More were laid in the Bight during October, November and December, and the remainder, as they were produced, were prepared for laying in the new minefield in the Straits of Dover.

_In the fourth quarter of the year a total of 10,389 mines was laid in the Heligoland Bight and in the Straits of Dover._ During this last quarter delivery of "H" pattern mines was as follows: In October 2,350, November 5,300, December 4,800; total 12,450.

So that it will be seen that the mines were laid as fast as delivery was made.
The great increase in projected minelaying operations during the year 1917 made it necessary also to add considerably to the number of minelaying vessels.
In January, 1917, the only vessels equipped for this service were four merchant ships and the Flotilla Leader _Abdiel_, with a total minelaying capacity of some 1,200 mines per trip.

It was not advisable to carry out minelaying operations in enemy waters during the period near full moon owing to the liability of the minelayers being seen by patrol craft.
Under such conditions the position of the minefield would be known to the enemy.

As the operation of placing the mines on board occupied several days, it was not passible to depend on an average of more than three operations per ship per month from the larger minelayers.
Consequently, with the intended policy in view, it was obvious that more minelayers must be provided.
It was inadvisable to use merchant ships, since every vessel was urgently required for trade or transport purposes, and the alternative was to fit men-of-war for minelaying.