The enemy’s submarine activity became much more marked during February. Early in the month the German Admiralty proclaimed that after February 18th all the waters round the British Isles would be declared unsafe for merchant-ships of all nationalities, and intimated that Allied merchant-ships would be destroyed in these waters and that neutral merchant-ships ran similar risks. Enemy submarines began to operate in increasing numbers in the English Channel, to the westward of the English Channel, in the Irish Sea and off the west coast of Ireland, as well as on the east coast of England, and the losses of merchant-ships from submarine attack became serious. The destroyers of the Grand Fleet that remained at the northern bases were kept fully employed in searching for and hunting reported submarines. In addition to the maintenance of the blockade by the 10th Cruiser Squadron, cruiser and light cruiser squadrons carried out various patrol and search operations during the month. The 3rd Cruiser Squadron cruised in the centre portion of the North Sea from February 1st to 3rd; the 2nd Cruiser Squadron cruised off the Shetland Islands from the 11th–13th, then swept down the Norwegian coast and returned to Cromarty on the 15th; the new 2nd Light Cruiser Squadron carried out a sweep in the southern portion of the North Sea between the 16th and 20th with destroyers in company; the new 3rd Light Cruiser Squadron cruised to the westward of the Shetlands for exercise between the 15th and 18th, then passed into the North Sea and swept to the southward, returning to Scapa on the 20th; the 1st Cruiser Squadron left Scapa on the 17th for the vicinity of the Norwegian coast, swept down towards the Naze and then returned to patrol north of the Shetlands until the 21st, when the squadron arrived at Scapa; the four light cruisers attached to the Battle Fleet, _Bellona_, _Blanche_, _Boadicea_, and _Blonde_, with four destroyers, left Scapa on the 18th for a line N. 37 E. 60 miles long from Lat. 57.30 N., Long. 0.30 W., with directions to sweep towards the Naze by day and patrol the line at night; they remained on this duty until the 21st. The 7th Cruiser Squadron cruised to the westward of the Fair Island Channel from the 19th to the 22nd, and available destroyers of the 2nd and 4th Flotillas were patrolling to the eastward of the Fair Island Channel and the Moray Firth respectively during the same period. The 3rd Cruiser Squadron, with four destroyers, left Rosyth on the 23rd to cover the Fleet mine-sweepers whilst searching for mines along a projected Fleet track in the North Sea, but, the sea being too heavy for mine-sweeping, the squadron carried out a patrol instead until the 25th, when the mine-sweeping operations took place, lasting until the 27th, when the squadron returned to Rosyth.