Next morning an "SOS" call came from the French tanker _Radioleine_, "attacked by submarine." The coast torpedo-boat _Hull_ (Lieutenant R. S. Haggart), rushed to her assistance. Zigzagging and firing her stern-gun, the steamer was putting up a good defense, though shells were falling around her. But before the _Hull_ could get within firing distance, the U-boat dived and scurried off. As the _Radioleine_, relieved, sailed away, the _Hull_ picked up the crew of the schooner _Edward R. Baird, Jr._, which had been bombed two hours before, but was still afloat, though water-logged, with decks awash. Moving around from point to point, in the next week the U-151 sank six steamships, one an American steamer, the _Pinar Del Rio_, and then headed for Germany. Naval vessels were on the lookout all the time. But when the submarine did attack any craft which had radio, it prevented them, if possible, from sending out signals or messages of distress. This was a great handicap to the naval commanders, as it prevented them from knowing where the U-boat was operating. The moment a periscope was reported, they speeded for the scene. As it departed for home, the submarine attacked two British steamers, the _Llanstephan Castle_ and _Keemun_, both of which escaped, and later sank two Norwegian barks, the _Samoa_ and _Kringsjaa_, 150 miles at sea. Though sighted several times by merchantmen, the U-151 made no further attacks until June 18th, when she torpedoed the British steamship _Dwinsk_, far out in the Atlantic. The vessel remained afloat and two hours later was sunk by gunfire. Soon afterward the _U. S. S. Von Steuben_ arrived on the scene and bore down on the lifeboats. The submarine fired a torpedo at her, but the cruiser transport avoided the deadly missile, and blazed away at the "sub's" periscope. She fired 19 shots and dropped numerous depth-charges. But the U-boat submerged and got away and three days later, about 200 miles further east, sank the Belgian _Chilier_. The Norwegian steamer _Augvald_ was sunk June 23. This was the last vessel sunk, though the submarine made several unsuccessful attacks on British and American ships. The U-151 reached Germany August 1, having left Kiel April 14. In a cruise of nearly three months she had sunk 23 vessels, of 59,000 gross tons. Some submarines in European waters had destroyed that much tonnage in a week or two. But this was only the beginning of submarine operations. The U-156, commanded by Kapitän-Leutnant von Oldenburg, left Germany for America June 15, and on July 5 attacked, almost in mid-Atlantic, the _U. S. S. Lake Bridge_, which after a running fight outdistanced her.