The two-decked ship was superior in speed and in handiness, and for
that reason, even when acting singly, she could put forth such power
as she possessed more quickly and more certainly. But these qualities
were most conspicuously valuable when ship had to act with ship. The
great secret of military success, concerted action in masses, was in
the hands of the two-decked ship, because in her were united to the
highest point individual power and facility for combined action. And
this was true not only of two-deckers in general, but of the particular
species known as the seventy-four-gun ship. Ships below that rate
lacked individual fighting power. Ships above it, the eighty and
eighty-four, lost manœuvring power because of their greater length and
weight. Under the conditions of sail a fleet of seventy-fours could get
out the whole power of the force more surely and more rapidly than the
equivalent number of guns in ships of any other kind. Thus offensive
power dictated its survival. To our own day it reads the lesson that
offensive power, the _sine quâ non_ of a military organization, lies
not merely in the greatest strength of the single ships, but in
the uniformity of their action and rapidity of their movements, as
conducive to the quick putting forth of the strength of the whole body
at once and in mutual support.
It may be asked naturally, why, then, were there any ships bigger
or smaller than this favored type? For smaller, the answer is that
short ships of lighter draught are best suited for shoal or intricate
navigation. The shoals of Holland forbade heavy ships to the Dutch
navy, materially reducing its fighting strength. Before France entered
our Revolutionary struggle the British sent only sixty-fours to
operate upon our comparatively shallow coasts and bars. As regards
bigger ships, they were useful exceptionally, as were forty-four-gun
frigates, and for the following reason: Every line of battle has three
particularly dangerous points—the centre, because there the line,
if pierced, divides into the two smaller fragments; and the flanks,
or ends, because the extremities are supported less easily by the
rest of the force than the centre is, one extremity being farther
from the other than the centre is from either. Such local weakness
could not be remedied by the use of two ships, for, if the line were
properly closed, one of them could fire at the enemy only through or
over the other. The sole way of giving the strength there required
was by concentrating it into individual ships, either by putting on
the additional battery, which gives a three-decker, or by making the
seventy-four heavier, resulting in an eighty-gun ship on two decks.
These stronger vessels were, therefore, stationed in the centre or on
the flanks of a line of battle. The particular functions, the _raison
d’être_, of the three leading classes of ships of war—the sloop, the
frigate, and the ship of the line—have now been stated. It remains to
give an account of the chief features of the armament carried on their
broadsides, as described.