May 15th.—A division of the 1st Flotilla left Rosyth to operate against a submarine off Aberdeen.
May 16th.—A division of the 4th Flotilla was searching for a submarine reported approaching the Fair Island Channel.
May 19th–20th.—A division of the 4th Flotilla was acting against a submarine reported west of the Orkneys.
The principal Fleet movements during the month were:
May 2nd to May 5th.—Two forces, each consisting of two light cruisers and eight destroyers, were engaged in carrying out a thorough examination of all vessels, especially fishing craft, found in the areas usually traversed by the Fleet during southerly sweeps in order to ascertain whether any were acting as German look-out ships under neutral colours. A considerable number of vessels were examined, especially trawlers, and some were sent in for more detailed examination at the bases, but nothing incriminating was discovered.
Between May 5th and 10th the 3rd Battle Squadron and 3rd Cruiser Squadron cruised in the northern portion of the North Sea, being screened out from Rosyth by a half flotilla. On the return towards Rosyth in Lat. 56.49 N., Long. 0.39 E., and before being met by the screening destroyers, the 3rd Battle Squadron, two torpedoes were fired by a submarine; they were aimed apparently at the Dominion, but both missed. The squadron was in division in line ahead, steaming at 15 knots, and was zigzagging at the time.
On May 6th the mine-layer Orvieto and eight destroyers left Scapa to carry out a mine-laying operation in the Heligoland Bight. The force ran into a dense fog, and a collision occurred between the destroyers Comet and Nemesis, the latter being seriously damaged. The force was directed to return and left Scapa again on the 8th, carrying out the operation successfully during the night of the 10th–11th; it returned on the 12th.
The light cruisers Phaeton and Royalist left Scapa on May 12th for a position north of the Shetlands, in order to intercept a neutral steamer reported to have left Bremerhaven on May 11th with wireless installations on board. The C Patrol of the 10th Cruiser Squadron was also moved to a position to intercept this vessel, and the light cruiser Sappho and armed boarding steamer Amsterdam were placed on the western side of the Fair Island Channel. The force returned on the 14th, the report proving to be incorrect.
The whole Grand Fleet carried out a sweep of the central part of the North Sea between May 17th and 19th, the forces from Scapa, Cromarty and Rosyth meeting at a rendezvous in Lat. 57.10 N., Long. 0.0 at 7 A.M. on the 8th, and sweeping to the south-eastward at a speed of 16 knots until the afternoon, with the Battle Cruiser Fleet some thirty to fifty miles ahead of the Battle Fleet. The Fleet returned to its bases on the 19th, not having sighted any hostile vessels. Battle tactics were exercised during the passage north.
On May 21st the Fleet mine-sweepers, which had been sent to Aberdeen beforehand in readiness, left with an escort of two light cruisers to examine the mine-field reported to have been laid in the centre of the southern portion of the North Sea. Two of the sweepers collided in a fog on leaving Aberdeen, and another went ashore; the remainder proceeded and located the north-east corner of the mine-field on the 22nd and 23rd; they returned to Aberdeen on the 24th, after examining en route a position in which it was reported that paraffin barrels were moored. These were destroyed. It was thought that they might be intended for German submarines.