There is no photograph of this damage in the damage report and a search of the USN archives did not find any. There are no inconsistencies with BuShip's estimate and, from the shell trajectory; this damage may have been caused by Kirishima's secondary battery during the 0101 to 0110 time period.

The first inconsistency in BuShips' report for this hit is that it concludes that the hit was made by an 8-inch AP projectile, yet the shell actually detonated on impact, which would normally indicate a nose-fuzed projectile. There is no evidence in any Japanese or USN document that the authors have found that would support a conclusion that Japanese AP projectiles of any caliber would detonate on impact on light plates. In fact, with their long fuze delay of 0.4 seconds and very small burster charge (6.85 lbs TNA), the Japanese 8-inch Type 91 AP projectile was incapable of producing the amount of damage that is documented for this impact. For these reasons, the authors of this essay have concluded that the hit must have actually been from an HE projectile.

The next inconsistency in BuShip's original report is that it has Hit 2 striking on 0.75-inches of STS steel with the six lower holes being made in HTS steel (see Figure 123). However, the Builder Plans for South Dakota show that the sheer strake where Hit 2 landed was made from HTS steel. In order to have a complete analysis in case the Builder Plans are in error, we will consider both types of steel in our damage calculations below.

The first step is to determine the caliber of the projectile that made this hit. During the battle, Atago fired six 8-inch HE shells and Kirishima fired twenty-two 14-inch HE shells. ¹³ Both of these used instantaneous nose fuzes, which mean that both would have exploded on impact against plates as thin as 0.25 inches thick. This means that the 0.75-inch thick outer shell of South Dakota would have been more than enough to detonate these shells on impact, regardless of whether the plate was made with HTS or STS steel.

Nathan Okun has developed an equation for nose-fuzed HE projectiles that detonate on impact with thin plates that can be used to determine the approximate amount of damage that the projectile caused to the plate:

This equation computes for US Navy World War II STS and Class "B" armor plate ¹⁴ a thickness "T" where a hole of roughly caliber width will be punched entirely through by all "typical" instantaneous-impact-nose-fuzed HE projectiles that do not have an Auxiliary Detonating Fuze (ADF, used only in most World War II-era US Navy nose-fuzed HE projectiles); hence the "(noADF)" part of the label to separate it from another formula for T sometimes used with ADF-equipped shells.

This equation also applies to those World War II time-nose-fuze or VT-fuzed HE shells when the nose fuze gets crushed by a plate impact prior to the fuze setting off the shell in its normal manner (high-order detonation), as well as even applying to ADF-equipped shells under some impact conditions.

The "phe" label in this equation stands for "Penetration by HE Shell." In addition to the shell's minimum explosive filler detonation and fragmentation effects part, "(0.156)(D)," it uses the shell's impact velocity (V), angle of impact (Ob2, the impact angle Ob limited as to the values that can be used in this formula), and diameter ("caliber," D). These formulae only apply as-is to the plate directly in front of the shell that is impacted by the shell's nose. It can be used for nearby plates to the side by setting V to zero and only using the "(0.156)(D)" blast/fragmentation component.

All units in this formula are English units: T (thickness of plate) & D (diameter of projectile) are in inches, V (Striking Velocity) is in feet per second, and Ob2 (Obliquity or impact angle with zero meaning right angles to the plate face) is in degrees.

Ob2 is set equal to 45 degrees (PI/4 radians in most computer languages) whenever Ob2 is less than or equal to 45 degrees. That is, under 45 degrees from normal (right angles), obliquity has no effect whatsoever and the COSINE term is always set to 1.00. Only over 45 degrees does obliquity start to have any effect. This is because if you look at the typical explosion pattern of a HE shell, there is a narrow jet coming out the nose aligned with the centerline of the shell when it goes off, made up of somewhat larger, but still small, pieces, compared to the sideways spray. This can assist in punching a small hole in the center of the impact site, but since it is pushed into the dent of the impact when the shell detonates, the angle of impact doesn't mean much. Then there is a kind of "dead area" over a conical arc to about 45 degrees to each side surrounding the nose, with almost no fragments whatsoever in it – just a few tiny fragments of the pointed nose region. These have little damage-causing effect into the blast-induced 0.156-caliber-thick-or-less plate hole. From the 45 degree angle to roughly 135 degrees (tilted forward due to the speed of the shell a little bit), there are the mass of the small, very high speed fragments created by the detonation, most in the 70-110-degree arc ring around the projectile middle (if the projectile is stationary, otherwise tilted forward a little). This is why you have to have the obliquity change to at least 45 degrees to begin to see any difference in the effects on a plate in front of the shell nose. However, this side spray effect does not make the hole larger than the 0.156-caliber stationary projectile value, since the blast/spray effect is what was calculated to give the 0.156-caliber non-moving projectile value in the first place. Increasing the obliquity over 45 degrees rapidly causes the velocity effect on increasing the depth to go away until at angles near 90 degrees obliquity (shallow glance just barely able to set off the nose fuze) the velocity has no effect at all and the shell acts like it is standing still when it detonates, as far as penetration of the hit plate is concerned.

Weaker plates with lower quality factors – HTS has a Q(armor) quotient of 0.85 – allow deeper penetrations, inversely proportional in depth to the quality factor of that material (if there were plates BETTER than STS, then the thickness T penetrated would go down by dividing by a value larger than 1.00 (= World War II STS Q(armor)). We call this value Tmod, and it is equal to T/[Q(armor)]. Thus, if an STS plate of T = 1 inch would just give a caliber-wide hole under the impact conditions involved, then a plate made with the lower-quality HTS steel would have Tmod = 1 / 0.85 = 1.176, which means that the HTS plate would need to be 1.176 inches thick in order to have the same size hole made in it.

After calculating Tmod per the Plate Quality factor as described in the above paragraph, the diameter of the hole created by a particular HE shell when the Plate Actual Thickness is less than Tmod can be calculated with the following equation:

This formula shows that the largest possible hole is approximately 40 calibers in width for foil-thick plates of very large size. The formula shows that an 8-inch HE shell can blow a hole 319.2 inches or 26.6 feet wide in a 30 x 30 foot aluminum-foil-thickness STS steel membrane that is supported tightly around the edges, assuming that the shell hits in the center.

As plates get thicker than Tmod, the hole size created goes down rapidly, with zero hole size (merely a large dent with cracks) occurring at a plate thickness of 1.2 x Tmod. For plates thicker than Tmod, we use the following equation:

The minimum hole diameter for this equation is zero.

These equations are valid for the filler weights of typical World War II HE shells which were in the range of 6.0% to 8.99% of the total weight of the shell. ¹⁵ The Japanese 8-inch Type 0 HE shell was a modern, long, streamlined design with a length of 4.33 calibers and had a filler weight of 6.5% of the total weight which was up to 283 lbs. Therefore, this projectile falls within the valid range for these equations. ¹⁶

Turning now to the damage caused by Hit 2; the BuShips' reports states that this shell made a 5 by 4 foot hole in a STS plate that was 0.75 inches thick. To determine if this damage was caused by an 8-inch HE shell fired with a muzzle velocity of 2,330 fps which at 6,000 yards would have a striking velocity of 2,103 fps, we use the following intermediate steps which together make up the calculations for Equation 1: ¹⁷

1. (2.576 x 10^-20)(D) = 2.576 x 10^-20 x 8 = 2.06 x 10^-19

2. V^5.6084COS[2(Ob2 - 45^o)] = 2103^5.6084 x COS [2(45 - 45)] = 4.32 x 10¹⁸

3. (0.156)(D) = 0.156 x 8 = 1.25 inches

4. 2.06 x 10^-19 x 4.32 x 10¹⁸ = 0.89 inches

5. Tphe (noADF) = 0.89 + 1.25 = 2.14 inch thickness of STS which will result in a caliber-width hole

To find the minimum thickness of STS that ensures that no crack will be made in the plate (just a dent), we multiply 2.14 x 1.2 = 2.57 inches.

These calculations show that an 8-inch Type 0 HE shell would produce an 8-inch hole (caliber width) in a 2.14-inch thick STS plate and that a 2.57-inch thick plate would defeat this size shell, achieving only a dent. Intermediate thicknesses of STS between the 2.14 inch and 2.57 inch limits would have progressively smaller holes and shorter cracks in the plate.

Now that we have these numbers, we can calculate for the actual plate where Hit 2 struck, which was 0.75 inches thick. As we are calculating for STS plate, this means that T = Tmod which in this case was calculated above as 2.14 inches. As the actual plate thickness of 0.75 inches is less than Tmod, we use Equation 2 to determine the created hole diameter. Filling in the values for this formula:

This is the approximate size hole that an 8-inch HE projectile would produce in a 0.75-inch thick STS plate. As can be easily seen, this estimated hole size of less than 2 feet is inconsistent with the BuShips reported hole size of 5 by 4 feet.

The above calculations were for a plate made of STS. What if the plate was actually HTS as in the Builders Plans? As HTS is 0.85% as strong as STS plating, we need to adjust Tmod per this lower quality factor:

This means that an 8-inch HE projectile would blow an 8-inch hole (caliber width) in 2.52 inches of HTS plating (for reference, the thickness of HTS plate that would result in only a dent can also be calculated using this same quality factor: 2.57 / 0.85 = 3.02 inches).

Using the HTS value of Tmod in Equation 2:

So again, the results of the calculations for an 8-inch caliber HE projectile are inconsistent with the documented damage.

Moving now to the next larger size HE projectile that was present for the battle, the 14-inch Type 0 HE, this projectile is only 3.38 calibers long, weighs circa 1,378 lbs ¹⁸ and has a relatively small filler of 63.4 lbs of TNA (4.6%). This low filler percentage means that the Japanese 14-inch Type 0 HE shell design has an explosive burster that falls below the normal World War II HE Shell filler range mentioned above of 6.0 to 8.99% of total weight (see Footnote 16), which means that this projectile instead falls under Nathan Okun's formula for Semi-Armor Piercing (SAP) projectile types. The first step in determining the hole size that can be made by a 14-inch Type 0 projectile is to calculate what a normal World War II HE projectile would produce and then modify that result based on the ratio between the normal HE projectile and a SAP projectile.

What Nathan Okun has discovered is that a normal World War II HE projectile can blow a caliber-wide hole at a distance of 5-calibers or less from a 0.11-caliber-thick STS plate. This 0.11 figure can be used for all normal World War II HE shells, including US World War II HC projectiles that have filler percentages between 6.0 and 8.99%. This is the blast effect's only minimum distance and below this distance the still-accelerating fragments will have more hole-punching power and the caliber-wide hole in STS plate thickness steps up instantly to a constant 0.156-caliber size for a regular HE round. ¹⁹ For all SAP projectiles in the 4.0 to 5.99% filler range; these will produce a caliber-wide hole at a distance of 5-calibers from a 0.095-caliber thick STS plate. The ratio between a normal HE and a SAP round is thus 0.095/0.11 = 0.864. ²⁰ Multiplying the results for a normal HE projectile by 0.864 will thus give the correct hole size for a SAP projectile and thus the hole size for the Japanese 14-inch Type 0 projectile. ²¹

As a last piece of data; at 6,000 yards, the striking velocity of a Japanese 14-inch HE projectile fired with full charges would be 2,131 fps (see Footnote 18).

With all the above information, we can now make the following calculations using the same intermediate steps for Equation 1 that were used above:

1. 2.576 x 10^-20 x 14 = 3.61 x 10^-19

2. 2131^5.6084 x COS [2(45 - 45)] = 4.66 x 10¹⁸

3. 0.156 x 14 = 2.18 inches

4. 3.61 x 10^-19 x 4.66 x 10¹⁸ = 1.68

5. Tphe (noADF) = 1.68 + 2.18 = 3.86 inches maximum thickness of STS for a caliber-wide hole

To find the minimum thickness of STS that ensures that no crack will be made in the plate (just a dent), we multiply 3.86 x 1.2 = 4.64 inches.

Intermediate thicknesses between 3.86 and 4.64 inches of STS have progressively smaller holes and shorter cracks in plate.

Continuing now for Hit 2, if the plate struck was made from STS, then as the plate thickness of 0.75 inches is less than T we use Equation 2 which gives us:

Calculating for the damage that the typical World War II HE projectile would make in HTS plating, we get:

Using Equation 2:

As the 14-inch Type 0 HE projectile has a lower amount of explosive filler than the average World War II HE projectile, the size of the holes needs to be reduced by the SAP adjustment factor of 0.864 calculated above. This means that the hole created in 0.75-inch thick STS plate would be:

And the hole created in 0.75-inches thick HTS plate would be:

These figures are far closer to the 4 x 5 foot exterior hole and the 8 x 6 foot interior hole in bulkhead 31 as documented by BuShips. This means that the 14-inch Type 0 HE projectile is far more consistent with the damage described by BuShips and is the best conclusion as to the projectile that caused this damage.

The timing of this hit is also important. When Kirishima re-opened fire at 0100, Lieutenant(jg) Michio Kobayashi, who was on her bridge at the time, thought that he saw Kirishima hit South Dakota in the area of Turret I. ²² This damage confirms that Lieutenant(jg) Michio Kobayashi did indeed witness one of Kirishima's projectiles impacting very close to turret one.

The next question then is what made the holes below Hit 2? First of all, BuShips' report and South Dakota's action report have significant disagreements as to what was the kind and extent of the damage to the hull below Hit 2. South Dakota's Enclosure D lists three holes of 16 x 24 inches, 14 x 14 inches and 10 x 12 inches in the hull at compartment A-206L. ²³ In contrast, BuShips reported finding six holes in this area of the ship's hull and that all of these were much smaller than the ones reported by South Dakota. ¹¹ Plate 1 (shown as Figure 123 in this essay) from BuShips' report shows the six holes below Hit 2, and these are listed on Plate 1 as being five holes of 6 x 6 inches plus an additional hole that is not dimensioned but appears to be somewhat larger than the other five holes. Finally, looking at Figure 8 above, one can see four patches on the ship's hull (apparently applied shortly after the battle) that are covering up the damage in this area. Also in the BuShips' report, there is an assertion that although the ship's crew had concluded that these holes were made by 6-inch shell fire, the BuShips investigators had determined that there was no area within the ship where the extent of the damage would indicate that a shell had detonated inside the ship's hull and that there were no exit holes through the ship's structure. For these reasons, the BuShips investigators came to a different conclusion that no additional shells were involved and that these holes were the result of the cap head and windscreen from the AP projectile that they had concluded had made Hit 2.

One thing that is almost certain about these holes is that BuShips' assertion that they were made by the cap head and windscreen from an 8-inch AP shell cannot be correct. Our estimate is that Hit 2 was made by a HE projectile, so there would be no cap head or windscreen from this projectile to make these holes. Even if Hit 2 was made by an 8-inch Type 91 AP projectile, the 5-inch diameter cap head and light-weight windscreen of that projectile could not have made more than a single hole each of the size found by BuShips.

The authors and editor of this essay had a long discussion on the causes of these small holes, but in the end we have concluded that the BuShips investigators were probably on the right track and that these holes were most likely the result of fragments that were thrown out by the 14-inch Type 0 HE projectile that made Hit 2.

Finally, note that Hit 2 made a larger hole in the interior bulkhead #31 than it did in the outside hull plate. This bulkhead is listed as being 2.5 feet inboard of the hull and parallel to it. Assuming that this inboard bulkhead is made of thin steel of about 0.25-0.5 inch thick HTS or regular construction steel (Q = 0.7 or so), then it is still within the contact blast distance with the blast wave accelerating the fragments of the HE shell (not a lot of projectile fragments in the forward direction, of course) and, to a lesser extent, the fragments of the 0.75-inch HTS 5 x 4 foot hole from the hull plate (which would have made lots of plate fragments). These all hit bulkhead 31 in a widening cone of blast and fragments, making a larger pattern of fragment impacts than in the hull plate. Since this inboard bulkhead is thin enough for all of the rather few forward-directed fragments of the projectile and of the many 0.75-inch HTS hull plate fragments to punch through (this is only for this first spaced plate, though, since this uses up almost all of their penetrating power, with very few fragments capable of penetrating a second spaced plate), it gets plastered and riddled over a wide area and then the blast (reduced somewhat by the energy lost in puncturing and accelerating the pieces of the outer 0.75 inch thick hull plate but still with a lot of "overkill" energy to punch through such a thin second spaced plate) hits it, tearing it open even wider as the fragment holes unzip like stamp perforations and form narrow tears radiating outward for several feet to all sides. Also, as in Hit 4, the narrow air gap concentrates the forward-directed and even some of the side-directed (that passes through the wide outer hole) concussion and blast pressure, further enlarging the hole. This is why that second inner hole is wider than the outer impact hole. Trying to do a detailed calculation on this inner hole is not really possible, as the variables are many and indeterminate. The above discussion is meant as an explanation of the chain of events that created this hole.

There are no inconsistencies between the reports for this hit and it probably was a 6-inch shell from Kirishima. Another possibility is a 5.5-inch shell fired by one of the light cruisers during the time between 0048 and 0054. The specific time of this hit is unknown and the exact bearing of Turret I at the time of the hit is also unknown, but it was certainly trained to starboard in the direction of the Japanese ships as shown above in Figure 10.

There are no inconsistencies with this damage or with BuShips' estimate of an 8-inch AP projectile. ²⁷ Although this shell was slowed down by its underwater trajectory, it still had enough velocity remaining to penetrate the torpedo defenses and reach the main belt but not enough to significantly damage the plate.

The 8-inch AP projectile punched a rectangular hole out of the 1.25-inch STS outer hull which implies that it must have hit at a significant horizontal obliquity, but with minimal angle of fall. The windscreen was smashed flat and broken up by the impact with the outer shell, but the cap head remained on the projectile nose until it went completely through and even then did not have time to move much before the projectile eventually terminated its flight up against the belt armor. The projectile with the cap head still "riding" on its nose then punched through the HTS upward extension of the first internal anti-torpedo bulkhead and then it hit the main belt, where it destroyed itself, leaving only a 5-inch wide black circular disk on the face of the belt plate with an 8-inch wide narrow black ring surrounding it. What made the black color is unknown, but it might have been due to the impact shock of the 5-inch diameter flat nose under the crushed cap head and/or transmitted blast shock of the shell detonation removing paint and a very thin surface layer of the cemented part of the plate face, exposing the dark carburized layer that makes up about 1 inch of the plate thickness. The 8-inch ring might be due to the thick 8-inch diameter base hitting the armor after the projectile body in front of it had been destroyed. Other than this, the belt plate had no damage whatsoever.

Note that the hole in the upward extension of the anti-torpedo bulkhead is about 35 to 40 inches wide and was almost exactly in the center between two of the ship's vertical ribs, so nothing was there to modify the size of the hole in the horizontal direction. This portion, which is above the main 0.75-inch HTS anti-torpedo bulkhead, is thinner at 0.625 inches thick HTS. This plate was possibly still wrapped around the base of the projectile when the nose hit the belt armor and the shell detonated by impact shock. The internal cushion would not prevent such a detonation when the front of the shell shattered and the damage cut into the explosive cavity and the shell seems to have fully detonated high order, though this is not absolutely assured.

We can use Equation 1 from Hit 2 to calculate the hole size here. As mentioned in that section, "V" in Equation 1 is equal to zero when calculating damage for any plate other than the plate that actually sets off the nose fuze. This greatly simplifies the calculations for an HE shell:

As the torpedo bulkhead is thinner than this value, we use Equation 2 to calculate the hole size as follows:

This shell, with only about 2.5% TNA filler (the rest of the 4% cavity was filled with inert cushion material), which makes it an AP-type shell. This reduces the hole-size calculation by 0.08/0.11 = 0.727:

Which is much smaller than the actual hole size of 35 to 40 inches.

What gives?

The only thing I can see is the fact that the blast is contained in the narrow space between the thin anti-torpedo bulkhead at its base, with the hole it made being partially blocked by the projectile base, and the essentially infinitely thick and rigid face-hardened belt plate in front of it. The blast pulse, which in a open area would only push up against the thin plate once as it moved outward from the projectile, is now confined in a rather narrow space only about 36 inches deep where it can expand sideways, but not forward or backward. This containment and the impact and super-sonic detonation blast shockwaves in the air reflecting from the belt plate into the thin plate would greatly increase the maximum size and duration of the blast pressure pulse on that thin plate, coming from the inside of the space between the two plates backward toward the projectile base. Note that the thin plate edges are all bent outward away from the belt, indicating the pressure was from the inside outward. This seems to have increased the damage diameter by almost 300% over what would normally be expected for a Type 91 AP projectile detonating on a 0.625-inch HTS plate.

This shell is certainly a nose-fuzed projectile. The original crew estimated it to be an 8-inch projectile and this appears to indeed be the case. Despite the level of description in South Dakota's Action Report about this hit, there was not a good sense of the hole it produced in the exterior bulkhead of the Flag Bridge until I found the photograph in Figure 16 which shows about a six foot hole in the Flag Bridge windscreen. The thickness of the exterior bulkhead on the Flag Bridge windscreen is 0.25 inches of STS steel. This projectile appears to have detonated on impact and blasted inboard into the Senior Staff Officer's stateroom and Admiral's cabin. The door to the Senior Staff Officers cabin was blown off due to blast overpressure from Turrets I and II, and the fact that it is missing is not associated with the 8-inch HE projectile hit above.

This is an actual case of a Type 91 Mod 1 fuze detonating on a 6 mm thick plate just as the Technical Mission Report documented that it would. ³⁰

The steel used for the superstructure was more likely to be HTS and not the STS that is listed in her original report. Using the figures established in Hit 2, an 8-inch HE projectile would produce a caliber size hole in 2.52-inch thick HTS plate. Using Equation 2 for the 0.25-inch HTS plate found here:

This calculated hole diameter is about 6.7 feet, which is close to the 6-foot hole size documented in the report.

To confirm this, we now look at the damage a normal World War II 14-inch HE projectile would have produced. This size shell will make a caliber size hole in a 4.54-inch thick HTS plate. We then can use Equation 2 as follows to calculate for the 0.25-inch thick HTS plate:

Even taking into account the smaller explosive filler of the 14-inch Type 0 HE projectile; 254.24 x 0.864 = 219.66 inches or 18.3 feet, this size projectile would have resulted in the bulkhead completely disappearing! Clearly, this hole was not made by a 14-inch projectile and the best estimate is an 8-inch Type 0 HE projectile.

The large number of shell fragments of relatively small size for this hit is typical of a HE shell due to the large cavity and thinner sides of that kind of projectile. The only heavy cruiser to fire Type 0 HE projectiles was Atago as Takao fired only AP ammunition during this battle. Atago was the last heavy cruiser to open fire at 0103 and there is only a brief period of time during which she is ahead of South Dakota, as she was in the lead of the Japanese formation. Since Atago was part of the bombardment group, she may very well have been loaded with Type 0 HE shells for her first salvo. Her ammunition report says that she fired a total of six HE shells during the battle. ³¹

There is not any inconsistency with this estimate of the shell being an 8-inch AP projectile. The reported 10-inch and 12-inch holes through the circular foundation eliminate any possibility this was from a larger caliber. The hit is documented in South Dakota's action report as occurring at 0102 and this is also the time when Takao opened fire. ³⁶

This hit is documented as being the first one received by South Dakota and occurred at 0049. At this time, the heavy cruisers are 11,000 yards off South Dakota's bow heading west and have not yet even spotted South Dakota. This makes BuShips' estimate of an 8-inch shell impossible. It also could not have come from any of the destroyers as they were equipped with only nose-fuzed projectiles which would have exploded on impact, which this shell did not, indicating that it was a base-fuzed projectile. The light cruisers Nagara and Sendai were engaged with South Dakota at this time and thus this hit is most likely a 5.5-inch capped Common projectile or a base-fuzed 5.5 inch Type 4 Common projectile from one of them. The shell detonated as it exited the port side, blowing the larger hole in the second bulkhead. The shell trajectory being almost straight through the compartment matches Sendai's position at 0049 which was abeam of South Dakota while Nagara was slightly aft of her beam.

A 5.5-inch base-fuzed projectile fired by the light cruisers may be a better estimate for this hit. An 8-inch shell should have caused much more damage to the director due to the nose coverings flattening out on impact. This hit may have occurred at a similar time as Hit 7, which struck just below this level and which would have occurred before the Japanese heavy cruisers opened fire. The dimensions of the damage for Hit 8 are not recorded, so it is difficult to make an accurate estimate for this hit.

This damage was documented in South Dakota's report as occurring around 0102, so BuShips' estimate of an 8-inch AP projectile is possible. This is probably the best estimate due to the 17-inch entry and exit holes through the 0.25-inch STS plate. The cap head flying off estimate by BuShips also makes sense and accounts for the second exit hole. Takao opened fire at about this time, so she may be responsible for this damage. ⁴²

There are no inconsistencies with BuShips' estimate of an 8-inch AP projectile. At high velocity, the rather blunt end of this kind of shell (flat if the cap head is gone) would shear out very thin plating more like a paper punch than a wedge, keeping the hole narrow with only some minimal widening around the hole as the plate bent back in a ring of truncated petals around the hole (the center area of the plate under the nose that usually forms the upper end of the petals in a pointed-nose impact is sheared off as a disk/plug; round if at right angles, oval otherwise). A 5-inch hole for the cap head sounds about right, though it cannot penetrate much due to its light weight – perhaps an inch of steel, but that would stop it. The timing of this hit is unknown.

The STS plate at this point was 1.25 inches thick. The long tear in the plate to the right implies that the projectile hit at a quite high velocity and was coming from the right at a rather high angle of obliquity (about 45 degrees or so from the normal). The detonation blast split the plate, possibly due to a pre-existing lamination or other weakness (the crack is very straight and probably is parallel to the rolling direction used when the plate was manufactured). There are few deep pits in the plate around the big hole, although there are no other holes other than those made by torn-out rivets and bolts. The hit was up against a vertical seam between two of the STS plates where the plates are reinforced by doubling plates and straps and braced from behind by girders, using rather a lot of rivets and bolts. A number of large holes, tears and folds were made in the thin bulkhead representing the upward continuation of the first inboard anti-torpedo bulkhead in front of the armor belt, most probably by chunks of the 1.25-inch hull armor punched out by the projectile impact.

The shell exploding on impact indicates a nose-fuzed projectile. Using the same figures for a typical World War II HE shell as established for Hit 2; an 8-inch HE projectile was calculated as being able to produce a caliber-size hole in a 2.14 inch STS plate. For the thinner 1.25 inch plate found here, we can use Equation 2 to derive the hole size:

This is significantly smaller than the documented damage.

Using the same figures as established in Hit 2; for a non-Japanese World War II HE projectile, a caliber-size hole would be produced in a 3.86-inch thick STS plate. For the thinner 1.25 inch plate found here, we can use Equation 2 to calculate the hole size as follows:

As noted in the Hit 2 analysis, the smaller explosive filler in the 14-inch Type 0 HE projectile means that we should treat it as a SAP projectile:

This is extremely close to the 3 foot hole documented in South Dakota's damage report. Thus, the best estimate for this damage is that it was made by a 14-inch Type 0 HE shell.

The key to determining which projectile caused this damage is the time that director one was first documented as being unable to train due to shell hits, which was at 0055. At this point in the battle, the Japanese reports show that only the light cruisers were firing on South Dakota and that this damage occurred some seven minutes before the heavy cruisers opened fire. This means that this hit cannot have been from an 8-inch projectile. Turning then to look at the 5.5-inch Common projectiles fired by the light cruisers; normally the Type 13, Mark 1, Mod 1 base fuze used in the 5.5-inch Common would detonate these shells approximately 0.003 seconds after the initial impact (there is always a slight delay before ignition even with an instantaneous fuze due to the inertia of moving parts). However, the US Naval Technical Mission reported that this fuze gave many blinds, so this hit could have been made by a dud passing through the superstructure. ⁹ The shell trajectory matches the position of the light cruisers during this timeframe as the heavy cruisers are well ahead of South Dakota and are in the process of turning around between 0052 and 0055 (see Figure 69). Takao will be the first heavy cruiser to open fire at 0102, long after this damage is documented to have occurred. ⁴² Therefore, the best estimate for this damage is that it is from a dud 5.5-inch base-fuzed projectile fired by one of the light cruisers.

The first inconsistency about BuShip's estimate of three 8-inch shells is that these hits are recorded long before the heavy cruisers opened fire. South Dakota entered this damage into her logs at 0057, however the damage actually occurred a few minutes earlier at 0052-53, which is the time that Kirishima first opened fire. At this same time, South Dakota recorded her first sighting of three ships at 11,000 yards and logged that she was taking hits to her foremast. ³⁷ Between 0052 and 0054, South Dakota veered south and this change in course was documented by USS Washington as having occurred at 0054. ⁴⁸ This places South Dakota as being broadside to Kirishima with her stern towards the light cruisers. The Takao will not open fire until 0102 and Atago not until 0103, so the estimate of 8-inch shells becomes impossible. In addition, the damage seen is not consistent with AP ammunition. These hits were eye-witnessed by Admiral Kondo and LCDR Ikeda as having occurred when Kirishima opened fire at 0052. Finally, what is entered into South Dakota's logs also matches Ikeda's description of how Kirishima opened fire: Ikeda said that his secondary battery fired first, quickly followed by the main battery. He saw two hits strike the target ship in the foremast from this salvo, which closely matches the time recorded in South Dakota's log. ⁴⁹

In looking at the entry holes shown in Figure 42, the hole created by Hit 13 is visibly larger than the other two and is 18 inches in diameter. Referencing the sketch in Figure 53, this impact occurred at point (A) and this shell then blew a 36-inch hole in the centerline bulkhead (D) and began to break up. The door leading to radar plot (H) and the passageway were blown out. Shell sections and fragments then hit the transverse bulkhead (I) at Frame 84, blowing a 30 by 60 inch hole. This projectile continued to disintegrate, breaking up completely and exiting through the port side in an area of 8 by 10 feet (J) and creating at least five holes in this area that are over 24 inches in diameter. The photographs for this damage show circular but also irregular shaped exit holes, a characteristic that indicates that the shell broke apart. Although this shell did not explode, it did start a large fire which gutted this compartment. In addition, the surrounding catwalk, wind and spray shields and the radio direction finder were all showered with shrapnel, causing many small holes.

Shrapnel also blew out the deck plating of the 09 level above the radar plot, creating one 12 x 18 inch hole in the deck plating at Frame 84 on the 09 level and an 18 x 36 inch hole through the deck plating at Frame 84 of the port radar transmitter room. The access ladders going between the 09 and 010 levels were also demolished.

This damage is consistent with two 6-inch shells and one 14-inch Type 3 incendiary shell. The nose fuze on the 14-inch Type 3 and the long fuze rod that ran down the middle of the shell to its base would have snapped under impact, preventing the detonation of the small explosive charge. As the shell ripped through bulkheads, the wood nose and thin sides of the shell would be torn away and the shell would disintegrate, throwing its shrapnel in every direction like a shot gun blast, taking out the doorways and bulkheads in its path. Some of the 3-inch long incendiary tubes ignited, probably low-order because the shell did not detonate properly, which started the fire within the compartment. From Admiral Kondo's point of view, it looked as if the shell had blown off the top of South Dakota's main mast. The display of the incendiary tubes igniting from this hit must have appeared to the eyewitnesses on the other ships like a giant firework. Two nights previously, two 14-inch Type 3 shells had struck the heavy cruiser USS San Francisco and these shells also broke apart and started low-order fires in the areas they went through. In her case, the shells passed through the lower superstructure and upper hull and hit the forward barbette such that most of the incendiary tubes were trapped inside the ship, causing much larger fires. In South Dakota's case, it appears that much of the contents of the Type 3 shell passed clean through the ship and went overboard, leaving relatively few tubes to ignite or be recognizable during the clean-up afterwards.

This damage confirms what is documented in the Japanese action reports; that Kirishima was not only the first ship of the Bombardment Group to open fire, but that she also hit South Dakota with her first salvo.

The documentation on these three hits is very inconsistent, but in the end the estimate of two 6-inch and one 8-inch projectiles appears to be correct. First, the photograph labeling the entry hits at WRSR 0203 ( Figure 54) is misleading in that two of the shells actually entered WRSR 0205 and into the starboard Signal Flag Locker room and only Hit 18 actually entered via WRSR 0203. Secondly, the shells were not part of a single salvo as the shell trajectories of the two 6-inch shells (Hits 16 and 18) are from forward moving aft while the 8-inch shell (Hit 17) must have came from aft moving forward or else it would have completely missed mount two. This can be seen in Figure 56 where Hit 17 came through a bulkhead moving right to left while Hit 18 was moving left to right. The two 6-inch shells appear to have detonated, causing blast and fragment damage to the staterooms. The relatively small 10-inch entry holes seen for these hits appear to be more consistent with 6-inch shells.

Hit 16 appears to have detonated on the inboard side of compartment WRSR 0205 as the deck plating was dished down over a 3 foot square area, 8 feet inboard of longitudinal structural bulkhead. The entire transverse aluminum divisional bulkhead between WRSR 0205 and the locker used for stowage of forms was completely blown out. This inboard longitudinal structural bulkhead also had a 30-inch diameter hole knocked in it approximately 3 feet above deck level. Plate 1 of BuShip's original report (shown as Figure 123 in this essay) has a notation that implies that none of these three projectiles detonated, but South Dakota's action report makes it clear that the two 6-inch projectiles did indeed detonate within the superstructure.

The holes in the bulkheads for Hit 17 appear too large for a 6-inch shell and, contrary to South Dakota's action report, there were no guns present at this battle that fired a 6.1-inch shell. The only 6.1-inch guns in the vicinity were part of the battleship Yamato's secondary battery and she was anchored miles away at Truk.

Based on the photographs, it appears that the entry hole caused by the shell passing through to hit mount 2 is significantly larger than 10 inches. The first clue to its identity is the shape of the entry hole shown in Figure 54 and Figure 55. Examining these two photographs show that Hit 17 made a "V" shaped entry hole along with two circular holes at the top giving it "Mickey Mouse" ears. This is an odd shape for an entry hole, as can be seen comparing it with the round holes made by Hit 16 and Hit 18.

What could have caused this oddly-shaped entry hole? A possibility is that the shell components separated before reaching the bulkhead. If we think of an 8-inch AP projectile as having a windscreen, a cap head and a shell body, then the bottom of the "V" may have been caused by the windscreen (point down) with the left and smaller circular entry hole being from the cap head and the larger circular hole on the right being caused by the shell body.

To have broken up like this, the projectile must have already hit something hard enough to dislodge its nose coverings prior to impacting this exterior bulkhead. This could only have been the water short of the ship, which would have also slowed it down considerably in the process. So, this hit could have struck at too shallow an angle to "bite" into the water and instead it ricocheted up to hit the superstructure, shedding its nose-coverings as it went. ⁵⁴

After hitting the water, the windscreen and cap head of the 8-inch AP shell were knocked off and the projectile slowed down considerably before ricocheting upward at a very shallow angle, slamming into the starboard bulkhead to form the Mickey Mouse Hole. In the water ricochet process, the nose acquired a significant "yaw" angle, which is the tilt of the nose away from the direction of motion of the projectile caused by the water impact pushing on the upper end of the projectile with a different force than on the base end. The projectile thus began to move forward like a surfboard, cocked off at an angle to the direction it was moving, in this case about 20-30 degrees, as shown by the oval hole in Figure 56. Since the projectile was still spinning at a high rate, however, this yaw started to "nutate" ⁵⁵ as soon as it left the water so that the nose punched through the superstructure bulkheads with the yaw angle pointed in progressively different directions, as shown in Figure 64.

While the direction of the yaw changed due to the nutation, the amount of yaw stayed more-or-less at the same 20-30 degrees it had when it initially made part of the Mickey Mouse Hole over most of its path through the superstructure, as shown in Figure 56 (the picture here is from the exit side of the hole, so it is a mirror image of the actual direction that the yaw was pointing when it punched through the bulkhead toward the camera).

Figure 66 shows how the nutation angles are used in this document. Zero degrees nutation is directly on top. Positive degree nutation angles are in a clockwise direction while negative degree nutation angles are in a counter-clockwise direction from the zero point. Negative angles may also be referred to as a Positive angle by measuring in the clockwise direction. For example: -124 degrees is equivalent to a Positive Angle of +236 degrees. The letters shown in Figure 66 refer to the nutation angles as the shell body impacted the bulkheads as it traveled through the superstructure as labeled in Figure 65.

For Hit 17, when this shell entered the exterior starboard bulkhead of the Flag Signal Locker, the shell nose was at a nutation angle of +15 degrees (Refer to Figure 65 Point A). The shell was nutating in a counter-clockwise direction.

The shell then ripped through a thin transverse bulkhead to exit the Flag Signal Locker (Refer to Figure 65 Point B) and entered Compartment 203 at a highly oblique angle, but very close to its inboard end, so the bulkhead has little deflection effect as the projectile tears through it. Since the projectile body has a flat nose and such a small yaw, the forces generated are still very close to directly down the centerline of the shell, so any added yawing effect (increasing or decreasing) by penetrating this transverse bulkhead was minimal.

The projectile then hit the longitude inboard bulkhead of compartment 203 (Refer to Figure 65 Point C). The nutation angle at this point had progressed to -124 degrees based upon Figure 56. The yaw angle remained at about 20-30 degrees. The distance from the exterior bulkhead to this inboard bulkhead is 16.0 feet and taking into account that the trajectory is on an approximate 10 degree composite angle, this changes the actual distance traveled to 16.24 feet [16 feet x 1/cos (10 degrees) = 16 feet x 1.015 = 16.24 feet]. There has been a total of 139 degrees change in nutation (-15 degrees + -124 degrees = -139 degrees), so -139 degrees/16.24 feet = -8.5 degree change per foot of travel.

The next bulkhead is the centerline bulkhead of the ship in Compartment B103L (Refer to Figure 65 Point D). This bulkhead is 9.0 feet from the inboard bulkhead of compartment 203. The 10 degree angle for the shell trajectory adjusts the actual distance traveled to 9.14 feet [9 feet x 1/cos (10) = 9 feet x 1.015 = 9.14 feet]. Maintaining the same nutation rate of -8.5 degrees per foot, an additional -78 degrees (9.14 feet x -8.5 degrees = -78 degrees) will result with the shell impacting this bulkhead with a nutation angle of +158 degrees (-124 degrees + -78 degrees = -202 degrees = Equivalent Positive Angle +158 degrees) with the yaw remaining constant.

The next bulkhead is the inboard side of compartment 202 (Refer to Figure 65 Point E). This bulkhead is also 9.0 feet away from the ship's centerline. The distance and nutation rate remains the same as for the previous bulkhead, so the projectile's nose impacted this bulkhead with a nutation of +80 degrees (+158 degrees + -78 degrees = +80 degrees).

However, there was a wall safe on the other side of this bulkhead inside compartment 202. The now-nearly-horizontal projectile's lower body broad-sided the 2-inch-thick left side of the large double-door safe, as shown in Figure 59 (also shown in Figure 57 and Figure 58, but not as clearly). ⁵⁶ That violent middle-body impact with the safe caused the yaw angle to begin swinging wildly in and out, to angles well above the original 20-30 degrees, perhaps up to 60 degrees away from directly along the flight path, and the nutation rate also changed to approximately -5.3 degrees per foot, although the shell would still be nutating in the counter-clockwise direction. This is to be expected since the larger yaw angle acts like a rapidly-spinning ice-skater spreading her arms out and slowing her spin rate down due to conservation of angular momentum.

The distance from the wall safe to the curved exterior bulkhead of compartment 202 (Refer to Figure 65 Point F), is 12.35 feet. With the new nutation rate, the projectile nutated an additional -65 degrees (12.35 feet x -5.3 degrees = -65 degrees), so that the shell on impact with the port exterior bulkhead had a nutation of +15 degrees (+80 degrees + -65 degrees = +15 degrees). As shown in Figure 61, the projectile then "belly-flopped" through this bulkhead and made that long slot that was almost identical, though longer, to the initial slot (mostly masked by the long windscreen hole) it made on the starboard bulkhead. The projectile nose had thus spiraled through one complete circle during its passage through the superstructure (see Figure 64).

As shown in Figure 61 and Figure 62, the projectile kept that high yaw angle in the gap between the port bulkhead and the back of the 5-inch gun mount (Refer to Figure 65 Point G). The gap distance is 3.25 feet and, using the nutation rate of -5.3 degrees per foot; -5.3 degrees x 3.25 feet = -17 degrees change in nutation angle), the shell impacted the gun mount at a nutation angle of -2 degrees (+15 degrees + -17 degrees = -2 degrees), angled almost exactly vertical, nose up, at the point where its forward motion was finally stopped.

Referencing Figure 68, the nose hit the 5-inch mount at the lower-right-hand corner of the left-side-gun's shell casing ejection hatch (A) and punched a deep pit and hole, but did not completely penetrate. The tapered flat nose was jammed into that hole and could not move while the base continued forward, slamming vertically nose-up into the rear of the gun mount (90 degrees yaw angle and -2 degrees nutation angle), as noted by the curved dent in the lower edge of the rear armor and the gash in the edge of the armor floor plate below that (B). As the nose was jammed into the deep dent and hole, this rotation pulled out the armor just above the nose hole, since it is now shallower than the dent higher up on the right edge of the case-ejection hole. The projectile body hit the lower-edge armor sideways at a high nutation rate, as shown by the depth of the dent, and then rebounded outward, pivoting on the jammed nose (C). The nutation inertia was still in force, however, so the rotation of the lower projectile body toward the horizontal, reducing the 90 degrees yaw angle toward zero, was accompanied by the nutation of the projectile base to the left, counter-clockwise, just as before the armor impact, but now pivoting on the nose tip, not the shell center-of gravity about halfway down the shell length (D). This caused the base to move in a curve like a question mark without the bottom dot and end up slamming horizontally on the far left side of the case-ejection opening from the nose hole (90 degrees yaw angle and a 90 degrees nutation angle), as shown by the rectangular dent there (E). This cross-wise slam across the closed hatch covering the case-ejection opening rammed the hatch cover through the opening into the gun mount, tearing out the edge hinges and locking clamps and causing deep tears/dents all around the edge of the opening. In the process, the nose pulled out more of the armor trapping it, pulling up the raised torn area to the right and below the nose hole.

After this second horizontal base impact, the projectile no longer had any energy and the base fell downward, so the weight of the shell finally twisted the nose free of the hole in the mount. The projectile then fell to the deck, still spinning for a few minutes in a circle, but not moving very far (F). It was found right there by crewmen after the battle and thrown over the side.

This shell did not explode on impact with the safe or gun mount because it was moving so slowly (at the range of the gun which fired it, a shell with no yaw that was not slowed down considerably by the water impact would have easily punched entirely through that 5-inch mount); hit rather soft, thin (compared to the shell diameter, that is), and easily dented steel (the force on the fuze firing pin was reduced because it was spread over a longer time than a sharp penetrating-impact shock); and hit at such a high yaw angle that the firing pin was probably jammed sideways and could not move in the fuze, even with a stronger force than actually occurred (such fuzes are not designed for such yawed impacts). Hit 26 on Turret III barbette, as will be discussed later, shows a similar lack of fuze initiation. Both of these impacts had rotations along two planes; one along the direction of flight (the base moving forward to hit the same plate the nose had previously hit) and one at right angles to that direction rotating from a nose-down vertical yaw to a horizontal yaw parallel to the deck using a counter-clockwise one-quarter-circle turn with the projectile nose tip as the pivot point.

Hit 18 probably detonated on the inboard, port side and aft close to compartments WRSR 0204 and 0206. In WRSR 0204 the metal joiner door and frame were blown out and distorted and the inboard longitudinal panel bulkhead was blown out. In WRSR 0206, the inboard longitudinal panel bulkhead was demolished and the metal joiner door and frame broken. Fragments damaged the Operations office, B-0201L, and B-103L as well.

We believe that Hit 17 was from the 8-inch AP shell that was later found on deck and that the correct shell size was indeed 8-inches, even though South Dakota's logs confuse which gun mount was hit. The heavy cruisers opened fire late, at which time they were abreast and then aft of South Dakota during their firing passes. The shell trajectory and timing of the 8-inch shell matches the heavy cruisers position while the trajectories of the 6-inch shells match Kirishima's position (see Figure 69 ⁵⁷) at 0104 when this damage was listed as occurring in South Dakota's time logs. This also eliminates the possibility of the shell being a larger caliber one as at the time this hit was made Kirishima was still forward of South Dakota and not aft. For Hits 16 and 18, the best estimate is that they were base-fuzed 6-inch Type 4 Common projectiles, as these shells did not explode on impact with the outer bulkhead but were able to penetrate inside the ship before they detonated.

The amount of damage to the search light was minimal. The shell did not detonate, indicating that it was not a nose-fuzed projectile. It also does not appear to have been an 8-inch AP projectile as the light windscreen of that shell would have ripped-off and flattened, causing much more damage than was the case (for example, Hit 6 from an 8-inch AP projectile created an 18-inch wide hole in a 0.25-inch thick STS plate and Hit 9 made a 17-inch hole). An 8-inch AP projectile would thus have created a hole approximately half of the diameter of the 36-inch searchlight. A smaller base-fuzed 5.5-inch Type 2 Common projectile or 6-inch Type 4 Common projectile would have nothing to come off and these are basically solid rounds. A hit by one of these projectiles would have gone right on through the searchlight, which is consistent with the damage as shown in Figure 70. Based upon examining this photograph; the hole is about 10 to 12 inches in diameter, which is consistent with the other 5.5-inch and 6-inch caliber hits. The timing of this hit is not known. Our conclusion is that Hit 19 was made by either a 5.5-inch Type 2 Common or a 6-inch Type 4 Common projectile.

There are no inconsistencies with this estimate and the best estimate is by a 6-inch Type 4 Common projectile from Kirishima. The base fuze allowed the shell to penetrate the outer layer and it exploded on the next bulkhead.

This impact was estimated by BuShips to be either a glancing hit from an 8-inch shell or the windscreen and cap head of an 8-inch shell. We believe this estimate to be incorrect. Hit 4 showed that at these ranges that even an 8-inch shell traveling underwater could penetrate the outer shell. Next, most nose-fuzed HE shells exploding on impact at a small angle would have punched a hole into the plate rather than denting it as was the case for this hit. That this blow was at a small oblique angle can be seen in Figure 73. A 5.5-inch nose-fuzed shell would punch a hole in any plate less than 1.36 inches thick, which means that the actual 1.25 inch plate is too thin to have prevented this from happening. A 5-inch shell fired from a 5"/40 would have only left a dent, but we believe that this projectile is too small to have caused the size of dent actually made in this plate.

In BuShip's original report, the authors proposed that this damage may have come from the windscreen and cap head from either Hit 11 or Hit 20. However, these two hits came from a forward direction while Hit 21 came from astern, which therefore eliminates any relationship between Hit 21 and the other two hits. After eliminating these other possibilities, what we are left with is that this damage appears to have been caused by the impact of a cap head and windscreen from an AP shell. Further work is needed to determine the size of this projectile.

Looking at the two types of AP cap heads fired during this battle; the 8-inch AP projectile has a thick cap head that comes to a rather blunt, but distinct point, and is more like a blunt projectile nose tip than any of the other cap heads used in other sizes of Type 91 AP projectiles. This design was intended to allow the 8-inch shell to better penetrate the homogeneous armor that most US cruisers were armored with during the 1930's when this shell was developed. By contrast, the cap head of the 14-inch AP projectile has a forward face that is flatter with no point, being more discus- or mushroom-top-shaped. Examining other information about these projectiles brings out these values:

These size differences between these two projectiles is also significant in that the 8-inch cap head is only 5.5 inches in diameter, is 5 inches thick and weighs 7.9 lbs. The 14-inch cap head is 12 inches in diameter by 8 inches thick and weighs 63 lbs. The struck plate is 1.25 inches thick, which is not an insignificant thickness. An area in this plate over 24 inches in diameter was pushed in to a depth of 6 inches. The shape of this dent matches the oval shape of the 14-inch cap head and the heavier cap head is by far more capable of pushing in this amount of steel than the much lighter cap head of the 8-inch shell. This damage largely matches the dimensions of the 14-inch cap head. Our conclusion is that Hit 21 was the result of a 14-inch Type 1 AP cap head and windscreen.

The shell itself seems to have missed South Dakota, either by going under her hull, if it could dive at the shallow angle of fall at these close ranges (circa 7 degrees is the minimum entry angle even for these specially-made diving shells), or after it skipped off the water itself, if not. This shell obviously came fairly close to South Dakota either way and, if it skipped off the water, perhaps it caused some of the less-than-well-defined superstructure damage noted (punching through as solid shot or as shell splinters after exploding in the air nearby due to fuze action after the ricochet). If so, it would be only the second 14-inch AP round to have hit South Dakota. Another possibility is that the shell ran parallel to South Dakota's hull as she turned away from Kirishima at 0110. For that possibility, the shell would have entered the water around frame 87 and loss its windscreen and cap head, which deflected into South Dakota's hull, and then dove and detonated around frame 56 near the bottom of the ship, causing seam damage to her hull. ⁶¹

This shell detonated on impact, indicating a nose-fuzed projectile. The bulkhead is probably 25 lbs. or 0.625-inches STS or HTS plate based on similar hits on the exterior superstructure of the forward mast such as Radar plot. The timing of the hit is unknown, so the exact range and velocity of the shell is also unknown. The following analysis is meant as a rough estimate.

Using Equation 1, the calculations show that a 5.5-inch projectile striking at 1,300 fps would produce a 14-inch hole in STS plate 0.625 inches thick while a 5-inch projectile at the same velocity would produce a 9-inch hole in the same STS plate. This latter figure is closer to the size of the exterior hole in Figure 76 and slightly under the 10 inch hole seen in Figure 77. A 5-inch Type 0 HE projectile appears to be the best estimate for this damage and this is consistent with BuShip's original estimate. This shell came from either the 5"/50 caliber guns on the destroyers or one of the 5"/40 caliber secondary battery guns on Kirishima, Atago or Takao.

This damage is very inconsistent with an 8-inch AP shell especially as the shell did not detonate. This shell disintegrated on impact which sent large numbers of small pieces of shrapnel into the surrounding structures. This type of damage is more typical of a 14-inch Type 3 incendiary projectile. The only ship to fire this shell type was Kirishima. The shell began breaking up on Secondary Battery (SB) director 3 which sent some of the stays and incendiary tubes into the stack. Some of the incendiary tubes ignited at the base of the stack and around 5-inch mounts 3 and 7. The nose of the shell entered into the stack and then the shell probably broke in half and continued to break up within the stack with parts hitting SB director 2 and sent shrapnel all over the superstructure. We believe that what is being described in the damage report as pieces of life jackets are actually the small rubber thermite incendiary tubes from the Type 3 shell which are 1 by 3 inches in size. These tubes burned at low-order as the shell did not detonate properly. CO₂ fire extinguisher gas would have had no affect on them due to their magnesium filler and they could burn as hot as 3,000 degrees Fahrenheit (1,650 degrees Centigrade), but for only 5 seconds. These tubes were quite capable of starting these small fires throughout the superstructure as described in the report. 5-inch Mount 7 reported that the armor shield had been exposed to extreme heat and 5-inch Mount 3 was reported on fire, but when fire fighters arrived they only found burnt-out fragments. Fires at the base of the stack but not at the point of impact are also an indication of incendiary tubes. For these reasons, we have concluded that the best estimate for this damage is that it was from a 14-inch Type 3 incendiary shell.

There are no inconsistencies with this estimate. The timing of the hit is unknown. The shell detonated on impact indicating a nose-fuzed projectile, probably a 6-inch Type 0 HE projectile. The other possibility as the timing is not known would be a 5.5-inch Type 0 HE projectile from one of the light cruisers.

Calculating for the larger of these two possibilities: At 6,000 yards, a 6-inch shell from Kirishima would be traveling at about 1,700 fps and the angle of fall would be about 4 degrees. The explosive filler for this shell was 6.5 lbs or 6.5% of the total shell weight, which puts it in the category of a normal World War II HE shell. Using the five steps for Equation 1:

1. (2.576 x 10^-20)(D) = 2.576 x 10^-20 x 6 = 1.55 x 10^-19

2. V^5.6084COS[2(Ob2 - 45^o)] = 1,700^5.6084 x COS [2(45 - 45)] = 1.31 x 10¹⁸

3. (0.156)(D) = 0.156 x 6 = 0.94 inches

4. 1.55 x 10^-19 x 1.31 x 10¹⁸ = 0.20 inches

5. Tphe (noADF) = 0.94 + 0.20 = 1.14 inch thickness of STS which will result in a caliber-width hole

To find the minimum thickness of STS that ensures that no crack will be made in the plate (just a dent), we multiply 1.14 x 1.2 = 1.37 inches.

Note that this calculated thickness is less than the 2 inches of STS that was actually on the back of the mount. Thus, the denting with no cracks caused by this hit is consistent with a 6-inch Type 0 HE shell.

There are no accurate, documented measurements for this damage. The hatch shown in Figure 84 is 26 inches long which would allow us to estimate that the hole is possibly 11 to 12 inches wide. The pipes in Figure 85 are no larger than 6-inch and this gives us a crude estimate as to the size of the pit in the plate. Only two types of projectiles would be capable of digging into the main belt as shown in this photograph and they are the 8-inch Type 91 AP and the 14-inch Type 1 AP. Based upon the size of the impact holes, this damage appears to be from the 8-inch projectile. This AP projectile ripped through the outer shell, losing its windscreen and cap head in the three prior impacts before it reached the main belt. The shell body impacted the main belt at its edge and it appears that the shell shattered at this point. If it exploded, then the explosion was probably low-order.

The hard face of the plate failed due to the close-range, high-velocity impact shock and compression force so near the edge of the hard, brittle face material, which cracked and folded back the face there like a door on its hinge, but the shell did not penetrate the back layer because, one, it broke up as it penetrated the face layer (the 8-inch Type 91 AP shell has no AP cap and had already lost its cap head), which reduced its penetration ability considerably, and, two, the armored second deck was bracing the Class "A" armor plate edge and preventing any of the back layer from being forced out of the broken projectile's path.

A 14-inch Type 1 AP projectile would have done much more damage due to its true AP cap not being removed by the thin plates this shell passed through before it reached the belt armor. Loss of the cap head would have reduced the penetration ability of the shell somewhat, but at near right-angles and at this close range, this 14-inch AP shell would still have been able to punch entirely through the belt and gouge a deep notch in the edge of the armored deck prior to slowing to a stop and exploding. None of this happened and the holes shown are too small to have been made by a 14-inch shell. The best estimate for this damage is that it was made by an 8-inch Type 91 AP shell.

This hit was from the last or one of the last salvos fired by Kirishima and her gunners deserve credit for still making their shots count even though their ship was wrecked and on fire by this time. The description of the damage for this impact was written in a difficult way to follow and only two photographs were used in the original BuShips report to illustrate the damage from this hit. There has never been a question as to caliber of the projectile that caused this damage, estimated by BuShips as 14-inch, but the type of 14-inch projectile was not given in the damage report.

The original authors of the BuShips report probably only used the two photographs they supplied in their report to make their conclusions. The first line in their report makes the association that the shell passed through both sides of Hatch 1-128 and then struck the barbette. However, the South Dakota's action report does not mention the hatch. In addition, there are two hatches, 1-122 and 1-128, that are listed as damaged in the report without any notes as to the causes of the damage, so once again the damage report is very confusing in the way it was written. By using more USN photographs of the original damage along with some recent photographs taken aboard USS Alabama of these same areas, we hope to be able to place into context what was really damaged by this impact and what type of shell caused it.

The photograph in Figure 88 was taken aboard USS Alabama and shows Hatch 1-122 in relation to Turret III. The damage listed in South Dakota's damage report is that there was a 15-inch deep semi-circular cut on both sides of the hatch. Though the BuShips report labeled this hatch as 1-128 in their report, most people believe they were actually referring to Hatch 1-122. Hatch 1-122 measures 56 inches wide x 96 inches long by 12 inches high. The forward edge lines up with frame 122 with the center seam of the barbette at frame 123.5. The aft side of the hatch is at frame 124. The distance from the inboard side of the hatch to the barbette is 118 inches. This matches the copies of USS South Dakota's builder's blueprints which were used for the damage report. The flange seen over the barbette is 7.5 inches wide and the distance from the deck to the bottom of the flange is 21.0 inches. The total height of the barbette measured from the top of the flange to the main deck is 28.5 inches at the center seam or frame 123.5.

The photograph in Figure 89 was also taken aboard the USS Alabama and shows the relationship of Hatch 1-128 to the forward edge of the barbette. The damage listed for this hatch in South Dakota's report is as follows:

"Davit holder besides [sic] Hatch 1-128 bent and twisted. Hatch coaming around Hatch 1-128 is torn, twisted, and cut by many pieces of shrapnel."

The forward edge of this hatch lines up with ship Frame 128. The barbette itself runs from frames 118.5 to 128.5 and each frame is 4 feet wide.

This photograph of South Dakota (Figure 90) shows that the forward flange, normally at the bottom of the turret face, has been destroyed and the steel bent up, which means that the blast occurred underneath the flange. In addition, two of the ladders have been blown off the face of the turret. Only the far left ladder remains attached of which the lower legs can still be seen on the right side of Figure 90. The turret in this photograph has been turned back to the centerline, which is why there is no deck damage seen in this photograph. The bloomers were reported to have caught fire after the explosion.

Figure 91 shows the damage to the right gun sleeve, which has been removed to make the gun serviceable. The damage to the gun sleeves and lack of damage to the gun barrels themselves indicates that the blast took place directly under these components. In all likelihood, the right gun was directly over the blast and the blast was then directed up and against the barbette itself. The right gun hoop received shallow indentations through the sleeve due to the fragment damage. The center gun sleeve also took damage but the gun was able to remain in service.

Figure 92 was not used in the original report but is the best photograph of the damage that we have found. This photograph shows the area around Turret III above the main deck and shows that the barbette actually has two impact scars. The lower scar is deeper and represents the 15-inch x 1.5-inch deep scar noted in the report. The upper scar is a surface blemish with the center approximately 17 inches from the top of the barbette. This indicates that the original BuShips authors are applying measurements from two separate impacts as if there was only one. This photograph is looking aft with the turret now trained to the centerline. The impact is just aft of the center seam of the barbette where two 17.3-inch plates come together and the impact dislodged the joint between these two plates 8 feet down the barbette.

The lower impact seen in this photograph is below the main deck level and the steel deck is bent down in this area. The hole is directly up against the barbette and there are two measurements within the original documentation for the size of the hole. These are 3 x 10-feet and 2.5 x 12-feet. The original authors also estimated the hole was caused by the explosion but without the use of this photograph they could not see how the wood deck overhangs where the steel is bent down. This is an indication that the steel was pushed down from under the wood prior to any explosion. The shape of the hole and it being directly up against the barbette are important clues to determining just what happened. In addition the riveted structure between the barbette and the deck supports has been pulled away and down, popping the rivet heads but leaving the steel strakes intact. There are no apparent fragments that penetrated the 1.5-inch STS steel.

The area of wood planking damage seen in this photograph is relatively small. There are about 14 or 15 four-inch wide planks shown damaged in this photograph, giving a width of 56 or 60 inches of damaged deck area as noted in Figure 92. There would be 7 planks remaining before the outer limit of the hole is reached so this means that the hole is approximately 28 to 32 inches wide, which is close to the 2.5 foot x 12 foot measurement given in South Dakota's action report. Looking closely at the lower scar, there is a vertical scar from the top of the dent and a different color line that runs through the top of the dent which will help identify this impact scar in other photographs. The different color line that runs through this scar also marks the lower edge of a circular 15 inch x 8 inch I-Beam that supports the main deck, which will help estimate the distance below the main deck that the center of the lower impact was. The lighter color band on the barbette is where the main deck was pressed up against the barbette and marks the original deck level. Based on the documentation in the reports, the deck and Athwartship I-beams 123 and 126 underneath was bent down out to 8 feet from the barbette and then severely bent down the last 3 feet.

Figure 93 is a close up of the upper scar damage to the plate. This photograph was used in the original BuShips report and may have been the only one of two that the original authors used. The top of the flange at the very top of the barbette can be seen in the upper right corner of the photograph. The vertical seam and right side gouge can also be seen along with the lines that marked where the main deck used to be. This scar did not significantly dent the armor and resulted in surface flaking of the plate with deeper cracks at the center. If viewed by itself this photograph would suggest that the impact was made by a HE shell due to the lack of damage to the plate surface.

Figure 94 is the second photograph used in the original report. This shows the lower impact site looking up from the 2^nd deck level. The photograph is looking aft and shows that Athwartship I-beam 126 has been bent down and the remains of the circular I-beam it supported that surrounded the barbette. The main deck has been pushed down and the center of the lower gouge (marked with an X) is approximately 4" below the original line that marked the bottom edge of the circular I-beam. It also shows circular cracks on the surface of the Class "A" plate that radiate out from this impact and a minor vertical scar at the top of the gouge which can be seen in the photograph looking at the scars from above the main deck. These are the circular cracks documented in South Dakota's report, which is quoted here: "Starboard side of #3 barbette has plating dished in 1.5" over an area of 15" in diameter aft of seam. Circular cracks extending over this area."

Concentric cracks in the brittle face of Class "A" armor are virtually always seen when a face-hardened plate is impacted hard enough to make a significant dent or hole in it. The surface layer is extremely brittle and the shock waves rippling outward along the face and those going into the plate and reflecting from the plate back or hard-face-to-soft-back plate boundary cause a Moiré (interference) Pattern on the surface where they null and reinforce each other, which is why the cracks seem to be so evenly spaced. This is a very important clue because it shows that the 17.3-inch Class "A" plate took a major shock below the normal level of the main deck. These cracks show that the shell body impacted here and not at the upper scar at 17 inches below the top of the barbette.

The center of the impact is approximately 4 inches below where the original bottom edge of the circular I-beam that supported the main deck was. This places the center of the lower impact at 20.5 inches below the top of the 1.5-inch STS steel weather deck and this is approximately 51 inches from the top of the barbette as measured from the top of the flange to the center of this impact site.

Figure 95 above is looking a bit forward. The lower impact scar is hidden due to the distorted main deck, but this view shows Athwartship I-beam 123 and how it is bent down. Also shown are the remains of the circular I-beam it once supported. You can still see the faint circular cracks along with the center seam between Class "A" plates.

This closer look in Figure 96 shows how the riveted structure between the circular I-beam and the barbette was pulled apart with many rivet holes remaining intact. This view also shows how the circular cracks crossed over the seam between the two plates and that the circular I-beam itself was twisted and ripped in half. Athwartship I-beams 123 and 126 were bent down 8 feet out from barbette with the last 3-4 feet being severely bent down.

The following photographs were taken aboard sister-ship USS Alabama to give an idea of how the same area on USS South Dakota would have looked before the battle.

Figure 97 shows Athwartship I-beam 123 which is seen supporting the 15 x 8 inch circular I-beam that surrounds the barbette. The small angle irons seen attached to the circular I-beam are supports for the mess tables that surround the barbette and do not imply any vertical support for the circular I-beam itself.

Figure 98 shows the gap between the circular I-beam and the barbette itself. The riveted structure attaching this I-beam to the main deck will be ripped down as seen in the damage photographs. The deck is not directly attached to the barbette but is sealed with a weather seal and pressed up against the barbette. The upper strength decks of the hull girder (main and second deck) are relieved of supporting the massive weights of the turrets. These weights are taken up by the platform decks, the ships sides, and the keel. In this way when the ship sags or hogs the upper strength decks are not bent by these actions. The armored weather deck, by being pressed so tightly up against the barbette, assists in holding the barbette structure rigid from lateral movements like when the ship heels or rolls. This however does leave a natural weak spot where the deck can be pushed down if the impact is heavy enough.

Figure 99 was taken on board USS Alabama looking aft and shows bulkhead 129 and doorway 2-129-1. The equivalent compartments on USS South Dakota were heavily damaged by shell blast. This photograph also shows the ceiling filled with ventilation ducts and piping and 20 feet of mess tables with their support structure, all of which were badly damaged or destroyed when this shell exploded. A large percentage of the fragments from this hit were thrown aft towards bulkhead 129 with a very few fragments traveling sideways or forward.

Figure 100 taken aboard the USS South Dakota shows the damage to bulkhead 129 and the size of the fragments. The large hole is probably the 26 inch x 35 inch hole documented in the report. There appear to be scars on the armored second deck where fragments were deflected through the bulkhead. The I-beams have been twisted and some cut.

Figure 101 taken on USS Alabama is of the same bulkhead. Note that even the vertical I-beams that make up the bulkhead are in identical locations. The two ships are framed identically around the turret with frame numbers painted on the hull and doors being labeled with identical numbers that match the South Dakota's damage report. The hatch leading to the third deck is Hatch 2-128-2. On the main deck Hatch 1-128 is directly above this hatch.

Figure 102 and Figure 104 show the ship's scullery on the opposite side of Bulkhead 129 as seen on board USS Alabama and give an idea of how the same area on USS South Dakota may have appeared.

Figure 104 shows the scullery looking aft. The wire screen is at Frame 131. Fragments ripped through this area damaging the kitchen supplies.

Figure 105 shows the compartment aft of the scullery. Both Stanchion 131 and Stanchion 134 on South Dakota took damage as did the ventilation ducts seen in the overhead.

Figure 106 shows Bulkhead 136 and Door 2-136-1 which were both damaged by fragments. Bulkhead 136 was the farthest that any fragments traveled from the blast point on the barbette, some of which penetrated this bulkhead.

Figure 107 shows the center seam between Class "A" plates within the barbette and the twisted and bent roller path that gave the turret difficulty in training after the battle. This damage was most likely caused by shock either by the impact force or by the explosion transmitted through the 17.3-inch Class "A" plate that protected the roller path.

Determining the true shell trajectory was one of the first obstacles for the analysis of this impact. BuShips assertion that the projectile passed through Hatch 1-122 and then struck the barbette gives us two impact points on the ship from which we can determine which impact obliquity angles were possible and then using the track chart for the ships movements determine the range and time Kirishima, the hatch, and the barbette line up. The hatch begins at Frame 122 and ends at Frame 124. The center seam of the barbette is at Frame 123.5 with the projectile hitting the barbette just aft of the center seam. Zero degrees is the normal line to the barbette face at a right angle to the impact site. For the shell to pass through this hatch and strike where it did on the barbette, it can be shown that the range of possible impact angles runs from +25 to +50 degrees as illustrated in Figure 108.

The times that Kirishima, Hatch 1-122 and the barbette line up are between 0101-0103 with the maximum range of 7,500 yards to as short as 5,600 yards At 7,500 yards the angle of elevation is 4.0 degrees and angle of fall 4.63 degrees. At 5,600 yards the angle of elevation 2.89 degrees and angle of fall 3.23 degrees. ⁷⁶ After 0103 Kirishima, the hatch and the impact site will never line up again based on the two ship's track charts. This is the first inconsistency. Captain Gatch was very specific that this impact occurred at 0110 near the end of the engagement. Either the impact occurred earlier than Captain Gatch knew or the shell trajectory did not pass through the hatch.

If the projectile impacted the upper scar implied by the original BuShips report and if South Dakota was on an even keel (no documented turn between 0101 and 0103), then with a 4 degree angle of fall a 14-inch projectile will miss the hatch entirely. The light blue lines in Figure 109 represent a 14-inch shell impacting the upper scar and the red lines represent it impacting at the lower scar. In the case of the lower scar, the shell would have impacted the deck prior to the hatch. ⁷⁷ It is, however, the lower impact scar which is the main impact site. The gouge is 1.5 inches deep with the major shock cracks radiating out from this site.

In fact, there is no trajectory at the ranges where this battle took place which will allow the hatch to be hit and the projectile impact the barbette where the photographs show us it occurred and still duplicate the damage documented in the reports. It becomes clear that the original assertion made by BuShips that the shell passed through Hatch 1-122 on its way to the barbette must be incorrect.

If the impact was truly at 0110 as reported by Captain Gatch, then at this time Kirishima has passed South Dakota and has turned north in her attempt to withdraw. At 0107 Kirishima begins circling to port out of control due to damage to her rudders. South Dakota is on a course of 285 degrees true and orders her maximum (flank) speed at 0102 to avoid gunfire. At 0110 she turns from 285 degrees to a new course of 235 degrees true so she can withdraw from the battle herself (see ship's track chart in Figure 69). Based on the track chart, Kirishima is approximately 11,350 yards away at 62 degrees true bearing from South Dakota just before she makes her turn. The angle of fall at this range using extreme wear for the liners is 8.1 degrees.

The new horizontal impact obliquity angle on the barbette for the lower pit is circa 44 degrees. This is from the computation that Kirishima is 62 degrees true from South Dakota and South Dakota is on a course of 285 degrees true, which gives an angle of 62 degrees - (285 + 90 - 360 for the transverse centerline of the barbette at right angles to the wood deck planks) - (3 degrees for the actual impact point on the barbette a few feet aft of this centerline) = 62 - 15 - 3 = 62 - 18 = 44 degrees horizontal impact obliquity on barbette face. This scenario is shown in Figure 110.

South Dakota is making a port turn at this moment at flank speed. She will heel over to starboard as she turns to port from 285 degrees to 235 degrees. The two following photographs show USS Indiana making a similar high-speed turn – this one to starboard and heeling over to port. We estimate that the absolute maximum heel angle for the South Dakota class battleships under these conditions was 9.5 degrees.

At this range of 11,350 yards, the angle of fall is 8.1 degrees (EB6.0G calculation), so the total angle is 9.5 (heel angle) + 8.1 (Angle of fall) = 17.6 degrees. Since the impact angle is now 44 degrees offset in the horizontal plane, coming from the stern the shell would impact the main deck about 78 inches from the barbette and strike the barbette approximately 24.7 inches below the steel deck (78 * TAN(17.6) = 24.7 inches). However, the impact resistance with the deck will also force the nose of the shell up approximately 3.0 inches and this places the center of the impact at the lower site to within 1.0 inch of our estimated depth. We used a worst case scenario, however, the effect of such small variations can be easily compensated by the spread in other estimated values, such as the possible upward curve of the nose due to the deck – perhaps it was 4 inches and not 3 inches, which would compensate for a steeper heel angle, or 2 inches which would account for a lesser heel angle – or else the shell was yawing slightly due to the worn gun, so the nose was tilted down about a degree, adding to the effective angle of fall (at small angles of yaw, a yaw of 1 degree can be replaced by an actual change in the trajectory by 0.5 degree in that direction with similar effects on the penetration calculations). Thus, for every minor tweak in one direction, we could have a tweak in another direction. The fact that this worst case scenario comes within 1.0 inch of our estimated depth shows that the principles used for this trajectory are valid.

The best estimate for the shell type that resulted in this damage is a 14-inch Type 1 AP projectile. The main deck was not blown down due to an explosive force but pushed down by the weight, velocity, and frontal density of the projectile impacting the deck. The wood deck overhang seen in Figure 92 again shows us how the steel was pushed down from under the wood. The shell impacting the deck approximately 78 inches away begins to bend the deck down and tear the weather seal and riveted structure away from the surface of the barbette. A simple analogy is the pull tab on a large soup can. When you lift the tab up the front edge of the tab forces the lid's lip into a large "smiley-face" arc. In the case of the barbette, the arc is in the opposite direction because the deck is outside the barbette and the lid for the soup can is on the inside of the can but the principle is the same.

When the shell impacted the deck it would lose its windscreen, cap head, and AP cap due to the extremely high obliquity impact with the 1.5-inch STS deck. However, the cap head and AP cap, continuing along, but now at a shallow upward angle (the shell's 44-degree horizontal obliquity angle to the lower barbette impact point) would bounce off the barbette above the deck level near the upper blemish point (which had not been formed yet) at almost exactly 90 degrees from the original direction of motion – for an impact that does not penetrate deeply, as these light-weight cap pieces could not against the hard, thick barbette face, the angle of reflection is very close to the incoming angle, just going the other way on the far side of the normal (right-angles) line through the impact point, which turns out to be in a direct line with Hatch 1-122. Thus, they hit the hatch moving away from the barbette and slightly upward, causing the semi-circular holes in the hatch as they fly outward to end up in the ocean. As the remaining shell nose and body moved forward and down, it struck the barbette at the lower impact site. However, at 44 degrees, this angle is much higher than the test proof angle for a Japanese Type 1/91 AP shell (any size), which were only proof tested to 20 degrees from right angles, resulting in the projectile having its nose tip snap off and eliminating any possibility of penetrating the barbette more than the tiny 1.5 inch deep notch at the lower impact site. ⁷⁸ Usually, this nearly horizontal impact would cause the projectile to ricochet slightly downward and mostly sideways away from the barbette, much like the AP cap and cap head mentioned above, but the deck prevents this motion by pinning the projectile nose to the barbette in the horizontal direction. The nose bends the deck away from the barbette as it tries to ricochet, but it is constrained to move almost straight down by the deck resistance, since this is the only direction that the deck will (relatively) easily bend under the force of the projectile nose from above. The result is the 28 to 32-inch width of the slot between the barbette and bent-down deck edge in the center where the projectile impact was, narrowing like a smile in either direction parallel to the barbette face until the deck is no longer bent at roughly 5-6 feet to either side of the projectile impact point.

The lower body of the projectile pivots up as the nose is forced down until the projectile is, in effect, standing on its nose with the broken tip sticking into the space beneath the bent weather deck and the base slammed up against the barbette near that upper "blemish" point just below the turret. This base-end rotation is so fast and violent that it is like a baseball bat hitting a home run (a rather extreme form of "base slap," as this lower body impact against the armor is termed in the US Navy). Since the armor's 1-inch-deep "cemented" face is about 650 Brinell hardness (approaching the hardness of hardened machine cutting tool steel), backed up by a circa 35% deep face of circa 500 Brinell, then another 20% dropping in a ski-slope curve to the circa 225 Brinell ductile back layer to the back surface of the plate (this last of "merely" bank vault steel hardness), the barbette armor face is essentially absolutely rigid and the rather soft lower body of the projectile flattens out against it as if the projectile was made from soft clay. A comparison of USN and Japanese hardening patterns for 14-inch AP projectiles is shown below in Figure 114.

This base slap causes the lower body to crush the explosive filler in from the barbette-impact side, where there is virtually no anti-shock cushion – only the upper end of the filler cavity has a heavy cushion to protect the filler from detonation on impact against thick armor head-on – for the very sensitive circa-1.5% (by weight) TNA filler. This causes the filler to detonate like British "Lyddite" (Japanese "Shimose") explosive did under similar impacts during World War I, acting just like it had been set off properly by a base fuze. This contact blast with the barbette at the upper blemish mark forms the surface damage pattern shown in the picture of that upper damage area on the barbette, with its irregular shock cracks and the small dislocations of the armor plates that have a joint very close to this spot (this is what caused the turret to be considered out of action due to the roller bearing path at the top of the barbette being misaligned, making turret traverse difficult). There is, however, no dent or pit in the barbette face at this upper blast point, it being merely slightly flattened and actually looks polished as the blast scoured off any surface lumps and removed the paint there.

This rotation and base slap is similar to what occurred for Hit 17. In both of these hits, the projectile nose failed to penetrate the final plate hit (the barbette for Hit 26 and the rear of gun mount for Hit 17) and the projectile nose was locked to the plate face (by the bent-down deck for Hit 26 and by being partially punched through the plate in Hit 17) at or near the initial impact point at a high angle (yaw angle circa 45 degrees in Hit 17 and obliquity angle in Hit 26) and rotated to end up broadside to and slammed up against the plate face (vertically nose-down in Hit 26 and horizontally nose to the right in Hit 17). In Hit 26 the shell slammed up against the unyielding barbette face and detonated and in Hit 17 it made a shallow dent in the thinner, ductile gun mount armor and remained intact. We think that these results against the plates that finally stopped the shells are very similar, regardless of any motion prior to the final impact.

With half of the shell below the main deck and the other half above the main deck and the shell in a vertical position pressed up against the barbette, we get the above main deck fragment pattern described in the report. The right gun was probably directly over the blast point with the base fragments being blasted up into the gun sleeve.

The fragment pattern below the main deck is largely traveling aft due to the curvature of the barbette as shown in Figure 116 and earlier in Figure 103. The size of the fragments that would create the holes in bulkhead 129 as seen in Figure 100 are huge but are also relatively few in number. These could only have been produced by the large nose pieces of a fragmented AP projectile. The armored second deck deflected all fragments and some of these fragments had enough mass and energy to be able to penetrate bulkheads as far aft as bulkhead 136.

When examining the other two types of 14-inch projectiles fired by Kirishima, the Type 0 HE and the Type 3 Incendiary AA shell; the Type 3 would have begun to break up on impact with the deck and, with its large wood nose adapter, is totally incapable of causing the type of fragment damage found here. Its small powder charge is also incapable of producing the type of blast damage found for this hit so this type of shell can be quickly eliminated as a possibility.

For the Type 0 HE, the way the BuShips damage report originally described this impact as passing through Hatch 1-122, impacting the barbette 17 inches from the top, and then detonating and blowing a 3 foot by 10 foot hole into the deck, has led many to believe this impact was made by a HE projectile. A closer examination of this idea as described above shows why this is not possible. Had a HE shell detonated horizontally to the deck, the damage around the barbette would have been greatly different. The impact from this type of shell would have given a shallow oval dent over a wider area, with no wood left for several feet on all sides, especially sideways. It would have created a small, irregular, roughly oval hole in the deck under the center of the shell, surrounded by many tiny holes and dents up close to the big hole which would have been caused by fragments going mostly sideways. The deck edge up against the barbette would have been bent up slightly as it had the most reinforcement from underneath and it would not have been bent down as much as directly under the explosion point. There would not have been any way for any projectile pieces other than a few tiny middle-body fragments from going below the weather deck, with only deck pieces blown out causing any major damage below the deck, and those being thrown straight down, not sideways. The likely damage caused by a HE shell is shown in Figure 117.

A Type 0 HE projectile is 4 feet long which places the center of the explosive force two feet away from the barbette surface. If the shell struck the upper impact scar 17 inches from the top of the barbette, then it would produce an open air explosion over the deck which would have caused the deck to dish. There would be no wood overhanging where the steel is bent down and the 64-pound TNA filler is not powerful enough to produce a 10 to 12 foot long hole in the 1.5-inch STS steel deck. The shell body of a HE projectile will never reach the barbette because when the fuze is crushed the shell will destroy itself almost instantaneously.

For the deck to get bent down and the hole to be directly up against the barbette surface due to an explosive force, the center of the charge must be placed directly up against the barbette and on the deck. The charge weight to produce such a large hole between 10 and 12 feet long in the 1.5-inch STS steel would need to be in the order of 200-300 lbs. of HE explosive. This size burster is impossible for a Japanese 14-inch Type 0 projectile.

We can compare Hit 11, which was made by a 14-inch Type 0 projectile striking on a 1.25-inch STS plate, and the deck area for Hit 26 to show how the damaged plates differ.

These inconsistencies show that the damage was not caused by a HE projectile detonating horizontal to the deck and that BuShip's original analysis was incorrect. Another consideration that also enters into this analysis is the fact that a Japanese nose-fuzed HE projectile simply does not have the capability of gouging a 1.5-inch deep gash in the face-hardened armor plate of the barbette. In other words, Japanese HE projectiles could not penetrate any thick, rigid Class "A" plate more than a slight flaking of the cemented surface layer caused by the burster exploding at point-blank range. There would be no deep conical pit in the armor as is the case for this hit. This alone can eliminate the HE shell type from consideration. Also, the only projectile type that could produce a Moiré (interference) Pattern due to reflected impact shock waves bouncing off the plate's rear surface, back into the brittle face layer, is from an AP projectile.

The fragment size and distribution also needs to be considered. A HE projectile, due to its larger shell cavity and thinner sides, breaks up into hundreds of small fragments with only a few large pieces coming from the base section. The actual projectile in this case produced many large fragments that passed through the scullery and through bulkhead 136. The fragment pattern for Hit 26 is typical of AP ammunition and inconsistent with HE ammunition.

Although not conclusive, the fact that this hit was from one of the last shots fired by Kirishima at a known battleship target would tend to make one surmise that the Japanese gunners had by now used up the Type 3 AA and Type 0 HE rounds already in the guns and hoists at the start of the battle and were by now firing AP rounds at this end stage of the battle.

When everything listed above is considered for Hit 26, the only projectile that fits all of the available evidence is the 14-inch Type 1 AP shell. This hit represents the only time in US Naval History that a US battleship was struck by a foreign battleship's main-caliber AP projectile and in this case South Dakota and her designers won the age-old contest between shell and armor. ⁷⁹

For this damage it is not clear if it was caused by fragments or a direct hit. In BuShips report Plate 1 it is listed as fragment damage but the BuShips' caption on the photograph in Figure 120 implies a direct hit. If so, a 5-inch nose fuze, Type 0 HE projectile is the most likely due to the relatively small area of the platform destroyed and it appears the shell detonated on impact. There are not many shell impacts close to the platform that actually detonated, so it seems unlikely that this damage was from fragments. Most of the shells that struck near Sky Control passed through the superstructure without detonating (Refer to Hits 9 and 12).

Bureau of Ordnance (BuOrd)
– OP 1667, Japanese Explosive Ordnance

Bureau of Ships (BuShips)
– War Damage Report No. 57, 1 June 1947. U.S.S. SOUTH DAKOTA (BB57), Gunfire Damage, Battle of Guadalcanal, 14-15 November 1942
– Builder plans for USS South Dakota

Reports of the U.S. Naval Technical Mission to Japan
– O-17 Japanese Naval Projectile Fuzes
– O-19 Japanese Projectiles General Types
– O-25 Japanese Explosives
– O-47(N1) Japanese Naval Guns and Mounts, Article 1 - Mounts under 18”
– O-54(N) Japanese Naval Guns

Japanese Action Reports
– Atago Direct Action Report No. 8, 12 to 14 November 1942 (submitted 18 November 1942)
– Ikazuchi Direct Action Report, 14 to 15 November 1942 (submitted 15 November 1942)
– Kirishima Brief Action Report JT 1, National Archives
– Sendai Brief Action Report JT 1, National Archives
– Takao Brief Action Report JT 1, National Archives

United States Action Reports and Deck Logs
– Admiral W.A. Lee. Report of Night Action Task Force 64 – Night of November 14-15, 1942
– USS South Dakota. Action Report, night engagement 14-15 November, 1942, with Japanese naval units, off Savo Island.
– USS Washington. Action Report, Night of November 14-15, 1942.
– USS Washington. Deck Logs – Night Action – 14-15 November 1942

United States Strategic Bombing Survey
– Interrogations of Japanese Officials, Interrogation Nav No. 33, USSBS No. 138, Interrogation of LCDR Tokuno Horishi

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Gakken Pacific War Series:
– Vol. 5: Soromon Kaisen [The Solomons Campaign], 2000.
– Vol. 6: Shitō Gadarukanaru [Deadly Battle for Guadalcanal], 2000.
– Vol. 21: Kongō-gata Senkan [Kongō Class Battleships], 1999.

Lengerer, Hans. “The Kongō Class” Contributions to the History of Imperial Japanese Warships, No. 2, March 2007, pp 18-30; No. 3, Sep. 2007, pp 25-44.
Lundgren, Robert. The Battleship Action 14-15 November 1942
Okun, Nathan
– TABLE OF METALLURGICAL PROPERTIES OF NAVAL ARMOR & CONSTRUCTION MATERIALS
– MISCELLANEOUS NAVAL-ARMOR-RELATED FORMULAE
– Kirishima’s Hit on South Dakota
– Underwater Projectile Hits

Kobayashi, Michio. Senkan 'Kirishima' no Saigo [The Last of Battleship Kirishima].” Saiaku no Senjō Gadarukanaru Senki, 1987, pp 350-361.
Yoshino, Kyûshichi. Senkan 'Kirishima' no Saigo [The Last of Battleship Kirishima].” Maru Extra Vol. 10, May 1998, pp 54-57.