boat, while certain prearranged warships
belonging to the escort proceeded to the attack with guns and depth
charges.

This means of masking the movements of ships--by no means new in naval
warfare--was employed with conspicuous success in the operations of
Allied squadrons off Zeebrugge. Individual merchantmen, when attacked by
one or more submarines, often threw out a smoke screen to avoid
destruction by the big surface guns of the more modern German craft, and
its use to cover the movements of transports was very frequently
resorted to.

CAMOUFLAGE

The use of camouflage, or the deceptive painting and rigging of ships,
came first into being owing to the method employed by submarines for
judging the speed of passing surface ships by the white wave thrown off
from their bows. It is of the utmost importance for the commander of an
under-water warship to correctly judge the speed of the vessel he is
about to attack before discharging a torpedo at her. If the estimated
speed is too high the torpedo will, in all probability, pass ahead of
the moving target, and if it is too low it will run harmlessly astern.

To cause this to happen as frequently as possible, and valuable
torpedoes to be wasted--even if the attacking submarine herself could
not then be discovered and destroyed--it became advisable to paint
imitation white waves on the bows of slow-moving ships in order to give
the appearance of speed.

[Illustration: FIG. 15.--A camouflaged ship. It will be observed that a
vessel so painted would, from a distance of several miles, give the
appearance of a ship sinking while headed in the opposite direction.]

So successful was this simple form of deceptive paint-work that a
special camouflage section of the naval service, with an eminent artist
as its director, was formed, and all kinds of grotesque designs were
painted on the broadsides and superstructures of almost every British
merchantman operating in the submarine danger zone.

There was method and meaning in the seemingly haphazard streaks of
black, green, blue and white. When looked at from close range only a
jumble of colours could at first be seen, but if the distance was
increased the effect became instantly apparent. In some cases the
deceptive decoration caused big ocean liners to appear small and
insignificant. In others it gave the appearance that the vessel was
sinking; while quite a favourite ruse was to cause the vessel to appear
as if she was t