VII. THE POSSIBILITY OF AERIAL TORPEDO ATTACK AT PEARL HARBOR

 

A. KNOWLEDGE AND EVALUATION OF SECRETARY'S LETTER:

 

Shortly after he assumed command, Admiral Kimmel saw the letter of the Secretary of the Navy to the Secretary of War, dated January 24, 1941, which discussed the security of the Fleet at Pearl Harbor and set forth the types of attack regarded as most likely (page 286).

In that letter, it will be recalled, the Secretary said that:

"If war eventuates with Japan, it is believed easily possible that hostilities would be initiated by a surprise attack upon the fleet or the naval base at Pearl Harbor . . . The dangers envisaged in their order of importance and probability are considered to be: (1) air bombing attack (2) air torpedo plane attack, (3) sabotage, (4) submarine attack, (5) mining, (6) bombardment by gunfire."

      Apparently, Admiral Kimmel also received a copy of the reply of the Secretary of War to that letter. It may be noted that the Secretary    of War in his reply of February 1941 (Exhibit 24), expressed complete concurrence as to the importance of the questions raised by the Secretary of the Navy, and as to the urgency of making every possible preparation to meet such a hostile effort. In his letter, the Secretary of War stated that the Hawaiian Department was the best equipped of the overseas departments and continued to hold a high priority for the comple­tion of its projected defenses because of the importance of giving full protection to the Fleet. The letter discussed the Army's pursuit planes at Hawaii and those to be sent to Hawaii, the present and prospective anti‑aircraft guns, the fact that the aircraft warning service equipment would be delivered in June, advised that the Commanding General, Hawaiian Department was being directed to give consideration to the question of employment of balloon barrages and the use of smoke in protecting the Fleet and base facilities. Also, it stated with reference to the other proposals for joint defense that a copy of the Secretary of the Navy's letter and of the reply were being forwarded to the Commanding General, Hawaiian Department with instructions that he cooperate with the local naval authorities in making those measures effective. It appears from the copies of the endorsements annexed to this letter that a copy of the letter was sent to CincPac and to ComFOURTEEN.

Admiral Kimmel's testimony showed some confusion as to his agreement with, and his evaluation of, this correspondence between the Secretary of the Navy and the Secretary of War. He testified that he felt that the most probable form of attack on Pearl Harbor was by submarine and that a bombing attack was the second most probable form of attack, and that the danger of an air torpedo attack was nil because the water was too shallow (page 286). He then corrected his testimony and stated that his previous testimony was erroneous and that he had regarded art air attack as no more than a possibility (page 287).

 

Captain McCrea described his conferences which he had had with the Commander‑in‑Chief, Asiatic Fleet, and the Commander‑in‑Chief, Pacific Fleet, early in 1941. He recalled that Admiral Kimmel, who was shortly to relieve Admiral Richardson, specifically discussed the short‑comings of the air defenses of Pearl Harbor. (p. 275)

 

Admiral Stark testified that the letter of the Secretary of the Navy to the Secretary of War had been prepared by Admiral Stark and his assistants (page 24).

 

Admiral Ingersoll was familiar with the correspondence between the Secretary of the Navy and the Secretary of War concerning the inadequacy of defenses at Pearl Harbor. He recalled that there was some subsequent discussion of the question of balloon barrages and that the Fleet did not want

PROCEEDINGS OF HEWITT INQUIRY                                                                    403

 

them at Pearl Harbor because of interference with aircraft operations. He recalled no further formal representations being made to the War Depart­ment on the subject of the deficiencies. (p. 418‑9)

 

General Marshall was familiar with the Secretary of War's reply to the Secre­tary of the Navy's letter of January 24, 1941 (page 853). In this connection he said that he personally took steps to meet the deficiencies discussed therein; that Hawaii for years held first priority on material and was by far the best equipped Army installation; that additional planes were sent to Hawaii, seriously handicapping the training program in the United States, and special efforts were made to expedite production. The problem of expansion was very serious in terms of limited equipment and personnel needed both for Hawaii and else­where, and also needed here for training essential to expansion (page 854).

 

Admiral Bloch said that after the Secretary of the Navy's letter of January 24, 1941, a large number of fighters and some bombers were sent to Hawaii, but that so far as he knew, no additional anti‑aircraft guns were sent. He said that they knew nothing about the defenses of the coast artillery and as to the adequacy of Army personnel, but that he was definitely of the opinion that the personnel of the Army was being increased all the time and was considered by the Army generally adequate for its task. Admiral Bloch knew that the Army had a deficiency in numbers and types of planes capable of performing inshore patrol. (p. 8)

 

General Short testified that he saw both the Secretary of the Navy's letter and the War Department's reply. He agreed with the Navy's recommendations except as to smoke and balloon barrages (page 237).

Admiral Schuirmann testified that the Secretary of the Navy's letter had not been shown to him, and that the State Department had not been apprised of it. He said, however, that the State Department was kept informed of the Navy's estimate of United States‑Japanese relations (page 199).

 

Admiral Schuirmann said that he was sure that the State Department had not seen the Secretary of the Navy's letter of January 24, and the Secretary of War's answer concerning the security of the Fleet at Pearl Harbor. He believed, however, that they were fairly well informed of the lack of certain equipment and of personnel shortages in the Army and Navy generally. (p 408)

In his voluntary statement, Admiral Anderson said that the Robert's report indicated that nothing was done about the Secretary of the Navy's letter of January 27, 1941 by the top commanders or any of the junior flag officers. He said that so far as he was concerned, he never knew about the Secretary of the Navy's letter. (p. 398)

 

B. CORRESPONDENCE ON ANTI‑TORPEDO BAFFLES IN PEARL HARBOR

 

On February 15, 1941 (Exhibit 49), the Chief of Naval Operations wrote to CincPac regarding anti‑torpedo baffles for protection against attacks on Pearl Harbor. This stated that the shallow depth of water limited the need for anti-­torpedo nets in Pearl Harbor and the congestion and the necessity for maneuver­ing room limited the practicability of the present type of baffles. The letter indicated that a minimum depth of water of 75 feet might be assumed necessary successfully to drop torpedoes from planes and that the desirable height for dropping is 60 feet or less. There were various other considerations stated. The recommendations and comments of the Commander‑in‑Chief were especially desired. A similar letter was sent by the Chief of Naval Operations to the Commandants of various Naval Districts, including the Fourteenth, on Feb­ruary 17, 1941 (Exhibit 54).

The reply to the request for recommendations and comments was made on March 20 1941, in a letter by Admiral Bloch, stating that the depth of water at Pearl Harbor was 45 feet, and for that and other reasons, he did not recom­mend anti‑torpedo baffles. CincPac agreed, until such time as a light efficient net were developed (page 293).

In June, 1941, the Chief of Naval Operations sent another letter to the Com­mandants of Naval Districts, copy to CincPac and others, referring to recent developments, and to experience at Taranto, which stated that no minimum depth of water could be assumed safe as regards torpedo attack if there were sufficient water around a ship to permit an attack to be developed and a Sufficient run to arm the torpedo, but that such attack in 10 fathoms or more was more likely than in shallow water (Exhibit 55). The torpedoes at Taranto,

 

404                                           CONGRESSIONAL INVESTIGATION PEARL HARBOR ATTACK

 

it was said, were launched in thirteen to fifteen fathoms although some may have been in eleven.

Admiral Kimmel testified that on this correspondence he based his opinion that there was no chance of an air torpedo attack on Pearl Harbor—and that even after the June letter, he did not think torpedoes would run in such shallow water. He pointed out that the Navy made no effort to place such nets in Pearl Harbor (page 293). He later stated that he did not think an aerial torpedo attack would be made because he did not think such torpedoes would run in Pearl Harbor and did not give this a great deal of consideration for that reason (page 331.

Admiral Smith recalled the first letter from the Chief of Naval Operations con­cerning anti‑torpedo nets, but not the June letter. He said they did not think the Japanese would attack with torpedo planes (page 536).

 

Admiral Smith said that he was familiar with the earlier correspondence on the subject of the need for anti‑torpedo nets, and that they concluded that because of the shallow water at Pearl Harbor no such nets were neces­sary; he did not recall ever having seen the second letter. Exhibits 17, 18 and 19 are copies of the letters in question. (p. 60‑1) Admiral Smith said that the decision of the Commander‑in‑Chief, as set forth in his letter of March 12, 1941, that anti‑torpedo nets were not necessary, was never recon­sidered. Admiral Smith complained that the Navy's torpedo information was kept too secret so far as the Fleet was concerned, other than the sub­marines. (p,. 62)

 

Admiral Bloch testified that he believed that air torpedoes could not be launched profitably in Pearl Harbor (page 394).

 

Admiral Bloch said that he was familiar with the discussions concerning the need for anti‑torpedo nets in Pearl Harbor; that he was familiar with the earlier correspondence but he never saw the later correspondence modifying the earlier views. (p. 26)

Admiral Halsey said that he had felt, prior to December 7, that the Fleet should have been protected at Pearl Harbor by anti‑torpedo baffles and was strongly in favor of having them. (p. 306)

Admiral Bloch pointed out that such nets in Pearl Harbor might interfere with the take‑off of seaplanes and with the sortie and entry of ships. Ad­miral Kimmel, he said, reached the conclusion and, insofar as Admiral Bloch was concerned, that settled the matter. Moreover, he said they had no nets available at the time except some makeshift nets used at harbor entrances which they had manufactured themselves. (p. 27)

 

It may be noted, incidentally, that on February 11, 1941, Admiral Stark wrote to the Chief of the Bureau of Ordnance stating that experimental and development work should be undertaken on nets and booms; that there appeared to be an urgent need for an anti‑torpedo net which could be laid and removed in certain harbors in a short time for temporary use; and that efforts should be made to reduce the weights of the present Admiralty nets and booms (Exhibit 56).