Mention should be made here of the very serious situation which arose during the year 1917 owing to the success attending the attacks by enemy submarines on oil tankers bringing oil fuel to the United Kingdom for the use of the Fleet.  A great many of these tank vessels were of great length and slow speed and presented the easiest of targets to the torpedo attack of a submerged submarine.  So many vessels were sunk that our reserve of oil fuel became perilously low.  Instead of a reserve of some five or six months we were gradually reduced to one of about eight weeks, and in order to economize expenditure of fuel it actually became necessary at one time to issue directions that the speed of oil-burning warships was to be limited except in cases of the greatest urgency.  Such an order in war was a matter of much gravity; the great majority of our light cruisers and destroyers were fitted to burn oil fuel only, as well as our latest and most powerful battleships.  The crisis was eventually overcome by drawing upon every source (including the Grand Fleet) for destroyers to escort the tankers through the submarine danger areas, and by the assistance given us by the Ministry of Shipping in bringing supplies of oil fuel to this country in the double bottoms of merchant ships.  By the end of 1917 the situation had greatly improved.

The losses of shipping during 1917 were particularly heavy in the Mediterranean.  Apart from the fact that the narrow waters of that sea render difficult a policy of evasion on the part of merchant shipping and give great advantages to the submarine, it was thought that the heavy losses in the early part of the year were partly due to the method of routeing the ships then in force, and in reply to representations made to the French Admiralty this system was altered by the French Commander-in-Chief.  It should be noted that the Mediterranean outside the Adriatic was under French naval control in accordance with the agreement entered into with France and Italy.  The cordial co-operation of the French Admiralty with us, and the manner in which our proposals were met, form very pleasant memories of my term of office at the Admiralty.  During the greater part of the year 1917 Admiral Lacaze was Minister of Marine, whilst Admiral de Bon held office as Chief of the Naval Staff during the whole year.  Nothing could exceed the courtesy extended to me by these distinguished officers, for whom I conceived great admiration and respect.

The result of the altered arrangement was a decided but temporary improvement, and the losses again became serious during the summer months.  I then deemed it desirable that the control of the traffic should be placed in the hands of officers stationed at Malta, this being a central position from which any necessary change in the arrangements could be made more rapidly and with greater facility than by the French Commander-in-Chief, who was also controlling fleet movements and who, for this reason alone, was not in a position to act quickly.