necessities of the naval defense of a country have caused the gradual
development of different types of vessels, each having its distinctive
work. If those different types operated in separate localities they
would lose that mutual support which it is the aim of organization
to secure, and each separate group could be destroyed in turn by
the combined groups of an enemy. For this reason, the types or
groups are combined in one large fleet, and an admiral is placed
in command.

The command of a fleet is the highest effort of the naval art. Its
success in time of war demands in the admiral himself a high order
of mind and nerve and body; and it demands in all the personnel,
from the highest to the lowest, such a measure of trained ability
and character that each shall be able to discharge with skill and
courage the duties of his station.

In order that the material fleet shall be efficient as a whole,
each material unit must be efficient as a unit. Each ship must
be materially sound; each pump, valve, cylinder, gun, carriage,
torpedo, and individual appliance, no matter how small, must be
in condition to perform its expected task. The complexity of a
fleet baffles any mental effort, by even those most familiar with
it, to grasp it fully. Each dreadnaught, battle cruiser, destroyer,
submarine, collier, tender, hospital ship, scout, supply ship, and
what-not, is a machine in itself, and is filled with scores--in
some cases, hundreds--of highly specialized machines, operated
by steam, oil, air, electricity, and water. A superdreadnaught
is a machine which, including the machines inside of her, costs
$15,000,000; a battle cruiser more.