Werner Hartenstein was a German naval officer during World War II who commanded the U-boat U-156. He was a recipient of the Knight's Cross of the Iron Cross , the highest award in the military and paramilitary forces of Nazi Germany during World War II. Hartenstein was credited with sinking 20 ships totaling 97,504 gross register tons (GRT), and with damaging three ships and a destroyer.
Born in Plauen, Hartenstein joined the Reichsmarine (navy of the Weimar Republic) in 1928. After a period of training on surface vessels and service on various torpedo boats during the Spanish Civil War and the first year of World War II, he transferred to the U-boat service in 1941.
In September 1942, Hartenstein torpedoed and sank the RMS Laconia, then attempted to rescue the survivors. He was forced to abort the rescue when his U-boat came under attack by a B-24 Liberator bomber of the United States Army Air Forces. The event became known as the "Laconia incident" and resulted in the "Laconia Order", an order from the Befehlshaber der Unterseeboote to the entire German U-boat force that forbade rescuing the survivors of sunken ships. Hartenstein and the entire crew of U-156 were killed in action by depth charges from a US PBY Catalina aircraft on 8 March 1943.