e rapid development of submarine piracy, however, compelled the
Admiralty, early in the year 1917, to resort to what was merely a new
form of the old system of protecting sea-borne trade. This comprised the
collection of all merchant ships passing through the danger zones into
nondescript fleets, and the provision of light cruisers, destroyers,
torpedo-boats, trawlers and occasionally (for coastal convoys) of patrol
launches to escort them. Certain types of aircraft were also frequently
used for observation and scouting purposes.

Previous to the adoption of the convoy system a merchantman, whether it
was a fast-moving liner or a sturdy but slow ocean tramp, _zigzagged_
through the danger zones with lights out and life-boats ready. Many were
the exciting runs made in this way, with shells ploughing up the water
around and torpedoes avoided only by the quick use of the helm; but the
courage of our merchant seamen was of that indomitable character
exhibited now for over three centuries, since the days of Drake,
Hawkins, Raleigh and the other sea-dogs of old.

But the danger zones grew wider as the radius of action of newer and
larger German submarines increased. At last no waters were immune, from
the Arctic circle to the Equator, or from Heligoland to New York.

The hour was one of extreme peril for the sea-divided Empire. To lose
several hundred ships, with many thousands of lives and much-needed
cargoes of food and munitions, when the valiant armies of civilisation
were battling with the Teuton hordes, was bad enough; but if the enemy
had been able, by casting aside the laws of humanity and sea war, to
compel British ships to remain in harbour or meet certain destruction on
the high seas, the result could only have been the complete failure of
the Allied cause, the conquest of Europe and the fall of the greatest
political edifice since Imperial Rome.

Between the world and these catastrophes, however, stood the undefeated
Mercantile Marine and the Allied navies. Councils were held in the
historic rooms of Whitehall and the old convoy system emerged from the
archives of Nelson's day. The commerce raiders were no longer the
canvas-pressed privateers of the sixteenth, seventeenth and early
eighteenth centuries, who fought a clean fight, often against great
odds, but were submarine pirates of the mechanical age, who only
appeared from the sea depths when their victims had been placed _hors de
combat_.

It is an old ax