e main blockading fleet,
which was unassailable except by a corresponding force of the enemy. The
advent of the torpedo and of its characteristic craft has changed all
this. No naval Power can now afford to place its battleships at a fixed
station, or even in close touch with a fixed rendezvous, which is within
reach of an enemy's torpedo craft. The torpedo vessel which operates
only on the surface is, it is true, formidable only at night; in the
daytime it is powerless in attack and extremely vulnerable. But the
submarine is equally formidable in the daytime, and its attack even in
the daytime is far more insidious and difficult to parry than that of
the surface torpedo vessel is at night. The effective range of the
surface torpedo vessel is thus, for practical purposes, half the
distance which it can traverse in any given direction from its base
between dusk and dawn--say from one hundred to two hundred miles,
according to its speed and the season of the year. The speed of the
submarine is much less, but it can keep the sea for many days together,
sinking beneath the surface whenever it is threatened with attack. It
can also approach a battleship or fleet of battleships in the same
submerged condition, and experience has already demonstrated that its
advance in that condition to within striking distance is extremely
difficult to detect. Moreover, even if its presence is detected in time,
the only certain defence against it is for the battleship to steam away
from it at a speed greater than any submarine has ever attained or is
likely to attain in the submerged condition. It should further be noted
that torpedo craft engaged in offensive operations of this character are
not confined to the blockaded port as a base. Any sheltered anchorage
will serve their purpose, provided it is sufficiently fortified to
resist such attacks from the sea as may be anticipated.

Thus, in the conditions established by the advent of the torpedo and its
characteristic craft, there would seem to be only two alternatives open
to a fleet of battleships engaged in blockade operations. Either it must
be stationed in some sheltered anchorage outside the radius of action of
the enemy's surface torpedo craft, and if within that radius adequately
defended against torpedo attack--as Togo established a flying base for
the use of his fleet, first at the Elliot Islands and afterwards at
Dalny, for the purpose of blockading Port Arthur; or it must cruise