IT is a mere truism to say that the sea outflanks all land operations in warfare. Yet how many people fully realise that the left wing of the Allied armies in Belgium and France depended for its safety on the naval command of the North Sea and English Channel? Had this sea flank been permanently penetrated or forced back by the German fleet, the result must have been disastrous to a large section of the Allied military line, which actually extended from the North Sea to the Mediterranean. Although the security of the North Sea flank did not entirely depend upon the naval forces based on Dover, Dunkirk and Harwich--as all operations, whether on land or sea, were overshadowed by the unchallenged might of the Grand Fleet, which hemmed in the entire German navy--it was upon these light forces, largely composed of units of the new navy, that the brunt of the intermittent flank fighting and the repeated attempts by the enemy to break through--with the aid of all kinds of ruses and weapons--was borne for four and a half historic years. The detailed story of their work on the Belgian coast and in the Straits of Dover could only be told in a separate volume, but the following account of a bombardment and its sequel may not be without interest here. Its relevance to anti-submarine warfare lies in the fact that the bombardment was carried out with the object of destroying the nests of these under-water craft established in and around Zeebrugge. Much that has also been said in former chapters bases its claim to inclusion in this book almost entirely on the fact that although it did not deal exclusively with submarine fighting or minesweeping, it nevertheless formed part of the daily operations of the anti-submarine fleets, and no account of their work would bear any resemblance to the actual truth in which such seemingly extraneous episodes were excluded as irrelevant. THE BOMBARDMENT AND ITS SEQUEL There was a flat calm, with the freshness of early summer in the air. Zeebrugge lay away in the darkness some fifteen miles to the south-east--awake, watchful, but unsuspecting--when the British bombarding squadron steamed in towards the coast to take up its allotted position and wait for daybreak. It was a heterogeneous fleet, screened by fast-moving destroyers, torpedo-boats, trawlers, M.L.'s and C.M.B.'s. The great hulls of monitors loomed black against the paling east, and the long thin lines of destroyers moved stealthily across the shadowy sea. No lights were visible, and only the occasional rhythmic thud of propellers and the call of an awakened sea-bird broke the stillness of the morning calm.