The keenness shown by officers and men of the merchant service contributed in a marked degree to the success of the courses instituted; just one example may be given. I visited the Royal Naval Depot at the Crystal Palace early in 1918, and amongst other most interesting scenes witnessed a large number of men of the merchant service at gun drill. I questioned several of them as to their experiences, and many of the men had had their ships torpedoed under them three, four or five times. Amongst the gun crews was a steward who had been through this experience four times. On my asking why he, as a steward, should be going through the gunnery course, he replied that he hoped that by so doing he might stand a chance of getting his own back by assisting to sink a submarine. The knowledge which I possessed of the measures introduced during the year 1917 to combat the German submarine warfare, and the continual increase in the efficiency of the anti-submarine work which I knew would result from increased production of anti-submarine vessels and weapons, led me in February, 1918, to state that in my opinion the submarine menace would be "held" by the autumn of the year 1918. The remark, which was made at what I understood to be a private gathering, was given very wide publicity, and was criticized at the time, but it was fulfilled, as the figures will indicate. CHAPTER IV THE INTRODUCTION OF THE CONVOY SYSTEM The question of the introduction of convoys for the protection of merchant ships was under consideration at various times during the war. The system had been employed during the old wars and had proved its value in the case of attack by vessels on the surface, and it was natural that thoughts should be directed towards its reintroduction when the submarine campaign developed. There is one inherent disadvantage in this system which cannot be overcome, although it can be mitigated by careful organization, viz. the delay involved. Delay means, of course, a loss of carrying-power, and when tonnage is already short any proposal which must reduce its efficiency has to be very carefully examined. The delay of the convoy system is due to two causes, (a) because the speed of the convoy must necessarily be fixed by the speed of the slowest ship, and (b) the fact that the arrival of a large number of ships at one time may cause congestion and consequent delay at the port of unloading. However, if additional safety is given there is compensation for this delay when the risk is great. One danger of a convoy system under modern conditions should be mentioned, viz. the increased risk from attack by mines. If ships are sailing singly a minefield will in all probability sink only one vessel--the first ship entering it. The fate of that ship reveals the presence of the field, and with adequate organization it is improbable that other vessels will be sunk in the same field. In the case of a convoy encountering a minefield, as in the