A widely extended patrol by one or more light cruisers with destroyers, working to the south-eastward from Scapa, was maintained during the month, in order to guard against any attempt at mine-laying in the Pentland Firth by enemy vessels disguised as merchant-ships. Similar precautions were taken at Rosyth. This patrol was henceforth regularly established when the conditions of the moon rendered attempted mine-laying operations at night probable.
The sweeping operations in the Moray Firth were continued on a large scale throughout the month, and clear channels on each shore were provided. Up to September 19th, 222 mines had been accounted for out of the 450 which survivors of the Ramsey stated had been laid by the Meteor. The Moray Firth mine-field, in the centre of the Firth, was purposely left undisturbed, as it formed an excellent anti-submarine defence in that position and reduced the area to be patrolled by our vessels.
The 3rd Cruiser Squadron became non-existent during the month, two ships being detached by the Admiralty on special service, and the remaining two sent into port for somewhat extensive repairs.
The 10th Cruiser Squadron’s weekly average for the month worked out at:
Ships intercepted, 64; sent in with armed guards, 11; number of vessels on patrol, 13; number absent or en route to or from patrols, 10.
The weather at Scapa showed fog or mist on the 6th, 8th, 9th, 10th, 14th, 18th, 23rd and 24th; a very heavy gale occurred between the 25th and 28th, during which great damage was done to the anti-submarine obstructions at Scapa, and a good deal of damage was suffered on the mainland in the north of Scotland, a portion of the Highland Railway being washed away.
Between June and August, 1915, I had pressed upon the Admiralty my opinion that we should carry out a much more comprehensive mining policy in the Heligoland Bight. I had urged this early in the War, but the view taken at the Admiralty was that mining on any large scale would impede both our submarine operations and also any Fleet operations that might be undertaken in those waters. I felt that unless we adopted one of two policies—namely, either a close watch by surface ships on the exits from the German bases, or an extensive mining policy—we could never feel that we should receive sufficient warning of the exit of enemy forces as to prevent mischief being done. The close blockade by surface ships was not a feasible operation in view of the number of craft at our disposal and the submarine danger; our submarines were too few in number and had not the necessary means of communication to take the place of surface ships.
I could see no alternatives to very extensive mining, limited only by the number of mines that could be produced. The mining proposed by me was intended to hamper the operations of both surface vessels and submarines. I pointed out that earlier in the War the view had been expressed to me by the Admiralty that we should not risk our cruisers too freely in the North Sea owing to the submarine danger, and that, if we adhered to this policy, it was impossible to insure that the exits to the Fleet bases would not be mined by surface mine-layers, as the Meteor incident had shown, and as was also indicated by the success of our own infrequent mining excursions to the Heligoland Bight.
The correspondence resulted in increased activity on the part of our mine-layers, but the success of our work was unfortunately handicapped by defects in the pattern of mine in use at that time, especially as against submarines.
In 1917, shortly after my return to the Admiralty, I undertook a very extensive mining policy. In the previous year, during Sir Henry Jackson’s period as First Sea Lord, a new and much improved mine was designed, the trials of which were carried out after I relieved him. This was one of the replies to the submarine. One hundred thousand of these mines were ordered by me early in 1917 to carry out various schemes for mining the Heligoland Bight and the Straits of Dover. Later in 1917, with the assistance of the United States, provision was made for the large mine-field across the North Sea known as the Northern Barrage. It was not until the large supplies of mines became available in the autumn that really effective results against submarines by mining began to be achieved, although the operations of German surface vessels had previously been hampered to a very considerable extent.