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Torpedo and Bomb Damage
December 7, 1941
There are 8 plates and 34 photographs appended. If only limited time is available for study of the full report a comprehensive summary will be found in Sections I, II and VIII, together with Plates I, II and VII, and Photos 1 to 12, which are arranged for quick scrutiny.
LIST OF PLATES
LIST OF PHOTOGRAPHS
1. U.S.S. CALIFORNIA was struck by two torpedoes and one bomb. Near-miss damage resulted from a second bomb and minor damage was caused by a third. Minor fragmentation damage resulted from bombs at a distance. There was one fire aboard as a result of the bomb hit. About two hours after the start of the attack a surface oil fire completely enveloped the vessel. Finally, a vapor explosion occurred forward just prior to completion of salvage operations.
2. The vessel sank slowly and did not approach the final position in the mud until late Wednesday night or early Thursday morning. She was floated on 24 March and docked on 9 April. Undocking occurred on 7 June with permanent underwater repairs complete. Completion of machinery reconditioning and modernization was undertaken at Puget Sound in October, 1942.
3. Precise information concerning the spread of water throughout the vessel subsequent to damage and which caused almost complete submergence to the upper deck in four days is lacking. Evidence relative to initial damage control measures is either missing or incomplete. Careful surveys were made by the Navy Yard, Pearl Harbor, when the vessel was drydocked. These revealed few of the reasons why liquid spread throughout undamaged compartments because complete flooding and salvage activities in the interim had obliterated evidence of the conditions causing such infiltration.
4. This report is based on the references, the Pearl Harbor surveys of damage and a study of the vessel's interior arrangements. Plates were prepared from plans submitted by Pearl Harbor. Photographs were supplied by Pearl Harbor and the Salvage organization.
5. CALIFORNIA was moored, starboard side to the interrupted quay, F-3, Pearl Harbor, on the morning of December 7, 1941. The depth of water here was about 40 feet. The bottom is mud, 90 feet deep, over coral. Weather was clear with scattered clouds.
6. Enemy action began with dive-bombing over the Air Station, Ford Island, just before 0800. Torpedo plane attack, with the line of battleships as the principal objective, followed immediately from the southeast and continued for about 15 minutes. Bombing attacks on battleships began prior to completion of torpedo plane attack and continued until about 0920. Both dive and high altitude tactics were used.
7. On CALIFORNIA, General Quarters was ordered just prior to 0800. Material Condition Zed was next ordered. Condition X-ray, with the exception of bolted manhole covers to outer and inner voids, was still in effect from the previous evening. References regarding the number of such voids are
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conflicting. The Commanding Officer, in references (c), (d) and (e), listed three outer and two inner voids on the port side as open. The Salvage Officer, in reference (h), stated that, during salvage operations, covers to six voids were found to "be missing and covers to twelve voids, were found with securing nuts slacked off, all on the port side in way of torpedo damage.
8. Immediately after Condition Zed was ordered two torpedoes struck the port side below the armor belt. One hit at frame 52 and the other at frame 101. The Commanding Officer, in reference (c), reported three torpedoes; two aft and one forward. Reference (d) stated that evidence was conflicting but at least one hit aft in addition to the one forward. Damage done indicates conclusively that only two actually hit, one forward and one aft. Apparently the forward one struck first followed almost at once by the after one.
9. The ship listed to port and flooding forward on the third deck, through the open manholes of the voids underneath, commenced. Flooding aft on the third deck through loose manhole covers and leaky deck seams, started at about the same time. Counterflooding of starboard voids to limit list to 4 degrees port was ordered and begun.
11. About 0820 a heavy shock, similar to that caused by a torpedo explosion, was felt. Although not identified at the time it appears certain that this was the explosion of the bomb which caused underwater near-miss damage to the port bow. All compartments forward of bulkhead 21 on the first platform, and three below on the second platform were flooded immediately. These, plus a few others which flooded more slowly put the CALIFORNIA down by the head by about 3-1/2 feet.13. In the meantime efforts to set Condition Zed on and below the third deck had been abandoned and third deck areas forward and aft in way of the torpedo hits evacuated. Regarding the evacuation of these areas the Commanding Officer, in reference (e), stated as follows: "Damage from torpedo hits prevented additional closures being effected on the third deck and below to any great degree.....this was due to the flooding and fuel oil fumes on the third deck which forced personnel in that area to evacuate it and denied access to the decks below except through the turrets."
14. Four bombs were observed to drop in the lagoon to starboard about 0825. Fragmentation damage to the starboard upper structure and the dish in shell 13 feet above the baseline at frame 52, starboard, were undoubtedly caused by these.
15. At about 0845 (this time was variously reported between 0830 and 0900 but 0845 is believed to be the best estimate) a bomb struck the upper deck at frame 59 about 7 feet inboard from the starboard side. It penetrated the main deck, ricocheted from the second deck inboard and exploded
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blowing a large hole in the main deck above. Fire broke out on the second deck spreading fore and aft up to the main deck. Finally, by 0915, casemates 3, 5 and 7 on the upper deck were in flames.
16. At 0855 light and power were restored. Pressure on the firemain was raised to 80 pounds by running pumps at speeds higher than for which rated. However, the riser through A-611-L vas destroyed by the explosion and not isolated. Three fireplugs on the main and upper decks closest to the fire were thus useless.
17. Earlier, orders to sortie had been issued (these were subsequently cancelled) and CALIFORNIA, insofar as engineering plant was concerned, was ready in all respects to get underway by 0910, using boilers 5, 6, 7 and 8. There was considerable smoke in the forward engine room drawn in from the starboard ventilation trunk, frames 60-62, which had been riddled by fragments on the second deck.
20. A large fire from burning oil on the surface of the water was noted approaching the CALIFORNIA sometime prior to 1000. The prevailing wind pushed the fire onto CALIFORNIA. By 0955 the stern was engulfed. The engineering plant was secured at 1000. At 1002 the Commanding Officer, with the approval of Commander Battle Force, ordered the ship abandoned and personnel departed shortly before the vessel was completely enveloped. However, the wind blew the fire rapidly clear and at 1015 the order was given to return to the ship. Some personnel returned and manned topside stations. Others left the scene to secure additional firefighting equipment.
21. Upon return, the list was about 8 degrees to port and the vessel had settled considerably with a 3-1/2 foot trim by the bow. Assistance from tugs and minesweepers was obtained. Just what time these appeared is unknown but from photographs and action reports of some of the vessels concerned it appears that the first ones did not arrive until afternoon. The records indicate that probably three minesweepers were alongside CALIFORNIA by 1730 and that VIREO moored alongside at 2100. Apparently these vessels furnished the fire-fighting and pumping facilities as there is no record of any portion of the engineering plant being placed in operation after 1000. The fire was extinguished during the night.
22. Boiler rooms Nos. 5 and 7 were flooded for counter-flooding purposes sometime after the return to the ship. An indeterminate number of starboard magazines were partly flooded while pressure was on the firemain between 0900 and 1000. (See paragraph 106).
23. On Monday additional portable pumps arrived although again there is no record of their time of arrival, number or capacity. Continuous pumping capacity appears to have been small, though. This will be discussed more fully in Section V.
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26. By Thursday morning maximum draft had increased to 57 feet indicating that the vessel was embedded about 16 feet in the mud. List was 5-1/2 degrees to port. She stayed in this position until she was floated on 24 March.
27. On 5 April a vapor explosion occurred in way of the forward near miss damage. The patch fitted by the Salvage organization over the hole was ruptured and blown off. Doors and hatches on and below the third deck forward of frame 21 were damaged permitting flooding more extensive than had resulted from the near miss damage. This flooding was controlled by two pumps and the patch was not reinstalled.
29. A discussion of the types of torpedoes and bombs used is given in Section VIII. The conclusions are that the charges of both torpedoes were under 500 pounds and possibly as low as about 337 pounds; and that both the bomb which caused near miss damage to the port bow and the one which struck the upper deck were of the 250 kilogram semi-armor piercing type, carrying 133 pounds of explosive.
30. Summing up the damage that resulted from the two aerial torpedoes, it is noted that torpedo bulkheads Nos. 3 and 4, although deflected, were not ruptured and that No. 5 bulkhead suffered no damage other than a small deflection of the order of 1 to 1-1/2 inches. The third deck over the forward hit was sprung only very slightly with little, if any, leakage resulting. The third deck over the hit aft was sprung to a greater degree with wrinkles about 6-inches deep outboard along the shell. Further, the longitudinal watertight bulkhead above the third deck inboard of the shell suffered almost no damage. The void compartments which were ruptured and flooded because of these two hits would have produced only a small list of the order of 5 to 6 degrees. It is thus apparent that the CALIFORNIA was in no sense vitally injured by these torpedoes.
33. The CALIFORNIA sank because of manholes left open (see paragraph 77) and loose manhole covers on the port side of the third deck and because most of the watertight closure fittings on the third deck and below were open, the ship at the time of the attack being in Condition X-Ray. In many cases these fittings were not closed due to the rapidity with which the compartments were evacuated because of fumes and flooding. (see paragraph 13).
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34. A highly significant fact in reaching the above conclusion is that after the CALIFORNIA had been raised she was kept afloat from 5 April to 9 April and placed in drydock with a draft forward of 41 feet and a draft aft of 39 feet without any external repairs whatever to the underwater damage. Only two pumps forward were in use to limit forward draft to 41 feet.
35. The forward torpedo exploded against the shell at frame 52 on the port side about 17 feet above the keel or about 18 feet below the water. There was a dull explosion accompanied by a heavy shock comparable to that caused by a main battery salvo. There was very little water thrown up externally. Shock broke some light bulbs and damaged an upper port ammunition hoist. No other derangements were observed. Details of structural damage are shown on Plate III and Photos 13 to 17, inclusive.
36. On Photo 14 is shown a remnant of the torpedo air flask in the hole. This is not an unusual phenomenon although it happens infrequently. Actual penetration of the shell by the torpedo prior to explosion is extremely improbable due both to the low striking velocity and the thickness of the plating (15 pounds). There is also no evidence of a delay action firing device. Apparently the inrush of water following the explosion carried the portion of the flask into the hole.
37. The torpedo defense system in this area is shown on Plate III. Aft of frame 48 there are five longitudinal bulkheads inboard of the shell. Forward of frame 48, in addition to the shell, there are only four longitudinal bulkheads. The extreme inner and outer spaces were voids with three layers of wing oil tanks in between aft of frame 48 but with only two layers forward of this point. Voids were empty and tanks were full when damage occurred. Longitudinal bulkheads are numbered 1, 2, 3, 4 and 5 beginning outboard and not including the shell.
38. The shell and Number 1 bulkhead were blown open by the explosion. Number 2 bulkhead deflected severely and had two fragment holes, the largest of which was about 15 inches in diameter. Numbers 3 and 4 followed closely the deflection of Number 2 but were not ruptured. Number 5 was undamaged except for a slight deflection of about 1 inch in way of transverse bulkhead 53 which is between numbers 4 and 5 bulkheads. The third deck outboard was wrinkled slightly with maximum depth of wrinkles (1-1/2 inches) between frames 48 and 56. The longitudinal watertight bulkhead on the third deck between frames 48 and 55 was lifted about 1/4 inch maximum and some rivets in the connecting angle were loosened. The bulkhead within the above limits was slightly dished. Outer lower corners of transverse watertight bulkheads 48 and 53 were lifted about 2 inches from the third deck and wrinkled at the
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bottom for a height of 9 inches. Bulkhead 53 was the only bulkhead damaged inboard of the longitudinal bulkhead. Wrinkles in it extended about 5-1/2 feet inboard of the longitudinal bulkhead.
39. Details of damage are shown on Plate III and Photos 13-17, inclusive. Shell plating just above the bilge keel was split in two places dovn to the bilge keel. In general, however, plating at the edges of the hole in the shell was not blown outboard, as is usually the case with an outboard void, but was blown definitely inboard. The hole proper measured about 24 feet long by ten feet high. The top of the hole was bounded by the lower edge of the armor. The armor shelf was twisted and ruptured although the armor suffered no displacement. Indentation of the shell extended over an area 64 feet long by 16 feet high, between frames 45 and 61. There was no tendency to blow out the bottom, as in the case of NEVADA and SARATOGA, but instead it was pulled very slightly upwards by bulkheads 2, 3, and 4 which did not pull loose at the shell.
40. The system of truss bracing between shell and number 1 bulkhead was destroyed between frames 47 and 60. In many cases the outboard ends of the channels punched through the shell. Transverse bulkhead 53, between numbers 1 and 2 bulkheads, oddly enough, was not demolished although badly crumpled. Transverse bulkheads and floors between numbers 2 and 3 bulkheads and numbers 3 and 4 bulkheads remained surprisingly intact although somewhat wrinkled in a vertical direction. Transverse bulkhead 53, between numbers 4 and 5 bulkheads, was smashed almost flat.
41. Apparently numbers 2, 3 and 4 bulkheads moved inward as a unit as a result of the floors on each frame locking them together. The heavy vertical I beam stiffeners on the inboard side of number 4 bulkhead together with transverse bulkhead 53 absorbed a large part of the energy of explosion.
42. The after torpedo struck and exploded at about frame 101, port, about 18 feet below the waterline and 17 feet above the keel. The explosion was dull and heavy. It occurred very shortly after the forward one.
43. Details of structural damage are shown on Plate IV and Photos 19 to 22, inclusive. The torpedo defense system is identical with that in way of the forward hit. Distribution of liquid prior to damage was also similar.
44. Damage resulting from this torpedo was almost a duplicate of that caused by the forward torpedo. The shell and number 1 bulkhead were blown open. Number 2 bulkhead deflected severely and had two fragment holes. Numbers 3 and 4 bulkheads deflected but did not rupture. Number 5 bulkhead was undamaged although it, as in the case of the forward torpedo damage received a small permanent deflection of 1-1/2 inches. In addition, number 5 bulkhead had an 8-inch bulkhead fitting on the fuel oil filling line puncture the bulkhead just below the first platform level at frame 102. No buckling of the first platform occurred. The third deck at shell, however, was quite severely buckled. The buckles were of the order of 5 to 6 inches deep and parallel to the shell. Transverse watertight bulkheads 100 and 103, on the third deck were lifted off the deck about 2 inches outboard of the longitudinal bulkhead and wrinkled at the bottom for a height of 9 inches. The outboard longitudinal bulkhead on the third deck was pulled very slightly from the deck between frames 100 and 104 and was slightly dished.
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While watertightness was impaired, damage was so minor that repairs were made by welding the connection angle in place and caulking rivets. The bilge keel was ripped off below the hole in the shell. The failure of riveted seams was slightly more extensive than forward. Again there was no tendency to blow out the bottom plating. Armor suffered no derangement.
45. Photo 19 shows the sea chest for the flood valve to D-166-V punched through the shell and the sea chest to C-126-V completely destroyed. These, of course, had no effect on internal flooding, but do illustrate the danger of such fittings. Magazine sea floods are not fitted in CALIFORNIA.
46. The excellent performance of riveted connections in these areas is worthy of comment. For example, a long fore and aft tear occurred in the shell plating, frames 47 to 49-1/2, just below a seam which remained intact. This is shown on Photo 13. In addition the top and bottom connections of the longitudinal torpedo bulkheads remained intact, although the deflection of the bulkheads must have exerted an enormous pull on the rivets of the angles. The fact that number 2 bulkhead did not rupture at seams and butts is particularly interesting as previous experience* has indicated that this bulkhead would be expected to rip extensively, particularly at boundary connections. Evidently design and workmanship were of the highest order.
47. Discussions of the size of the charge carried by the torpedoes and the distribution of liquid will be found in Section VIII.
49. Above water the catapult on top of Number III turret was damaged slightly by fragments, the outboard bulkhead of number 9 casemate had a hole, two by four inches, near the top and the shell was holed at Frame 58 about 18 inches above the second deck. Size of this latter hole was three by eight inches. There were also several small holes through the top portion of the smokepipe which appeared to have been caused by bullets from a strafing attack. Small holes in the starboard windshield of the navigation bridge could have been caused by both bullets from strafing and small bomb fragments.
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at frame 52. See Photo 28. The transverse bracing between shell and number 1 bulkhead was crushed, but number 1 bulkhead was undamaged except for a slight deflection.51. Several bombs were reported to have fallen and exploded off the port bow. At least one of these caused rupture of the shell and numerous dents fore and aft of this rupture indicate that additional explosions were the cause.
52. The entire damaged area of the shell extended from frames 2 to 21 and from the third deck down to the turn of the bilge. A large hole was opened in the side from Frames 11 to 15 between the first and second platforms. Shell plates were sheared through the vertical line of tapped rivets on armored bulkhead 15 and "D" strake was pushed in to the centerline. Rivets in the seams connecting "D" strake to lower and upper strakes had their countersunk points pulled through. The seam joining "C" and "D" strakes crosses the second platform at bulkhead 15 and this intersection seems to have provided a good starting point for rupture of the seam forward of bulkhead 15. Details of riveting failure are shown on Photo 25. Frames 12, 13 and 14 were sheared at the first and second platforms. Frames 10 and 11 were buckled. Dents in the shell between frames existed forward to Frame 2 and aft to Frame 21.
53. The second platform was slightly wrinkled between bulkheads 9 and 15 but not otherwise damaged. Bulkheads 9 and 5 were also wrinkled, the worst areas occurring between the first platform and third deck. The first platform was ruptured at shell and bulkhead boundaries. Armored bulkhead 15 was undamaged. Aft of it the inner longitudinal bulkhead of oil tank A-204-F, full at time of damage, was ruptured at the seam midway between first and second platforms. Deflection of the shell transmitted shock through the full tank and apparently caused the rupture.
54. Damage caused by the bomb explosions was aggravated by the vapor explosion in this area during salvage operations. This explosion will be described in Section IV. A large part of the damage to the first platform between bulkheads 5 and 14 seems to have been caused by the vapor explosion rather than by the bomb. The third deck was relatively undamaged, until the vapor explosion. Hatch covers on first and second platforms, between frames 13 and 14, were reported to have been ruptured and blown off by the bomb explosion.
55. One bomb struck the upper deck at frame 59, starboard, about 7 feet from the side. It penetrated the upper deck, traveled slightly aft and inboard, passed through partition bulkhead 60 on the main deck, pierced the main deck just aft of frame 60, struck the second deck at frame 60-1/2 about 8 feet inboard of the side and ricocheted up and inboard to explode in A-611-L. Holes in the upper and main decks are shown in Photos 30 and 31 and are about 14 inches in diameter.
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56. The bomb passed through about 27.5 pounds of medium steel and 50 pounds of H.T.S. prior to being rejected by the second deck (two courses of 70 pound S.T.S.). Total travel after striking the upper deck until explosion was between 18 and 22 feet.
57. On the second deck watertight bulkhead 51 was blown out, the junior officers' country aft to frame 71 destroyed and crews space A-611-L, starboard, riddled by fragments. Vent trunk A-611-T, frames 62 to 64, was punctured in numerous places but did not collapse.
60. Destruction of pipelines and ventilation ducts on main and second decks was general between frames 54 and 70. The second deck in the vicinity of frame 60 had previously been pierced by several pipe lines. On removal, the holes had been plugged by plates welded in the two 70 pound courses. One such plate was struck by a fragment and knocked out. Existing pipe lines and small ventilation ducts were carried away leaving holes in the second deck as large as 6 inches in diameter. The deck was scored in some places, in addition to the dent caused by impact at frame 60-1/2, but suffered no other damage.
61. The shell between second and main decks was pushed out a slight amount between frames 55 and 65 and the rivets through the outboard bounding angles, joining the second deck to the shell, were strained and loosened.62. The bomb explosion was followed immediately by fire. This is described in Section IV.
63. The explosion of the bomb in A-611-L on the second deck was followed immediately by fire in that area. It swept up through the hole in the main deck and traveled forward and aft. Efforts to extinguish the fire were unsuccessful up to the time the CALIFORNIA was abandoned. Water and CO2 were used with little effect. Finally, A-611-L, second deck and A-705-L, main deck, were closed and isolated insofar as blast damage permitted.
64. One riser, at frame 67 second deck starboard, was destroyed and never isolated. This eliminated the use of fire plugs at frame 67 on the main and upper decks. Dense smoke and heat on second and main decks prevented efficient utilization of other fire plugs forward and aft and on the port side although 80 pounds pressure at the pumps was available for the firemain from 0855 to 1000.
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65. While the vessel was abandoned the fire spread rapidly. Upon return of the crew there was little which could be done immediately as there was no pressure on the fire main and C02 extinguishers were exhausted. Efforts to smother the fire by closing the affected compartments confined it between frames 22 and 87 on the main deck and frames 30 and 93 on the second deck.
66. During the afternoon, fire extinguishers, both foam and CO2 were obtained and used effectively. As little water as possible was used to prevent further list, which at one time, had approached 16º. Firefighting facilities of the minesweepers were, however, used to a moderate degree. Thus the fire was extinguished primarily by the smothering and the use of chemicals rather than by large-scale employment of water. It was finally and completely extinguished some time Sunday evening.
67. Some time before 1000 a large surface oil fire, pushed by the prevailing wind, was noted bearing down on CALIFORNIA. It had originated at ARIZONA and WEST VIRGINIA where great quantities of oil were released from ruptured tanks. The size of this fire is shown in Photos 1, 2 and 3. Shortly after 1000 the vessel was completely engulfed by flames and smoke. By 1015, however, the fire had blown clear.
68. The damage done by both fires was surprisingly small. The fire resulting from the bomb explosion warped partition bulkheads on the main deck, caused slight buckles in main deck plating and seems to have contributed to the buckling of the upper deck in Casemates 3, 5 and 7. The surface oil fire blistered paint on the shell up to the weather decks and burned exposed canvas and other readily ignited materials, but does not seem to have started any serious fires aboard, as were caused on the TENNESSEE.
69. The most important effect of the fire following the bomb explosion was the restriction of damage control efforts on second and third decks during the vital period from 0900 to 1000. Likewise, the surface oil fire resulted in abandoning ship at a critical time. With regard to the machinery plant the Commanding Officer, in reference (c), reports as follows: "The engineering plant suffered no mechanical or electrical casualty that would have prevented its operation during the engagement. The fire in A-611, however, produced such heat and smoke in the forward engine room as to make its operation possible only with great difficulty." With light and power not available (see paragraph 10) and smoke infiltrating throughout the second and third decks it was difficult to penetrate below in the damaged and flooding areas. Twenty-eight of the old type oxygen rescue breathing apparatuses were reported available to the repair parties. Although these were used, it is reported that they were insufficient in number.
B. Vapor Explosion
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71. In view of precautions taken to minimize danger in this area from gasoline fumes an investigation was made to determine if sabotage could have been a possibility. A very thorough inquiry failed to find any evidence of a fixed charge of explosive.
72. The investigation brought out that fuel oil vapor and hydrogen sulphide gas could have been present in compartment A-201-A. Gasoline and gasoline vapor from A-102-Gas had been present at various times although just a few days before the explosion A-102-Gas had been entered and all free gasoline removed from the partly flooded compartment by the use of an air-driven skimming pump. At the time of the attack about 3000 gallons of gasoline had been in the tanks. Most of it had disappeared by 5 April, apparently going off through ruptured filling lines. Several reports had been made during the morning to the effect that A-201-A and A-303-A were gas free. In addition, there was present an energized portable electric light lead down the trunk to A-201-A with a naked bulb on the end.
73. From the reports of men on the main deck near the top of the trunk at the time of the explosion and from the damage done it appears that the explosion occurred in A-201-A and flame vented through the centerline hatch at frame 13 into A-303-A where other gases were ignited causing flame to vent up through the trunk just forward of frame 14 to the main and upper decks.
74. The composite wood and steel patch fitted over the near-miss hole in A-23l-A was blown off and, oddly, had a square hole blown in it just above the second platform level. Three 10 by 12 inch timbers were sheared about three feet above the deck to create the hole.
75. Within the ship the first platform was completely ripped loose from bulkhead 9. Transverse deck beams were twisted. Bulkhead 9 received additional damage. The third deck between bulkheads 9 and 14 was pushed up although boundaries were not severed. Third deck beams were twisted and the deck was open and later leaked through seams and rivets. Trunk A-302-T was ruptured at the first platform and pushed aft and to port. The hatch on the third deck could not be dogged tight because of warping of the coaming. Bulkhead 14 on the first platform was strained and seams sprung so that A-304-A flooded from A-303-A as well as from port shell seams at the first platform level which were reopened. Bulkhead 5 received additional damage.
A. Condition Prior to Damage
77. At the time of damage material Condition X-ray was in effect, set from the evening before, with the exception of certain manhole covers on voids. These were off for inspection and maintenance purposes. Mean draft was 35'-9" which put the third, or damage control, deck about 5' below the waterline.
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78. The Commanding Officer, in references (c), (d) and (e), reported that third deck manhole covers to port outer voids A-184-V, A-186-V and A-188-V, frames 32 to 50, and those to port inner voids A-146-V and A-148-V, frames 33 to 45, were off at the time of attack. But the Salvage Officer, in reference (h), reported that during salvage operations six port covers were found to be missing and twelve covers were found with nuts slacked off. Of these latter, three had gaskets blown out. The locations of 17 of these 18 covers were not precisely determined during salvage operations (because they were replaced by arduous diving operations) other than that all were in way of either damaged or flooded voids on the port side. The eighteenth was the cover to outer void C-126-V. This was identified after raising the vessel by the fact that divers had made it tight by wedges around the periphery driven between the cover and the deck. The cover itself was dished up a total of 3 inches. This excessive deflection was apparently due to blast of the explosion directly underneath (manhole is between frames 103-104) aided by slackness of the nuts.
80. These manholes are rectangular in shape with a clear opening of 15" x 23" and are of two types; flush covers with bolts through the lower 20 pound medium steel course and raised covers with bolts tapped into both the lower and the upper 40 pound STS courses.
81. At the time of attack all wing fuel tanks were full and all voids were empty. Thus, the torpedo defense layers were in the condition designed for maximum underwater protection.* As explained in paragraph 37 and by reference to Plate VII it will be noted that forward of frame 48 there are only four layers of protection. However, the forward torpedo impact at frame 52 was sufficiently aft so that damage did not extend inboard to number 4 bulkhead forward of frame 48. Accordingly, to both torpedoes there was opposed an outer void, 4 feet thick, three wing fuel tanks each 3 feet thick, and an inner void, 4-1/2 feet thick, or a total of 17-1/2 feet of protective layer.
82. In references (c), (d) and (e) the Commanding Officer emphasized that Condition Zed was ordered set immediately after General Quarters but that torpedo explosions followed so closely on the order that almost no time was available for execution. Thus, very few Zed closures on and below the third deck were made prior to damage although the number of closures effected aft was greater than forward. Precise knowledge of the location and number of such fittings actually closed is lacking. During salvage operations all such fittings were opened to facilitate drainage to pump suctions.
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outboard compartments flooded by the forward torpedo explosion were closed. However, this implication is contradicted by paragraph C(l6) of the same reference which states, "It is known that compartments A-509 and A-518 commenced to flood on the port side with fuel oil and salt water immediately after the explosion of the torpedo directly outboard of them". The watertight longitudinal stepped bulkhead outboard and to port of the above compartments (which extend from frame 30 to 57) received very minor damage. Bureau records indicate that no ventilation ducts pierce this bulkhead and, further, that the only pipelines penetrating it are a 1/2 inch saltwater line and a 3/4 inch fresh water line, both to A-520-E, close under the second deck and abaft frame 48. The above, together with other evidence of rapid flooding on the third deck and below, the darkness prevailing within five minutes of the forward torpedo explosion and the almost immediate evacuation of this area reported in references (c) and (d), lead to the conclusion that several doors and hatches on the port side of the third deck between frames 30 and 57 must have been open at the time of damage and were not subsequently closed.
84. In way of the after torpedo hit the situation with respect to Zed closures and doors and hatches seems to have been somewhat better although reference (c) reports an abnormally large number of compartments leaking and flooded as a result of this hit. Some of these are completely outside of the range of damage and could only have flooded through open Zed closures and watertight doors.
85. On Plate VII tanks full prior to damage are marked in red. Probable flooding before 1200 attributable to structural damage, missing or loose manhole covers, fractured piping below the third deck and open ventilation ducts or trunks on and below the third deck is marked in green. This estimate is based on inspection of damaged structure, piping, ventilation ducts and a study of all reports and evidence. Subsequent progressive flooding at a slower rate eventually filled all compartments up to the upper deck. Yellow on Plate VII indicates counter-flooding by the ship's force.
86. The forward torpedo explosion at frame 52 ruptured outer voids A-188-V, A-190-V and B-156-V, extending from frame 44 to 62. Outboard wing tanks A-174-F, A-176-F, A-178-F and B-146-F, frames 4l to 64, were also opened to the sea. Outer void A-186-V, frames 38 to 44, apparently flooded from the third deck down through the open manhole in A-514-A a little later inasmuch as bulkhead 44 separating it from A-188-V received no damage other than a slight dish. Inner wing tank A-162-F was contaminated through the two splinter holes in number 2 bulkhead. Inner wing tanks A-160-F and A-164-F were contaminated by fractured sluice valves and some leakage through bounding angles at top and bottom peripheries. Inner wing tank A-150-F, bounded by numbers 3 and 4 bulkheads, was contaminated from fractured or leaky sluice valves. Inner
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void A-148-V, frames 45-51, flooded down through an open manhole in A-516-L and also from a fractured 4-1/2" oil line 8 feet from the bottom and which pierces both numbers 3 and 4 bulkheads. Inner voids A-136-V and A-138-V, frames 48 to 59, flooded slowly through 4-1/2" fuel lines leading from the 8" main through number 4 bulkhead. The 4-1/2" lines ruptured at the flange at the stop valve. (Photo 17).
87. Immediate flooding of compartment A-516-L through the open manhole and loose covers on the third deck occurred. B-504-A and A-520-E must have flooded quite rapidly through transverse bulkheads 48 and 53 which had lifted about 2 inches off the deck. Possibly the manhole cover to A-190-V in the former was loose and permitted flooding. A small amount of flooding into all three of these compartments through the third deck at the shell probably also occurred as on the SARATOGA*.
88. At this point, roughly 0815, the CALIFORNIA had a port list of probably 5-1/2 to 6 degrees, putting the third deck on the port side about 8 feet below the waterline. Counterflooding was started at this time.
89. The ensuing spread of water from the forward torpedo explosion is difficult to establish from this point. The following is a reconstruction, based primarily on a study of the vessel's arrangements:-
(1) A-518-L and A-509-T began to flood rapidly probably as explained in paragraph 84, through open doors in the longitudinal bulkhead. Flooding through the longitudinal bulkhead other than through doors could only have been very slow. Flooding of these spaces was reported in references (c) and (d). Passage B-502-T must have also flooded at about the same time and for the same reason.
(2) Electrical storerooms A-512-A and A-514-A appear to have also flooded through open or loose doors from A-509-T.
(3) With A-518-L and A-509-T flooding, water and oil spread fore and aft on the third deck and down to the first and second platforms primarily through open ventilation ducts. The systems chiefly involved were numbers 28, 29, 30, 31 and 32, all of which have fans and motors on the third deck between frames 38 and 60. These are large systems which supply magazines, radio rooms, IC room, Central Station and Plotting Room on the first and second platforms. Natural exhaust trunks from some of these spaces also terminate above the third deck in this area and flooding down them must have occurred as the level on the third deck increased.
(4) Lower handling room trunk A-228-1/2-M started to flood about 0820. It is probable that this flooding occurred from void A-136-V through bulkhead 48 when the void was half filled inasmuch as an 8" firemain, a 3" fresh water main and a 2-1/2" distilling main pierce this bulkhead about 15 inches below the first platform level. All of these lines
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were damaged in A-136-V although bulkhead 48 was structurally tight. It is worthwhile noting here that none of these lines are equipped with closures at bulkhead 48. Plate VIII shows this particular arrangement.
(5) The Main Radio Room, A-332-C, first platform, frames 48 to 55, port, was reported flooding and abandoned at 0820. Very likely this was from open ventilation trunks as explained in (3) above. Although this space is directly inboard of number 5 bulkhead in way of the torpedo explosion at frame 52, number 5 bulkhead was not damaged and is not pierced by any pipe lines between bulkheads 48 and 60.
90. After 0830 flooding seems to have been general but slow below the third deck and forward of bulkhead 60. The Commanding Officer, in reference (c), reports the opinions of observers that "the spread of liquid was chiefly by means of ventilation ducts and further attributes the spread to either open deck and bulkhead fittings or ruptured ducts. Later examination, however, revealed no ruptured ducts on or below the third deck. System 21 on the second deck, starboard, frames 52-65, was destroyed by the bomb explosion and parts of the corresponding port system, Number 22, were similarly destroyed. These had no effect on flooding until the second deck was submerged.
91. The after torpedo explosion occurred at Frame 101 below the armor belt. Outer voids C-124-V, C-126-V and D-166-V were ruptured as were outer wing tanks C-120-F, C-122-F, D-152-F and D-154-F. Outer void B-166-V must have flooded slowly through bulkhead 92 which was dished and had bounding angles at the peripheries loosened. Middle wing tank C-118-F was rapidly contaminated through the two splinter holes in number 2 bulkhead as well as leaky peripheries and damaged sluice valves. Middle wing tanks C-116-F and D-144-F were contaminated by leaky boundaries and sluice valves, as were inner wing tanks C-112-F, C-114-F and D-130-F. Inner voids C-110-V and D-126-V flooded primarily because of ruptured fuel oil lines (4-1/2" diameter) piercing number 4 bulkhead.
92. On the third deck, D-502-E started to flood quite rapidly through the loose manhole cover over void C-126-V and the third deck at shell. Fuel Oil Relay Tank Room, C-510-F, also started to flood immediately. This occurred from at least three sources; first, under bulkhead 103 from D-502-E, second, up through the two fractured 8" fuel oil filling lines which lead from voids underneath up and into the relay tank (see Plate VIII) which was open at the top, and third, through the third deck at shell.
93. In addition to the above spaces the Commanding Officer listed the following as either leaking or flooded due to this hit: B-164-V, C-106-E, C-108-V, C-504-E, D-501-L and D-506-A. Examination in drydock revealed no apparent reason why outer voids B-164-V and C-108-V should have quickly flooded.
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Boundaries were intact, no ruptured pipe lines existed and third deck over was undamaged. The Port Thrust Block Room, C-106-E, flooded through a fractured 8" fuel oil filling line, and around the bulkhead spool, which pierces number 5 bulkhead just aft of frame 102 under the first platform. This line is shown on Plate VIII. C-106-E did not flood rapidly and, when evacuated, the overhead hatch into C-304-A on the first platform was dogged tight. The rapid flooding of C-504-E is difficult to explain as no ventilation ducts or major pipe lines pierce the compartment and further, the passage inboard, C-506-T, does not seem to have flooded prior to abandoning ship at 1000. Possibly watertight bulkhead 93 leaked through cable stuffing tubes but such leakage would have been slow. It is possible that D-501-L and D-506-A flooded from D-502-E as the after transverse and the longitudinal bulkheads of the latter space are pierced by ventilation ducts. Any leakage under the longitudinal bulkhead could only have been very slow. Although the ventilation ducts have proper closure fittings they could not have been closed. It is also possible that the door from D-501-L to D-502-E was loose or open. Rapidity of flooding indicates this.
94. The flooding of D-501-L was as disastrous to the after portion of the CALIFORNIA as was the flooding of A-518-L and A-509-T forward. Four large ventilation fans are located in this compartment and supply air for the first and second platforms and hold from bulkhead 103 aft. With many watertight fittings open spread of liquid down must have been quite rapid.95. Reference (c) states that the Center Motor Room, C-102-E, flooded through a ruptured ventilation duct. Flooding must have been after 1000 inasmuch as reference (c) also states that the engineering plant was ready in all respects for getting underway from 0910 to 1000 using the after four boilers. The engineering plant was secured at 1000 when the ship was ordered abandoned. No ruptured ventilation duct was found on drydocking. However, as shown on Plate VIII, the 8-inch filling line, which caused the Port Thrust Block Room to flood, also pierces the longitudinal bulkhead separating the Motor and Thrust Block Rooms. The expansion joint just outboard of this bulkhead and the bulkhead fitting were pushed inboard when number 5 bulkhead deflected and thus caused the bulkhead to be fractured around the fitting permitting slow flooding of the Motor Room. Further, with respect to ventilation, a 6-inch exhaust duct from the Fuel Oil Relay Room taps the centerline exhaust trunk to the Motor Room. This arrangement is shown in detail on Plate VIII. Eventual rapid flooding of the Motor Room through this source must have occurred when the head of water approached the main deck level. This exhaust duct is fitted with two watertight closures, as shown, neither of which could have been closed.
D. Flooding as a Result of Bombs (Plate VII)
96. The large hole opened in the port bow plating and the numerous leaky seams, fore and aft of the hole, resulted in the immediate flooding of A-2-V, A-l-V, A-103-A, A-201-A, A-303-A, A-204-1/2-A, A-104-A, A-304-A, A-102-Gas and A-301-A. If the forward peak was empty it probably flooded quite rapidly as bulkhead 5 leaked from the second platform to the third deck. The third deck appears to have been tight as no damage to it was apparent when the vessel was first raised.
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97. Small arms magazine A-201-1/2-M did not flood immediately as reference (c) indicates that ammunition was withdrawn from it after the damage to the bow occurred. However, it was known to be flooding before 0900. The cause is not clear but probably the port longitudinal bulkhead leaked under the large head of water imposed. The flooded spaces listed in paragraph 96 were sufficient to put the bow down 3-1/2 feet and this created an average head of more than 25 feet on the bulkhead in question.
98. Watertight integrity forward of about frame 24 seems to have been satisfactory. The third deck, particularly, gave a good performance. Probably all forward spaces, being in a little used portion of the ship, had not been opened during the early morning.
E. Damage Control
100. The brief interval between the ordering of Condition Zed and the torpedo explosions did not permit closing the CALIFORNIA. Flooding was not confined because of the open and loose manhole covers and the open condition of watertight fittings and doors and hatches. Flooding could not be controlled initially because power for pumps was lost almost immediately and was available again only from 0855 to 1000.
101. The immediate flooding of voids from the underwater explosions caused a port list of 5 degrees. The list continued to increase as water flowed onto the third deck. Counter-flooding to limit list to 4 degrees was ordered and the starboard after voids were opened.
102. Third deck compartments A-518-A and A-509-T, forward, and A-501-L, aft, began flooding with fuel and water soon after the explosions. While this was occurring and repair parties were attempting to stem the flooding light and power were lost plunging the third deck into gloom. Auxiliary lighting was reported in reference (e) to be inadequate. The flooding oil fumes and darkness were the causes given for evacuating vital third deck areas with Condition Zed largely incomplete. The time of evacuation is not given in the references but it seems to have taken place within 15 or 20 minutes of damage.
103. Damage to the port bow was received about 0820. Flooding under the third deck occurred immediately. Transverse bulkheads 15, 18 and 20 and the third deck limited flooding, at least for some time.
105. The bomb hit at frame 59 about 0845 riddled the main deck and destroyed watertight integrity on the second deck. The fire, which started immediately, further handicapped damage control efforts to close the vessel on second and third decks between frames 48 and 75. Smoke was drawn into the forward engine room via ruptured trunks.
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106. About 0850 light and power were restored. Damage control measures taken and results obtained between 0900 and 1000 were not reported beyond general statements. All that is definitely known in this period is that counterflooding of starboard voids continued, the port thrust block room, C-106-E, started to flood and was closed and abandoned and that an indeterminate number of starboard magazines (valves to which had been opened during the period of no pressure on the fire main) were partly flooded. The necessity for flooding these was not reported. Main and secondary drainage systems were not used because valves in the vicinity of damage were not accessible and could not be opened and in addition it was thought dangerous to dump oil and water in unknown quantities into the bilges.
108. At 1015 the fire had cleared. The order to abandon ship was canceled and some personnel returned while others remained on Ford Island to attempt to gather firefighting equipment and other gear. Upon return, the CALIFORNIA had a list of 8 degrees and the fire was burning with new vigor.
109. Subsequent to 1015 the center motor room flooded from leakage around the 8-inch bulkhead fitting and through the ventilation trunk. Later, boiler rooms 5 and 7 were flooded as a means to reduce list. Plate VII shows in yellow the spaces known to have been counterflooded. At least 1758 tons of water were admitted. This was sufficient to correct a list of 16º port and put the vessel 26 inches down by the stern.
111. Some time in the early afternoon the first minesweeper arrived. By 2100 four were alongside. The fire was extinguished Sunday night. Pumping from the minesweepers seems to have been ineffective due to frequent interruptions.
113. In reference (c), the Commanding Officer estimated that the average number and size of suctions maintained during the period of sinking was about eight 6" and four 3". This seems to be a high estimate. The Salvage Officer, who eventually floated the CALIFORNIA, on the basis of conditions found during unwatering, gave as his opinion that sinking would not have occurred had a few pumps, of the size subsequently used, been available. Rough calculations show that approximately 12000 tons of water, in addition to that pumped out, entered the vessel between Sunday morning and Tuesday afternoon when draft approached 5 feet. This is approximately equivalent to that which would enter through a 4-1/2" diameter hole located a few feet below the armor belt.
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114. From the above and from the records it appears that the sinking of the CALIFORNIA would have been avoided if more closures on the third deck could have been made and if more pumps had been available during the 48 hours after damage. Thus water was permitted to infiltrate through open valves and fittings, mainly in ventilation ducts, fuel oil lines and, later when draft approached the second deck, through plumbing drains. Infiltration was quite slow when it is considered that about four days elapsed before the final position was approached.
116. The first of these was the decision, followed later by successful execution, to float the CALIFORNIA without using patches over the torpedo holes. Once the vessel was drydocked, it was apparent that such procedure was by far the easiest and quickest as there was actually almost no inflow of water due to structural damage when such damage had been isolated by closing surrounding boundaries using existing fittings. At the time the decision was made, though, underwater damage was assumed to be greater than it was. Diving operations to replace missing manhole covers and tighten others was a tedious job, but one which was expeditiously accomplished.
117. Another was the design, construction and placement of the wooden cofferdam around the maindeck and on the starboard side of the upper deck. The cofferdam is shown in Photos 7, 8 and 9. The use of the cofferdam, instead of standpipes down to hatches for pump suctions, was made necessary by the head of water on the main deck. This head, approximately 17 feet on the port side, would have resulted in collapse of the main deck if the vessel had been unwatered from below by stand-pipes without shoring the deck. Considerable difficulty would also have been encountered not only in making the deck tight, but also in shoring it sufficiently from below. The cofferdam was ingeniously designed and braced. It was placed in a remarkably short time.
118. The vapor explosion which blew off the patch over the near-miss bomb hole would have again placed the vessel in jeopardy if two large pumps had not been quickly available and if the flooding had not been quickly limited by closing doors and hatches. As it turned out, replacement of the patch was not necessary to safe docking. This is particularly noteworthy because the damage from the explosion resulted in considerably more flooding than from the near miss on 7 December.
119. Pumping operations were started when manholes were closed, broken pipelines secured and isolated and the cofferdam placed. About three days were required to float the CALIFORNIA. Pumping from the interior commenced on 21 March after the main deck had been cleared of water. The vessel floated when the water level inside was at about the second deck level. The mean draft at that time was roughly 45 feet. Draft was further reduced by pumping until 5 April when the vapor explosion occurred.
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causing loss of some of the buoyancy which had previously been gained. Mean draft on docking was about 40 feet.
120. Possibly the best indication of the ability of the CALIFORNIA to absorb the damage sustained without serious effect is the fact that she was drydocked without any underwater repairs whatsoever and with the use of only two pumps on the forecastle.
122. A most formidable part of the repair job was the simply described one of cleaning. Oil flooding on and above the third deck was complete. The quantity of mud and oil in way of the torpedo and near-miss bomb damage was considerable. More than 200,000 gallons of loose oil were removed prior to docking. The resulting mess and filth in all compartments was indescribable. The magnitude of the job can best be explained by stating that after four months of work by several hundred men only about half the job was done.
123. Underwater repairs were accomplished, in general, by cutting out all damaged structure and replacing it with welded sections. Thus, torpedo bulkheads back to and including number four, were removed by burning. A considerable number of the plates in numbers 2, 3, and 4 were saved and rerolled. The bulkheads, shell and lower armor shelf were largely prefabricated in the shop. All torpedo bulkhead plates were joined by welding using butt joints for both horizontal and vertical connections. All lines of rivet holes and joggled seams on plates to be reused were removed. Shell plates were joined using vertical strakes with flush butts and lapped seams. In general, final connections to undamaged structure were made by welded butt joints, held about six inches clear of existing riveting. In some few cases plug welds were employed, chiefly where existing angles or beams had to be attached to new plates. Very few existing rivets were loosened. These were either caulked or welded over when found on test.
125. In way of port near miss bomb damage the shell plating was replaced by welded structure. The completed shell is shown in Photo 27. Photos 18 and 23 show the completed job in way of torpedo damage.
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127. The starboard near-miss bomb damage was repaired by removing dished shell plates, straightening and reinstalling on frames. The trussed structure here between shell and number 1 bulkhead was renewed for the few frames which were crushed.
128. Description of the rehabilitation of the electric drive main propulsion equipment is beyond the scope of this report. Suffice it to say that two main motors and one alternator were completely rewound at Pearl Harbor. The two remaining motors and the other alternator were done at Puget Sound during modernization. The job has been described as the largest field job of its type ever to be undertaken in the United States or possessions. The General Electric Co. was in general charge assisted by Pearl Harbor and Puget Sound.
129. Miscellaneous motors were removed and shipped to the Coast for rewinding. Some of these were, of necessity, returned to Pearl Harbor for reinstallation prior to the return voyage. Others were shipped to Puget Sound for later installation.
130. The entire power, lighting, IC and F.C. wiring systems had to be renewed. Switchboards were rebuilt. Advantage was taken to bring wiring up to date using material of present day specifications. Pearl Harbor rewired the vessel below the second deck, except for magazines. Puget Sound completed the wiring above the second deck.
132. It was necessary to strip the ship almost completely of all equipment to allow cleaning and painting of the compartments as well as thorough cleaning and overhaul of the equipment. This included removal of all furniture, fittings, ventilation fans and ducts, shelving, some pipelines, sheathing, etc. Essentially, re-outfitting, starting with a bare ship, was necessary.
133. Some of the technical features involved in the damage and sinking of the CALIFORNIA are discussed in the following paragraphs. The CALIFORNIA has received extensive alterations, in addition to re-outfitting, at Puget Sound. The alterations accomplished include some designed to increase resistance to damage. These will be discussed below where appropriate.
134. Not much is known about Japanese aerial torpedoes but estimates by the Bureau of Ordnance indicate that types carrying moderate charges of about 452 and 337 pounds of explosive have been employed and that that Bureau considers that the torpedo carrying about 450 pounds of explosive is the one in general use by the Japanese. The extent of damage indicates only a moderate charge. The transverse depth of protective layers at points of impact was about 17-1/2 feet, as
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previously described. Bulkheads 3 and 4 vere not penetrated, although severely deflected. Bulkhead 5 received only a minor deflection. Deflection of numbers 3 and 4 was confined between frames 47 and 59 forward and 95 and 107 aft. The damage done, while somewhat greater in longitudinal extent, corresponds in other particulars to that done on NEVADA. It appears logical to conclude that warhead charges used were somewhat less than 500 pounds in weight. (The Type 91 Mod 2 torpedos used by the Japanese at Pearl Harbor featured a 452 lbs. or 205 kg warhead)
B. Liquid Loading
135. The efficacy of a void space inboard of the liquid layer and directly outboard of the holding (in this case number 5) bulkhead is clearly presented here. It will be noted that transverses between numbers 2 and 3 and numbers 3 and 4 bulkheads suffered comparatively little distortion and rumpling, the liquid layers acting as a unit. However, transverse bulkheads 53 and 101, between numbers 4 and 5 bulkheads, crumpled deeply. These and the heavy I beam stiffeners (which deflected considerably) on number 4 bulkhead, seem to have absorbed most of the explosive energy and acted to shield number 5 bulkhead.
136. As a result of this and other war experience the fitting of a blister has been accomplished. It is 8-1/2 feet in width, extends from the turn of the bilge to the main and upper decks and is subdivided by a vertical longitudinal bulkhead. Thus, two additional layers are created on each side of the vessel. The new outer layer will be kept filled to the waterline at all times. The next, or new inner layer, will be kept filled to the 20'-3" waterline and the next inner (between old shell and number 1 bulkhead) layer will be carried completely full. The remaining inner four layers will be voids except the layer between old bulkheads 3 and 4 from frames 57 to 93 which will be utilized for service tanks. The advantages deriving from the new layers and liquid loading are, briefly;
a) Increased freeboard, thus raising both the armor belt and the damage control deck.
b) Less possibility of oil flooding internally in the event of underwater damage. This follows from carrying fuel farther outboard.
(c) A smaller initial list in event of underwater damage. By virtue of having outboard spaces initially full, at least to the water-line, these, when ruptured, will not contribute to the list. Void spaces, being farther inboard, will not create so large a heeling moment when flooded because of the smaller moment arm.
137. The bomb which struck the upper deck traveled through only 2 decks before rejection by the second deck and explosion. The total travel prior to explosion was about 20 feet from point of impact. The extent and nature of the damage
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corresponds closely to that caused on NEVADA, CURTISS and PENNSYLVANIA by 250 Kg bombs. The penetration hole on upper deck was between 13" and 14" in diameter. Blast and fragment effect were considerable. It is believed probable that the bomb was a 250 kilogram "semi-armor piercing" type with delay action fuse. One of this type was recovered at Schofield Barracks shortly after the raid and was found to carry 133 pounds of explosive. *
138. Rejection by the second deck of this bomb is interesting. The armor on this deck, composed of two 70-lb. STS strakes, has long been considered too light for adequate protection against A.P.bombs released from either high altitudes or by dive tactics. The bomb, of course, was not an A.P. type, but considering that it passed through only two comparatively light decks and one thin bulkhead prior to striking the armored deck it is probable that a lighter deck would have been penetrated. It is noted that there was less travel of this bomb prior to explosion than that of any other similar bomb yet studied. Modernization included the fitting of an additional 80 pound STS strake (120 pounds over the magazines) on this deck.
139. While the vapor explosion forward occurred late in the salvage operations it serves to emphasize again the necessity for utmost precautions in guarding against such hazards. Part of the gas hazards existing in that area, however, are not likely to occur except in salvage operations.
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effects of piercing the holding bulkhead with pipes. In this particular case flooding of the port Thrust Block Room was directly attributable to this. The arrangement of this line is shown on Plate VIII. It will be noted that a cut out valve was not installed at the bulkhead and this omission, while of no final consequence, was nonetheless an error. When the line was moved bodily to starboard the bulkhead fitting not only fractured number 5 bulkhead but damage occurred to the expansion joint at the bulkhead between the Thrust Block Room and the Center Motor Room and this bulkhead was also fractured at the bulkhead fitting. It is clear that unnecessary perforations of the holding bulkhead should be avoided. Where such perforations cannot be avoided, recent design practice specifies that the pipes pierce the holding bulkhead either as high or as low as possible and that the pipes be equipped with a closure at the bulkhead.
141. The fuel oil relay tank was a source of a difficulty although it should not have been. The two 8" lines into the bottom of the tank were each equipped with valves operated from the third deck which apparently were never closed. See Plate VIII.
142. The 8-inch firemain and the two smaller water lines which pierce transverse bulkhead 48 just below the first platform level outboard of No. 5 bulkhead were also sources of weakness. Although it has been impossible to trace definitely the flooding from these lines it is extremely probable that 5" lower handling room A-228-1/2-M was flooded from this source. By reference to Plate VIII it will be noted that the portion of bulkhead 48 outboard of the holding bulkhead is, in effect, a continuation of the holding bulkhead. These lines were run outboard in the voids aft of Frame 48 in order to clear the magazines. Furthermore, the level at which run is the height at which maximum deflection of No. 4 bulkhead is apt to occur in the event of torpedo damage. Also, these lines were not equipped with valves at the bulkhead.
143. The General Specifications require that water lines be kept clear of magazines. The reason for this is to obviate the possibility of damage to powder by leaks in the lines. However, it is not the intention of the General Specifications to require that such lines be lead in the damage control voids in lieu of the magazines inasmuch as their presence in damage control voids constitutes a major hazard to the vessel.
144. The entire question of piping in damage control voids has been the subject of much study on the part of the Bureau in recent years. The dangers of running any lines in the damage control voids have been clearly recognized. Accordingly, on recent capital ships, all water lines and even the fuel oil main have been run fore and aft well inboard of the holding bulkhead. The General Specifications will be revised to bring them into agreement with this practice.
145. The design of ventilation systems on the CALIFORNIA followed, in general, the principle of vertical segregation. However, a definite error was made in running the exhaust system from the fuel oil relay room to the trunk on the third deck.
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This assisted the flooding of the Center Motor Room. It would have been better, but not as convenient, to run this system straight up and through the second deck rather than penetrate the longitudinal bulkhead. Of course the system was equipped with watertight closures (which were not closed) but even so, third deck longitudinal bulkheads are highly important members of the damage control system and should not be weakened for any cause.
146. There is no doubt that open ventilation systems assisted the spread of water and oil through the vessel. Other than the case mentioned above, however, there is no evidence that flooding through them was the result of improper design or construction. It must be remembered that the ship was in Condition X-Ray (see paragraphs 13 and 33) when the attack was delivered.
147. On CALIFORNIA some plumbing drains penetrated the shell and armor between second and third decks. Recently, as a general principle, plumbing in deck drains has been raised above the second deck on the larger combatant vessels now in service. The designs of such system in vessels now under construction also provide that such lines pierce the shell at least one deck height above the waterline and even higher as the arrangement of washrooms and lavatories will permit.
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Photo 1: Dec. 7, 1941 - About 0950 - Oil fire, approaching stern.
Photo 2: Dec. 7, 1941 - About 1000 - Oil fire engulfing stern.
Photo 3: Dec. 7, 1941 - About 1005 - CALIFORNIA completely enveloped by fire.
Photo 4: Dec. 9, 1941 - Entering mud - Mean draft 46' - list 6° port.
Photo 5: Dec. 12, 1941 - Well embedded in mud - Mean draft about 56' - list 5-1/2° port.
Photo 6: Dec. 27, 1941 - Starboard side-upper deck about 18" above water - mean draft 57-1/2' - list 5-1/2° port.
Photo 7: March 19, 1942 - Just prior to raising.
Photo 8: March 21, 1942 - Just prior to raising - Details of cofferdam on quarterdeck.
Better quality copies of Photos 9 & 10 have been located and can be enlarged by clicking on them.
Photo 9: April 4, 1942 - Afloat - Mean draft about 4l'.
Photo 10: April 9, 1942 - Crossing Sill No. 2 Dry Dock - 2 pumps forward handling leakage resulting from vapor explosion.
A better quality copy of Photo 11 has been located and can be enlarged by clicking on it.
Photo 11: April 10, 1942 - In No. 2 Dry Dock - Note mudline.
Photo 12: June 7, 1942 - Leaving No. 2 Dry Dock -Permanent underwater repairs complete.
Photo 13: April 9, 1942 - Hole in shell and No. 1 torpedo bulkhead, caused by torpedo explosion at Fr. 52. Note mud.
Photo 14: April 10, 1942 - Same as Photo 13 with mud washed out. Note remnant of Japanese air flask.
Photo 15: April 13, 1942 - Looking forward along torpedo bulkhead No. 2. Frs. 48-55. Note the two holes at Frs. 51 and 52-1/2. These were the only perforations or ruptures in this bulkhead.
Photo 16: April 21, 1942 - View looking forward of torpedo bulkhead No. 3, Frs. 50-59. Bulkhead No. 3 is intact but deflected inboard.
Photo 17: April 25, 1942 - View looking aft, forward torpedo damage. No. 5 bulkhead is numbered. Valve shown is 4-1/2" angle stop valve. The line ruptured at the flange is branch leading outboard to wing oil tank. Frame 52 is point of maximum deflection of No. 4 bulkhead.
Photo 18: June 6, 1942 - Looking forward - Permanent repairs completed in way of forward torpedo damage, Frs. 45-61 port.
Photo 19: April 9, 1942 - Hole in shell and No. 1 torpedo bulkhead. Mud has been washed out. Arrow marks hole in No. 2 bulkhead. Note seachest thrusting through the shell. Frames 96-108
Photo 20: April 13, 1942 - Looking aft, Frs. 99-105 port. Torpedo bulkhead No. 2. Note fragment holes at top of ladder. These were only ruptures in this bulkhead.
Photo 21: April 21, 1942 - Looking aft along torpedo bulkhead No. 2, Frs. 98-105 port.
Photo 22: April 25, 1942 - Looking forward. Bulkhead No. 4, Frs. 103-99 port. 8" fuel oil main in lover right. Arrow indicates intact 4-1/2" high and low suction valve. Fr. 101 is in way of torpedo impact.
Photo 23: June 6, 1942 - Permanent underwater repairs, Frs. 95-109 port, almost complete.
Photo 24: April 9, 1942 - Near-miss bomb damage, port side, Frs. 9-18, between first and second platforms.
Photo 25: April 13, 1942 - Looking aft. Details of bomb near-miss damage between first and second platforms.
Photo 26: April 13, 1942 Looking to starboard along forward side of armored bulkhead 15. First platform over has been deflected down by vapor explosion on April 5.
Photo 27: June 6, 1942 - Permanent repairs to near bomb miss, Fr. 2-21, completed.
Photo 28: April 9, 1942 - Starboard minor bomb damage Fr. 46-57. Note mud line.
Photo 29: June 6. 1942 - Permanent repairs to minor bomb damage, Fr. 46-57, starboard, completed.
Photo 30: Dec. 10, 1941 - Bomb hole, upper deck, Fr. 59, 7 feet inboard of side.
Photo 31: April 10, 1942 - Bomb hole, main deck, Fr. 60-1/2 starboard 7-1/2 feet inboard of side. Looking up from second deck.
Photo 32: April 13, 1942 - Ruptured main deck plating, from bomb explosion below. Starboard side, looking forward from Frame 63.
Photo 33: Dec. 10, 1941 - Ruptured main deck plating, from bomb explosion below. Starboard side, looking aft from Frame 60.
Photo 34: March 22, 1942 - Second deck, starboard, looking aft from Frame 55. Bomb exploded at about Fr. 60 in this space.
Transcribed by RESEARCHER @ LARGE. Formatting & Comments Copyright R@L.
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