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.