Preparation for the passage across the seas involved yet another matter of considerable importance. Vast numbers of mines had been laid, both by ourselves and by the enemy, during the previous three and a half years, in the areas through which the expedition must pass before reaching the permanent German defence mine-fields near the Flanders coast. Doubtless other mines had dragged with the tide {94} across our desired route. Special mine-sweeping work was, therefore, necessary to render the major portion of the passage even tolerably safe from mines. The reader can probably appreciate the difficult nature of that task with its attendant risks and necessity for thoroughness. In addition to the one hundred and sixty-two vessels whose duties have been mentioned, other supporting squadrons were necessary far out at sea. The possibility of our intentions having become known to the enemy had to be borne in mind. In such an event the enemy would, of course, adopt special measures to ensure giving the expedition a warm reception on arrival, but a most important eventuality for us to guard against was that of meeting a superior concentrated enemy force already at sea waiting to intercept us _en route_. Scouting craft, both aerial and naval, were therefore required; it was also advisable that our fighting fleet should be conveniently situated in case the chance arose of defeating any such counter to our expedition. [Sidenote: German High Seas Fleet] Whenever we employed our small craft to operate in enemy waters we had to bear in mind a certain possibility. The enemy on becoming aware of our movements, or intentions, and perhaps feeling unusually courageous, _might_ say, "Here are a number of small enemy vessels close to our harbours, let us engage them with the whole strength of our fleet and thereby achieve a great victory for the Fatherland." And so, in case the German Fleet left their harbours, unlikely though it might be, our Grand Fleet was always "in the offing" at such times ready to meet the so-called High Seas Fleet and send them down to the place where they ought to go. {95}