Accordingly I looked for other and more easily obstructed ports, and eventually decided on Lough Swilly for the main part of the Fleet, and Loch-na-Keal in the Island of Mull for the ships for which berthing-space could not be found at Lough Swilly. Both ports possessed comparatively narrow entrances, and at Lough Swilly the water was so shallow as to make it difficult for a submarine to enter submerged. It was also a “defended port” and therefore possessed an organisation which would be useful for regulating the entry of ships.
The extensive dispositions necessitated by the temporary change of base were at once ordered. Colliers, store-ships, and auxiliaries of one kind and another, which were either en route to, or at, Scapa Flow, were diverted to the new bases; the 2nd Battle Squadron and 1st Battle Cruiser Squadron were ordered to Loch-na-Keal to fuel and to improvise anti-submarine obstructions at the entrance; and the Illustrious was ordered there from Loch Ewe to act as guard ship; the 1st and 4th Battle Squadrons and 2nd Battle Cruiser Squadron were detached to cruise to the north-westward of the Hebrides for blockading purposes, and to carry out practices; and the 1st Light Cruiser Squadron, 2nd Cruiser Squadron and 3rd and 6th Battle Squadrons were sent to Lough Swilly to coal. The cruiser blockade and look-out line was withdrawn farther to the northward owing to the danger from submarines incurred in operating in the central or southern portions of the North Sea on a regular patrol, and the impossibility of providing destroyers as a screen for the ships. The new line was to the northward of the Shetland Islands, and the 3rd and 10th Cruiser Squadrons and armed merchant-cruisers carried out the patrol. There were, therefore, two lines of blockade, one formed by the heavy ships north-westward of the Hebrides, the second to the northward of the Shetland Islands. The organisation was such that it was probable that vessels attempting to evade the blockade would pass one of the two lines during daylight hours. In making these new dispositions it was still intended to keep the North Sea itself under observation by frequent cruiser sweeps.
Numerous reports of submarines in the Minch at this time led to the Active and two divisions of destroyers being sent there to search for them, and the remainder of the 2nd and 4th Flotillas were divided between blockade duty in the Pentland Firth, work at Scapa Flow, and in the vicinity of the Orkneys and Shetlands, and with the ships at Loch-na-Keal and Lough Swilly.
On October 21st the 2nd Battle Cruiser Squadron arrived at Cromarty to coal. Owing to the receipt of information from the Admiralty early that day, that it was reported that some German cruisers, destroyers and submarines had left Danzig on October 17th for the North Sea, the 1st Battle Cruiser Squadron and 1st Light Cruiser Squadron were ordered to leave their bases that morning, proceed into the North Sea, and sweep down on a broad front to the Skagerrak, screened by the 4th Flotilla of destroyers. The latter had to be sent back to their base on October 22nd owing to heavy weather. The remainder of the force swept up to the Skaw without sighting any enemy vessels, then north along the Norwegian coast, and proceeded, the 1st Battle Cruiser Squadron to Cromarty and the 1st Light Cruiser Squadron to Scapa.
On October 21st a submarine was reported just outside Cromarty by an armed trawler, and another report was received of one having been sighted by the destroyer Lynx. The submarine obstruction at Cromarty, designed by Captain Munro, had now been completed, and the base was considered secure. It would, however, only accommodate a small portion of the Fleet.
The dispositions given above were maintained until October 22nd, when the Iron Duke, 1st and 4th Battle Squadrons, the Active and two divisions of destroyers of the 2nd Flotilla, arrived at Lough Swilly. The 3rd and 6th Battle Squadrons and 2nd Cruiser Squadron took their place to the north-westward of the Hebrides as an outer blockade line and support for the cruiser squadrons. The 2nd Battle Cruiser Squadron and four destroyers were detached to the southern part of the North Sea on the 23rd to support the Commodore (T) in carrying out aerial operations in the Heligoland Bight. The operations failed owing to the difficulty the sea-planes experienced in rising off the water, and the 2nd Battle Cruiser Squadron returned to Cromarty.
On arrival of the 1st and 4th Battle Squadrons at Lough Swilly, steps were immediately taken to lay an anti-submarine obstruction at the entrance, and this was very smartly completed with the limited resources of the squadrons by 4 P.M. on the 23rd, and for the first time since the declaration of war the Fleet occupied a secure base. Wire hawsers provided by the ships of the Fleet were suspended at varying depths between six colliers which were anchored across the entrance, with target rafts as intermediate supports.
It was a fairly effective obstruction, and armed steamboats from the fleet patrolled near it with destroyers as a support.
The relief to those responsible for the safety of the Fleet was immense, and attention was at once turned to the well-being of the personnel, which had been pressed very hard, and to improving the efficiency of the ships in gunnery and torpedo work. Battle practice targets were ordered over from Lamlash, in the Island of Arran, a pre-War practice base, with the intention of carrying out practice in the waters north-west of Ireland. The work of retubing the condensers of the Iron Duke was once more taken in hand, and ships were given the opportunity of overhauling and adjusting machinery, steam being put back to longer notice than had previously been possible. The anti-submarine defence was continually strengthened and improved during the stay of the Fleet, and the colliers supporting it were gradually replaced by trawlers and drifters.
In order to give the men some much-needed diversion and exercise a pulling regatta was organised and held on October 26th, and the men were landed for route marches as frequently as possible during the stay of the ships at Lough Swilly.