SM UB-10 - Second Submarine Offensive

Second Submarine Offensive

By early 1916, the British blockade of Germany was beginning to have an effect on Germany and her imports. The Royal Navy had stopped and seized more cargo destined for Germany than the quantity of cargo sunk by German U-boats in the first submarine offensive. As a result, the German Imperial Navy began a second offensive against merchant shipping on 29 February. The final ground rules agreed upon by the German Admiralstab were that all enemy vessels in Germany's self-proclaimed war zone would be destroyed without warning, that enemy vessels outside of the war zone would be destroyed only if armed, and—to avoid antagonizing the United States—that enemy passenger steamers were not to be attacked, regardless of whether in the war zone or not.

UB-10's first victim in the new offensive (and Saltzwedel's first as a commander), came on 19 March when the U-boat torpedoed Port Dalhousie, a 1,744-ton Canadian steamer, 2 nautical miles (3.7 km) from the Kentish Knock Lightvessel. Nineteen men on the ship—headed from Middlesbrough to Nantes with a cargo of steel billets—were lost in the attack; the mate, a pilot, and five crewmen were rescued. About two weeks later, UB-10 torpedoed and sank the Norwegian steamer Peter Hanre in nearly the same location; fourteen men on the 1,081-ton cargo ship were lost. Near the end of April 1916, Admiral Reinhardt Scheer, the newest commander-in-chief of the High Seas Fleet, called off the merchant shipping offensive and ordered all boats at sea to return, and all boats in port to remain there. Port Dalhousie and Peter Hanre were the only ships sunk by UB-10 during the six-week offensive.