For the immediate protection of the Grand Fleet seaplane and aeroplane bases were established at Scapa Flow and Thurso at the beginning of the war, but, owing to damage from a gale in November, 1914, aircraft operations with the Fleet were carried out from the seaplane carrier "Campania." The problem of using carriers with the Fleet had not been seriously tackled before the war, and though experiments were strenuously carried out, and there were fourteen carrier ships in commission in 1918, and a seaplane carrier operated with the Battle Cruiser Squadron at Jutland, the use of aircraft in this way did not become very efficient. One of the chief difficulties was limitation in size, and consequently in radius of action, of aircraft employed from carriers or the decks of battleships. The total number of aeroplanes and seaplanes allotted to the Grand Fleet in 1918 was 350. Seaplane carriers occasionally co-operated with fighting ships. For instance in October, 1915, a fast carrier at the Dardanelles accompanied ships detailed for the bombardment of Dedeagatch, and her seaplanes not only co-operated in spotting but also made a valuable reconnaissance of the Bulgarian coast and railway. But as a rule fighting and reconnaissance aircraft had mainly to work from shore bases. To assist in this direction, units were sent overseas to be nearer their sphere of action, as, for instance, the R.N.A.S. squadrons stationed at Dunkirk which, besides general reconnaissance, helped the Navy to keep open the Straits of Dover, carried out bombing raids against German bases and dockyards, such as Ostend, Zeebrugge, and Bruges, and co-operated with monitors in the bombardment of the Belgian coast. The development of a long-range seaplane or flying boat was also taken in hand, though an efficient type was not produced until the last year of the war. As with the Army, an important part of naval aircraft duties was spotting for gunfire; and likewise single-seater fighters were required for the protection of our own aircraft, for preventing enemy aircraft reconnaissance, for attacking the enemy's fleet and protecting our own. The use of offensive patrols steadily increased during the war. _Bombing._