would be required to keep open the sea communications of huge armies in
Macedonia, Egypt, Palestine, Mesopotamia and East Africa, against attack
by surface vessels, submarines and mines, whilst at the same time
protecting the merchant shipping of ourselves, our Allies, and neutral
Powers against similar perils, and assisting to ensure the safety of the
troops of the United States when they, in due course, were brought
across the Atlantic? Compare those varied tasks with the comparatively
modest duties which in pre-war days were generally assigned to the Navy,
and it will be seen how much there may be to learn of the lessons of
experience, and how sparing we should be of criticism. Wisdom distilled
from events which were unforeseeable should find expression not in
criticisms of those who did their duty to the best of their ability, but
in the taking of wise precautions for the future.

Little mention is made in this volume of the work of the Grand Fleet
during the year 1917, but, although that Fleet had no opportunity of
showing its fighting power, it must never be forgotten that without the
Grand Fleet, under the distinguished officer who succeeded me as
Commander-in-Chief at the end of 1916, all effort would have been of no
avail, since every operation by sea, as well as by land, was carried out
under the sure protecting shield of that Fleet, which the enemy could
not face.

I am conscious of many shortcomings in the book, but it may prove of
interest to those who desire to know something of the measures which
gradually wore down the German submarine effort, and, at any rate, it is
the only record likely to be available in the near future of the work of
fighting the submarines in 1917.

June, 1920.