Numerous officials predicted the attack on Pearl Harbor
In October 1941, Lord Louis Mountbatten visited the United States Naval installation at Pearl Harbor. Having recently been assigned to command the British aircraft carrier Illustrious, then under repairs in Norfolk, Virginia, Mountbatten’s ostensible purpose for the visit was to brief American officers over British tactics against the Germans in the Mediterranean. Upon his return, Mountbatten visited Admiral Harry Stark, American Chief of Naval Operations. Mountbatten cited the general lack of preparedness present in Hawaii, in both the fleet and the defensive operations. He made several specific recommendations to Stark, based on the known Japanese penchant for surprise attacks and the British success at Taranto. Few, if any, were implemented. Mountbatten predicted a surprise attack at Pearl Harbor would bring the United States into the war, though he did not say when.
Among his recommendations was the deployment of torpedo nets to protect the battleships in port, which the Navy ignored. Senior Pacific Fleet staff argued the harbor itself offered protection against torpedo attack, being so shallow, and that deployment of the nets hampered other operations. Both the US Army and Navy in Hawaii remained in training status, rather than operational status, a small but significant bureaucratic distinction. Operational units had priority over training units for budget purposes. It also meant that live ammunition for the harbor defenses, and even aboard some ships, remained locked up. Aboard the American battleships, watertight doors remained open, and the ships presented little in the way of material readiness for combat, despite the fleet being under a war warning. Only the carriers were on an operational basis, but they weren’t in Pearl Harbor on December 7.