A Lake type vessel designed for planting contact mines. In naval
warfare it is sometimes of advantage to plant mines, either to defend
harbors, or in some cases the mines are planted in the course of the
approaching enemy. This is a vessel designed for that purpose. The
enemy is seen approaching, and the mine-planting submarine runs in
ahead of them in a submerged condition and drops a number of contact
mines on their course; the enemy strikes the mine and is blown up. A
number of vessels were blown up by contact mines of this type in the
Russian-Japanese war.]
Accidents and Their Causes.
The accidents which submarine vessels must guard against are as
follows: collision, foundering, explosions and asphyxiation. The
first danger is, however, no greater than those to which vessels that
run entirely on the surface of the water are exposed. The eye of the
submarine places the commander on a practical level with the commander
of other vessels, so that if a collision occurs it is due to the same
lack of watchfulness which causes collisions on the surface of the
water.
The submarine boat is less liable to founder than an ordinary vessel,
because she is built to withstand a greater pressure of water than
other kinds of vessels. Of course, if a submarine springs a leak, she
is in grave danger of sinking to the bottom, and there is less chance
of the crew being rescued from a submarine, because no one but those on
board know of the danger if the boat is under the water.
How Explosions May Occur.
In submarine vessels explosions may occur either through a collection
of gases from the batteries or by reason of leaks in the pipes or
tanks of the fuel supply system, or through the bursting of the air
flasks belonging to the boat, or the air reservoirs in the automobile
torpedoes. The greatest danger is from explosive gases and have been
the cause of all explosions in modern submarine craft, and the greatest
danger in this connection is the liability of a leak in the gasolene
pipes or tanks. This gas is a heavy gas and so goes to the bottom of
the vessel, where it is not so easily detected as a gas which rises.
There is no certain way of guarding against leaks of gasolene. A leak
may occur at any time in a pipe or tank of gasolene through some cause
or other no matter how carefully inspected, and the gas from this is
so active that it will go through the tiniest hole imaginable--even
through a hole which water will not penetrate. The crew of a submarine
is always subject to this danger unless the tanks are built outside the
hull of the ship.
How the Air May Become Poisoned.
There is a constant danger of asphyxiation to the men in the submarine.
A very small leakage of gas or the exhaust from an internal combustion
engine may make the air so impure that those aboard will be overcome. A
great deal of care must be taken to keep the air pure and to warn the
crew at the first sign of danger from this.
When submarines first came into practical use, it was found a good idea
to take a number of little white mice down with the vessel to warn all
if the air began to become impure. As soon as this occurred, the mice
became distressed and squealed as loudly as they could, thus warning
those aboard the ship of danger. The mice felt the impurity of the air
quicker than the men, not because they had any special gift to discover
when the air was bad, but because they breathe much more quickly than
man--take shorter and many more breaths.
Now, however, a chemical device has been invented which is affected in
such a way as to ring a loud bell, if the air in the vessel becomes
impure to such an extent that there is any danger.
Breathing the same air over and over may fill the vessel with carbonic
acid gas. There should be no great danger from this, however, as
submarines are now built sufficiently large to provide enough actually
pure air for each man aboard for forty-eight hours, and it is hardly
conceivable that a submarine need be submerged more than half that
length of time under any conditions.
Of course, then, too, there is the danger of accident due to
carelessness or ignorance. In other words, it is just as difficult to
make a fool-proof submarine as a fool-proof anything else. Wherever
anything is constantly dependent upon the continuous careful attention
of human beings, there is constant danger of accident, whether it be on
board a submarine, a railroad train, steamship or in connection with
anything else.
[Illustration: A SUBMARINE UNDER THE ICE