The anti-submarine measures initiated during the year 1917 and continued throughout the year 1918, as well as those in force in the earlier years of the war, depended very much for their success on the work carried out by the Admiralty Departments responsible for design and production, and apart from this these departments, during the year 1917, carried out a great deal of most valuable work in the direction of improving the efficiency of the material with which the vessels of the Grand Fleet and other warships were equipped. Early in 1917 certain changes were made in the Naval Ordnance Department. When Captain Dreyer took up the post of Director of Naval Ordnance in succession to Rear-Admiral Morgan Singer on March 1, the opportunity was seized of removing the Torpedo Department, which had hitherto been a branch of the Naval Ordnance Department, from the control of the Director of Naval Ordnance, and Rear-Admiral Fitzherbert was appointed as Director of Torpedoes and Mines, with two assistant Directors under him, one for torpedoes and the other for mines. It had for some time been apparent to me that the torpedo and mining work of the Fleet required a larger and more independent organization, and the intention to adopt a very extensive mining policy accentuated the necessity of appointing a larger staff and according it greater independence. The change also relieved the D.N.O. of some work and gave him more liberty to concentrate on purely ordnance matters. Captain Dreyer, from his experience as Flag Captain in the _Iron Duke_, was well aware of the directions in which improvement in armament efficiency was necessary, and a variety of questions were taken up by him with great energy. Some of the more important items of the valuable work achieved by the Naval Ordnance Department during the year 1917, in addition to the provision of various anti-submarine measures mentioned in Chapter III, were: (1) The introduction of a new armour-piercing shell of far greater efficiency than that previously in use; the initial designs for these shells were produced in the drawing office of the Department of the Director of Naval Ordnance. (2) The introduction of star shell. (3) The improvement of the arrangements made, after our experience in the Jutland action, for preventing the flash of exploding shell from being communicated to the magazines.