Though merchantmen had gone to the bottom as victims of German submarines before the proclamation of a "war zone" was issued they were individual cases; the first instance of a merchant ship being sunk as a result of the new policy of the German admiralty was the sinking of the British steamer Cambark on the 20th of February, 1915. This ship was bound for Liverpool, from Huelva, Spain. While off the north coast of Wales, on the morning of the 20th, the periscope of a hostile submarine was sighted only 200 yards ahead. The engines of the steamship were immediately reversed, but she had no time to make off, for a torpedo caught her amidships and she started to sink immediately. Her crew managed to get off in small boats, but all of their personal belongings were lost.
The small Irish coasting steamer Downshire was made a victim on the 21st of February, 1915, but instead of sending a torpedo into her hull, the commander of the U-12, the submarine which overhauled her, resorted to boarding. After trying to elude the submarine by steering a zigzag course, the Downshire was finally overtaken. The crew was ordered to take to the small boats, while nineteen men of the submarine, which had come above water, watched the operations from the deck. A crew from the submarine took one of the small boats of the steamship and rowed toward her. They placed a bomb in a vital spot and set it off, sinking the merchantman. In this way the submarine's commander had saved a torpedo. A conversation which took place between the captains of the two craft revealed the methods by which the submarine commanders were able, not only to steal up on their intended victims, but to elude being sighted by the patrolling British warships. Some fishing smacks had been in the vicinity while the Downshire was sunk, and the British captain asked the German captain why they had not been attacked. The latter hinted that his plans worked best if the fishing boats were unmolested. When asked whether he had hidden behind one these little boats he changed the subject, but it was learned later that the commanders of the submarines made a practice of coming to the surface right near fishing boats and bade them act as screens while they lay in wait for victims. By keeping the small boats covered with a deck gun or by putting a boarding crew aboard, it was possible for the commanders of the submarines to keep their periscopes or the hulls of their vessels behind the sails of the fishing boats, unobservable to lookouts on larger ships.
By the 23d of February, 1915, the success of German submarines had been so marked that the insurance rates on merchantmen went up. Lloyd's underwriters announced that the rate on transatlantic passage had gone up nearly one per cent. And on the same day it was announced that the British Government would thereafter regulate steamship traffic in the Irish Sea. Certain areas of the Irish Sea were closed to all kinds of traffic; lines of passage were defined and had to be followed by all merchantmen, and vessels of all descriptions were ordered to keep away from certain parts of the coast from sunset to sunrise.
The comparatively small size of the submarines made it possible for the German admiralty to load them on to trains in sections and transport them where needed, and in this manner some were sent from the German ports on the North Sea to Zeebrugge, there assembled and launched. Others were sent to the Adriatic, arriving at Pola on the 25th of February, 1915. These were intended for use in the Mediterranean as well as in the Adriatic Sea.
Neutral ships, in order to escape attack by German submarines had to resort to unusual methods of self-identification. The use of flags belonging to neutral countries by the merchantmen of belligerent powers made the usual identification by colors almost impossible, the German admiralty claiming that the commanders of submarines were unable to wait long enough, after stopping a vessel, to ascertain whether she had a right to fly one flag or another. Consequently the ships belonging to Dutch and American lines had their names painted with large lettering along their sides. At night, streamers of electric lights were hung over the sides to illuminate these letterings; and on the decks of many of the neutral ships their names and nationalities were painted in large letters so that they might be identified by aircraft. Owing to such precautions the Dutch steamship Prinzes Juliana escaped being sunk by a torpedo on the 3d of March, 1915. A submarine ran a parallel course to that followed by the Dutch ship, but after examining the lettering on her sides the commander of the German craft saw that she was not legitimate game and turned off.
Not always did the German submarines themselves succeed in escaping unharmed in their raiding of allied merchantmen. Rewards were offered in Great Britain for the sinking of German submersibles by the commanders of British merchantmen. Instructions were issued in the British shipping periodicals, showing how a submarine might be sunk by being rammed. It was officially announced on the 5th of March, 1915, by the British admiralty, that the U-8 had been rammed and sunk by a British warship. The crew of twenty-nine was rescued and brought to Dover. For the British this was a stroke of good fortune, for while the U-8 was of an earlier type it was a dangerous craft, having a total displacement of 300 tons, a radius of operation of 1,200 miles, a speed of 13 knots when traveling "light" and a speed of 8 knots when submerged. On the same day the French minister of marine announced that a French warship had come upon a German submarine of the type of the U-2 in the North Sea and that after firing at the hull of the vessel and hitting it three times it was seen to sink and did not reappear.
During the last week of February and the first week of March, 1915, bad weather on the waters surrounding the British Isles hampered the operations of German submarines to an extent which led the British public to believe that the submarine warfare on merchantmen had been abandoned, but they were disillusioned when on the 9th of March, 1915, three British ships were sunk by the underwater craft. The steamship Tangistan was torpedoed off Scarborough, the Blackwood off Hastings and the Princess Victoria near Liverpool. Part of this was believed to be the work of the U-16.
In the three days beginning March 10, 1915, eight ships were made victims of German submarines in the waters about the British Isles. Most novel was the experience of a crowd gathered on the shore of one of the Scilly Islands on March 12, 1915, when two of these eight ships, the Indian City and the Headlands, were torpedoed. At about eight in the morning the islanders on St. Mary's Island saw a German submarine overtake the former and sink her. The German vessel then remained in the adjacent waters to watch for the approach of another victim, while two patrol boats near by put out and opened fire on her. The crowd saw the enemies exchange shots at a distance of ten miles off shore. But neither side put in any effective shots, and the combat ended when the submarine dived and retired.
The steamship Headlands was then sighted by the commander of the submarine and he immediately started to pursue her. The steamship steered a zigzag course, but the submarine got in a position to launch a torpedo, and at about half past ten in the morning the crowd on the shore saw steam escaping from her in large quantities. Some time after they saw a large volume of black smoke and débris fly upward and they knew that another torpedo had found its mark. She then settled, her crew and the men from the Indian City reaching St. Mary's in small boats.
To keep British harbors free from the German submarines the British admiralty had to set their engineers to work to devise some method of trapping the underwater craft automatically, for there seemed to be no sort of patrol which they could not elude. Steel traps, not unlike the gill nets used by fishermen, were finally hit upon as the best thing to use against the submarines, and by March 13, 1915, a number of these were installed at entrances to some of the British harbors. They were made of malleable iron frames, ten feet square, used in sets of threes, so arranged that they might hold a submarine by the sides and have the third of the set buckle against its bottom. They were suspended by buoys about thirty feet below the surface of the water. When a submarine entered one of these it was held fast, for the frame which came up from the bottom caught the propeller and made it impossible for the submarine to work itself loose. The disadvantage to the submarine was that, while traveling under water, it traveled "blind"; the periscopes in use were good only for observation when the top of them were above water; when submerged the commander of a submarine had to steer by chart. By the end of March, 1915, a dozen submarines had been caught in nets of this kind.