The reasons governing the selection of the mine barrage area were fully given, and the advantages arising from the use of the United States pattern of mine instead of the British mine for Areas A and C were stated.
Admiral Mayo was also informed of our intention to establish a mine barrage in the Channel, on the Folkestone-Grisnez line, as soon as mines were available, with a strong force of patrol vessels stationed there, whose duty it would be to compel enemy submarines to dive into the minefield. He was further made acquainted with our intended policy of still closer minelaying in the Heligoland Bight.
Although Admiral Mayo was not actually informed of the details of the future policy which it was hoped to adopt in the Adriatic for the improvement of the Otranto Barrage, various schemes were at the time being worked out between the British, French and Italian Admiralties, having as their object the prevention or obstruction of the exit of enemy submarines from the Adriatic, in the same way as it was hoped to obstruct German submarines from making their exit from the North Sea without incurring heavy losses. The great depth of water in the southern part of the Adriatic constituted the main difficulty facing us in the solution of this problem. In August, 1917, it was, however, definitely decided to establish a barrage of nets and mines across the Straits of Otranto, and the work was put in hand. This became effective during 1918.
The paper on Naval Air Policy showed the aim of the Admiralty to be:
To provide in sufficient numbers a type of airship which would be able to scout with the Grand Fleet, and, in this respect, to perform the duty of light cruisers. Airship stations had been established on the East Coast for this purpose.
To provide also a type of airship for coastal patrol work and for the escort of merchant ships in convoy. For these airships stations had been established on the East, South and West Coasts and at Scapa.
To provide a sufficient supply of kite balloons for the work of the Grand Fleet. Fleet kite balloon stations had already been established at Rosyth and Scapa, and the resources of the latter station were supplemented by a kite balloon ship. It was intended also to provide kite balloons for flotillas or single vessels engaged in submarine hunting or in convoy work. A large number of kite balloon stations for anti-submarine work had been or were being established round the coast for this work.
As to the future programme of rigid airships, Admiral Mayo was told that it was under consideration to construct three new rigid stations, also that three new stations for the use of non-rigids for anti-submarine work were to be established, while it was also proposed to provide sufficient resources to allow of a number of kite balloons being worked in vessels between the North of Scotland and Norway and to the eastward of the English Channel.
Admiral Mayo was also informed that it was proposed to provide sufficient "heavier than air" craft of various types for the Fleet, both to insure adequate air reconnaissance and to drive off hostile aircraft. The Grand Fleet was at the time already provided with three seaplane carriers, and the Furious and other special vessels were being fitted to carry aircraft. Many of the armoured vessels and light cruisers of the Fleet had also been fitted to carry aircraft, whilst the Harwich light cruiser force possessed one seaplane carrier; two carriers were devoted to anti-submarine work, and three were employed in the Mediterranean.
It was further stated that machines for naval reconnaissance were working from several East Coast stations, and that lighters to carry seaplanes for more extended reconnaissance and offensive work were under construction. The work carried out by our naval aircraft off the Belgian coast, comprising the duty of keeping the coast under constant observation, of spotting the gunfire of ships, of fighting aircraft and bombing objectives of importance, were also mentioned, as well as the work in the Mediterranean, where there were four bases in the Aegean.