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. The only old vessels of this type suitable for mining in enemy waters were ships of the "Ariadne" class, and although their machinery was not too reliable, two of these vessels that were seaworthy were converted to minelayers. In addition a number of the older light cruisers were fitted with portable rails on which mines could be carried when minelaying operations were contemplated, in place of a portion of the armament which could be removed; a flotilla of destroyers, with some further flotilla leaders, were also fitted out as minelayers, and several additional submarines were fitted for this purpose. For a projected special scheme of minelaying in enemy waters a number of lighters were ordered, and some of the motor launches and coastal motor boats were fitted out and utilized for mining operations on the Belgian coast towards the end of 1917. By the end of that year 12 light cruisers, 12 destroyers and flotilla leaders and 5 submarines had been fitted for minelaying. Two old cruisers had been added to the minelaying fleet and several other vessels were in hand for the same purpose. The detailed plans of the arrangements were prepared and the work of fitting out minelayers carried out under the supervision of Admiral R.N. Ommanney, C.B., whose services in this matter were of great value. The rapidity with which ships were added to the minelaying fleet was largely due to his efforts.