June 21st.—Four destroyers and six gunboats were operating to the east of the Pentland Firth against a submarine.
June 23rd.—Submarine U 40 was sunk 50 miles S.E. by S. of Girdle Ness at 9 A.M. by submarine C 24, working in company with a trawler.
June 23rd.—A division of destroyers was sent to operate against a submarine to westward of the Fair Island Channel.
June 24th–26th.—Three sloops were engaged in searching for a submarine to the eastward of Orkneys and Shetlands.
June 26th.—A large force, comprising 20 armed trawlers from Granton in the Firth of Forth, began to operate against submarines in an area round Lat. 57 N., Long. 1 E., remaining out until July 7th. Two armed trawlers, with C class submarines in company, were also operating to the southward of this position.
June 30th–July 1st.—A force of eight destroyers was operating against submarines in the Fair Island Channel.
The anti-submarine operations by destroyers or sloops met with no success. The invariable difficulty was the provision of a sufficiently large number of vessels to keep the submarine down long enough to cause her to exhaust her battery power, a period of some 48 hours. When destroyers belonging to the Grand Fleet were used for anti-submarine operations at any distance from the base, the disadvantage of their not being available to accompany the Fleet to sea in an emergency had to be accepted. This would have led to awkward results had the Fleet proceeded to sea with any considerable shortage of destroyers for screening purposes on passage south and for Fleet purposes during a Fleet action. The dilemma was one which faced me during the whole period of my command of the Fleet.
My experience convinced me that anti-submarine operations by destroyers in such open waters as existed near the northern bases had but little prospect of success unless undertaken by a considerably larger number of vessels than were usually available at Scapa for such operations; a contributory reason for the shortage of destroyers was that in addition to the operations carried out by the heavy ships, cruisers and light cruisers, for which the presence of destroyers was necessary, there was a constant call on these vessels for escort work during the movements of single ships or of squadrons between bases.
Other events of interest during this month included:
The formation of the 4th Light Cruiser Squadron of new light cruisers under the command of the late Commodore Le Mesurier, C.B., in the Calliope. This squadron was attached to the Battle Fleet, and in cruising order at sea was usually stationed from three to five miles ahead of the Battle Fleet to act as an advanced submarine screen forcing submarines to dive. From this position it could reach the van of the Fleet on deployment for action, and was stationed there for the purpose of attacking enemy destroyers with gunfire and the enemy’s Battle Fleet with torpedoes. It was a squadron on which, as Commander-in-Chief, I kept a hold so that I might be certain it would be at my disposal when action with the enemy was joined. Other light cruiser squadrons, which occupied an advanced position in the cruiser screen, could not be depended upon with the same certainty to occupy the van position to which they were allotted during a fleet action, since they might become engaged with enemy vessels of the same class.