Hypothetical Battle of the Java Sea...

[dunmunro]

I agree that the number of torpedo hits is completely unrealistic. The Japanese attacked the USN with far more and better torpedo planes and didn't achieve that kind of hit ratio. Also, your "star" attack is an ideal and didn't often succeed in the actual event.

At Coral Sea and Midway, a very small number of IJN torpedo bombers, probably 23, (since most were destroyed by the CAP) were able to achieve 4 hits, two on Lexington and two on Yorktown. USN AA was also largely ineffective against these attacks despite claims at the time to the contrary.

[tommy303]

Lexington was hit by two torpedoes, but Yorktown dodged the eight launched against her. She was, however hit by a bomb which damaged her flight deck. At Midway her luck ran out and she took two torpedoes and several bombs from attacking Japanese aircraft. However, one does have to wonder how the Swordfish would have compared to the Japanese aircraft.

[dunmunro]

I hope you realise this is an estimate at best, and not an exact estimate.

There were enough surviving aircraft that the numbers lost to AA can be fairly well established. IJN AA was not very effective, and this was so for a variety of reasons:
Low density of fire due to IJN AA doctrine which favoured, open lose ship formations rather than the circular formations used by the RN and USN, which were designed to achieve maximum density of AA fire.
Low density of fire due to small numbers of medium AA and small numbers of light AAA.
Poor fire control.

[dunmunro]

Lexington was hit by two torpedoes, but Yorktown dodged the eight launched against her. She was, however hit by a bomb which damaged her flight deck.

Yorktown had been crippled, by DBs, prior to the TB attack, but she was able to work up to about 20 knots during the TB attack:

"...By 1350 the ship was in condition to do about 20 knots, and fires were sufficiently under control to permit refueling of fighters on deck...

The planes which our fighters intercepted at about 12 miles distance proved to be 12 to 16 type 97 Kogekiki (Navy torpedo bombers), escorted by about the same number of fighters. Our fighters shot down 5 to 7 of the torpedo planes before our ships opened fire. About 8 came on, one of which fell soon after coming within range of our anti-aircraft fire. When fire was opened, the Pensacola and Portland were on the side of the screen advanced toward the attack. The approaching planes were in two groups. One of five headed to pass astern of the Pensacola toward the Yorktown, and two or three to pass ahead of her. They had already started their glide when our vessels to port of the Yorktown opened fire at 1441 at a range of 12,000 yards. The curtain of fire thrown up by our ships was so heavy that it seemed impossible for a plane to pass through it and survive. Indeed, according to some reports, a few enemy planes circled outside, not daring to come in. Seven or eight, however, came through. As they passed our screening vessels our gunners followed them even though our own ships lay beyond in the line of fire. It seems that only four or five survived long enough to drop their torpedoes. Two of these the Yorktown avoided by skillful maneuvering, so that they passed under her bow. Two others, however, could not be avoided, and they caught her admidships on the port side. The two explosions at 1445 were about 30 seconds apart. The planes which scored these hits were shot down either in passing the Yorktown or in attempting to pass through the fire of her escorting vessels. It is believed that not one of the attacking squadron returned to its carrier.(26)"
http://funsite.unc.edu/hyperwar/USN/USN ... way-8.html

[dunmunro]

. However, one does have to wonder how the Swordfish would have compared to the Japanese aircraft.

Most of the attacking TBs would be Albacores. During the attack phase the Albacore and the A6N would not vary much in terms of dropping speed, while the Albacore actually cruised faster than the Devastator.

[Bgile]

Most of the attacking TBs would be Albacores. During the attack phase the Albacore and the A6N would not vary much in terms of dropping speed, while the Albacore actually cruised faster than the Devastator.

I assume you mean the B5N "Kate". Wouldn't the "glide" or approach phase be a lot faster for the B5N? Also, Albacores would be exposed to fighters for a longer period because they were slower.

I think Japanese aircraft torpedoes were a lot more destructive, weren't they?

[dunmunro]

Most of the attacking TBs would be Albacores. During the attack phase the Albacore and the A6N would not vary much in terms of dropping speed, while the Albacore actually cruised faster than the Devastator.

I assume you mean the B5N "Kate". Wouldn't the "glide" or approach phase be a lot faster for the B5N? Also, Albacores would be exposed to fighters for a longer period because they were slower.

I think Japanese aircraft torpedoes were a lot more destructive, weren't they?

Yes, the B5N, "Kate". I don't know what the maximum speed of the B5N would be, since maximum speed and maximum loaded speed while maintaining formation are likely to be quite different, but I doubt there would be a substantial difference.

in early 1942, IJN torpedoes had either a 330 or 450lb warhead in 1942 versus 388 lb for the FAA Mk XII.

[tommy303]

The Kates would have used the Type 91 Mod 2 with 451-lbs warhead pretty much exclusively in 1941-42. The older Type 91 mod 1 with the 331-lbs warhead was not shipped aboard the carriers, but was available to land based bombers such as the Nell (which used them against POW and Repulse (although the Bettys used in that attack as well, carried the Mod 2 with its heavier warhead), The Japanese explosive used in these torpedoes was 60% TNT and 40% hexanitrodiphenylamine, developed in Germany in about 1907 and used in World War 1 German torpedoes. It was approximately 7% more powerful than straight TNT, and was referred to as Type 97 explosive.

[neil hilton]

I assume you mean the B5N "Kate". Wouldn't the "glide" or approach phase be a lot faster for the B5N? Also, Albacores would be exposed to fighters for a longer period because they were slower.

The glide approach would have to be slowing down to reach a sufficiently low speed to safely drop torps, I think the pilots chopped the throttle way back and then nosed over to perform a gradual reduction in speed while decreasing altitude.

I believe Japanese offensive doctrine would be to send their fighters as escorts first before CAP, if they only had enough to do one or the other. Also remember that the ABDA airstrike is escorted by fighters so the TBDs wouldn't be exposed. This would allow the Albacores or Swordfish to perform a co-ordinated 'Star formation' attack on 2 targets.

[Bgile]

The glide approach would have to be slowing down to reach a sufficiently low speed to safely drop torps, I think the pilots chopped the throttle way back and then nosed over to perform a gradual reduction in speed while decreasing altitude.

The whole point of a "glide" approach is not to slow down until the last minute so you are a difficult target.

[lwd]

...How do you think the following situation was qunatified: one plane badly damaged by a Zero, but destroyed by the AA ? Or viceversa?

I ran across a couple pages on US heavy bomber losses and damage in Europe that indicated the former was by far the most common. On the otherhand some accoutns of Midway I've read indicate that the Japanese fighters concentrated on US fighters and incoming attack planes with planes exiting the battle area often getting a free ride as long as there were still fighters and attackers around.

Furthermore, it's nearly impossible to know exactly who killed who during a serious Pacific battle. There are to many planes, to many explosions for that to happen.

True but if it's 1% or 2 % or even 5% does it matter?

And something else: the amount of AA guns available for the IJN in this scenario is comparable ONLY to MIDWAY. All the others raids faced significantly lower concertration of AA.

That depends to a large extent what's going on. Have the Japanese seperated into a surface strike group and a carrier group? If so then there may be fewer guns. Indeed the strike group may have minimal air cover. Then there's also the factor that the Japanese airdefence doctrine didn't involve maximizeing the effectiveness of AA fire especially early war. Each ship maneuvered independently so they opened up the formation to avoid collisions.

Please remember that at Midway the raids were badly beaten until the carriers were sunk and the task force scattered. Because in our hypothetical scenario there is ONLY ONE RAID, we should expect a good concetration of AA fire, because the TF is not (yet) scatterded.

No. It depens a lot on what happens. Are there other air attacks for instance. The result of the torpedo attacks at Midway was to give the dive bombers a free ride. If there are dive bombers in this scenario there attacks may well do the same for the torpedo planes.

One final point: 15 Swordfish vs 1 BB = 1 hit. Don't forget that when you elucubrate 8-12 hits coming from 20-30 surviving planes!!!

Sea conditions were pretty severe at the time weren't they? And Bismrack was hardly constrained by all her accompanying escorts. According to wiki at:
http://en.wikipedia.org/wiki/Japanese_a ... %8Dh%C5%8D
Shoho was attacked by 22 torpedo planes (along with bombers and fighters) and hit by 7 torpedoes. Considering the quality of US torpedos at the time that doesn't sound all that far off fromt the above.

[dunmunro]

The glide approach would have to be slowing down to reach a sufficiently low speed to safely drop torps, I think the pilots chopped the throttle way back and then nosed over to perform a gradual reduction in speed while decreasing altitude.

The whole point of a "glide" approach is not to slow down until the last minute so you are a difficult target.

Assuming that the Albacores came it at, say, 10K ft, then they could also use a shallow dive to increase their speed.

The differences in performance between the Albacore, B5N2 and Devastator have been exaggerated because the performance specs for the B5N2 and Devastator are given with the aircraft in "clean" condition, while the range, ceiling and max speed of the Albacore are given at max TO weight, while carrying a torpedo.

[alecsandros]

hello man,

True but if it's 1% or 2 % or even 5% does it matter?

Nop, it doesn't matter if it's that small of a margin... but who can say for sure what the margin was ?...
Furthermore, most of the sorties dunmuro posted above were performed by fighters adn dive-bobmers, while the recorded losses come mostly from torpedo-bobmers.

If we are to substract only the torpedo-bombers sorties at Midway, we would have ~ 40 carrier-based TBD - sorties, out of which, probably 12-15 were destroyed by AA. And who can say how many MORE woudl have been destroyed, if they wouldn't have been eaten up by the zero's before hand...?

That depends to a large extent what's going on.

Of course it does. I'm still thinking about an early strike, some 200 miles away from the carriers. So, the Japanese formation should be "clean" and ready to defend. Just like at Midway, early phases...

If there are dive bombers in this scenario there attacks may well do the same for the torpedo planes.

I agree - the dive bombers would be bats out of hell :) However, they aren't presented in this scenario. I don't know even if the Royal Navy ever had something like that?

Sea conditions were pretty severe at the time weren't they? And Bismrack was hardly constrained by all her accompanying escorts.

She wasn't backed up by hundreds of AA guns either.
Another story: Tirpitz alone, 1942, Artctic ocean. 12 Albacores attack. No hits. 2 planes shot down.

There is a situation that I'm not to familiar with: the torpedoing of Littorio in the Med. I know it was done by carrier-based torpedo planes, but how many, and under what circumstances, I don't know. Perhaps it would help if we could find out more about this?

As for Shoho, I don't know for sure, but I think it was hit at first by dive-bombers, and then, when it was in flames and barely moving, it was torpedoed again and again...

[alecsandros]

The differences in performance between the Albacore, B5N2 and Devastator have been exaggerated because the performance specs for the B5N2 and Devastator are given with the aircraft in "clean" condition, while the range, ceiling and max speed of the Albacore are given at max TO weight, while carrying a torpedo.

B5N2 normal cruising speed (with warload)~ 300km/h, max speed 340km/h
Swordfish normal cruising speed (with warload) ~ 180km/h, max speed 210km/h
Albacore normal cruising speed (with warload) ~ 200km/h, max speed 260km/h
Devastator normal cruising speed (with warload) ~ 180km/h, max speed 250km/h (the figures given in Wiki http://en.wikipedia.org/wiki/TBD_Devastator are indeed for an aircraft with no torpedos or bombs)

The slow speed with warload made the TBD's extremely vulnerable, and they were instantly replaced after Midway.

[tommy303]

I agree - the dive bombers would be bats out of hell :) However, they aren't presented in this scenario. I don't know even if the Royal Navy ever had something like that?

The British entered the war with the Blackburn Skua, a rather attractive fighter/divebomber that proved fairly effective initially and was responsible for sinking the Koenigsberg during the Norwegian campaign. It was not so handy when opposed by modern fighters such as the Bf109 and by 1941 surviving Skuas had been withdrawn from frontline service. From that point until 1943 the RN lacked a dedicated dive bomber until the introduction of the Barracuda dual role torpedo bomber and dive bomber.