Submarines were again active during the latter part of the month in the vicinity of the cruising-ground of the 10th Cruiser Squadron, the position of the squadron being shifted for that reason.
On the 26th two light cruisers and four destroyers left Rosyth to search the waters to the southward of the German North Sea mine-field, returning on the 28th.
On the same date the yacht Conqueror II., the patrol trawler Sarah Alice, and two British steamers were torpedoed in the Fair Island Channel by enemy submarines. On receipt of the news at Scapa Flow, destroyers were detached from the Grand Fleet flotillas to operate against the submarines, and to strengthen the patrol in these waters.
Early on the 30th the Lion, with the 1st and 2nd Battle Cruiser Squadrons, and the 2nd Light Cruiser Squadron, and accompanied by a destroyer escort, left Rosyth and swept in the direction of the Naze, then turned to the northward and proceeded to Scapa.
During September the cruiser patrols were continuously maintained to the northward of the Shetlands and on the Archangel routes, each patrol consisting of a cruiser and an armed boarding steamer. The submarine patrol, consisting of three submarines, was maintained off the Horn Reef. The enemy had presumably found the patrols inconvenient, and German destroyers on several occasions during the month cruised at night in the area patrolled with a view to interrupting our submarines when recharging their batteries. This was met by a frequent change of position at night. Submarine G 12, when returning from patrol on the 29th, sighted an enemy submarine on the surface, and, being unable to get into position to attack by torpedo, engaged her by gunfire, but did not score any hits before the enemy submarine submerged.
The formation of a new Grand Fleet Submarine Flotilla (the 10th Submarine Flotilla) was begun during the month, the base being the River Tees, and the parent ship the Lucia, with two attendant destroyers. The formation of the 15th Destroyer Flotilla was also commenced, this being the last of the Grand Fleet Flotillas to be formed to complete the total number of Grand Fleet destroyers to 100.
On the 21st the new battle cruiser Repulse, heavily armed and of high speed, but with inadequate protection for a battle cruiser, joined the Fleet at Scapa to work up gunnery and torpedo practices. The armour protection of this ship was about equal to that of the Australia and New Zealand, and she was greatly inferior in this respect to the Lion, and later battle cruisers. As already stated, experience during the War had demonstrated very clearly that our battle cruisers were at a marked disadvantage in engaging German vessels of the same class, unless they were provided with better protection than that given to the Australia and earlier vessels. Proposals were, therefore, forwarded to the Admiralty for adding very considerably to the deck protection of both the Repulse and her sister ship, the Renown. These proposals were approved and the work carried out at the Fleet bases. Although the ships were much improved by the alteration, they were still far inferior in protection to the German battle cruisers.
On the 23rd a new floating-dock, which had been built on the Tyne, for light cruisers and destroyers, arrived at Invergordon, and was a very useful addition to that most valuable refitting base.
The average weekly results from the 10th Cruiser Squadron during September were:
No. of ships intercepted, 135; No. sent in, 45; No. on patrol, 15; No. absent at ports or en route to or from patrol, 9; No. on special service, 0.