Pearl Harbor Advance-knowledge Conspiracy Theory - "Inherent Invulnerability" of Pearl Harbor

"Inherent Invulnerability" of Pearl Harbor

Making an attack against Pearl Harbor was unimaginable to many because the depth of Pearl Harbor was generally less than 40 ft (12 m). Such depths were widely believed insufficient for torpedo attack; at the time, a torpedo dropped from a plane dove deeply before rising again to running depth. In water that was not deep enough (like Pearl Harbor) the torpedo would hit the bottom, detonating or embedding itself in the mud.

Not all in the U.S. Navy shared this opinion. A mock air attack on Pearl Harbor during war games in the 1930s was judged to have been a success. Shortly after taking office, Navy Secretary Knox wrote an overview memo which specifically noted the possibility of an attack at Pearl Harbor. However, neither observation led to formal policy recommendations to forestall such an attack. Admiral James O. Richardson, who was fired by President Roosevelt for refusing to station the Pacific Fleet in Pearl Harbor, blamed the President for the "initial defeats in the Pacific" as "direct, real and personal." Richardson believed stationing the fleet in Pearl Harbor made the ships extremely vulnerable against attack and provided a poor and unstrategic defense.