The blockade was becoming daily more effective, although the blockading cruisers worked at so great a distance from the German coast. The only interference ever attempted by the enemy was by submarine attack or by mines, and during the year 1915 no great success was achieved by them in this respect when the conditions are considered. The regular blockading squadron, the 10th Cruiser Squadron, was assisted in its work by the sweeps of our cruisers and light cruisers, accompanied occasionally by the Battle Fleet. In addition to the discharge of these duties, the Battle Fleet engaged in periodical cruises, during which battle exercises were carried out for the purpose of maintaining efficiency in the handling of the ships and squadrons and of giving the fresh officers, who were frequently joining the Fleet, to replace others required for the new ships, experience in the work of the Grand Fleet under the novel war conditions. Pursuant to this general policy, the Dreadnought Battle Fleet remained in harbour until January 10th, and then left for a cruise to the westward of the Orkneys and Shetlands. Gunnery practices were carried out by day and at night, as well as battle exercises, and the Fleet returned to Scapa during the day and the night of the 13th. The 3rd Battle Squadron left Rosyth on the 12th for a cruise in the North Sea, and on the night of the 13th–14th passed to the westward of the Orkneys for gunnery practice, returning to Rosyth on the 15th. Other events of interest during the first fortnight of January were the return of the _Princess Royal_ from North American waters on the 1st; a short cruise in the centre of the North Sea by the 1st Battle Cruiser Squadron and the 1st Light Cruiser Squadron between the 3rd and the 5th, and by the 3rd Cruiser Squadron between the 6th and the 8th; a cruise by the 1st Cruiser Squadron to the westward of the Orkneys between the 4th and 6th, and by the 6th Cruiser Squadron between the 6th and the 9th, and the 10th and 14th. On January 4th the _King George V._ completed the work of retubing her condenser. On the 9th all ships at Scapa raised steam ready for leaving, in consequence of a report of a submarine being sighted in Hoy Sound, and available destroyers and trawlers were sent to patrol in the vicinity of the Hoy anti-submarine Fleet obstructions until the Battle Fleet left harbour on the 10th. Gales were experienced at Scapa on the 1st, 13th, 16th and 19th of January.