true
ships-of-the-line. Sometimes classed as a battleship, and taking her place
in the line, the 50-gun ship came to be essentially a type for stiffening
cruiser squadrons. They most commonly appear as the flagships of cruiser
commodores, or stationed in terminal waters or at focal points where
sporadic raids were likely to fall and be most destructive. The strategical
effect of the presence of such a vessel in a cruiser line was to give the
whole line in some degree the strength of the intermediate ship; for any
hostile cruiser endeavouring to disturb the line was liable to have to deal
with the supporting ship, while if a frigate and a 50-gun ship got together
they were a match even for a small ship-of-the-line.

In sailing days, of course, this power of the supporting ship was weak
owing to the imperfection of the means of distant communication between
ships at sea and the non-existence of such means beyond extreme range of
vision. But as wireless telegraphy develops it is not unreasonable to
expect that the strategic value of the supporting or intermediate ship will
be found greater than it ever was in sailing days, and that for dealing
with sporadic disturbance the tendency will be for a cruiser line to
approximate more and more in power of resistance to that of its strongest
unit.

For fleet service a cruiser's power of resistance was hardly less valuable;
for though we speak of fleet cruisers as the eyes of the fleet, their
purpose is almost equally to blindfold the enemy. Their duty is not only to
disclose the movements of the enemy, but also to act as a screen to conceal
our own. The point was specially well marked in the blockades, where the
old 50-gun ships are almost always found with the inshore cruiser squadron,
preventing that squadron being forced by inquisitive frigates. Important as
this power of resistance in the screen was in the old days, it is tenfold
more important now, and the consequent difficulty of keeping cruisers
distinct from battleships is greater than ever. The reason for this is best
considered under the third and most serious cause of complexity.

The third cause is the acquisition by the flotilla of battle power. It is a
feature of naval warfare that is entirely new.[10] For all practical
purposes it was unknown until the full development of the mobile torpedo.
It is true that the fireship as originally conceived was regarded as having
something of the same power. During the Dutch war