The official despatches dealing with the blocking operations on the Flanders coast were published early {xvii} in 1919, and, as far as despatches can go, gave a splendid account of the enterprise forming the subject of this book. But despatches are strictly limited in length and necessarily deal more with cold-blooded statements of fact than with psychological aspects. When one reads despatches of the great leaders of the past concerning the operations in their campaigns one cannot fail to notice the almost complete absence of any reference to the moral factor in war. Yet Napoleon himself declared, "The moral is to the physical as three is to one." Material results can easily be gauged under peace conditions, whereas moral effect on human nature in war is only discoverable from one's own war experiences, which are necessarily limited, and from the experiences of others as set forth in the historical records of past wars. It was partly for that reason, presumably, that Napoleon studied the campaigns of Cæsar and Hannibal although their instruments of war were long since out of date. The usual reasons for the omission of the moral factors from despatches are twofold. Firstly, the leader from whom the despatch emanates may consider it inadvisable to publish his preconceived ideas as to the eventual effect of the operations on the morale of the enemy; this concealment is especially necessary if the despatch is published before the declaration of peace. Secondly, the writer of the despatch is often unaware, at the time of writing, of the effect already obtained against the enemy's morale; such effects may not be discoverable for many months after the operations have been concluded. Under certain circumstances it may also be temporarily {xviii} inadvisable to present to the enemy, through the medium of despatches, information concerning psychological effects on one's own personnel. These omissions, therefore, must not be taken to infer that the moral factors were ignored. It is clear, then, that post-war accounts of operations may be far from superfluous whether considered from the point of view of the man-in-the-street or that of the student of war. Without some conception of the strategical situation arising from the German occupation of the Flanders coast it would be difficult to grasp the true nature of the enterprise described herein. An examination of the strategical outlook alone, however, would be insufficient. The geographical and hydrographical, and even the meteorological, situations largely influenced the choice of tactical methods to be pursued for the attainment of the object in view. It is therefore important to consider the situation from these various standpoints in some detail.