War diary of Kapitšnleutnant Walter Schwieger recording the attack and sinking of the Lusitania, May 7, 1915, page 8

This copy of Schwieger’s diary came to the Department of the Navy (and, eventually, to the National Archives) through the U.S. Army’s Military Intelligence Division.

In the diary, typed from his handwritten notes, Schwieger stated that he caught sight of the Lusitania in the distance, while his submarine was surfaced; he quickly submerged his vessel, moved into an attack position, and at 3:10 p.m., ordered the launch of the torpedo from a distance of 700 meters.

The diary chronicles the chaos and panic he observed while the ship’s crew and passengers tried to put the lifeboats in the water as the ship listed sharply starboard. The ship sank after eighteen minutes; only six of the forty-eight lifeboats had made it safely into the water.

The cause of the explosion on board the Lusitania has been the subject of study and debate since 1915. Experts tend to agree now that the explosion was caused by an industrial accident (likely the detonation of coal dust or aluminum powder ignited by fire resulting from the torpedo hit), rather than the combustion of explosive munitions on board.

National Archives, Naval Records Collection of the Office of Naval Records and Library