Whilst the Fleet sweepers located the north-east corner of the mine-field, paddle sweepers, under the escort of two light cruisers from Harwich, located the south-west corner. The search was subsequently continued under the same conditions, and the limits of the mine-field, which covered a large area south of Lat. 56 N. and east of Long. 2.30 E., were determined. The enemy made no attempt to interfere with the sweeping operations, if indeed he was aware of them.
On the 21st the patrol, comprising the Sappho and armed boarding steamers, hitherto maintained in an area east and south-east of the Pentland Firth, was moved temporarily to the west of the Firth on account of submarine activity. Destroyers from the Grand Fleet replaced the original patrol at night, the interception of mercantile traffic being carried out by the armed boarding steamers to the westward. The destroyer Rifleman grounded in a fog on the 22nd, necessitating docking for repairs.
A new form of anti-submarine operation was begun on May 23rd by the Commander-in-Chief Coast of Scotland (Admiral Sir R. Lowry). This consisted of two C-class submarines operating with an armed trawler, the idea being that the trawler should invite attack by a submarine, thus giving our submarines an opportunity of sinking the enemy by torpedo attack.
On May 24th the Admiralty telegraphed that Italy had entered the War on the side of the Allies.
On the next day I proceeded in the Iron Duke to Rosyth to confer with Admiral Sir Henry Jackson, who had succeeded Lord Fisher as First Sea Lord. The conference took place on the 26th and was of an important nature. The general naval policy, so far as it concerned the Grand Fleet, was discussed, and arrangements made as to the procedure to be followed in future. Sir Henry Jackson asked that Commodore Everett might join him at the Admiralty as Naval Assistant, and, with the consent of Commodore Everett, this was arranged. His place as Captain of the Fleet was filled by Captain Lionel Halsey, C.M.G., of the New Zealand. It was with great regret that I parted with Commodore Everett; his long experience in the Fleet under Sir George Callaghan and his intimate knowledge of fleet work and unfailing tact had been of the greatest possible assistance. The Iron Duke returned to Scapa on the morning of the 28th. On the 26th Rear-Admiral the Hon. Horace Hood, C.B., had hoisted his flag in the Invincible as Rear-Admiral commanding the 3rd Battle Cruiser Squadron. The battleship Queen Elizabeth arrived at Scapa from the Dardanelles on the same day.
From May 29th to 31st the Grand Fleet carried out another sweep in the North Sea, the direction on this occasion being towards the Dogger Bank. The forces from Scapa and Cromarty concentrated in Lat. 57.35 N., Long. 0.0 at 7.15 A.M. on the 30th, and steered to the southward at 17 knots’ speed. The Rosyth force steered for a point farther south and was in sight from the cruiser line at 9.30 A.M., being ordered to keep ahead of the Fleet. The sweep was continued until the Dreadnought Battle Fleet was in the vicinity of the Dogger Bank. No enemy vessel was sighted.
The Fleet then turned to the northward and, owing to a northerly swell, speed had to be reduced on account of the destroyers. During the night the Rosyth force was detached to its base. Speed was increased as the weather improved, and the Scapa and Cromarty forces arrived on the morning of May 31st. The Iron Duke left Scapa for Cromarty during the afternoon of May 31st, and arrived that evening.
During the month the procedure of moving squadrons between Scapa and Cromarty was continued. At this period a second line of submarine obstructions, which was designed to prevent the entry of destroyers, as well as submarines, into Scapa Flow, advanced considerably towards completion. Progress was also made with the laying of mine-fields at the entrance. The anchorage at Swarbachs Minn, in the Shetlands, had been selected as a secondary coaling base for the ships of the 10th Cruiser Squadron, and steps were taken to prepare a submarine obstruction for the entrance, and to provide the necessary labour for coaling the ships from colliers.
The blockade work of the 10th Cruiser Squadron continued actively during the month, the average number of ships intercepted per week being 62, and the average number sent into port for closer examination, 16.
The weather at Scapa during the month was misty, fog being experienced on the 5th, 6th, 21st, 23rd, 24th, 27th and 28th, and snow on the 11th and 12th. The wind during the month was not strong.