rtially damaged by submarines during the week ending March
31, 1915, some 1,559 vessels entered and sailed from British ports
during the same period.

Efforts were made to damage the base, from which many of the German
submarines had been putting out at Zeebrugge, with aircraft. On the
1st of April, 1915, the British Government's press bureau announced
that bombs had been dropped, with unknown success, on two German
submarines lying there, and that on the same day a British airman had
flown over Hoboken and had seen submarines in building there.

The steamship _Lockwood_, while off Start Point in Devonshire, was hit
abaft the engine room by a German torpedo on the morning of April 2,
1915, and though she went down almost immediately, her crew was able
to get off in small boats and were picked up by fishing trawlers.

The _U-28_, which had done such effective work for the Germans during
the month of March, 1915, was relieved of duty near the British Isles
during the first week of April by the _U-31_, which sank the Russian
bark _Hermes_ and the British steamship _Olivine_ off the coast of
Wales on April 5, 1915.

The British admiralty decided in April, 1915, to use some other means
besides the employment of torpedo boats and destroyers to keep watch
for German submarines, and innocent-looking fishing trawlers were used
for the purpose. While these could give no fight against a submarine,
it was intended that they would carefully make for land to report
after sighting one of the hostile craft. The Germans, discovering this
strategy, then began to sink trawlers when they found them. On the
morning of April 5, 1915, one of these small craft was sighted and
chased by the _U-20_. After a pursuit of an hour or more the German
ship was near enough for members of her crew to fire on the trawler
with rifles. Her crew got into the small boat and were picked up
later by a steamer. The trawler was sent to the bottom.

The _U-20_ still kept up her raiding. On the 5th of April, 1915, she
overtook the steamer _Northland_, a 2,000-ton ship, and torpedoed her
off Beachy Head. The crew of the steamer were able to escape, although
their ship went down only ten minutes after the submarine caught up
with it.

The use of nets to catch submarines was vindicated, when on the 6th of
April, 1915, one of these vessels became entangled in a steel net near
Dover and was held fast. The loss of the _U-29_, which was commanded
by the famous Otto