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
Sinking of the RMS Titanic the hull plates. This suggests that the iron rivets along the plate seams snapped off or popped open to create narrow gaps through which water flooded. An engineer from "Titanic"s builders, Harland and Wolff, suggested this scenario at the British Wreck Commissioner's inquiry following the disaster but his view was discounted. "Titanic"s discoverer Robert Ballard has commented that the assumption that the ship had suffered a major breach was "a by-product of the mystique of the "Titanic". No one could believe that the great ship was sunk by a little sliver." Faults in the ship's hull may have been a