pride in their vessels, credited them with speeds in excess of those
actually attained. Frequently coal of poor quality or the fact that a
ship had a dirty bottom reduced her speed to a very appreciable extent,
and convoy commodores had occasionally to direct ships under such
conditions to drop out of the convoy altogether and make their passage
alone. Obviously this action was not taken lightly owing to the risk
involved. Decision as to the sea speed of convoys was taken by the
convoy officer at the collecting port, and he based this on the result
of an examination of the records in the different ships. As a rule
convoys were classed as "slow" and "fast." Slow convoys comprised
vessels of a speed between 8 and 12-1/2 knots. Fast convoys included ships
with a speed between 12-1/2 and 16 knots. Ships of higher speed than 16
knots did not as a rule sail in convoys, but trusted to their speed and
dark hours for protection in the submarine area. The Gibraltar convoy
(an exception to the general rule) contained ships of only 7 knots
speed.

With the introduction of convoys the provision of efficient signal
arrangements became a matter of importance. The issue of printed
instructions to each master and the custom introduced of assembling the
masters to meet the captain of the escorting cruiser before sailing, so
that the conduct of the convoy might be explained, had the effect of
reducing signalling to a minimum, but it was necessary that each ship
should have a signalman on board, and the provision of the number of
signalmen required was no easy matter. A good wireless installation was
essential in the escorting cruiser and in the Commodore's ship in order
that the course of the convoy could be diverted by the Admiralty if the
known or suspected presence of submarines rendered it necessary, and
also for the purpose of giving to the Admiralty early information of the
position of a convoy approaching the coast, so that the escorting
destroyers could be dispatched in time.

Fortunately for us, German submarines constantly used their wireless
installations when operating at sea, and as a consequence our wireless
directional stations were able to fix their positions by cross bearings.
This practice on the part of the enemy undoubtedly went far to assist us
both in anti-submarine measures and in diverting trade to a safe course.

The introduction of the convoy system rendered the provision of
anti-submarine protection at ports o