Steps were at once taken to divert traffic from passing between Cape Wrath and the Pentland Firth, and a large force of mine-sweepers was detached to ascertain the limits of the mine-field and to sweep clear a passage along the coast. The mine-sweepers were based, some on Loch Eribol, an anchorage between Strathie Point and Cape Wrath, and some on Scapa, but continuous bad weather interfered with the sweeping operations to such an extent that, between January 7th and January 21st, no sweeping was possible except close in shore in sheltered water. On January 14th a German mine drifted ashore in Dunnet Bay, near Thurso, and any doubt as to the cause of the loss of the _King Edward VII._ was thereby removed. On January 7th the battleship _Albemarle_ left Scapa for Archangel, and, on the 9th, Submarine D 7 left Blyth to operate in the Skagerrak; she returned on the 16th, having met with no success. On January 12th a very heavy north-westerly gale was experienced at Scapa. The oiler _Prudentia_ drifted across the bows of the _Iron Duke_ during the night and sank, and one ammunition-ship, one store-carrier, a tug and three trawlers went ashore. The wind registered 80 miles an hour at the shore observatory during this gale. The _Iron Duke_ was undamaged. Between January 20th and 22nd three ships of the 10th Cruiser Squadron on patrol suffered considerable damage from the heavy seas. The month of January, as a whole, was indeed conspicuous for the exceptionally bad weather prevailing in northern latitudes and over the whole North Sea. Great injury was done to all the anti-submarine obstructions at Scapa, many of them being entirely destroyed. In order to make the base temporarily as secure as possible from submarine attack, the Fleet was directed to make and lay improvised net obstructions. On January 24 the destroyer _Talisman_ reported that a torpedo had been fired at her off Blyth. The _Botha_ and 10 destroyers were sent out from Rosyth to locate and destroy the submarine, but they saw nothing of her. On January 25th the _Ebro_, of the 10th Cruiser Squadron, picked up a dismasted Norwegian sailing-ship and towed her to Lerwick, arriving on the 28th.