1916 | 188 | 50 | 138
1917 | 291 | 122 | 169
1918 | 372 | 202 | 170
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It is evident from her limited supply of submarines at the outbreak
of war that Germany did not contemplate their use as commerce
destroyers. To the Allied navies also, in spite of warnings from
a few more far-sighted officers, their use for this purpose came
as a complete surprise. New methods had to be devised, new weapons
invented, new types of ship built and old ones put to uses for which
they were not intended--in short, a whole new system of warfare
inaugurated amidst the preoccupations of war. As usual in such
circumstances, the navy taking the aggressive with a new weapon
gained a temporary ascendancy, until effective counter-measures
could be contrived. It is easy to say that all this should have
been foreseen and provided for, but it is a question to what extent
preparations could profitably have been made before Germany began her
campaign. It has already been pointed out in the chapter preceding
that, had the German fleet been destroyed at Jutland, subsequent
operations on the German coast might have made the submarine campaign
impossible, and preparations unnecessary.

[Illustration: U 71-80 OCEAN-GOING MINE-LAYERS

U B 48-149

U C 80 CLASS OF MINE-LAYERS

OCEAN-GOING TYPES U 30 TO U 39

OCEAN-GOING TYPES FROM ABOUT U 51 to U 70

OCEAN-GOING TYPES FROM U 19 TO U 28

OCEAN-GOING TYPES FROM ABOUT U 30 UP TO U 39

U 151-157 (OCEAN-GOING)

OCEAN-GOING TYPES OF GERMAN SUBMARINES]

_Anti-Submarine Tactics_

Of the general categories of anti-submarine tactics,--detection,
evasion, and destruction--it was naturally those of evasion that
were first employed. Among these may be included suspension of
sailings upon warning of a submarine in the vicinity, diversion
of traffic from customary routes, camouflage, and zigzag courses
to prevent the enemy from securing favorable position and aim.
The first method was effective only at the expense of a severe
reduction of traffic, amounting in the critical months of 1917
to 40 per cent of a total stoppage. The second sometimes actually
aided the submarine, for in confined areas such as the Mediterranean
it was likely to discover the new route and reap a rich harvest.
Camouflage was discarded as of slight value; but shifts of course were
employed to advantage by both merc