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*WARNING* Photos 1 & 2 in this report are of a graphic nature; those who are troubled by photographs of deceased servicemen should avoid them. That said, how many of you are now going to look for them first before reading any of the report?






(BB 57)




19 JUNE 1944















Prepared by Puget Sound Navy Yard



Introduction     1
Free Water Effect on Stability     3
Structural, Description and Discussion of Damage     4
Piping, Description and Discussion of Damage     5
Ventilation, Description and Discussion of Damage     6
Electrical and Machinery, Description and Discussion of Damage     9
Ordnance, Radar & Radio, Description and Discussion of Damage    12
  U.S.S. SOUTH DAKOTA (BB57) Photographs Nos. 1, 2, 5, 6, 9, 10, 14, 18, 19, 20, 21, 22, 23, 25, 27, 28, 29, 32, 33, 34, 36, 37, 38, 39, 41, 42, 44, 46, 47, & 50.
Nos. 2217-44 to. 2230-44 incl. U.S.S. SOUTH DAKOTA (BB57) War Damage Report
  BuShips Plan No. BB57-S1101-187478 - War Damage Investigation, Structural
 (a) C. 0. SOUTH DAKOTA War Damage Report of 26 June 1944.










1.   The U.S.S. SOUTH DAKOTA was struck on the 01 deck by a bomb dropped from a Japanese plane at about 1049 on the morning of 19 June 1944. As noted in reference (a) the bomb was estimated to have been a 250 K.G.G.P, with instantaneous fuse setting. The vessel was steaming at about 22 knots in an area one hundred and fifteen miles West Northwest of Guam. As nearly as can be determined the bomb hit and detonated on the 01 deck at frame 73, about 22 feet to port of the centerline. The condition of the ship at the time of the hit, and the measures taken immediately afterward to maintain military efficiency and seaworthiness, are described in the ship's report, reference (a). The damage due to the bomb explosion, as determined by this Yard from examination of the damaged area and discussion with the ship's personnel, is described in this report.














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l.   It was believed by the ship that the excess water used in fire fighting as reported in reference (a) and the leakage and drainage from ruptured piping caused enough water to accumulate to produce a slight list to port and a "free surface effect". After discussion with the ship's personnel on arrival at Puget Sound, it was determined that the vessel had a slight list to port when the bomb hit and hence water was pocketed on the port side of the main and second decks. It is estimated that not more than 35 to 40 tons of water were involved, which due to the free surface, caused a reduction in GM of approximately 0.30 feet and an additional port list of a negligible amount.

2.   Other than the inconvenience of the free water sloshing about on the decks no important effect on the stability or military efficiency of the ship was involved.













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l.   The principal structural damage occurred in the immediate vicinity of the bomb hit although fragments pierced structure at some distance from this point and the blast deflected or destroyed light divisional bulkheads and fixtures on the main and Ol decks. The radius about the point of impact within which appreciable damage occurred is approximately 20 feet.

2.   The hole torn in the 01 deck at the point of the explosion is shown on the ships photograph's nos. 1, 2, 14, 19, 28, 36, 42, and 46 and the attached sketch. The temporary patch installed over the hole appears on P.S.N.Y. photographs nos. 2217-44, 2218-44, and 2225-44. The portion of the deck house bulkhead which was blown in is shown on the ships photographs nos. 2 and 46 and the attached sketch. A temporary patch was also installed over this hole and is shown on P.S.N.Y, photographs nos. 2221-44, 2222-44, and 2225-44.

3.   It is of interest to note that the light sheet metal bulkhead on frame 89, starboard side, and shown on ships photograph no. 41, was bulged aft, although it was about 80 feet from the point of explosion and the intervening structure was not affected.

4.   It was noted that in most cases, damaged welded stiffeners, deck beams, and welded seams in decks and bulkheads within the blast area were broken adjacent to the weld and parallel to it. One instance of this is shown on ship's photographs nos. 21 and 22.

5.   The additional photographs herewith and the ship's report, reference (a) give a detailed picture of the damage which need not be repeated in this report.

6.   It is believed that the ship's structure stood up well under the effects of the explosion and no major changes in design are warranted. It does appear however, that increased protection for gun crews on the inboard side of gun mounts would be desirable.






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Section IV - PIPING

1.   The piping systems in the immediate area of the damage were extensively perforated by bomb fragments and were twisted and mashed by the collapse of light weight bulkheads and vent ducts to which they were attached. These systems included steam heating supply and drains, hot and cold fresh water, and salt water flushing and plumbing drains and are not considered vital.

2.   The 2-1/2" firemain branch located about 17 feet to port of centerline between frames 65 and 72 under the 01 deck was not damaged except for temporary leaks at the flanged joints. Apparently the firemain was not in the path of any sizable bomb fragments. The absence of leakage at the silver brazed joints or in the tubing itself is, however, a testimonial to the inherent ruggedness of copper nickel tubing joined by the silver brazing process.

3.   It is interesting to note that the two 500 gallon fresh water pressure tanks located on the main deck about 22 feet port of centerline between frarnes 65 and 68 were not damaged except for failure of the safety valves which allowed the tanks to drain onto the decks.

4.   Piping located just under the main deck in way of the explosion was not affected by the deflection of the deck or vibration of the supporting structure.

5.   It is not believed that any change in design of the piping systems which were damaged would result in material improvement of the functions of the systems or resistance to damage.









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1.   In general damage to ventilation systems consisted of distortion and carrying away of ducts in the vicinity of the explosion. No weaknesses in construction or particularly unusual aspects were observed other than the fact that the two vent sets, systems 1-67 and 1-70, remained undamaged, although the blast split the intake and discharge ducts adjacent to each fan. The motors, impellers, and casings were not affected and performed satisfactorily without noticeable vibration as soon as power was restored. The following detailed list of damaged ventilation equipment amplifies and adds to the list furnished with reference (a):

      2nd Superstructure Deck (02 Level)
            1.    Admirals Cabin (B-0201L)
Supply terminal and six feet of connecting ductwork damaged, frame 75-76. Small branch duct missing from frame 74 to 75, 6 feet to port. (Supply System 03-79-2)
      lst Superstructure Deck (O1 Level)
1.    Seams split in discharge duct from Exhaust System 1-67, frame 68-69, 10 feet to Port. Baffle support damaged in Forced Draft Intake, frame 70, Port.
            2.    Wardroom Staterooms 0102, 0104, 0106, Captain's Pantry, Registered Publication Locker, and Passage, frame 72-1/2 to 78, Port.
All ductwork was demolished except spools through overhead girders. (Supply System 1-70 and Exhaust System 1-67)
3.    Captain's Cabin, frame 72-1/2 to 78, Starboard.
Fragment tore section of duct out between frame 75 and 76, 3 feet to starboard of ship's centerline (Supply System 1-70)
4.    Passage, frame 78-8l, Starboard.
Exhaust ducts demolished, 5 feet to starboard of centerline (Exhaust System 1-67). Supply ducts damaged (Supply System 1-70)



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      lst Superstructure Deck (O1 Level) (Continued)
5.    Wardroom Stateroom 0108.
Supply terminal missing and branch ducts damaged (Supply System 1-70)
6.    Captain's Linen Locker
Exhaust duct from Captain's bath demolished. Terminal in Captain's Bath undamaged.
      Main Deck (Supply System 1-70, Exhaust System 1-67)
1.    Wardroom Stateroom 102.
Supply terminal missing and branch damaged.
2.    Wardroom Stateroom 104.
Terminal and branch damaged.
3.    Wardroom Stateroom 106.
Terminal missing and branch damaged.
4.    Wardroom Stateroom 108 and 112.
All terminals and branches demolished.
5.    Wardroom Stateroom 110 and 114.
Terminals and branches damaged.
6.    Passage (B-101L)
Branches leading to W.R.S.R. 108,110, and Wardroom, and all reheaters demolished aft of frame 69. Sub-main leading to outboard staterooms damaged throughout its length.
7.    W.R.W.R. & W.C, frame 65-67, Centerline

Sub-main from Supply System 1-70 damaged throughout compartment. Branch from Exhaust System 1-67 damaged for 8 feet on Port side of centerline only.

Natural supply louver in non-tight bulkhead at frame 67-68, 13 feet to Port damaged.

8.    Fan Rooms, frame 67-69, 10 feet to Port.
Intake and discharge fittings to Exhaust System 1-67 split open. Vent set not damaged.



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      Main Deck (Supply System 1-70, Exhaust System 1-67) Continued
9.    Repair #1, frame 67-73, 5 feet to port.
Duct damaged from frame 67 to 69 and from frame 70 to 73.
10.    Fan Room, frame 70-73, 12 feet to Starboard
Discharge fitting from Supply System 1-70 split open, but vent set not damaged.
11.    Transverse main at frame 72-73 from System 1-70 supplying wardroom damaged throughout its length from 14 feet to starboard to 14 feet to port.
12.    Wardroom (B-102L)

Supply terminal missing from branch 18 feet to starboard.

Supply branch 8 feet to port demolished between frames 73 and 78. Terminal and portion of branch from frame 78 to 78-1/2 was not damaged.

Supply branch to Wardroom Pantry demolished between frames 73 and 76, 10 feet to port, and section four feet in length damaged at frame 78-79 inboard of the Wardroom Pantry.

Supply branch to Wardroom at 38 feet to port damaged and terminal missing.

Exhaust duct missing between frames 73 and 75 from four feet to port to 23 feet to port. Remainder of exhaust duct damaged but intact.







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1.   The greatest damage to electrical equipment occurred in the port passage on the main deck between frames 68 and 78. A fore and aft cable rack under the 01 deck was located directly under the point of impact and was consequently completely destroyed in this area. Other cables adjacent to the rack, ship's service telephone trunk line, connection boxes, various fixtures and fittings, etc., were also demolished. Some of the above damage can be seen on the ship's photographs nos. 14, 18, 19, 28, 36, 39, and 50.

2.   In the case of connection and distribution boxes, fixtures, and fittings, it was observed that in general they were either completely demolished or remained serviceable. On the other hand comparatively delicate instruments such as ship's service telephones, announcing loud speakers, etc., which cannot stand severe shock were extensively damaged as described in reference (a).

3.   A great deal of local wiring and equipment in the area just outboard of the centerline, frames 72 to 78 port side, under the Ol deck, was destroyed. However no vital electrical circuits or equipment were located in this area. The ship's photographs nos. 25, 32, and 46 show the general extent of this damage.

4.   The destruction of the wire rack and adjacent wiring in passage B-101-L, mentioned in paragraph one above, severed a number of electrical cables which are listed under the heading of either vital or semi-vital and non-vital with comments as follows:


(a) FB 743 - Normal power supply to the common transfer switch 40 MM Quad Mounts No. 4 & 5.
(b) 6FB743 & 4FB743 - Power mains to 40 MM Quad No. 4 elevation & train motor controller respectively.
COMMENT: Since the alternative power supply feeder to this transfer switch was not damaged, it was possible to immediately restore power to 40 MM Mount No. 5 as soon as Mount No. 4 mains 6 & 7 FB743 were cleared. In view of the fact that local Ordnance wiring on Mount No. 4 was extensively damaged there was no necessity for the immediate restoration of power supply to that mount.
(c) GM100 - DHFA23 - 115 Volt A.C. Synchro Supply from I.C. SWbd. to MK. 3 fuse box at base of 40 MM Mount No. 4.



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Section VI - ELECTRICAL (Continued)

Vital Circuits (Continued.)
(d) MHFA30 (designated as Ord. Ld. No. 1) from 40 W.C.B. at base of Mount No. 4 to associated MK. 51 Dir., containing circuits GM & 4 PA.
(e) Five local sound powered battle telephone leads containing JY circuits for control of 40 MM Quad No. 4.
NOTE: Exclusive of Normal Power supply FB743, the above circuits were eventually restored to service by ship's force through the use of temporary jumper cables.
Semi-Vital & non-vital Circuits
(f) Ship's service telephone main trunk leads No. C-J89 and No. C-J111. This caused the loss of ship's service phones in the entire area on the main deck and above, forward of frame 95, affecting an approximate total of 88 phones.
COMMENT: Had lead No. D-J111 been routed through the director tube at frame 82 centerline, the greater portion of phone circuits serving the 2nd superstructure deck and above, would have remained in service.
(g) FB413, Alternative 440 Volt supply to transfer switch located at lst superstructure deck, frame 82, starboard, for lighting transformers and distribution panel O1-82-1. FB411, alternative 440 Volt supply to transfer switch located on the main deck, frame 82 port, for lighting transformers and distribution panel 1-82-2. These panels supply battle and general lighting circuits in the area from approximately frame 89 forward on main and 01 decks, also for entire 02 deck and above.
NOTE: As the normal 440 Volt supply cables to these units were not damaged, lighting in the above areas remained in service, with the exception of that portion in the demolished areas. It is understood that these normal supplies were secured as a safety precaution and immediately restored after clearing of faults in the demolished area. It is noted that the ship's report, reference (a), erroneously listed the normal lighting supply cables as being the ones that were severed.




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Semi-Vital & non-vital Circuits (Continued.)
(h) 1-FB-769, power supply cable to vent set no. 1-69. (This covered exhaust ventilation for W.R. Mess, lounge and pantry.)
(i) Cease firing circuits 4U & 5U to 40 MM Quad No. 4 & 20 mm Guns Nos. 20, 22, 28, 18 & 19.
(j) Battle telephone circuits "JZ". (Associated phone Jack & switch box for Repair I were also demolished)
(k) Local general announcing circuits "IMC-2MC".
(l) Various Officer's Call Bell System cables. (This damage reflected into all circuits on the main deck forward and above.)

5.   The list furnished in reference (a) appears to accurately cover the details of damaged electrical equipment.

6.   From discussion with the ship's officers it was determined that no circuit breakers tripped or fuses dislodged due to shock on the intact circuits. There was no evidence of any sustained short circuits on damaged power or lighting leads. In general, exclusive of the loss of vital circuits to 40 mm Quad. Mount No. 4, it is considered that damage to the electric plant did not impair the immediate military efficiency of the vessel.

7.   No damage was sustained by machinery or other electrical equipment.





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1.   Ordnance equipment damage was limited to the 40 mm Quad. Mount No. 4, the 5" loading machine, and 20 MM Ready Service boxes, the details of which are thoroughly covered in reference (a). In connection with the damage to the 40 mm mount involving the severing of electric cables and hydraulic piping by splinters (see ship's photo No. 34) it will be noted that this damage would have been minimized if the splinter shield had been continuous on the inboard side.

2.   The 20 mm ready service boxes on the 01 deck, port side frame 67, shown on ship's photograph no. 20 were so badly damaged by fragments that they were thrown over the side. In spite of this severe damage no ammunition in the boxes exploded. However the boxed 40 mm ammunition which had been passed to the Ol deck for the no. 4 mount and was stowed about 10 feet from the point of impact of the bomb all exploded.

3.   It is of interest to note that the Radar equipment Mk. 4 transmitter located in the passage between the Admiral's cabin and the Senior Staff Officer's cabin at about frame 76 on the 02 deck which is approximately 30 feet from the point of the explosion was not injured. The transmitter was in operation at the time and continued to operate satisfactorily without the necessity for re-tuning. Since the transmitter operator was thrown 10 to 15 feet by the force of the explosion the transmitter undoubtedly received a severe shock.

4.   No damage was sustained by radio or other radar equipment.













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Orginal Blueprint Scans

Plan 1st Super Deck
Port Side Only
Plan, Main Deck.
Port Side Only
Section at Frame 73,
Looking Forward
Port Side Only

Inverted Scans For Printing
Plan 1st Super Deck
Port Side Only
Plan, Main Deck.
Port Side Only
Section at Frame 73,
Looking Forward
Port Side Only

SOURCE: National Archives & Records Administration, Seattle Branch
Record Group 181, Ship Files ca 1940-1950
Declassification Review Project NND 958357

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

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