During the unrestricted campaign, the area of the enemy operations may be divided into four main groups (I) the English coast, (2) the western approaches north and south of Ireland, (3) the South Atlantic from Land's End to the neighbourhood of the straits of Gibraltar, and (4) the Mediterranean. Round the English coast, the losses from enemy submarines showed little variation from the beginning of the cam paign in Feb. 1917 until the blocking of Zeebrugge and Ostend in April 1918, when the losses fell from an average of 56 vessels per month to 28. The east coast section suffered heavily in June 1918 mainly in the north-east convoy when 21 vessels were lost as compared with an average otherwise of seven. The English Channel section was subjected to a burst of activity by the enemy in Dec. 1917 when the previous average of 22 vessels lost per month went up to 37, after which it fell to 23 and later to six. In the Irish Sea section, Feb. to April 1918 were bad months, the losses averaging 16 monthly compared with 5 and 4 per month respectively for the periods before and after that quarter. In the
second group (western approaches), the fall in the monthly losses from 41 in the 6 months Feb. to July 1917 to 4 in the sub sequent 6 months was attributable to the convoy system, as was also that in the third area (South Atlantic) from 26 to 16 per month. In the Mediterranean, the losses in the 6 months Feb. to July 1917 averaged 3o per month and in subsequent similar periods were 27, 21 and 11 vessels per month. The improvement was greater in the western Mediterranean than in the eastern.
Devices for the protection of indi vidual ships included "paravane" and "otter" gear for use against mines, smoke apparatus for spreading a screen against the enemy and dazzle-painting, a colour scheme to create a confusional effect as to the vessel's course and speed. But the greatest protection lay always in the watchfulness and resource of the officers and men of the merchant service, undismayed by the fact that 62% of the vessels struck sank within 15 minutes. (H. W. G.)