SUBMARINE SIGNALS
Then there are submarine signals to tell of near-by vessels
or shores. This signal arrangement includes a small tank
on either side of the vessel, just below the water line. Within
each is a microphone with wires leading to the bridge. If
the vessel is near any other or approaching shore, the sounds;
conveyed through the water from the distant object are
heard through the receiver of the microphone. These arrangements
are called the ship's ears, and whether the sounds come
from one side of the vessel or the other, the officers can tell the
location of the shore or ship near by. If both ears record,
the object is ahead.
