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Ok, I was thinking on 1941 battles, anyway Peter C. Smith, a dive-bomber enthusiast if there is one, in his Junkers Ju 87 Stuka (Crowood 1998) and Armoured Aircraft Carriers (armouredcarriers.com) agreed that Indomitable was hit by two 250 kg bombs. And what "strong evidence that they used the same on HMS Illustrious in Jan 1941." there is. I have not seen a German report showing the ordinance used in the attacks but Report: (armouredcarriers.com) says that the 6th hit was at first estimated to be made by a 500 kg bomb but then re-valuated to be a 1000 kg bomb, but according to Smith it also was a 500 kg bomb as were the 4th and 5th hits and the 8th [I corrected this, I had missed the one hit of undetermined size achieved during the last attack on 10th Jan. which was the 7th hit] on 16th Jan at Malta.The Luftwaffe (OB from Operation Pedestal) was flying JU87Ds and I know that they were carrying 1000kg bombs, because they hit Indomitable with two of them. In the Fall of 1941 Ju87Bs hit the Soviet battleship Marat with 1000kg AP bombs and there is strong evidence that they used the same on HMS Illustrious in Jan 1941. The JU87R could carry the same bomb weight for short range missions, and due to the operational requirements of the Malta Convoys FAA carriers had to operate within the JU87B radius of action with a 1000kg bomb. I already indicated, in a prior post (#245), that the JU87-R traded bomb weight for extra fuel for long range missions.
Ok, I was thinking on 1941 battles, anyway Peter C. Smith, a dive-bomber enthusiast if there is one, in his Junkers Ju 87 Stuka (Crowood 1998) and Armoured Aircraft Carriers (armouredcarriers.com) agreed that Indomitable was hit by two 250 kg bombs. And what "strong evidence that they used the same on HMS Illustrious in Jan 1941." there is. I have not seen a German report showing the ordinance used in the attacks but Report: (armouredcarriers.com) says that the 6th hit was at first estimated to be made by a 500 kg bomb but then re-valuated to be a 1000 kg bomb, but according to Smith it also was a 500 kg bomb as were the 4th and 5th hits and the 7th on 16th Jan at Malta.
On Marat, IIRC something what I read decades ago, a few 1000 kg bombs were allocated to some specially selected pilots for the attack, not something to be used by an ordinary pilot flying Ju 87 B.
German account of attack on Illustrious:
"On or about 10 January the Geschwader received news that the British
aircraft carrier "Illustrious" was bound from Gibraltar for Malta.
It was expected to pass in the next few hours the offshore island
of Pantellaria, south of Trapani. It was said to cruise quite
unsuspectingly as if the British ruled the Mediterranean,
proudly ignoring the existence of any Italian Fleet or Air Force,
not to mention the German Stukas on Sicily. It seemed to be a
fine catch for us. It was decided to attack the carrier, taking
it by surprise. Our two Gruppen prepared for action, loading the
500-kg bombs with armor-piercing heads. Soon we were given the
operation order. My friend, the valiant commander of II/Stuka 2,
Major Enneccerus (Brigadier General after the war), flew the
first attack while I was on another mission...
...Now this aircraft carrier was for the Supreme Command of the Luft-
waffe a matter of prestige, also a precedent. It had to be sunk
under all circumstances. If the Supreme Command of the Wehrmacht
could have reported the sinking of an aircraft carrier by German
Stukas, both friend and foe would have sat up and taken notice.
So commenced our attacks, with heavy losses, against the aircraft
carrier in La Valetta. In La Valetta more than 90 AA batteries
of all calibers spit their fire against us, the attackers. At
the same time a strong unit of "Hurricanes" seriously interfered
with us on the approach route and after our departure. In prac-
tically every sortie I lost three or four of my old-battle-tested
crews--an irreparable loss. It was just impossible to replace
those thoroughly trained and experienced pilots and their back-
seaters. During those actions the carrier was hit by four 1,000-kg
bombs, the heaviest a JU-87 could carry. Still we did not succeed
in sinking it, though she must have suffered terrible inner damage...
from:
"CONVERSATIONS WITH A STUKA PILOT"
CONFERENCE FEATURING
Paul-Werner Hozzel
Brig. General (ret.). German Air Force
AT
The National War College
November 1978" pages 44-45.
The Ju87s that attacked Illustrious was a specialist anti-shipping unit that was specifically tasked with sinking her. Even If they carried 'only' 500kg bombs this is still double the load of a D3A1 Val, and gave the Ju87 the ability to potentially sink heavily armoured ships, such as Illustrious or damage them severely enough that they would be forced to scuttle. A dive-bomber delivered 250kg bomb could never penetrate the armoured box around her machinery spaces. However, we know that 1000kg bombs were available to the JU87s in Jan 1941 and we know that they could carry them, and that Illustrious was within range of the JU87 armed with a 1000kg bomb.
Interesting, but Stukas got only one hit during their attacks on HMS Illustrious at Malta. Plus one or two damaging very near miss(es)while flying 44 sorties on 16 (causing the 8th hit) and 42 sorties on 19th (one or two near misses). Now Valletta situates only under 100 km south of Sicily and Germans knew the exact position of Illustrious, so they could keep the rear gunner and simply took 100 - 120 kg less fuel, same goes to Marat. But in open sea shipping strikes one needs some fuel reserves for possible search for targets, so IMHO your scenario that Ju 87 is worth of 4 Vals as load carrier is not very realistic, at least when talking on Bs and Rs. D model was fairly different animal, capable to carry even 1,800 kg bomb for short range sorties, but I don't have just now time to study it closer.
It looks like Indomitable was indeed hit by two 500 kg bombs dropped by Stukas of StG 3. The same unit also scored four hits on the HMS Warspite during the earlier operation Excess, but it too failed to sink. Later the same Stukas managed to damage the light cruiser HMS Southampton badly enough that it was scuttled. They never sunk any capital ships as far as I could determine.
This is footage of the actual attack here:
And yet, unlike HMS Hermes in the Indian Ocean, the Stukas couldn't sink Indomitable. Apparently at least in part because even with bombs twice as big (possible due to the very short range at the time of the strike) they got comparatively much fewer hits. Apparently 40 250kg or smaller bombs was fatal whereas 2 x 500kg bombs were not. Indomitable went on to survive till the end of the war and was flying Seafires and Albacores from 1943, then Hellcats and Avengers in 1945....
Hermes was an older design, but the key factor in the difference is the ability of the bombers to score hits. Air defense was similar though it is possible that Indomitable was flying 12 x Martlets at the time of Pedestal, which would have been more effective air defense than the Fulmars.
Additional differences relative to survival that should be noted:
Hermes was ~1/2 the displacement of Indomitable and built along heavy cruiser lines, while the Illustrious/Indomitable class was built along capital ship lines.
The Hermes had only a 1" flight deck, while the Illustrious/Indomitable class had a 3" armoured deck, with a 1" hanger deck on the Illustrious group, or the 1" of both hanger decks (I think) on the Indomitable.
Do not misunderstand, I do not think the Illustrious/Indomitable class would have survived an attack equal to the one against Hermes. I doubt that any carrier operational in WWII would have survived that many hits, unless it was due to luck.
Neither Warspite or Valiant was hit during operation Excess. This is the official damage summary:
"WARSPITE 10th Jan., 1941- One Near WARSPITE was operating off Malta when a near miss bomb burst off the starboard side
No major damage was caused to the hull structure but the starboard lower hawse pipe was split, the anchor damaged and the peravane chains severed.
Fighting Efficiency - Not impaired.
Bomb, judged
to have been 1000kgm
VALIANT 10th Jan., 1941
Five near misses with 500kgm direct action fuzed bombs.
VALIANT operating off Malta, suffered superficial splinter damage from five near miss
bombs. The yoke on the starboard rudder was loosened and dropped 3/16 inch.
Fighting Efficiency - Not impaired" from: HM Ships damaged or sunk by enemy action.
However during the Crete operation on 22 May Warspite suffered heavy damage from a 250kg SAP bomb via an Me109 fighter bomber attack.
Understood, good points. My main point is that other factors like range and how accurate the bombing is also matter quite a bit in assessing the effectiveness of a bomber (and what was needed for a bomber to destroy targets), not just the bomb load. This has been a debate that has come up over and over on this forum in many threads. Some people think bomb load was the only real measure of a bomber. The Stuka was a very accurate bomber by WW2 standards, that's why it remained in use for so long after it's slow speed and other limitations made it obsolete, but it did also have a very short range compared to pretty much all 'modern' naval aircraft by the time of Pedestal, no matter how you try to spin it.
And nearly every one of the Japanese bombers were exceptionally accurate as well, based on their combat histories, at least when they still had their highly trained crews. Not just the D3A but also the land based strike aircraft like the G4M and G3M and many of the Army types as well. B5N Kates even sunk some ships with level-bombing attacks in that Indian Ocean raid, a very rare accomplishment by WW2 standards.
One of the realities of WW2 aviation is that many, arguably most bomber designs were pretty ineffective at their main job (bombing), because they couldn't hit their targets often enough. Bombing accuracy was typically abyssmal. Even unusually accurate bombers like the Stuka only hit their targets a small percentage of the time. This was true both for Strategic bombing and Tactical bombing of the type so important in Naval War.
No doubt Indomitable was a tough ship and aptly named. It was apparently also hit by a torpedo later in the war launched from an SM.79 and survived that too.
Against the Hermes, Cornwall and Dorsetshire the D3A had a hit accuracy of better than 80%.
My understanding is that the 80% figure (specifically 82%) includes the strikes on all of the RN ships they hit in that one day engagement . I agree about the small sample size skewing results, that 82% number is often and prominently mentioned in conjunction with the D3A though it's not something I cherry picked for this debate.
The source cited for the number is listed as Francillon, René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 (2nd edition 1979
In the strike against Hermes, 18 D3A pilots from Shōkaku struck first, and claimed 13 hits, then Zuikaku's 14 pilots attacked, also claiming 13 hits. After that, the Hermes was already sinking, so only 11 of Hiryū's 18 attacked the carrier and they claimed 9 hits. Lt. Zenji Abe and FPO 1/c Tamotsu Akimoto of Akagi were the last two to attack, both claiming hits on the sinking carrier. The other 12 bombers from Akagi broke off their attack.
The remaining 7 bombers from Hiryū, seeing that Hermes was already doomed, then joined 12 more from Akagi to attack HMAS Vampire, which was split in half and "torn apart" according to the British report, with three direct hits and five near misses according to the RN report. This ship also sunk very quickly and of the 19 D3A which attacked, only 15 were able to drop bombs before it disappeared into the water in a series of violent explosions. So four D3A from Hiryū and Akagi flew back to their original target and dove on the now definitely sinking hulk of the Hermes, scoring four more hits (and these were confirmed by RN survivors floating in the water who were later picked up by the hospital ship)
After that 18 aircraft from Sōryū arrived and since Hermes was half underwater, they flew off to look for more targets, which they soon found and they were the ones which sunk Hollyhock, Athelstane, and Norviken. This was when the four D3A were shot down by 14 Fulmars, as this group was caught without their escorts. One more D3A from this group crashed while landing on the Sōryū.
So that's actually a total of 40 hits claimed on the Hermes, plus 3 on the destroyer Vampire and an unlisted number on three other ships. You are right we can't take all the claims at face value, but the damage was rather telling. Hermes sunk so fast that many of the D3A which were intending to bomb it had to find other targets.