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 von Weddigen, who commanded the _U-9_ when she sank the _Hogue_, _Cressy_, and _Aboukir_ in September, 1914, was confirmed by a report issued by the German admiralty on April 7, 1915, after rumors of her loss had circulated throughout England and France for a number of weeks.