How devastating were the naval losses at Pearl Harbor Did FDR move most of the fleet elsewhere before the attack Is it true j Edgar hoover knew about the Pearl Harbor attack prior to the event?

Answer 1

7 of the 8 Battleships damaged or sunk

FDR moved the Pacific fleet from San Pedro California to Pearl Harbor in 07 May 1940

The US lost almost 4,000 people, killed or wounded, as well as many damaged or destroyed ships and aircraft. It was a major blow to the US Pacific Fleet.

1. No, the fleet was mostly there. However, the three aircraft carriers Enterprise, Lexington and Saratoga were not present- they were all away on other business. For example, Saratoga was in San Diego picking up her pilots, who had been doing training on the mainland.
2. It seems that Hoover and the FBI were indeed aware that the attack was about to happen. About ten days prior to the attack, the Japanese codes were broken and most of the attack plans were uncovered.

1. OK

2. In May 1940, President Roosevelt (on the advice of Stanley Hornbeck) ordered the Fleet in the Pacific to move from its base in San Diego to Hawaii, later decided to be at Pearl Harbor by June 1940. In May 1941 about 25% of the Pacific Fleet was transferred to the Atlantic Ocean to assist US efforts to support Britain.

On December 7, 1941 (US & Hawaii date/time), these were the general dispositions of the US Navy:

In the Atlantic: 4 Aircraft Carriers, 1 Escort Carrier, 3 old battleships, 3 battleships, 2 fast battleships, 5 heavy cruisers, 8 light cruisers, 31 old destroyers, 49 destroyers, 50+ submarines.

At Pearl Harbor: 8 battleships, 2 heavy cruisers, 6 light cruisers, 4 old destroyers , 25 destroyers, 4 submarines, & 51 other ships.

At Sea in Pacific: 2 aircraft carriers, 10 heavy cruisers, 2 light cruisers, 4 old destroyers, 12 destroyers, 10 submarines & 28 other ships.

At US West Coast: 1 aircraft carrier, 1 battleship, 1 light cruiser, 9 destroyers, 9 submarines, & 5 other ships.

At Philippines, Borneo & en-route to Singapore: 1 heavy cruiser, 2 light cruisers, 13 old destroyers, 29 submarines & 17 other ships.

The ships that were at sea, were primarily involved in operations to reinforce Midway & Wake Islands, escort convoys to/from the Philippines, or were on patrol in waters not far from Hawaii.

As you can see from the above information, that a large part of the US Pacific Fleet was not at Pearl Harbor on the morning that it was attacked. The major exception, and the primary target of the attack, were the 8 battleships. It was these battleships that suffered most of the destruction and damage inflicted on the ships during the attack. At the time, these losses appeared to be quite severe and the American naval leaders, politicians & public were shocked. However in hindsight, these losses were not as devastating to the American war effort as originally thought.

Here is a brief summary of US ship losses & damage to the 8 battleships at Pearl Harbor:

Battleship-USS Arizona, sunk; 1,103 killed

Battleship-USS Oklahoma, sunk; 415 killed

Battleship-USS West Virginia, sunk; 106 killed

Battleship-USS California, sunk; 98 killed

Battleship-USS Nevada, beached; 60 killed

Battleship-USS Pennsylvania, slight damage; 29 killed

Battleship-USS Tennessee, minor damage; 5 killed

Battleship-USS Maryland, some damage; 4 killed

Only the USS Arizona & USS Oklahoma were total losses. The USS West Virginia, USS California, and USS Nevada were all raised/refloated and then repaired & improved on the US west coast in time to fight in the Pacific war.

The USS Pennsylvania, USS Tennessee, and USS Maryland were all repaired on the US west coast and returned to service in less than four months.

There were several reasons that the loss and damage to the battleships was not as devastating to the US fleet as it otherwise could have been.

• Because the attack happened while the ships were in harbor, a vast majority of the crews survived the attack.
• These battleships (all completed 1916-1923) had already lost much of their importance & usefulness in the Pacific, because they were much slower than the fleet aircraft carriers, cruisers and destroyers that made up most of the fleet's task forces. They also required huge amounts of fuel to operate at even cruising speeds.
• There was before the war and immediately after the Pearl Harbor attack, a shortage of US oilers that could be used to refuel ships at sea. The US Navy chose to operate the aircraft carriers & cruisers instead of the battleships.
• The US Navy was already greatly increasing the number of warships available for combat soon.

Besides the ships not at Pearl Harbor, or not damaged at Pearl Harbor, the US Navy was already expanding. Specifically…

Already under construction at shipyards in the US at the time of the Pearl Harbor attack were:

6 fleet aircraft carriers, 4 light aircraft carriers, 1 escort carrier, 8 fast battleships, 4 heavy cruisers, 11 light cruisers, 6 AA light cruisers, 124 destroyers and numerous submarines.

Additionally the following ships were already funded & ordered to be built soon:

2 light aircraft carriers, 4 escort carriers, 2 fast battleships, 6 fast battle cruisers, 4 heavy cruisers, 12 light cruisers, 2 AA light cruisers, 60 destroyers and more submarines.

3. Now as to the question of whether J. Edgar Hoover or anyone in the FBI knew of the Pearl Harbor attack beforehand:

No. There was no one in the United States that could know in advance about the Japanese attack on December 7th, 1941 at Pearl Harbor and at the other US military facilities & ships in Hawaii.

For security purposes, only specific Japanese military leaders in Japan and those that undertook the attack were aware of it. The Japanese went to great lengths to keep the operation secret. Additionally, no person in a European country was told of this specific pending attack, including Hitler. Therefore, no one in Europe could provide a warning to the United States.

The FBI was not involved in code-breaking of Japanese diplomatic or military messages. The FBI was involved in surveillance of Japanese diplomats and citizens in Hawaii and on the US mainland. Also the FBI was involved in uncovering suspected spy/intelligence networks of Japan, Germany, Italy & the Soviet Union. No Japanese citizen or Japanese-American in the US (including those working at the embassy and consulates) knew of the attack beforehand. Therefore there was not a means available to the FBI to learn of the specific attack beforehand.

The US military had partially broken the primary Japanese diplomatic code before the attack. These are referred to by US intelligence as the "Magic intercept of the Purple Codes". However none of the messages sent by the diplomats included any reference to an attack at Pearl Harbor. The Japanese diplomats themselves were not privy to the information about this attack.

The 14-Part Message that the Japanese Embassy received on December 6/7, 1941, and was supposed to deliver before the attack, was not a Declaration of War by Japan. Instead, the message only stated that negotiations (between Japan & the US) had reached an impasse, and blamed the US. There was no mention of a pending attack, or a threat of one.

Neither the British, Dutch or American military had been successful at breaking the Japanese Navy codes before the Pearl Harbor attack. In the popular movies: Tora, Tora, Tora & Pearl Harbor the coded messages that the US intelligence officers are reading, are the Diplomatic Messages only.

What the United States did know or suspect (by late 1941) was that the Japanese were planning to attack the British territories in Hong Kong, Malaysia & Borneo, and attack the Dutch East Indies in late November or early December 1941. There were no specific details available, just Japanese military preparations & "saber rattling".

The United States also considered that the Japanese may also attack the United States at the Philippines, Guam, Wake & Midway. Again, no specific information was available.

Some American military leaders, by late 1940, also thought that the Japanese could launch an attack against Hawaii, however that was considered less likely. US Army Chief of Staff General Marshall considered it a sufficient threat that he reinforced Hawaii with air & ground units in 1941, and assigned General Short with the specific task of using the Army units (air/ground) to defend the US Pacific Fleet at Pearl Harbor.

US military preparations for the likely war with Japan focused on the Philippines. Indeed, it was because of the US military presence in the Philippines that caused Japanese military leaders to decide that it would be necessary to attack the United States in addition to the British & Dutch. The Japanese were uncertain if the United States would remain neutral if the Japanese attacked the British & Dutch. So they decided, to their great disadvantage, to attack the United States.

Meanwhile late in 1941 in Moscow, Soviet Dictator Josef Stalin (now at war with Hitler) had learned from his spies in Japan, that Japan was planning to go to war with Britain & Netherlands, and not with him in Siberia. It is not clear if Stalin knew of Japan's plans to attack the United States. In any event, Stalin gave no warning to either of his future "allies", and actually welcomed the idea that Japan would leave him alone.

The coming war with Japan was becoming obvious to most American & British leaders (and some astute in the public) by late 1941; the only question was where & when. When the Japanese did attack, they attacked the British & Americans simultaneously everywhere they could reach, including at Hawaii.

Neither the US or British ever learned of any specific plans before the attacks, because the Japanese kept these very secret as expected. The Japanese intended to, and did launch these attacks as surprise attacks before any declarations of war.

Also, it was the stated policy of the US government in 1941, to not start the war. If the United States was going to war, then the enemy would have to attack first, which it did!

Remember, as it is true today and was true then, planned "surprise" attacks will usually be a "surprise" to those attacked!