the wrecks of HMAS SYDNEY and HSK KORMORAN

The Loss of HMAS SYDNEY II 215

12 Empirical evidence: the wrecks of HMAS SYDNEY and HSK KORMORAN

12.1 The finding of the wrecks and debris fields of HMAS SYDNEY and HSK KORMORAN in March 2008 and the capture by underwater video and still photography of images of aspects of those wrecks and debris fields have enabled scientific analysis to be applied to the physical evidence of the battle between the two vessels. This allows empirical conclusions to be drawn about two matters of controversy. The first concerns the accuracy of the account the German survivors of KORMORAN gave of the battle with SYDNEY: it is now possible to compare their evidence about the course of the battle and the damage occasioned to SYDNEY and its crew with the observed damage. The second concerns the provision of a scientific explanation for why SYDNEY sank and why there were no survivors from her.

12.2 The Inquiry commissioned the Maritime Platforms Division of the Defence Science and Technology Organisation and the Australian Division of the Royal Institution of Naval Architects to prepare a report on the technical analysis of the sinking of SYDNEY and KORMORAN.1

The scientific methodology

12.3 In the examination of the wrecks of SYDNEY and KORMORAN a number of modern scientific tools were applied. The studies conducted are discussed briefly in the following paragraphs.

Vulnerability analysis

12.4 A vulnerability assessment was conducted using a method known as XVAM. This methodology allows for mapping of damage originating from a detonation point, in this case the 15-centimetre shells fired by KORMORAN. It calculates a probability of such damage occurring to the systems, personnel and structures within the damage zone. The simulation provides a statistical measure of the likelihood that an event will occur, rather than an accurate measure of the failure mechanism

1 For a brief statement of the qualifications and experience of the authors of the resultant joint report, see DSTO.003.0001 at 0007 to 0011.

http://www.defence.gov.au/sydneyii/FinalReport/Report/images/DSTO.003.0001.pdf

216 The Loss of HMAS SYDNEY II

incurred. An electronic model of SYDNEY was created in order that the XVAM analysis of likely damage from shellfire could be conducted.2

Flooding analysis

12.5 A flooding analysis was conducted using two computerised codes known as FREDEYN and PARAMARINE. With the electronic model that had been created, these tools allowed predictions to be made of the progressive flooding of areas of SYDNEY in her damaged condition resulting from torpedo and shell damage, which could be observed and measured from the photographs of the wreck. This enabled an assessment to be made not only of the progressive flooding of the ship but also of the consequences of that flooding for the motion and stability of the vessel in various sea states. It was also possible to estimate the time it would have taken for SYDNEY to capsize and sink.3

Sea-keeping loads analysis

12.6 Software known as PRECAL was used to determine the magnitude of loads experienced by SYDNEY in various conditions. This enabled the calculation of pressures exerted by sea water acting on individual elements of the hull surface.4

Structural integrity analysis

12.7 Software known as ULTSTR (Ultimate Strength) was used to identify the circumstances in which a particular section of SYDNEY might have collapsed.5

Computer-aided design modelling

12.8 Underwater photographs of the wreck of SYDNEY showed damage caused by shell penetrations and other physical effects of damage. A CAD system was used to measure the size of the penetrations and the extent of the damage.6

2 DSTO.003.0001 at 0039 para 1.2 3 DSTO.003.0001 at 0040, para 1.2.2 4 DSTO.003.0001 at 0044, para 1.2.3 5 DSTO.003.0001 at 0047, para 1.2.4 6 DSTO.003.0001 at 0048, para 1.2.6







Visualisation

12.9 Visualisation software known as BLENDER was used to construct a three-dimensional visualisation of the outcomes of the scientific analysis. This allowed for a clear understanding of the technical analysis. The visualisation accompanied the Defence Science and Technology Organisation’s report.7

Fire assessment

12.10 Underwater photographs showed evidence of major fire damage in various parts of the ship. The fire damage was analysed, as were the consequential effects of the spread of smoke and fire throughout the vessel.8

The SYDNEY wreck site

The debris field

12.11 The wreck site of SYDNEY was discovered on 16 March 2008. Following an extensive survey by SV GEOSOUNDER, a pictorial map of the debris field was produced (see Figure 12.1). The image shows the compactness of the SYDNEY site on the sea bed.9 SYDNEY’s bow is detached from the hull and lies about 470 metres from the main section of the hull. Numerous parts of the ship were dislodged during the sinking process, and they are shown close to the bow. The relative compactness of the debris field is important because it is indicative of two things: first, that the bow did not separate from the hull before SYDNEY sank; second, that the sinking was rapid.10 When the bow did detach from the hull it is probable it descended roughly perpendicularly to the seabed floor, other heavy objects detaching from the sinking ship falling with it11, as demonstrated in Figure 12.2.

12.12 Although the various portions of the ship (such as the foremast, searchlight, main mast and high-angle control station base) shown in the debris field might have been damaged in the battle, the image of the debris field suggests that they did not separate from SYDNEY until she began to sink and, being heavy objects, thereafter descended to the ocean floor, when they separated from the vessel.

7 DSTO.003.0001 at 0048, para 1.2.5 8 DSTO.003.0001 at 0049, para 1.2.7 9 DSTO.003.0001 at 0166, Figure 111 10 TRAN.021.0001_R at 0003_R at line 1 11 DSTO.003.0001 at 0290





http://www.defence.gov.au/sydneyii/FinalReport/Report/images/TRAN.021.0001_R.pdf


Figure 12.1 The debris field of SYDNEY on the sea bed12

Figure 12.2 A schematic of SYDNEY’s sinking process13

12 DSTO.003.0001 at 0166, Figure 111 13 DSTO.003.0001 at 0312, Figure 278

Foremast

Searchlight

Bow

DCT

HACS

Boat

Not seen

Not seen

Torpedo

Two boats Boat cradle

HACS base

Boat

Pieces of debris

Mainmast base

Funnel

BoatCatapult

4-in guns (stbd 1)

Torpedo tubes (4)

Wire

Torpedo tubes (4)

‘Cross-talk’ image

ROV analysis of sidescan sonar images, HMAS SYDNEY wreck and

debris field

Near S10: - searchlight - 12ft rangefinder - Rack depth charges (3)- 44 gal. drum

Near S9: - Tyres (fenders)? - Plane wreckage - boat anchor

Note: DCT-direction control tower HACS-high-angle control station ’Cross-talk’ is a phantom image seen on opposite side of data. It appears directly opposite the real object

The hull of the HMAS SYDNEY with stern to the north, can clearly be seen on the dark image. The shadow (in white) gives a better indication of the vertical relief.

http://defence.gov.au/sydneyii/FinalReport/Report/images/DSTO.003.0001.pdf

http://defence.gov.au/sydneyii/FinalReport/Report/images/DSTO.003.0001.pdf


Torpedo damage

12.13 SYDNEY’s bow lies inverted on the ocean floor, on its starboard deck edge (see Figure 12.3). The bow section shows significant damage resulting from its being torn apart from the main hull and its final impact with the ocean floor (see Figure 12.4). The tear along the port side of the bow (see Figure 12.5) appears, however, largely undamaged by these effects, and it is possible to show that the bow broke off at frame 19. The break where the bow separated from the hull is shown by the splits apparent in the forecastle deck. This is illustrated in Figure 12.4.

Damage close to the port side of the bow’s keel shows the typical concave indentation of an explosion on this surface, consistent with torpedo damage (see Figure 12.5). The damage suggests that SYDNEY was hit by a torpedo on the port side. The hole edge is at frame 19, so the detonation occurred aft of this frame, somewhere between frame 19 and frame 30. The probable location was in the vicinity of frame 25, around the Type 125 Sonar Dome (see Figure 12.6).

Flaring on the starboard side panels (see Figure 12.7) indicates that the damage from the port side torpedo detonation has progressed and caused either a hole or bulging on the starboard side of the hull.

Figure 12.8 shows significant damage to the internal structure inside the bow, the decks and bulkheads lying at the top of the inverted bow section. The heavy anchor cable is still attached and is trailing out of the break in the hull. The collapse of the deck probably occurred as a result of the sinking, not as a direct result of the torpedo detonation.

The main section of the wreckage of SYDNEY shows that significant secondary damage has resulted from a number of mechanisms—the torpedo explosion, the ripping of the bow from the main hull section during sinking, the force of the water flowing over the ship during sinking, and the impact of the main hull section on the ocean floor. It is difficult to determine which of these factors is the most likely cause of particular damage shown in some photographs.

Notwithstanding this difficulty, the damage sustained is consistent with what one would expect from a single torpedo with a 280-kilogram warhead detonating close to the port side of the hull. Figure 12.9 shows the approximate extent of the damage to SYDNEY’s port side.14

14 DSTO.003.0001 at 0167, para 5.2.2



Photo copyright Finding Sydney Foundation. Photographer David Mearns

Figure 12.3 Forward section of SYDNEY’s inverted bow resting on the ocean floor15

Figure 12.4 Splits in SYDNEY’s forecastle deck16






Figure 12.5 The break in the bow on the port side, showing indentation due to torpedo detonation17

Figure 12.6 Probable torpedo detonation location on SYDNEY’s port side18






Figure 12.7 Flaring on starboard side panels suggesting the torpedo caused a hole or bulge on the starboard side19


Figure 12.8 Internal structure of the bow, showing collapsed decks and connected anchor chains20





Figure 12.9 The port side torpedo hole overlaid on a diagram of SYDNEY. Note a starboard

side profile has been used.21

Shell and fragment damage

12.14 SYDNEY was extensively damaged by shell hits on her port and starboard sides.

Lack of clarity in the images, fire damage, collateral damage from sinking and failure to capture some areas of the wreckage all mean that the damage that has been positively identified probably materially understates the extent of damage actually suffered from the 15-centimetre shells fired by KORMORAN. The images are also insufficient to allow identification of hits from the 3.7-centimetre anti-aircraft guns and the 2-centimetre machine guns.

Further, penetrations identified and recorded as a single hit might in fact have been the subject of several hits. Tables 12.1 and 12.2 summarise the 15-centimetre shells known to have hit SYDNEY, as disclosed in the video imagery, on each of the port and starboard sides.

Figures 12.10 to 12.18 show the location of the weapons damage to various portions of the ship.22

21 DSTO.003.0001 at 0174, Figure 124 22 DSTO.003.0001 at 0174, para 5.2.3




Table 12.1 Weapon hits on SYDNEY’s port side: a summary23

Location Contact

detonation Shell

penetrated Not

penetrated Unknown Total

Structure 17 14 2 1 34

A Turreta 2 2 0 0 4

B Turreta 1 0 0 0 1

Catapulta 2 0 0 0 2

Total 22 16 2 1 41 a. Structure can independently rotate, so direction of shot needs to be determined by SYDNEY’s operational status at the time of a specific hit.

Table 12.2 Weapon hits on SYDNEY’s starboard side: a summary24

Location Contact

detonation Shell

penetrated Not

penetrated Unknown Total

Structure 13 17 12 0 42

X Turreta 0 1 0 0 1

Director control towera 0 1 0 0 1

Starboard torpedoa 1 0 0 0 1

4-inch gun locker 1 0 0 0 1

Total 15 19 12 0 46 a. Structure can independently rotate, so direction of shot needs to be determined by SYDNEY’s operational status at the time of a specific hit.

Figure 12.10 Location of weapons damage to SYDNEY’s port side and around B turret25

23 DSTO.003.0001 at 0175, Table 18 24 DSTO.003.0001 at 0175, Table 19 25 DSTO.003.0001 at 0176, Figure 125





Figure 12.11 Location of weapons damage to SYDNEY’s port side around the bridge26

Figure 12.12 Location of weapons damage to SYDNEY’s port side around the catapult27





Figure 12.13 Location of weapons damage to the port side of SYDNEY’s X turret28

Figure 12.14 Location of weapons damage to SYDNEY’s starboard side around A turret29





Figure 12.15 Location of weapons damage to SYDNEY’s starboard side around the bridge30

Figure 12.16 Location of weapons damage to SYDNEY’s starboard side around the bakery31





Figure 12.17 Location of weapons damage to SYDNEY’s starboard side around the 4-inch high-

angle guns32

Figure 12.18 Location of weapons damage to SYDNEY’s starboard side around Y turret33





Fire damage

12.15 Fire damage is apparent on painted surfaces in many of the video and still images taken of the wreckage. There is fire damage to:

• the entire bridge structure and across the breadth of the forecastle deck, as well as down to the lower deck hull on the port side and down to the upper deck hull on the starboard side

• midships below the aircraft platform and across the upper deck

• the aft superstructure and upper deck on the port side and aft superstructure on the starboard side, below the aft control position. The upper deck is also burnt below X turret. The starboard hull (lower deck) is burnt around the site of a shell impact or penetration.

The fires were caused by superheated fragments of exploded shells lodging in combustible material, creating small fires that joined to produce larger conflagrations.34

Figure 12.19 shows the areas of SYDNEY affected by fire damage on the lower deck, upper deck and forecastle and from starboard and port elevations.

Ship’s boats and Carley floats

12.16 No Carley floats were found in the wreckage or the debris field.

No boats were found still in their original position. Five boats were found in the debris field, in various stages of physical deterioration (see Figures 12.20 to 12.30). Some boats were physically broken, probably as a result of impact with other equipment. Clinker-built boats show more deterioration than carvel-built boats. Some of the boats show damage that is possibly the result of fragment impacts.35

34 DSTO.003.0001 at 0255; TRAN.021.0001_R at 0112_R 35 DSTO.003.0001 at 0193, para 5.2.5





Figure 12.19 Areas of SYDNEY affected by fire damage36

36 DSTO.003.0001 at 0193, Figure 146




Figure 12.20 The mid-section of a badly damaged motorboat on the sea bed37


Figure 12.21 The bottom of a motorboat on the sea bed with stern missing38

37 DSTO.003.0001 at 0195, Figure 147a 38 DSTO.003.0001 at 0195, Figure 147b





Figure 12.22 The bow of a motorboat on the sea bed, showing several holes believed to have been caused by the impact of fragments39


Figure 12.23 A whaler boat (top) and a motor and sailing pinnace lying on the sea bed40

39 DSTO.003.0001 at 0195, Figure 147c 40 DSTO.003.0001 at 0197, Figure 149a





Figure 12.24 A whaler boat showing where the planking has rotted away41


Figure 12.25 Enlargement of the bow section of a whaler, showing evidence of fire damage to the timber frame42

41 DSTO.003.0001 at 0197, Figure 149b 42 DSTO.003.0001 at 0198, Figure 149c





Figure 12.26 Side of the bow of a pinnace, showing multiple penetrations to outer timber consistent with fragments from weapons43


Figure 12.27 The stern of a pinnace, showing much of the boat’s interior missing44

43 DSTO.003.0001 at 0198, Figure 149d 44 DSTO.003.0001 at 0198, Figure 149e





Figure 12.28 A whaler on the sea bed, seen from the starboard side45


Figure 12.29 A whaler on the sea bed, showing a shell hole46

45 DSTO.003.0001 at 0200, Figure 150a 46 DSTO.003.0001 at 0200, Figure 150b





Figure 12.30 The forward part of a whaler with anchor still intact47


Figure 12.31 Damaged cutters and missing davits48

47 DSTO.003.0001 at 0200, Figure 150c 48 DSTO.003.0001 at 0202, Figure 151b





Figure 12.32 Starboard side end of a whaler cradle, showing fragment damage to the cradle frame and weapons damage to the hull49


Figure 12.33 Port side of a whaler cradle50






Figure 12.34 The port cradle where two Carley floats were located, showing extensive gunfire damage51

SYDNEY’s crest can be seen in Figures 12.24, 12.25 and 12.26.

The davits holding the cutters were damaged and the davits were shot away (see Figure 12.31).

The whaler cradles show evidence of extensive weapons damage. (see Figures 12.32 and 12.33)

The port cradle where two of the 20 Carley floats were located was extensively damaged by gunfire (see Figure 12.34).

Implosion damage

12.17 Implosion damage occurs when an airtight container has pressure applied externally to the extent that the container collapses. The failure is associated with excessive buckling of the structure. Such damage happens to many ships that are sinking, particularly those that sink rapidly before all spaces in the ship have filled with water.52

SYDNEY exhibits considerable implosion damage. Figure 12.35 shows the forward section of the ship’s upper deck on the starboard side. The

51 DSTO.003.0001 at 0204, Figure 154 52 DSTO.003.0001 at 0205, para 5.2.6




upper deck has collapsed downwards and the side shell is bent inward over a considerable length, possibly as far forward as the watertight bulkhead at frame 154.

Similarly, Figure 12.36 shows the quarterdeck bollards on the port side of the upper deck at frame 196 aft. The deck has been forced down several feet, exposing the capstan shaft on the ship’s centreline and bending the ship’s side slightly inwards.

Moving further aft, Figure 12.37 shows significant collapse around the stern section.

The buckling and collapsing damage extends from the stern through to about frame 154 and is evident on both sides of the ship. Figure 12.38 shows the extent of the collapsed region (in red). The two solid red lines identify the splits between the upper deck and the Y turret barbette as a result of implosion. This is shown in detail in Figure 12.39.53


Figure 12.35 The upper deck on the starboard side, looking forward54






Figure 12.36 Quarterdeck bollards on the port side of the upper deck aft55


Figure 12.37 SYDNEY’s collapsed stern56





Figure 12.38 SYDNEY’s upper deck, showing collapsed region57


Figure 12.39 Split in the deck abreast of Y turret on SYDNEY’s starboard side58

Impact with the sea bed

12.18 SYDNEY’s main hull shows some evidence of damage caused when the ship hit the sea bed, although some of that damage (shown in Figure 12.40) might have been caused by implosion.59

The impact with the sea bed caused major damage to the propellers, shafts and associated supporting structures. The port inner propeller

57 DSTO.003.0001 at 0209, Figure 162 58 DSTO.003.0001 at 0209, Figure 163 59 DSTO.003.0001 at 0209, para 5.2.6.1.2





and shaft have been partly withdrawn by about 8 to 10 feet. The shaft bracket has separated from the hull; this is shown in Figure 12.41.

The bilge keel is buckled, and a section of the side shell plating below the armour plating appears to be imploded. The imploded section seems to begin around the forward end of the A engine room and continues aft some distance, probably to the bulkhead at frame 135. Figure 12.42 shows SYDNEY’s bent starboard bilge keel.

The extent of imploded or collapsed shell plating is shown in Figures 12.43 and 12.44.

Towards the forward section of the main part of the wreckage, the forecastle deck has been bent down almost 90°. This could have occurred during the sinking process, but it is more likely that it occurred when the hull hit the seabed.60


Figure 12.40 The stern of SYDNEY on the sea bed61

60 DSTO.003.0001 at 0209, para 5.2.6.1.2 61 DSTO.003.0001 at 0210, Figure 164





Figure 12.41 One of SYDNEY’s propellers on the sea bed62


Figure 12.42 The bent starboard bilge keel63





Figure 12.43 Imploded or collapsed shell plating on SYDNEY64

Figure 12.44 Imploded or collapsed shell plating on SYDNEY’s starboard65





Collision damage

12.19 As SYDNEY was sinking several large pieces of wreckage—including the masts and funnels—broke away from the hull and collided with other parts of the wreck.66 For example, the front of the bridge structure is collapsed and crushed above the captain’s cabin and the navigating officer’s cabin. It is evident that the bridge has been crushed. The starboard side of the bridge has been torn away and the port side bent in. It can be deduced that this severe damage occurred as the ship sank, since the bulletproof roof over the compass platform on the upper bridge deck is lying intact in the debris field, resting against the director control tower. It is unlikely to have survived intact if it had not left the ship before the damage to the bridge and the upper bridge deck occurred. It is possible that a large piece of wreckage hit the bridge as the ship sank. The damage to SYDNEY’s bridge superstructure is shown in Figure 12.45.


Figure 12.45 SYDNEY’s damaged bridge superstructure67

66 DSTO.003.0001 at 0213, para 5.2.6.1.3 67 DSTO.003.0001 at 0213, Figure 170




Damage due to deterioration

12.20 Deterioration caused by the presence of rusticles associated with the degradation of steel has occurred, and there has also been shrinking of the wooden decking, although the corking material appears undamaged.68

The weapons system

The 6-inch guns and fire control

12.21 Figure 12.46 shows a reconstruction of the approximate final orientation of SYDNEY’s guns, as shown in footage obtained from the wreck.

Figures 12.47, 12.48 and 12.49 show a reconstruction of the approximate final orientation of A and B turrets and photographs of those turrets.

Figure 12.46 A reconstruction of the final orientation of SYDNEY’s guns69

Figure 12.47 A reconstruction of the final orientation of A and B turrets70

68 DSTO.003.0001 at 0213 to 0216, para 5.2.7 69 DSTO.003.0001 at 0216, Figure 174 70 DSTO.003.0001 at 0217, Figure 175






Figure 12.48 The final orientation of A turret71


Figure 12.49 The final orientation of B turret72





In Figure 12.48 it is evident that A turret has part of the deck wrapped around the guns. B turret’s barrels appear to be on different elevations. As can be seen, B turret received a single non-penetrating shell hit to the front of the turret and also a shell hit to the base on the port side.

Figure 12.50 is a reconstruction of the final orientation of X and Y turrets; Figures 12.51 and 12.52 show pictures of those turrets.

The aft turrets are both bearing on approximately 45° to port. The X turret guns are elevated at approximately –5° and the Y turret guns are at approximately 0° and –5° respectively. Y turret appears to be essentially undamaged.

Caution is required when interpreting the elevation and orientation of these turrets because of uncertainty about the nature of the damage sustained during the sinking process. Nonetheless, all are oriented to port.73

Figure 12.50 A reconstruction of the final orientation of X and Y turrets74

73 DSTO.003.0001 at 0216, para 5.2.8;TRAN.021.0001_R at 0037_R to 0039_R 74 DSTO.003.0001 at 0218, Figure 178






Figure 12.51 The final orientation of X turret75


Figure 12.52 The final orientation of Y turret76





12.22 The fire control for the 6-inch guns was carried out by the director control tower, which was located in the debris field. Holding up the DCT is the bridge roof. Because the DCT and the bridge roof are both located close to the ship and with the rest of the equipment found in the debris field, it seems that the DCT fell from the ship as a result of the sinking. Having regard to the crushing of the forward section of the bridge, it is deduced that the DCT did not fall as a result of a weapon hit before the sinking. Figure 12.53 shows the DCT in the debris field.

The 4-inch high-angle guns and fire control

12.23 The 4-inch gun deck has sustained damage on its port side, where it has been depressed downwards. The aft gun deck strut on the port side has also been damaged. On the starboard side of the gun deck there appears to be a shell hit on the deck above the torpedo tubes. The aft gun deck strut on the starboard side has also been dislodged.77

Figure 12.54 shows the approximate final positions of the 4-inch guns. Three of SYDNEY’s 4-inch guns (P1, P2 and S2) are still fixed to their mounts on the gun deck, as shown in Figures 12.55 to 12.57. The forward port side 4-inch gun (P1) has material wrapped around its mount; the material is thought to be part of the aft funnel. P1 is bearing approximately 135° port, with an elevation of about 15°. The aft port side 4-inch gun (P2) is shown to be at an elevation of about 80° and on a bearing of about 125°. The aft starboard 4-inch gun was bearing approximately 135° to starboard with an elevation of about 15°. The fourth 4-inch gun was found in the debris field. Figure 12.58 shows the fifth gun mount.

Protective plating was fitted to the guard rails around SYDNEY’s 4-inch gun deck, as shown in Figure 12.57.

Four of the ‘ready-use’ lockers are missing from the starboard side (see Figure 12.59); one of them lies in the debris field and has sustained weapons or fragment damage.

The fire control for the 4-inch guns was controlled by the high-angle control station, which is in the debris field. The high-angle control station was probably lost early in the battle as a result of a direct hit to the base of the tower, which would have affected the accuracy of any fire from the 4-inch guns. There is evidence of considerable damage to the starboard side superstructure below the high-angle control station, which could be attributable to the control station falling shortly after being hit. Figure 12.60 shows the damage to the tower.

77 DSTO.003.0001 at 0220 to 0223, Para 5.2.8.1.2.




Figure 12.53 The director control tower in the debris field78

Figure 12.54 A reconstruction of the orientation of guns on SYDNEY’s 4-inch gun deck79






Figure 12.55 SYDNEY’s forward port side 4-inch gun (P1)80


Figure 12.56 SYDNEY’s aft port side 4-inch gun (P2)81






Figure 12.57 SYDNEY’s aft starboard side 4-inch gun (S2)82


Figure 12.58 The forward starboard 4-inch gun mount83






Figure 12.59 Ready-use lockers missing from the starboard side of SYDNEY’s 4-inch gun deck84


Figure 12.60 Damage to the high-angle control station tower85





Small-calibre weapons

12.24 SYDNEY’s quad machine guns are no longer on the decks. They were probably washed off the deck during the sinking (see Figure 12.61).86

Torpedoes

12.25 The images show that both the port and the starboard torpedo tubes have separated from their mountings. The remains of the torpedo tubes were found in the debris field.87

Figure 12.62 shows that the 4-inch high-angle gun deck above the port side tubes has been deformed downwards. This is possibly a result of secondary damage and is probably not a direct result of weapons damage. The aft strut in this deck has collapsed. There is evidence of damage to smaller weapons below the port side tubes, but it is difficult to tell definitively if the damage was caused by smaller calibre weapons because of lack of photographic resolution.

Below the starboard torpedo tubes there are four non-penetrating 15-centimetre shell hits. It is possible that the torpedo tubes were damaged by fragments generated by these detonations. Figure 12.63 shows the hits.

Two torpedo tube mounts were found lying inverted in the debris field. One of these contains two torpedoes and the other three. Each of the three torpedoes in the latter mount has suffered damage, the outermost torpedo showing the greatest damage (see Figure 12.64).

86 DSTO.003.0001 at 0223, para 5.2.8.1.3 87 DSTO.003.0001 at 0224 to 0229, para 5.2.8.1.4





Figure 12.61 The mounting for a 0.5-inch quad machine gun88


Figure 12.62 Collapsed deck over the port side torpedo mount89






Figure 12.63 Four 15-centimetre shell hits below the starboard torpedo mounting ring90


Figure 12.64 Starboard torpedo quad tubes, showing damage to the three remaining torpedoes91





That the mount containing three torpedoes is the starboard torpedo mount is established from two circumstances. Figure 12.65 shows the presence of the torpedo tube platform and manoeuvring gear on the inner side of the torpedo tube. This identifies the tube as coming from the starboard side. The second indicator is the letters embossed on the end caps of the tubes, which were originally used to show the firing sequence of the torpedoes. Figure 12.65 shows the embossed letters, the letters ‘Q’ and ‘Z’ being on the outer tubes. Figure 12.66 shows an enlarged view of the end cap, showing ‘Z’. This identifies this quad tube mount as starboard. Thus that the starboard torpedo tubes still contain three torpedoes, the last torpedo (Z) being missing.

One torpedo was found in the debris field (see Figure 12.67). It is probably torpedo Z because the order of firing of torpedoes was Q-X-Y-Z, and there was no ability to fire Z before firing torpedoes Q, X and Y. This means it is unlikely that any torpedoes were fired from the starboard tubes. The damage to the three torpedoes, particularly the outside two, is to the air cylinder behind the warhead. Had the damage been elsewhere, there would have been sympathetic detonation.92

The port torpedo quad tubes contained two torpedoes (see Figure 12.68). These tubes were embossed with the letters ‘F’, ‘I’, ‘R’ and ‘E’, which again is the order of firing. Figure 12.69 shows the end cap of the port quad tube with the letter ‘E’ embossed on the outer tube. The second appears to have the letter ‘R’, although that is not so clearly visible. It would appear that the two torpedoes that were fired from the port torpedo quad tube were torpedoes F and I.

It is more likely that the starboard torpedo tubes were trained outwards, as opposed to stowed, and that the torpedoes were damaged by a shell as SYDNEY was turning to port astern of KORMORAN.93

92 DSTO.003.0001 at 0225 to 0226 93 TRAN.021.0001_R at 0042_R, line 25





Figure 12.65 The end caps of the starboard quad tubes, showing embossed lettering94


Figure 12.66 An enlarged view of the end cap from the starboard torpedo tube95






Figure 12.67 The torpedo found in the debris field96


Figure 12.68 The port torpedo quad tubes, containing two torpedoes97






Figure 12.69 The end cap of a port quad tube with the letter ‘E’ embossed on outer tube98

The KORMORAN wreck site

The debris field

12.26 The KORMORAN wreck site has two main features. The first feature is a large section of KORMORAN’s hull, which remains intact on the sea bed. The section is about 90 to 95 metres long and coincides with the unhatched section shown in Figure 12.70. The bow is intact up to the start of the superstructure.

The bow section clearly shows damage from the sinking process and the effects of its masts falling onto the upper decks. There are, however, no obvious signs of weapons damage along the intact hull section.

The second feature consists of the large pieces of the aft section of the hull and superstructure, which are scattered in a tangled mess in the debris field. No shell weapon damage can be seen on this section of the hull, and no individual weapon event can be distinguished from the wreckage except that the damage was caused by an extremely large detonation.

98 DSTO.003.0001 at 0228, Figure 199



Figure 12.70 Extent of damage to KORMORAN as it lies on the sea bed99

The KORMORAN wreck provides sufficient information to allow confirmation of the identity of the German merchant raider and its weapons and camouflaging arrangements.

Identification of KORMORAN’s guns and camouflaging100

12.27 The images of KORMORAN reveal the following:

• KORMORAN’s No. 3 15-centimetre gun in hold (see Figure 12.71)

• KORMORAN’s No. 2 15-centimetre gun forward port side (see Figure 12.72). This shows that the forecastle deck has collapsed onto KORMORAN’s No. 2 gun, most probably because of damage to the masts or the sinking process, or both. There are no signs of weapon damage from SYDNEY’s shells

• KORMORAN’s No. 1 15-centimetre gun on the forward starboard side (see Figure 12.73). This shows that the forecastle deck has collapsed onto KORMORAN’s No. 1 gun, most probably because of damage caused by the collapse of the masts or the sinking process, or both. There are no signs of weapon damage from SYDNEY’s shells. The hinges for the camouflaging plates can be identified on the forecastle deck

• the forward port side 2-centimetre gun (see Figure 12.74). This shows the gun with the camouflaging cover open next to it

99 DSTO.003.0001 at 0158, Figure 97 100 DSTO.003.0001 at 0158 to 0163, para 5.1.2




• the 2-centimetre starboard gun (see Figure 12.75). The gun platform is separate from the deck, allowing for the gun to be raised from below the deck.

The above-water torpedo101

12.28 Figure 12.76 shows the flap disguising the above-water torpedo on the starboard side. The flap camouflaging the port side torpedoes is shown in Figure 12.77.

The below-water torpedo102

12.29 The below-water torpedo tubes, fixed in the hull, are shown for the starboard side in Figure 12.78 and for the port side in Figure 12.79.

The weapon mountings and locations that are identifiable on the bow section of KORMORAN match those in the drawing of KORMORAN that are shown in green in Figure 12.80. The other weapons cannot be identified because of the wreckage of KORMORAN’s aft section.


Figure 12.71 KORMORAN’s No. 3 15-centimetre gun in hold103

101 DSTO.003.0001 at 0161 to 0162, para 5.1.3 102 DSTO.003.0001 at 0162, para 5.1.4 103 DSTO.003.0001 at 0159, Figure 98






Figure 12.72 KORMORAN’s No. 2 15-centimetre gun forward port side104


Figure 12.73 KORMORAN’s No. 1 15-centimetre gun forward starboard side105






Figure 12.74 KORMORAN’s 2-centimetre gun forward port side106


Figure 12.75 KORMORAN’s 2-centimetre gun forward starboard side107






Figure 12.76 The above-water torpedo flap starboard side108


Figure 12.77 The above-water torpedo flap port side109






Figure 12.78 The below-water torpedo tube starboard side110


Figure 12.79 The below-water torpedo tube port side111





Note: Identified weapons shown in green.

Figure 12.80 Weapons identified from KORMORAN wreckage112

Kormoran’s vulnerability to shell fire

12.30 Having been built as a merchant vessel, KORMORAN had no additional protection for her engines or magazines. She could, however, fire salvos from four 15-centimetre guns to either port or starboard. Given the spread of those guns, accurate firing would be required to disable all four. She also had both above-water and below-water torpedo capacity to port and starboard, although the underwater torpedoes could be fired only in the fixed direction of the tubes (that is, 125° from the bow113) and only when KORMORAN was travelling at 3 knots or less.114

KORMORAN’s greatest vulnerability was to a high-explosive shell because of the large quantity of mines she carried. She could stow 360 EMC (moored contact) mines, each having an explosive weight of 290 kilograms. These were stored above the waterline in a large compartment extending along most of the aft structure. Detonation of one of those mines would result in a mass detonation of over 100 tonnes of explosive and totally destroy the rear of the ship. Figure 12.81 shows the stowage of mines on KORMORAN. Figure 12.82 shows the extent of damage likely to result from mass detonation of the mines, as predicted using XVAM. The prediction accords well with the hull remaining after the scuttling of KORMORAN and the explosion of her mines.

112 DSTO.003.0001 at 0163, Figure 107 113 See SBLT Greter’s sketch showing angle to target: BUA.100.0176.0001 at 0036. 114 TRAN.020.0001_R at 0110_R


http://www.defence.gov.au/sydneyii/FinalReport/Report/images/BUA.100.0176.0001.pdf



Figure 12.81 Stowage of mines on KORMORAN115

Figure 12.82 Probable extent of damage resulting from mass detonation of mines on

KORMORAN116

Interpretation of the observed physical wreckage

12.31 The damage SYDNEY suffered in the battle with KORMORAN is now known with certainty: the battle’s consequences are observable in the video and still images taken of the wreckage. That known damage has enabled experts from the Defence Science and Technology Organisation and the Australian Branch of the Royal Institution of Naval Architects to draw conclusions based on established data in relation to the impact of the damage to KORMORAN on her personnel, her operability, her fighting capacity and her sinking. It has also allowed conclusions to be





drawn about the manner in which SYDNEY sank and her crew perished.

The effects of weapons damage117

12.32 It is known that SYDNEY suffered at least 87 hits from 15-centimetre shells. There probably were more. When using the XVAM simulation to assess the damage likely to be caused by such hits, shells that failed to penetrate or breach the hull were ignored, although they would certainly have caused damage from fragments created when they struck. In the case of shells that penetrated the shell or superstructure, it was assumed that they detonated about the centreline of the ship, unless structures in the line of fire prevented this. The ricocheting of shells and fragments within the internal structure—which certainly would have occurred—was also ignored. The analysis is thus a conservative assessment of probable damage internally in the ship and to crew and equipment.

12.33 The primary cause of damage resulting from the detonation of high-explosive Naval fragmenting rounds is the penetration of fragments into the surrounding structure and the loading on the structure from blast overpressure. For large shells such as 15-centimetre shells, significant damage results from the shell itself as it penetrates the structure, creating a fragment field of debris along its path. Fragments that are superheated are a source of fire if they lodge in flammable material. The proportion of damage resulting from the penetration and blast overpressure mechanisms depends on the fusing and the type of shell.

Among the structural damage caused by exploding shells are the blowing out of non-strengthened partition doors and the jamming of heavier dogged doors into their door frames. Non-strengthened compartment partition bulkheads, as existed in SYDNEY, are generally riveted into frames and are dislodged into the passageway, making passage through the ship for damage control or evacuation extremely difficult and time-consuming.

12.34 KORMORAN used two types of 15-centimetre shells. The number of each fired at SYDNEY is not known, although the total number fired was about 450. The two types of shells were the nose- or base-fused 15-centimetre high-explosive (HE) shell and the base-fused armour-piercing (AP) shell. Both types had a mass of about 45.3 kilograms and a striking velocity of 670 metres per second over a range of 5,000

117 DSTO.003.0001 at 0236, para 7.1.1.; TRAN.021.0001_R at 0011_R




metres. Such a shell thus had considerable destructive power as a result of its momentum, even if it failed to detonate.

Nose-fused HE shells are designed to detonate on contact with a significant ship structure. On detonation, a spray of an estimated 4,000 fragments is generated at velocities up to 1,200 metres per second. The shells create significant blast overpressure. Human casualties will occur within an estimated 5-metre radius of the detonation.

Base-fused AP shells are designed to penetrate armour and then explode. While penetrating metal surfaces they create a spray of secondary fragments. The distance they penetrate depends on the internal structure of the ship. Such a shell contains about 1 kilogram of explosive and generates a modest blast overpressure on explosion. The explosion produces more than 2,000 lethal fragments of high velocity as a result of the residual velocity of the warhead plus the detonation velocity.

12.35 KORMORAN was also armed with 3.7-centimetre anti-aircraft guns and 20-millimetre machine guns. The number of rounds that were fired from these armaments and struck SYDNEY cannot be determined. Conservatively, the 3.7-centimetre gun had a rate of fire of 80 rounds a minute, and the 20-millimetre machine guns had a rate of fire of 120 rounds a minute. In view of the range between the vessels, it is likely that many of these projectiles struck SYDNEY.

The 3.7-centimetre gun was capable of firing 0.7-kilogram AP shells or 0.65-kilogram HE shells at a velocity of 800 metres per second. The fragment damage caused is similar to that for 15-centimetre shells, there being fragmentation of the round on impact and damage as a result of the explosive detonation.

The 20-millimetre gun fired a 120-gram shell at a velocity of 900 metres per second. The lethality of the HE shells fired by these guns was increased because the HE charge detonated on impact.

Weapon trajectories

12.36 The 15-centimetre shells were designed to be propelled over a range of 25,000 metres. At a range of 5,000 metres a gun elevation of only 1.7° was required, producing an angle of fall of 2.2°. At a lesser range the angle of elevation would be less, as would be the angle of fall.

12.37 The images obtained of SYDNEY do not allow for accurate measurement of the actual impact angle of the shell. If, however, the distance between the vessels was 1,500 metres or less, as measured by KORMORAN’s artillery officer, LEUT Skeries, the actual angle of impact would have been extremely shallow.


The extent of damage

12.38 Figures 12.83 and 12.84 show the damage contours the Defence Science and Technology Organisation developed based on shell design, weight of explosive charge and casing material. The majority of fragments are driven outwards in a main beam spray from the detonation point, in a zone of 50° to 120° from the warhead nose. Fewer, larger fragments will be thrown forward and back, especially for the AP shell, which will propel a very large fragment forward. The casualty radius from each 15-centimetre shell was either 4 or 5 metres; less severe injuries would probably have been caused beyond that radius.

Figure 12.83 Estimated blast and fragment damage contours for stationary 15-centimetre

armour-piercing weapon detonation118

118 DSTO.003.0001 at 0240, Figure 203



Figure 12.84 Estimated blast and fragment damage contours for a stationary nose-fused

15-centimetre high-explosive shell detonation119

The port side engagement

12.39 As noted, SYDNEY suffered severe damage to her port side in the engagement with KORMORAN. The main causes of the damage were a single torpedo, forty-one 15-centimetre shells, and undoubtedly multiple hits from the 3.7-centimetre and 20-millimetre guns.

Torpedo damage120

12.40 In 1941 German torpedoes were contact-fused weapons. The primary damage mechanism when a torpedo detonates on contact with a ship is the explosion, which tears a hole in the hull. The size of the hole depends on the net explosive weight of the torpedo and the strength and design of the hull in the area of detonation. Rupture of the bulkheads in the vicinity of the detonation can result from direct exposure to the explosive forces or the deformation of the hull or bulkheads in the area of the explosion.

119 DSTO.003.0001 at 0241, Figure 204 120 DSTO.003.0001 at 0241 to 0246, para 7.2.1




Further damage will result from the penetration of fragments generated as a result of the exploding weapon and from fragmentation of the structure immediately adjacent to the detonation point. This fragmentation adds further to the internal damage to ship systems and structure directly in the area of the explosion. Structural damage from a contact explosion is generally limited to the immediate area of the explosion.

A secondary damage mechanism depends on the depth of the explosion below the waterline. An underwater explosion generates a large gas bubble. The bubble for a 280-kilogram explosive torpedo has a radius of about 9.8 metres. It displaces a large volume of water, and when it collapses water is forced into the hole caused by the explosion. In shallow explosions a lot of the gases are lost to the atmosphere or into the hole generated by the explosion. As the bubble breaks the surface a large plume of water is thrown into the air. The consequence is that flooding spreads rapidly to compartments adjacent to the hole.

The third damage mechanism from a torpedo explosion is the initial heave upwards the ship receives. The shock wave from the explosion generates a shock loading throughout the ship, which can result in damage to vital components, including crew, throughout the ship.

Little or no whipping of the structure occurs.

Flooding consequence of torpedo damage

12.41 It is beyond doubt that the torpedo strike to SYDNEY’s port side caused flooding in her. The extent of the flooding is less certain. The effect of flooding is to change the draught of the vessel at the forward and aft perpendicular. As the draught at the forward perpendicular increases, the draught at the aft perpendicular decreases, resulting in the vessel being trimmed by the bow. The extent to which these draughts will change depends on the sections that are damaged and are thus accessible to sea water. Table 12.3 shows the results of modelling to determine the changes to forward and aft draughts resulting from torpedo damage.

The experts considered that frame 53 was the location of the first intact watertight bulkhead aft of where the torpedo hit. In consequence, the theoretical portion of the ship liable to flooding due to the torpedo hit on SYDNEY’s port side can be determined. This is shown in Figure 12.85, although the shaded area will in fact flood up to the waterline level. This will result in SYDNEY trimming by the bow, which is consistent with some of the accounts of the battle saying that occasionally SYDNEY’s propellers could be seen coming out of the water.


Shell damage121

12.42 The location of the port side 15-centimetre hits to SYDNEY is shown in Figures 12.10 to 12.13. The hits are primarily concentrated around the forward part of the ship, the superstructures and the upper and lower decks below the forward superstructure. A second concentration of hits is amidships, in the region of the catapult. Although the order in which the 46, and probably more, 15-centimetre shells struck is not known precisely, a visual representation of the combined effect of forty-one 15-centimetre shells striking the port side simultaneously is shown in Figure 12.86.

Table 12.3 Forward and aft draughts resulting from torpedo damage122

Sections damaged Approx. distance from

FP (metres)

Draught at aft perpendicular TAP

(metres)

Draught at forward perpendicular TFP

(metres) Intact – 5.56 4.05

FP—frame 14 12.80 5.46 4.24

FP—frame 19 17.37 5.39 4.38

FP—frame 25 22.86 5.24 4.68

FP—frame 35 32.00 4.98 5.26

FP—frame 53 48.46 4.22 7.01 Note: ‘FP’ denotes forward perpendicular; ‘TAP’ denotes draught at aft perpendicular; ‘TFP’ denotes draught at forward perpendicular.

Figure 12.85 Potential flooding extent resulting from the torpedo strike on SYDNEY123

121 DSTO.003.0001 at 0246, Para7.2.2 122 DSTO.003.0001 at 0245, Table 23 123 DSTO.003.0001 at 0245, Figure 206





Figure 12.86 Shell detonations on the port side of Sydney occurring simultaneously124

The effect of these hits was described by Naval architect Mr John Jeremy in the following terms:

Mr Jeremy: We’re talking about some of the most important areas of the ship – the bridge superstructure and that area of the hull which happens to control the main switchboard rooms, transmitting stations, lower power rooms and some of the W/T compartments, as well as the lower steering position.

CMDR Rush: So is there any opinion formed as to the effect of the damage on the capacity in that area of the ship for control of the ship?

Mr Jeremy: Substantially incapacitated.125

SYDNEY’s bridge area received multiple hits on the port side, two of the most significant being to the director control tower and the high-angle control station. Figure 12.87 shows the damage to the base of the director control tower. This was probably caused by the detonation of a 15-centimetre shell, and it probably put the director control tower out of commission for the rest of the battle. All crew in the tower would have sustained injuries from the weapons damage.

The high-angle control station also received a very significant hit on the tower support, as shown in Figure 12.88.

124 DSTO.003.0001 at 0247, Figure 209 125 TRAN.021.0001_R at 0067_R at line 23





Figure 12.87 Damage to the base of SYDNEY’s director control tower126


Figure 12.88 SYDNEY’s high-angle control station support127





Figure 12.89 shows a representation of the original configuration of the high-angle control station. As is evident, there was considerable structure above where the station broke off after the shell damage. Examination of the damage to the support and damage to the surrounding structure has led to the conclusion that this hit came in from the port side, resulting in the high-angle control station buckling over toward the starboard side of the ship. The damage to these two structures would have left SYDNEY with seriously diminished fire-control capabilities.

Other hits to the bridge area have been identified, and it is likely that there were even more hits than that. German survivors reported that the 3.7-centimetre gun was trained on the bridge area. This gun fired 0.7-kilogram shells and would have caused additional damage that is not obvious in the video imaging.

Shell hits on and adjacent to B turret and the loss of the roof section on B turret, which might have been the result of shock from a shell hit, are likely to have rendered both A and B turrets unserviceable.128 And if that did not happen they would have been rendered unserviceable by the torpedo hit. The evident damage would have made it impossible to train them.

Figure 12.89 A representation of SYDNEY’s high-angle control station before being damaged129

128 TRAN.021.0001_R at 0067_R to 0068_R at line 44 129 DSTO.003.0001 at 0249, Figure 213




There is also evidence of numerous holes from shells that have penetrated the hull (see Figures 12.90 and 12.91). These are likely to have been armour-piercing shells and, although the damage to the hull appears non-lethal, internal detonation of these shells would have caused major damage to structures, equipment and crew and had a deleterious effect on the function of the ship. The hits would also have had a major effect on the effort to control damage from the torpedo hit. Damage-control station 1 was based in this location, and heavy casualties would have occurred. One important area of damage breached the watertight bulkhead between number 3 and number 2 lower messes.

The weapons damage to the port side shown in Figure 12.92 suggests that a large number of fragments would have been produced in the vicinity of the ship’s boats and floats. The port side whaler shows a large hole on both the port and the starboard sides. Extensive damage to the adjacent shipwright’s workshop is unlikely to have occurred without the shell also striking the whaler. Figure 12.93 shows a visualisation of the shell trajectory.

The figure shows a very shallow or flat angle of trajectory, consistent with a close range of engagement. Although this is the only trajectory able to be measured with accuracy because of the existence of ingoing and outgoing penetrations in the whaler, it is improbable that other 15-centimetre shells fired from the guns on KORMORAN had a different trajectory. The closeness of the vessels during the engagement in the port battle is thus confirmed.

12.43 As Figure 12.94 shows, there was extensive damage to the bakery, which was on the port side adjacent to the location of the pinnace and two Carley floats. This would have resulted in extensive fragment damage to those vessels. Figure 12.95 shows the location of those vessels in relation to the bakery.

The boat cradles showed varying degrees of fragment and weapons damage. The damage to several of them suggests that the boats would also have been damaged to such a degree as to make them unusable for evacuation. There is also evidence of fire damage in the superstructure close to the boats.



Figure 12.90 Site of a contact-detonating shell penetrating the hull130


Figure 12.91 Sites of armour-piercing shells entering the hull131





Figure 12.92 Weapons impacts on the port side amidships132

Figure 12.93 Visualisation of the shell trajectory to cause damage to the port side whaler133






Figure 12.94 Damage to the bakery134

Figure 12.95 Reconstruction of midships around the bakery135





The hits to the area surrounding the davits supporting the 32-foot cutter, as shown in Figure 12.96, are likely to have caused major damage to that boat. Although the collateral damage might not be obvious in the underwater photographs, a reconstruction of the ship in this region (see Figure 12.97) makes the potential for fragment damage to the cutter and surrounding structures obvious.

The davits for the cutter are missing and were probably destroyed during the engagement. The boat and davits are slightly aft of the bridge, where extensive weapons damage is visible. It is probable that the cutter was also blown or fell into the water during the engagement. It was not found in the debris field.

The sea plane catapult received two shell hits that would have sprayed hot fragments over the aircraft and surrounding structures. This probably caused the aircraft to be destroyed by fire, as some German witnesses stated.

Although there are hits to the bakery and the catapult, the majority of the identified hits appear to have been centred on the bridge and A turret, a large number of shells penetrating the hull under these structures. A hit to the engineering workspace would have further affected damage-control capability with damage to damage-control station 2.

Fire damage

12.44 The hot fragments produced by the shattering and explosion of incoming warheads would have started small fires that coalesced into a larger conflagration, which would have been exacerbated when the fire near the catapult ignited aviation fuel in the aircraft. One consequence was that smoke would have been drawn into the ventilation shafts below the upper deck and into the aft machinery spaces. No fire insulation was fitted to SYDNEY, the method of slowing fire spread being to cool bulkheads using fire hoses. This was likely to have been impractical because of the damage to damage-control stations 1 and 2.



Figure 12.96 Contact detonation around the davits supporting the 32-foot cutter136

Figure 12.97 A reconstruction of the 32-foot cutter137





Smoke and toxic gas

12.45 Fires and gases resulting from weapon detonation on SYDNEY would have produced smoke that caused problems with visibility as well as irritation and breathing problems for the crew. A number of toxic chemicals are likely to have been produced by the fires on the ship and to have been present in the smoke. One toxic compound produced by smoke is carbon monoxide. Incapacitation occurs when carbon monoxide is present in high concentrations, and the uptake of the gas is cumulative. An increase in breathing rate is caused by the presence of carbon dioxide, another compound produced in fires that can reduce the time to incapacitation.

In view of the multiple hits suffered, the extensive fires likely to have been caused and the generation of smoke and toxic gases, many of the crew would probably have rapidly become incapacitated if the ventilation system could not be closed and the smoke extracted. Smoke from fires forward of the machinery spaces—for example, on the bridge superstructure—would have been drawn into the forward machinery spaces as a result of the location of the air intake vents for those spaces. Ventilation to those spaces could have been closed, but this would have required that the equipment in those spaces be shut down because it was cooled by such ventilation and the boilers required an air supply in order to burn fuel. The ventilation could be closed electrically or physically, but if this occurred there was no means of evacuating the smoke.

Casualties

12.46 Damage on the port side was the initial damage SYDNEY suffered in the engagement. Having regard to the number of 15-centimetre shells known to have hit SYDNEY on the port side, and the torpedo damage, the experts from the Defence Science and Technology Organisation and the Royal Institution of Naval Architects described the likely casualties in the following terms:

Given the number of shells fired on Sydney and the consequential fires produced it is highly likely that crew members in many parts of the ship would have been enveloped by both smoke and toxic gases in the first five minutes of the encounter. The forward fire in the bridge structure would have been initiated by Kormoran’s early salvos to the DCT and bridge by both the 15cm and 3.7cm shells. Most of the command centre personnel on the Bridge would have been incapacitated. The total number of crew affected would have been of the order of 60, including those on the Flag deck (signal area aft of HACS Tower) and Searchlight platform areas.

The damage caused by the shells penetrating the upper and Lower Deck areas would have included the incapacitation of crew as well as damage to the bulkhead at Frame 53 above the waterline. Number 2


Lower Mess was used as the Damage Control Station 1. This area contained between 30 to 50 men who would have been waiting for damage reports before disbursing on patrol. Other shells caused damage to, and casualties in, the Lower Steering Position on the Platform deck.

The continuous barrage of shells and smaller calibre weapons on the upper deck, would have incpacitated the crew on the open decks of Sydney. The port torpedo area would have been under heavy fire to prevent the discharge of a torpedo. All the life boats in this area would also have been raked with shrapnel … The A turret received a hit that would have severely impaired the 20 crew operating it and probably caused casualties down in the Ammunition lobby below on the Lower deck.

The number of crew on the open decks, Aft Control Tower and Bridge decks number about 170. Of these, only the crew on the quarterdeck at the depth charges, the Aft Control Tower and the ‘X’ and ‘Y’ turrets could be considered as unaffected by the engagement during the first five minutes.

When the torpedo impacted, the shock to the ship would have caused many more casualties in the forward section, including the crew in the 6” Magazines in the Hold, and would have flooded the ‘A’ shell room. The forward magazine compartments contained about 11 crew members, and survivors would have had difficulty in evacuating, as access through the deck areas above would be obstructed due to shell damage and fires. The compartments forward of the torpedo hit are unlikely to have contained crew.

The section between bulkheads located at Frames 64 and 76, (Switchboard Rooms, Lower Steering Position, HAC Calc Room, Aux. W/T and Telephone exchange) which was heavily populated, would have felt the shock of the torpedo. Although casualties here would have been low, damage to sensitive equipment would be expected … The torpedo impact shock may have caused damage to or the collapse of the W/T aerial structure.138

Movement of the Executive Officer

12.47 Had SYDNEY been at action stations, the Executive Officer would have been be based at the lower steering position, in which damage-control headquarters was located. This separation was to enable the Executive Officer to assume command if senior officers on the bridge were incapacitated. To control the ship the Executive Officer would then move to the after control position. Assuming that the bridge was destroyed by an early salvo and that the Executive Officer avoided the open deck on the port side of the ship, it being under fire, the Defence Science and Technology Organisation experts considered four possible

138 DSTO.003.0001 at 0257 to 0258, para 7.2.4



routes from the lower steering position to the after control position. The routes are shown in Exhibit 106, paragraph 7.3.

The time taken to traverse those routes was estimated at between 2 minutes and 35 seconds and 4 minutes and 18 seconds.

The turn to port

12.48 After being severely damaged on the port side, SYDNEY turned to port, passing astern of KORMORAN. That she did so is beyond doubt because she suffered severe shell damage to the starboard side. The question that arises is whether the turn to port was intentional or involuntary.

The evidence suggests that the turn was intentional. This follows from the nature of the telemotor system operative on SYDNEY. Experts explained that, if the telemotor system that steered the vessel was damaged by gunfire and air entered the system, the wheel and rudder would automatically revert to midships. SYDNEY would then proceed on a straight course. An involuntary turn to port was thus not possible, even if the steering system was damaged. If, as the German evidence suggests, SYDNEY turned to port astern of KORMORAN and thereafter again changed course, SYDNEY must have had steering capacity and a person on board SYDNEY must have controlled those turns.139

The starboard side engagement

12.49 The damage observable on the starboard side of SYDNEY suggests that she was exposed on that side to KORMORAN’s port side armaments.

Shell damage

12.50 The starboard side of SYDNEY received at least forty-six 15-centimetre shell hits. The hits were widely distributed (see Figures 12.98 and 12.99), affecting the bridge, the director control tower, X turret, the starboard torpedo area, the 4-inch gun locker and the mess areas in the lower deck. The concentration of shell hits around the midships section of the upper and lower decks and in the engineer’s workshop, the upper section of the forward boiler room and the stoker’s mess had severe consequences. There were no shell hits apparent aft of X turret.

139 DSTO.003.0001 at 0264, para 7.4, TRAN.020.0001_R at 0072_R to 0073_R at line 38




Figure 12.98 Weapons damage to SYDNEY’s starboard side around A turret140

Figure 12.99 Weapons damage to SYDNEY’s starboard side around Y turret141





The location and damage evident in some images make it clear that a number of the shells were fired over the bow of SYDNEY as she turned to port. This is particularly evident from the four hits to A turret’s side plate. This means SYDNEY was under continuous fire both while she turned to port to pass behind KORMORAN’s stern and after she had done so.

Figure 12.100 shows that A turret incurred considerable damage from hits to the starboard side. The starboard side armour shows that A turret received four separate hits, two of them detonating on contact and the other two penetrating the armour plating (Figure 12.101). These hits destroyed the turret and would have occurred when it was pointed to port, probably indicating that the hits occurred as SYDNEY swung around the stern of KORMORAN.

The director control tower suffered at least one starboard side hit, possibly two additional hits to the support structure (see Figure 12.87) and another penetrating starboard hit to the main director control tower (see Figure 12.102). If any function in the director control tower had remained operational after the hit to the port side—which is extremely unlikely—the additional hits on the starboard side would have undoubtedly put the tower’s firing control permanently out of operation. The bridge superstructure received hits on the starboard side, but fire and sinking damage make it difficult to determine the number and extent of the hits (Figure 12.103).

Although X turret received a hit on its port side armour, it is likely that, because of the port bearing of the gun, this hit came from the starboard side. The shell penetrated the gun turret and detonated inside, removing the rear port hatch (see Figure 12.104).

There is also damage to the starboard side torpedo tubes caused by a shell hit or fragment damage. This hit would have disabled the torpedo tubes, preventing them from being fired (see Figure 12.105).



Figure 12.100 Damage to SYDNEY’s A turret142


Figure 12.101 The starboard side armour of SYDNEY’s A turret143






Figure 12.102 The hit to SYDNEY’s director control tower144


Figure 12.103 Damage to SYDNEY’s bridge145






Figure 12.104 The hit to SYDNEY’s X turret146


Figure 12.105 Damage to the starboard side torpedo tube147





SYDNEY’s starboard side received multiple hits along the hull, particularly around the armour plating protecting the engine room. The concentration of shell hits is indicative of the area at which KORMORAN was probably firing and of the accuracy of its gunnery. The value of the armour plating around the engine space is demonstrated by images showing there is obvious shell impact but the hull has not been penetrated (see Figure 12.106). At least one shell did penetrate the armour plating, though (see Figure 12.107), and it is probable this shell detonated inside SYDNEY.

The hits shown in Figures 12.108 and 12.109 are hits that have probably detonated on the outside of SYDNEY but fragments from the detonation have penetrated the armour. Those hits would have caused some internal damage, although much less than would have occurred had the shell detonated on the inside of the ship. The hit shown in Figure 12.108 is illustrative of a shell that hit at an angle. It was probably fired from a position somewhere forward of SYDNEY, as is evident from the markings on the hull. It is not possible to predict with any accuracy the angle at which this shell hit SYDNEY. The shell detonation that occurred would have resulted in fragments spraying over the deck, probably causing damage to surrounding structures such as boats and aircraft on the deck (see Figure 12.110).

Figure 12.111 shows a reconstruction of the area that was the subject of the hits, which is likely to have received extensive fragment sprays, damaging the boats shown. All the boat cradles show varying degrees of fragment or weapons damage. The boats probably were similarly damaged, such that they were rendered unusable.

The photographic evidence showing that the davits of the cutters are not in place suggests that the cutters were either blown off SYDNEY during the encounter or fell into the sea when their davits were destroyed by weapons effects. It follows that the cutters were unlikely to have been in a state that allowed them to be used for life-saving purposes.



Figure 12.106 Non-penetrating shell damage to the armour plating148


Figure 12.107 Penetration of the armour plating149






Figure 12.108 An example of a shell that hit SYDNEY at an angle150


Figure 12.109 An example of a shell that hit port side armour, with fragments causing the penetration151






Figure 12.110 An example of a shell that probably sprayed hot fragments over the surrounding deck152

Figure 12.111 Reconstruction of midships, showing boats that would be damaged by fragment

sprays to the deck153





Fire damage

12.51 The main fire in the forward section would have become a large conflagration during the period of engagement and thereafter. Smoke from this fire would have been drawn into the forward machinery spaces because of the location of the ventilation inlets. Shell hits on the aft superstructure near X turret would have ignited more fires during the engagement.

Casualties

12.52 As a consequence of shell damage, fragment damage, fire and smoke inhalation, the number of casualties would have been extremely high.

Conclusions154

12.53 Using the vulnerability assessment method XVAM, the Defence Science and Technology Organisation analysed the overall shell damage incurred by SYDNEY and the consequences for the ship’s capabilities when battle ceased. The analysis allows for a deck-by-deck assessment of SYDNEY and shows the likely spread of both blast and fragments through adjacent structures.

Figures 12.112 to 12.117 show the combined effects of the eighty-seven 15-centimetre shells that struck SYDNEY on the port and starboard sides.

The zones shaded red have a high probability of having been affected by the fragments and blasts resulting from detonating 15-centimetre shells and the damage incurred as a result of the flight path of the armour-piercing shells into the structure. Overlaid onto this damage are the regions affected by the torpedo (shaded in blue) and the areas vulnerable to being hit by the smaller calibre 20-millimetre and 3.7-centimetre shells (shaded grey).

Most of the superstructure and bridge compartments were affected by fragment damage, and the exposed spaces on the superstructure deck were likely to have sustained damage from small-calibre weapons and fragments. All equipment and personnel in these areas would have been incapacitated.

154 DSTO.003.0001 at 0272, para 7.6



Figure 12.112 The predicted extent of weapons damage to the superstructure and bridge

compartments155

Figure 12.113 The predicted extent of weapons damage to forecastle deck compartments156

Figure 12.114 The predicted extent of weapons damage to the upper deck compartments157

Figure 12.115 The predicted extent of weapons damage to the lower deck compartments158

155 DSTO.003.0001 at 0274, Figure 243 156 DSTO.003.0001 at 0274, Figure 244 157 DSTO.003.0001 at 0274, Figure 245 158 DSTO.003.0001 at 0275, Figure 246






Figure 12.116 The predicted extent of weapons damage to the platform deck compartments159

Figure 12.117 The predicted extent of weapons damage to the hold160

The forecastle deck was very exposed to small-calibre weapons and the effects of thousands of fragments generated from hits to the forward superstructure region and the hits on the catapult and similar regions. The boats, Carley floats and personnel on this deck would have been severely affected.

There is significant damage to the forward upper deck region. The number of hits identified would have severely limited the access and passage of the damage-control crews—not only in repairing the damage from the torpedo but also in fighting fires and repairing the associated damage from the shell hits in this region, the superstructure and the bridge compartments.

The lower mess deck compartment is extensively damaged by shell fragments and debris. Damage-control stations 1 and 2 would have been showered with fragments, leading to a large number of casualties among crew involved in repairing the ship and controlling the flooding and fires.

The damage to the forward section of the platform deck is indicative of important areas—such as the forward steering room, the switchboard room and the breaker rooms—being hit by weapon fragments. The aft compartments of this platform are free of any weapons damage. As a result of the damage, it is unlikely that any electrical equipment was operating forward of the machinery spaces.





Apart from the torpedo damage, the damage to the water main service was similar to that affecting the electrical system, which would have caused fire-fighting options to be limited to the fires amidships (below the aircraft catapult) and the aft superstructure. The fire in the forward superstructure was probably not fought, so it would have been able to spread below decks. The openings in the hull from shell penetrations would have provided a source of oxygen. It is unlikely that any damage control was carried out in the forward section of SYDNEY.

The surviving able-bodied crew would probably have been trying to control the ship from the machinery spaces and steering compartments, provide electrical and fire-fighting services, and help treat the injured. While the ship was afloat and some limited control was maintained, it was the ship that offered the best, and probably the only, chance of survival.

the wrecks of HMAS SYDNEY and HSK KORMORAN

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Transcript of the wrecks of HMAS SYDNEY and HSK KORMORAN