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Code 424



21 Norember 1947

To: Memorandum fop File.
Subj: Magazine Explosion In ARIZONA.
Ref: (a)  Section 424 memo for File of 31 October 1944.
(b) Roll of 35 mm movie strip of explosion of ARIZONA magazine on 7 December 1941. (The individual photos noted below were part of this film and were not included in this report)
(c) N.Y. Pearl Harbor ltr. C-Lll-1/BB/NYlO, Serial Y-02149 of 7 October 1943.
(d) The Campaigns of the Pacific War - United States Bombing Survey.
(e) C.0. ARIZONA ltr. BB 39/588 of 26 January 1942.
(f) C.0. ARIZONA ltr. BB 39/A16 of 15 December 1942.

1.      The camera that took pictures of reference (d) (likely a typo and they meant the film in reference (b).) was probably on the SOLACE which was anchored in berth X48 on the morning of 7 December 1941. The line of sight is definitely established by the 200-ton hammerhead crane located at berth B-12 in the Navy Yard appearing in pictures 1 to 45 directly between the foremast and the mainmast of ARIZONA. The YD-25, 150-ton floating crane, which was moored across the end of 1010 dock on the morning of 7 December 1941 (see photo 3 in War Damage Report No. 13, Cassin and Downes), appears behind the mainmast of WEST VIRGINIA. Paragraph 6 of reference (a) incorrectly located the camera on the northwest shore of Kushua Island. This error was made because the film was turned over when making the print, available in 424 files, thus reversing everything from left to right. By viewing the print through a mirror, proper left to right relationship is obtained. Unless this is done it will appear that WEST VIRGINIA and OKLAHOMA listed to starboard whereas they actually listed to port.

2.      In the first 45 pictures there is no apparent damage to ARIZONA. However, there is some evidence that she may already have been hit by bombs. Just forward of turret I smoke is visible and at the foot of the forward kingpost on VESTAL is some evidence of smoke. Just off ARIZONA's bow and in line with WEST VIRGINIA is a white whisp on the water which may be



Code 424


spray from a bomb near-miss. WEST VIRGINA has already takact a considerable port list. Smoke from the fire on WEST VIRGINIA is very apparent.

3.      Between pictures 45 and 46 there was an indefinite period of time. This period of time is indicated by the hand that appears on the right side of picture 46, the disappearance of the obstruction on the left side of the pictures, the movement of the piling at the stern af the tug in the foreground relative to VESTAL and the appearance of smoke from VESTAL's smoke stack. TENNESSEE appears in picture 46 for the first time, while WEST VIRGINIA is practically obscured by the fire at ARIZONA's bow.

4.      Picture 46 definitely shows an explosion on the bow of ARIZONA. The flames appear to be as high as the mast and very little smoke is associated with this flame. In picture 53 black smoke is just starting to rise vertically out of ARIZONA's stack. Between pictures 53 and 110 the black smoke from the stack rises vertically to a height about three times that of the foremast in about 2-1/2 seconds. The effect is believed to be similar to that noted at Crossroads after test "A" when soot was shaken loose and drawn out of the stacks of dead ships. If so, it is evidence that picture 46 was taken very soon after the explosion on the bow of ARIZONA and that this explosion was of considerable mangnitude.

5.      In picture 67 the OKLAHOMA becomes visible on the left side. It is incorrectly labeled as WEST VIRGINIA in pictures 69 and 72. The WEST VIRGINA is obscured by the flame and smoke of the exploeion. (see pictures 44 and 46).

6.      From time to time the development of specific flames can be noted in the fire. Observe the development of the flame forward of ARIZONA's bow in pictures 62 to 69 and pictures 99 to 140.

7.      By picture 96 the effect of the explosion is beginning to subside as indicated by flame just forward of the foremast being replaced by smoke. The smoks from ARIZONA's stack has stopped rising so rapidly and the wind is beginning to blow it toward the bow.

8.      In picture 98 is the beginning of another flash forward of ARIZONA's bow. The relative gain in the height of the smoke above this flash between pictures 98 and 140 and the incandescent particles visible near this flame in picture 104 to 150 indicate that these flame are part of the magazine fire and not gunfire


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on TENNESSEE. The "mushroom" that develops over this area that becomes apparent in picture 135 and is well developed by picture 150 is definite evidence of a fire of considerable magnitude. The flame in picture 98 is about level with the upperdeck, but by picture 120 its lower edge has moved down to the waterline. This may indicate progressive failure of the ship's shell.

9.      In picture 100 the tripod masts of OKLAHOMA can be clearly seen. In picture 122 the foremast on ARIZONA has again become visible. The foremast has already bent forward at this time. MARYLAND becomes visible forward of ARIZONA at the edge of picture 125.

10.      By picture 160 the intensity of the fire has definitely decreased. Very little flame is visible and the smoke is being blown clear by the wind.

11.     Oil floating on the surface of the water appears to be burning near the bow of ARIZONA. In this connection observs pictures 190 and 200.

12.      Between pictures 207 and 208 was an indefinite period of time. The most conclusive proof of this is the entirely different configuration of the smoke in pictures 207 and 208. While it might be possible for the smoke of a high order detonation to change this much between 2 pictures (one-twenty-fourth of a second) it is inconceivable that it would also practically stop changing in shaps in this interval as indicated in picture 209. Also the flame in picture 208 is being blown to one side by the wind instead of rising vertically as would be expected after a high order detonation. Pictures 206 and 207 are blurred just like picture 45 which occurred the other time that the camera was stopped. Picture 208 shows the very intenss fire of the burning smokeless powder rather than the magazine explosion as estimated in reference (a).

13.      By picture 300 the fire has decreased considerably. This is indicated by the shorter flame length and the fact that the smoke is rising more slowly so that the wind has time to blow it further away from the vertical.

14.      The following sequence of events appeare to be in line with most of the available evidence. ARIZONA was attacked by a group of horizontal bombers carrying armor-piercing bombs. (Reference (b) (likely a typo and they meant reference (d), "The Campaigns of the Pacific War - United States Bombing Survey") reported that the Japanese horizontal bombers which


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Code 424


were assigned BB's as targets each carried one 800 kg. armor-plercing bomb.) Several bombs were dropped simultaneously by these bombers. It is believed that pictures 1 to 48 was taken shortly after these bombs hit. The smoke in line with the forward kingpost on VESTAL is from the bomb that hit the face plate of turret IV on ARIZONA. The smoke above turret 1 is from the detonation of a bomb that hit the forward part of ARIZONA, reportedly abreast of turret II. The white whisp forward of ARIZONA is spray from a bomb near-miss. A small amount of smoke would be expected from the detonation of an armor-piercing bomb deep within a ship. The flash in picture 46 is much higher and lasted longer than the flash from a bomb detonation.

15.     The evidence is not clear as to whether the bomb penetrated the third deck or a fire started by the bomb detonation passed through an open hatch in the third deck into the magazines. Reference (a) stated that most of the armored hatches on the third deck were probably open at the time. Reference (c) indicated that fragments from 4 of 5 bombs of which definite evidence was found of having hit ARIZONA penetrated the third deck. The fifth bomb hit the faceplate of turret IV which may account for its detonation above the second deck.

16.     It appears that there was an interval of several seconds between the bomb hit and the magazine explosion. In the statement of Ensign Hein, Reference (a), note that the quartermaster had time to report the bomb hit on turret II before the magazine explosion. The shaking of the ship is definite evidence of a magazine explosion rather than the detonation of an armor-piercing bomb. From the known characteristics of smokeless and black powder, enumerated in paragraph 10 of reference (a), it ie believed that the 1075 lbs. of black powder in magazine A-415M detonated. It is believed that this detonation is shown in picture 46. Ens. Hein reported that he was able to leave the bridge after the magazine explosion and make his way down the foremast superstructure to the quarterdeck. This would have been impossible through the fire shown in picture 208. The smoke that rapidly rose out of the stack, beginning at picture 53, is evidence of an explosion of major proportions.

17.     Very shortly after ths exploslon of the black powder, a fire started in one of the smokeless powder magazines. Evidence of this spread of the fire is seen on the forward side of the fire beginning in picture 61. Pictures 99 through 140 indicates further development of this fire. By picture 160 the fire appears to have become stabilized and remains so through picture 207, a period of about 2 eeconds. After an interval of indefinite length,


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picture 208 shows the smokeless powder fire after it had spread throughout the smokeless powder magazine.

18.     It is noted that there is some evidence of a time interval between the bomb detonation and the initiation of the magazine explosion. There is very definite evidence of a period of over seven seconds between the initiation of the magazine explosion shown in picture 46 and the general conflagration of the smokeless powder shown in picture 208. These time intervals suggests that if automatic magazine sprinkling apparatus had bean installed, the magazine explosion might have been avoided, or after the magazine explosion the spread of the fire in the smokeless powder mipht have been controlled.




F. F. Menefee













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National Archives & Records Administration, College Park
Record Group 19, War Damage Reports & Related Records, 1942-49

Transcribed by RESEARCHER @ LARGE. Formatting & Comments Copyright R@L.

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