Naval mine ship, HMHS "Britannic", which was the sister ship of the RMS "Titanic." During World War II, the U-boat fleet, which dominated much of the battle of the Atlantic, was small at the beginning of the war and much of the early action by German forces involved mining convoy routes and ports around Britain. German submarines also operated in the Mediterranean Sea, in the Caribbean Sea, and along the U.S. coast. Initially, contact mines (requiring a ship to physically strike a mine to detonate it) were employed, usually tethered at the end of a cable just below the surface of the
Russian hospital ship Vpered German Navy submarine SM "U-38" in the Black Sea between Rizeh and Batum. She sank shortly after. She was not carrying any wounded soldiers at the time, but seven people died in her sinking. Her survivors were saved a short time later. The Russian Empire claimed that Ottoman forces sank "Vperiod" rather than the Germans. The Ottoman Empire replied that both ships were sunk by mines. Russian hospital ship Vpered HS "Vpered" () was a Russian hospital ship that was torpedoed by the Imperial German Navy submarine SM "U-38" on 8 July 1916. SS "Vpered" was built at the Stabilimento