Courtesy of the Scientific American
Rapid-fire disappearing guns may be quickly elevated above armored turret when the submarine rises to the surface.
Divers' Compartment.—Some submarines are fitted with a divers' compartment, from which compartment mines may be planted, either when on the surface or when submerged. This compartment is fitted with a door which opens outwardly in the bottom of the boat. It is shut off from the living and machinery rooms of the vessel by an air lock and heavy pressure-resisting doors. The divers' door may be opened when the vessel is submerged and navigating on the bottom, and no water will come into the vessel when the door is opened. This is accomplished in the following manner: The members of the crew who wish to go outside the vessel first go into the diving compartment. They close the door which shuts them off from other parts of the vessel. They then turn compressed air gradually into the compartment until the air pressure in the compartment equals the water pressure outside. If the depth is one hundred feet the air pressure in the compartment would need to be 43.4 pounds per square inch; if the depth is two hundred feet, twice that, or 86.8 pounds per square inch, etc. When the air pressure in the compartment equals the water pressure outside, at any depth, the door in the bottom may be opened and the water will not rise up into the compartment, because the air pressure keeps it out. Tests have been made which show that it is safe for divers to go out from compartments of this kind in depths up to two hundred and seventy-five feet.
DIVING COMPARTMENT
This view shows the diving compartment being used for the purpose of grappling for the electric cables controlling fields of submarine mines. Operating in this manner, the diving compartment becomes a veritable travelling diving-bell, and when the air pressure in the diving chamber is made to balance with the water pressure outside the diving door may be opened and yet the water will not enter the working chamber.
Dangers.—Years of painstaking development work have eliminated most of the dangers connected with the operation of submarines in times of peace. The experienced designers have learned the importance of having great submerged stability, so that no modern craft is likely to make an unexpected headfirst dive into the mud, hard sand, or rocks on the bottom. This was a common occurrence not many years ago. Another danger to be avoided is that of asphyxiation by the escape of noxious gases from the engines. The blowing up of the vessel by the ignition of hydrogen fumes from the battery is another risk to be guarded against. In the latest vessels the noxious gases from the engine are not permitted to escape into the engine-room; gasolene is rapidly giving place to heavy-oil engines which do not use an explosive fuel, and the hydrogen gas given off during the charging of batteries is pumped overboard as rapidly as it is generated. Consequently modern submarines, when navigating on the surface, are as safe as any surface ship. In fact, they are safer, from the fact that they are so much more strongly built and that they are divided into compartments. Any one of these compartments could be filled by water in an accident and the remaining compartments would keep the ship afloat. In submerged peace-time navigation the dangers are those of collisions with surface vessels, uncharted rocks, or sunken ships. The danger of collisions with surface ships may be avoided by keeping below the depth of keel of the deepest draft surface ship, when long under-water runs are being made, and always stopping machinery to listen for the sound of surface ships before rising to the surface. If running near the surface where periscopic vision is possible, constant vigilance must be maintained, as there are no rules of the road or right of way which may be claimed by the submarine commander, owing to the fact that the lookout on the surface craft, in all probability, cannot see his little periscope in time to avoid collision.
A MODERN SUBMARINE CRUISER, OR FLEET SUBMARINE (LAKE TYPE)
The parts indicated by numbers in this illustration are as follows: 1, main ballast tanks; 2, fuel tanks; 3, keel; 4, safety drop keel; 5, habitable superstructure; 6, escape and safety chambers; 7, disappearing anti-aircraft guns; 8, rapid-fire gun; 9, torpedo tubes; 10 torpedoes; 11, twin deck torpedo tubes; 12, torpedo firing tank; 13, anchor; 14, periscopes; 15, wireless; 16, crew's quarters; 17, officers' quarters; 18, warhead stowage; 19, torpedo hatch; 20, diving chamber; 21, electric storage battery; 22, galley; 23, steering gear; 24, binnacle; 25, searchlight; 26, conning tower; 27, diving station; 28, control tank; 29, compressed-air flasks; 30, forward engine room and engines; 31, after engine room and engines; 32, central control compartment; 33, torpedo room; 34, electric motor room; 35, switchboard; 36, ballast pump; 37, auxiliary machinery room; 38, hydroplane; 39, vertical rudders; 40, signal masts.