In view of the distance of the Grand Fleet from German bases and the short time available in which to intercept the High Sea Fleet if it came out for such a purpose as a raid on our coasts, or on convoys, the information thus gathered would have proved of great value.
In planning mining operations in the Heligoland Bight, it was necessary to take into consideration certain facts.

The _first_ was the knowledge that the Germans themselves had laid minefields in some portions of the Bight, and it was necessary for our minelayers to give such suspected areas a wide berth.

_Secondly_, it was obvious that we could not lay minefields in areas very near those which we ourselves had already mined, since we should run the risk of blowing up our own ships with our own mines.
Mining operations had necessarily to be carried out at night, and as there were no navigational aids in the way of lights, etc., in the Heligoland Bight, the position in which our mines were laid was never known with _absolute_ accuracy.

Consequently an area in which we had directed mines to be laid, and to which a minelayer had been sent, could not safely be approached within a distance of some five miles on a subsequent occasion.
The use in mining operations of the device known as "taut wire" gear, introduced by Vice-Admiral Sir Henry Oliver, was of great help in ensuring accuracy in laying minefields and consequently in reducing the danger distance surrounding our own minefields.
As our mining operations increased in number we were driven farther and farther out from the German ports for subsequent operations.

This naturally increased the area to be mined as the Heligoland Bight is bell-mouthed in shape, but it had the advantage of making the operations of German minesweepers and mine-bumpers more difficult and hazardous as they had to work farther out, thus giving our light forces better chances of catching them at work and engaging them.