rifice, and
unflinching endurance the submarine
danger was defeated

INTRODUCTION

Owing to the peculiar nature and demands of naval warfare, but few
dispatches, corresponding to those describing the work and achievements
of our great armies, were issued during the progress of the war. In a
former volume I attempted to supply this defect in the historical
records, which will be available for future generations, so far as the
Grand Fleet was concerned, during my period as its Commander-in-Chief.
The present volume, which was commenced and nearly completed in 1918,
was to have been published at the same time. My departure on a Naval
mission early in 1919 prevented me, however, from putting the finishing
touches to the manuscript until my return this spring.

I hesitated as to the publication of this portion of what is in effect
one complete narrative, but eventually decided not to depart from my
original purpose. There is some reason to believe that the account of
the work of the Grand Fleet gave the nation a fuller conception of the
services which the officers and men of that force rendered in
circumstances which were necessarily not easily appreciated by landsmen.

This second volume, dealing with the defeat of the enemy's submarine
campaign, the gravest peril which ever threatened the population of this
country, as well as of the whole Empire, may not be unwelcome as a
statement of facts. They have been set down in order that the sequence
and significance of events may be understood, and that the nation may
appreciate the debt which it owes, in particular, to the seamen of the
Royal Navy and the Mercantile Marine, who kept the seas during the
unforgettable days of the intensive campaign.

This book, therefore, gives the outline of the work accomplished by the
Navy in combating the unrestricted submarine warfare instituted by the
Central Powers in February, 1917. It would have been a labour of love to
tell at greater length and in more detail how the menace was gradually
overcome by the gallantry, endurance and strenuous work of those serving
afloat in ships flying the White or the Red Ensigns, but I had not the
necessary materials at my disposal for such an exhaustive record.

The volume is consequently largely concerned with the successive steps
taken at the Admiralty to deal with a situation which was always
serious, and which at times assumed a very grave aspect. The ultimate
result