ound and found quickly if the Allied cause was to be saved from
disaster.

None of the anti-submarine measures that had been under consideration or
trial since the formation of the Anti-Submarine Division of the Naval
Staff in December, 1916, could _by any possibility_ mature for some
months, since time was necessary for the production of vessels and more
or less complicated materiel, and in these circumstances the only step
that could be taken was that of giving a trial to the convoy system for
the ocean trade, although the time was by no means yet ripe for
effective use of the system, by reason of the shortage of destroyers,
sloops and cruisers, which was still most acute, although the situation
was improving slowly month by month as new vessels were completed.

Prior to this date we had already had some experience of convoys as a
protection against submarine attack. The coal trade of France had been
brought under convoy in March, 1917. The trade between Scandinavia and
North Sea ports was also organized in convoys in April of the same year,
this trade having since December, 1916, been carried out on a system of
"protected sailings." It is true that these convoys were always very
much scattered, particularly the Scandinavian convoy, which was composed
largely of neutral vessels and therefore presented exceptional
difficulties in the matter of organization and handling. The number of
destroyers which could be spared for screening the convoys was also very
small. The protection afforded was therefore more apparent than real,
but even so the results had been very good in reducing the losses by
submarine attack. The protection of the vessels employed in the French
coal trade was entrusted very largely to trawlers, as the ships
composing the convoy were mostly slow, so that in this case more
screening vessels were available, although they were not so efficient,
being themselves of slow speed.

For the introduction of a system of convoy which would protect merchant
ships as far as their port of discharge in the United Kingdom, there
were two requirements: (a) A sufficient number of convoying cruisers or
armed merchant ships, whose role would be that of bringing the ships
comprising the convoy to some selected rendezvous outside the zone of
submarine activity, where it would be met by the flotilla of small
vessels which would protect the convoy through the submarine area. It
was essential that the ships of the convoy shoul