ANTI-SUBMARINE OPERATIONS The previous chapters have dealt with the changes in organization carried out at the Admiralty during the year 1917 largely with the object of being able to deal more effectively with the submarine warfare against merchant ships.

Mention has also been made of the submarine problem with which the Navy had to deal; particulars of the anti-submarine and other work carried out will now be examined.
A very large proportion of the successful anti-submarine devices brought into use during 1917, and continued throughout the year 1918, were the outcome of the work of the Anti-Submarine Division of the Naval Staff, and it is but just that the high value of this work should be recognized when the history of the war comes to be written by future historians.

As has been stated in Chapter I, Rear-Admiral A.C.Duff, C.B., was the original head of the division, with Captain F.C.Dreyer, C.B., Commander Yeats Brown, and Commander Reginald Henderson as his immediate assistants.

Captain H.T.Walwyn took the place of Captain Dreyer on March 1, 1917, when the latter officer became Director of Naval Ordnance.

When Admiral Duff was appointed Assistant Chief of the Naval Staff, with a seat on the Board, in May, 1917, Captain W.W.