The situation in regard to destroyers or other fast vessels presented equal difficulties.  Early in February, 1917, we had available for general convoy or patrol work only fourteen destroyers stationed at Devonport and twelve sloops at Queenstown, and owing to repairs and the necessity of resting officers and men periodically, only a proportion of these were available at any one time.  A number of these vessels were required to escort troop transports through the submarine danger zone.  During the month of February six sloops were diverted from their proper work of minesweeping in the North Sea and added to the patrol force at Queenstown, and eight destroyers were taken from the Grand Fleet and sent to southern waters for patrol and escort duty.  There were obvious objections to this weakening of the North Sea forces, but it was necessary in the circumstances to ignore them.

This total of forty destroyers and sloops represented the whole available force at the end of February.  Simultaneously a careful investigation showed that for the institution of a system of convoy and escort for homeward-bound Atlantic trade alone to the United Kingdom, our requirements would be eighty-one destroyers or sloops and forty-eight trawlers (the latter vessels being only suitable for escorting the slow 6-7-knot ships of the trade from Gibraltar to the United Kingdom).  For the outward Atlantic trade from the United Kingdom our estimated requirements were forty-four additional destroyers or sloops.

The deficiency in suitable vessels of this class is best shown by the following table, which reveals the destroyer position at different periods during the year 1917: 

-------------------------------------------------------

-------------
Mediterranean.
------------------------------------------------------------

----+
Pembroke.                                                       |
------------------------------------------------------------

-+  |
Queenstown.                                                  |  |
---------------------------------------------------------+   |  |
Bunerana.                                                |   |  |
------------------------------------------------------+  |   |  |
North Channel.                                        |  |   |  |
---------------------------------------------------+  |  |   |  |
Scapa and Invergordon.                             |  |  |   |  |
------------------------------------------------+  |  |  |   |  |
The Tyne.                                       |  |  |  |   |  |
---------------------------------------------+  |  |  |  |   |  |
The Humber.                                  |  |  |  |  |   |  |
------------------------------------------+  |  |  |  |  |   |  |
Lowestoft.                                |  |  |  |  |  |   |  |
---------------------------------------+  |  |  |  |  |  |   |  |
The Nore.                              |  |  |  |  |  |  |   |  |
------------------------------------+  |  |  |  |  |  |  |   |  |