected, completely revolutionized naval warfare, it has at least so far asserted itself that it can never be left wholly out of the reckoning. Its improvement has kept pace with that of the torpedo-boat in stability, in size and in manageableness. The newest boats have a displacement of a thousand tons, and long sea voyages are now possible. Germany has far fewer torpedo-boats than has England, but claims that hers are much stronger and much better adapted for service in rough weather and on the high seas.
Armored Cruiser Moltke [6]
When there is no enemy in the immediate vicinity the submarine rides the waves like any other boat; when there is danger she dives like a duck. Just before firing her torpedo she comes to the surface for an instant to get one last good look. She is helpless at that moment, of course, but trusts to not being seen in time. When under water her speed is only about ten miles an hour, as the pressure is very great; on the surface she can travel about sixteen. Her slowness is a disadvantage, for she can only lurk for and intercept a fleet, not pursue and overtake it. She labors under another disadvantage, too, for she has to carry two motors and can not use the same one above and under water. Why? Because the one is an oil motor and generates gases which would be fatal when all outlets are closed. The other is run by an electric storage battery, the filling of which requires time and patience.
A Submarine Flotilla
How can the submarine communicate with its own fleet? It has wireless telegraphy and also deep-water signals, but these do not work so well as might be desired. It has one other connection with the visible world as wonderful as anything described by Jules Verne in his Twenty Thousand Leagues Under the Sea, the periscope, or literally the “looker round.” I can not do better than describe it in the words of a naval officer, Count Ernest zu Reventlow:
Roughly speaking, the apparatus consists in this: If the boat is under water and yet wishes to see what is going on above, it pushes up a long thin pipe until the surface is reached and a little beyond. At the farther end of this pipe is a contrivance with glass prisms, or mirrors and lenses. This throws down the image reflected from the surface of the water, through the vertical pipe, into the interior of the boat. The image is caught on a plate and the commander of the submarine, although he may be several yards under water, can see everything that is floating and happening on the surface and consequently can make his attack with the sole guidance of this image and steer the boat until it is at the right distance for firing the torpedo.
Torpedo Boat