It was only possible to provide a force of twenty old destroyers and forty-five trawlers for the East Coast convoys instead of the numbers recommended by the conference, and owing to the age of a large majority of these destroyers and the inevitable resultant occasional breakdown of machinery, the number available frequently fell below twenty, although it was really marvellous how those old destroyers stuck to the work to the eternal credit of their crews, and particularly the engineering staffs.

The adoption of the system, however, resulted during the comparatively fine summer weather in a considerable reduction in the number of merchant ships lost, in spite of the fact that great difficulty was experienced in keeping the ships of the convoys together, particularly at night, dawn frequently finding the convoy very much scattered.
It became obvious, however, that with the approach of winter the old destroyers of the 30-knot class would have the greatest difficulty in facing the heavy weather, and very urgent representations were made by Sir Frederick Brock for their replacement by more modern vessels before the winter set in.

All that could be effected in this direction was done, though at the expense of some of the Channel escorts.

Urgent requests for good destroyers were being received at the Admiralty from every Command, and it was impossible to comply with them since the vessels were not in existence.
Certain other steps which may be enumerated were taken in connection with the Scandinavian traffic.
The convoys received such additional protection as could be given by the airships which were gradually being stationed on the East Coast during the year 1917, and decoy ships occasionally joined the convoys in order to invite submarine attack on themselves.

This procedure was indeed adopted on all convoy routes as they were brought into being, the rule being for the decoy ship to drop behind the convoy in the guise of a straggler.
Some of our submarines were also detailed to work in the vicinity of convoy routes in order that they might take advantage of any opportunity to attack enemy submarines if sighted; due precautions for their safety were made.
Among the difficulties with which the very energetic and resourceful Admiral Commanding the Orkneys and Shetlands had to contend in his working of the convoys was the persistent mining of the approach to Lerwick Harbour by German submarines; a second difficulty was the great congestion that took place in that harbour as soon as bad weather set in during the autumn of 1917.