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 of all Naval warfare must naturally rest with those who are
serving afloat, but it is only just to the Naval officers and others who
did such fine work at the Admiralty in preparing for the sea effort,
that their share in the Navy's final triumph should be known. The
writing of this book appeared also to be the only way in which I could
show my keen appreciation of the loyalty and devotion to duty of the
Naval Staff, of the many clever, ingenious and audacious schemes
developed and carried through for the destruction of submarines and the
safeguarding of ocean-borne trade, and of the skilful organization which
brought into being, and managed with such success, that great network of
convoys by which the sea communications of the Allies were kept open.
The volume shows how the officers who accompanied me to the Admiralty
from the Grand Fleet at the end of 1916, in association with those
already serving in Whitehall and others who joined in 1917, with the
necessary and valuable assistance of our comrades of the Mercantile
Marine, gradually produced the measures by which the Sea Service