e majority of the ships therein
engaged were slow. But trawlers are unsatisfactory escort vessels.

In the early stages of the convoy system difficulties were experienced
from the fact that all the available destroyers and most of the sloops
were used as escorts, with the result that the ships not under convoy
were left with but little protection.

CHAPTER V

THE CONVOY SYSTEM AT WORK

As has been mentioned in Chapter II., the first ships to be brought
under a system of convoy were those engaged in the French coal trade and
in the trade between Scandinavia and the United Kingdom.

In the case of the _French coal trade_, commencing in March, 1917, the
steamships engaged in the trade were sailed in groups from four
different assembly ports, viz.:

Southend to Boulogne and Calais.
St. Helens to Havre.
Portland to Cherbourg.
Penzance to Brest.

Between Southend and Boulogne and Calais the protection was given by the
vessels of the Dover Patrol in the course of their ordinary duties, but
for the other three routes special escort forces were utilized, and
daily convoys were the rule.

Owing to the great demand for coal in France, sailing vessels were also
used, and sailed under convoy from several of the south-west ports.

A large organization was required to deal with the trade, and this was
built up under the supervision of Captain Reginald G.H. Henderson, C.B.,
of the Anti-Submarine Division of the Naval Staff, working under
Vice-Admiral (then Rear-Admiral) Sir Alexander Duff, head of the
Division, in conference with the Commanders-in-Chief, Portsmouth and
Plymouth, under whose direction and protection the convoys were run. The
immunity of this trade, carried out in the infested waters of the
English Channel, from successful attack by submarines was extraordinary.
No doubt the small size of the vessels concerned and their comparatively
shallow draught were a contributory cause to this immunity. The figures
for the period March to August, 1917, show that 8,825 vessels crossed
the Channel under convoy, and that only fourteen were lost.

The history of the _Scandinavian and East Coast convoys_ dates back to
the autumn of 1916, when heavy losses were being incurred amongst
Scandinavian ships due to submarine attack. Thus in October, 1916, the
losses amongst Norwegian and Swedish ships by submarine attack were more
than three times as great as the previous highest monthly losses. Some
fear existed that the