Bismarck vs USS Iowa coass

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T. A. Gardner
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Re: Bismarck vs USS Iowa coass

#61

Post by T. A. Gardner » 04 May 2020, 02:52

Carl Schwamberger wrote:
04 May 2020, 00:21
My question concerning the penetration of aircraft bombs came from thoughts about mobility reduction. The CV Ranger is not supposed to have torpedoes or torpedo planes in May 1941. So, its all on the 40 odd dive bombers it had to sortie vs the target. A look at the pictures suggests 2/3s of the Bismarcks length, from rudder mount to forward boiler compartment was mobility dedicated. & it looks like all that was under armor.

If notionally 30 dive bombers attack a 10% hit rate or three bombs seems reasonable. So continuing with crude numbers 2/3s or two bombs hit over or adjacent to boiler, engine, propulsion & steering, with 1000lb bombs cause enough damage to reduce speed. If not the Bismarck escapes, otherwise the speed/manuver damage OTL are reproduced & its run down.
Well, a quick check on

https://www.history.navy.mil/research/h ... -1942.html

Shows VT-4 was aboard Ranger with 6 TBD-1 in March and Wasp had VT-7 aboard with 6 TBD-1 at the same time...

On April 15th 1942 Ranger had VT-4 aboard with 7 TBD-1...

The squadron was formed in January 1942.

You might also note that the Ranger was flying SB2U Vindicators in 1941 not SBD...

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Re: Bismarck vs USS Iowa coass

#62

Post by Carl Schwamberger » 04 May 2020, 03:18

Thanks for that confirmation. Looks like the USN would be stuck with validating, or not, their dive bomber doctrine in this hypothetical battle.

However whilst trawling for data for the neutrality patrols this turned up. I'd previously been under the impression the Wasp was back in Norfolk readying for the Icelandic occupation in June. This says otherwise.
May 1941, the German battleship Bismarck engaged British Royal Navy warships HMS Hood and HMS Prince of Wales in the Denmark Strait and then disappeared. Surface ships of United States Navy Task Force 2 and American long range patrol aircraft then began a special effort to locate and shadow the Bismarck. In a way, it was fortunate for the United States that the reports from these sweeps all reported in the negative since to provide Britain with information of an actual sighting during what was arguably a running battle on the far side of the Atlantic would have been hard to explain away as neutral shipping observations. What's more, the ships of Task Force 2 (Wasp, Quincy, Livermore, and Kearny) were given secret orders that, if Bismarck were to be sighted, they were to engage and sink her. During the critical air search, an American plane did not spot Bismarck but a US Navy pilot did. Ensign Leonard B. Smith flying as pilot/advisor in a PBY Catalina of the British Coastal Command was first to spot the German battleship. Two other American "advisors" flying British PBYs helped track Bismarck the rest of that day. This sighting allowed British capital ships to converge on the Bismarck before she could reach the French coast.
Above from: https://ww2db.com/battle_spec.php?battle_id=336

Perhaps the author of this text has conflated the Wasp & Ranger, or the Ranger was also part of TF2 even if back at Bermuda.


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Re: Bismarck vs USS Iowa coass

#63

Post by Thoddy » 04 May 2020, 19:28

Bismarck in any realistic scenario would be up against more than one battleship and that means Bismarck loses--PERIOD.
You dont need to scream. :wink:

That was not the assumption of the author.

In every serious battle, Bismarck was involved, she was outnumbered. Despite the odds against her she won a battle at the cost of cumulative battledamage thus making your "realistic" conclusion in the first view incorrect...

and lost the second while almost immobilized and beeing a fairly stationary target. The british attackers could choose optimal approach against Bismarck with maximising own weapons effect and minimising Bismarcks in return.

And yes in general I agree with you, for the case more than one BB vs Bismarck - Bismarck likely lose;
and I also agree with the statement the first who hits delicate equipment would likely win.

Thats why the Bismarck class had three independent general artillery comand facilities and two independent plotting rooms and excessive protection of vital areas, reducing Mr. Random.

But in 1941 Opening fire against american ships was prohibited. So this ship would avoid american warships in general.
And she would not fire against unidentified warships.
What matters most is who is on target first and gets solid hits.
does Bismarcks performance in the first battle shows such performance.
about five salvos for Hood-- result unlikely but ship happens Hood sunk
shift to new target
POW was then instantly hit in three or five succeding 4 gun salvos by one shell in each salvo given the trajectory analysis at HMSHood.com
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

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Re: Bismarck vs USS Iowa coass

#64

Post by Takao » 04 May 2020, 22:18

Carl Schwamberger wrote:
04 May 2020, 03:18
Thanks for that confirmation. Looks like the USN would be stuck with validating, or not, their dive bomber doctrine in this hypothetical battle.

However whilst trawling for data for the neutrality patrols this turned up. I'd previously been under the impression the Wasp was back in Norfolk readying for the Icelandic occupation in June. This says otherwise.
May 1941, the German battleship Bismarck engaged British Royal Navy warships HMS Hood and HMS Prince of Wales in the Denmark Strait and then disappeared. Surface ships of United States Navy Task Force 2 and American long range patrol aircraft then began a special effort to locate and shadow the Bismarck. In a way, it was fortunate for the United States that the reports from these sweeps all reported in the negative since to provide Britain with information of an actual sighting during what was arguably a running battle on the far side of the Atlantic would have been hard to explain away as neutral shipping observations. What's more, the ships of Task Force 2 (Wasp, Quincy, Livermore, and Kearny) were given secret orders that, if Bismarck were to be sighted, they were to engage and sink her. During the critical air search, an American plane did not spot Bismarck but a US Navy pilot did. Ensign Leonard B. Smith flying as pilot/advisor in a PBY Catalina of the British Coastal Command was first to spot the German battleship. Two other American "advisors" flying British PBYs helped track Bismarck the rest of that day. This sighting allowed British capital ships to converge on the Bismarck before she could reach the French coast.
Above from: https://ww2db.com/battle_spec.php?battle_id=336

Perhaps the author of this text has conflated the Wasp & Ranger, or the Ranger was also part of TF2 even if back at Bermuda.
Ranger was patrolling with Vincennes, Sampson, and Eberle from Bermuda to 40N,35W(about 100 miles NW of the Azores). They were relived there by Ranger & her group on May 23.

There is a DTIC paper online...Search for "The U.S. Navy, The Neutrality Patrol, And Atlantic Fleet Operations, 1939-1941"

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Re: Bismarck vs USS Iowa coass

#65

Post by Carl Schwamberger » 05 May 2020, 05:37

Takao wrote:
04 May 2020, 22:18
... Ranger was patrolling with Vincennes, Sampson, and Eberle from Bermuda to 40N,35W(about 100 miles NW of the Azores). They were relived there by Ranger & her group on May 23. ...
Did you mean 'Wasp was patrolling with Vincennes ... relived there by Ranger...' ?

If I had more time this month I do the research and plot out the courses & try to guess what might happen had Langesdorfs little fleet evaded the Brits and done a bit of raiding into the mid Atlantic.

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Re: Bismarck vs USS Iowa coass

#66

Post by Takao » 07 May 2020, 00:03

Carl Schwamberger wrote:
05 May 2020, 05:37
Takao wrote:
04 May 2020, 22:18
... Ranger was patrolling with Vincennes, Sampson, and Eberle from Bermuda to 40N,35W(about 100 miles NW of the Azores). They were relived there by Ranger & her group on May 23. ...
Did you mean 'Wasp was patrolling with Vincennes ... relived there by Ranger...' ?

If I had more time this month I do the research and plot out the courses & try to guess what might happen had Langesdorfs little fleet evaded the Brits and done a bit of raiding into the mid Atlantic.
Sorry for the mistake.
Ranger left Bermuda on May 9th. Ranger's group was relieved on May 23 by Wasp & her group.

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Re: Bismarck vs USS Iowa coass

#67

Post by Carl Schwamberger » 07 May 2020, 14:58

Ok. So if this pair evades the Brits undamaged & is making a search of cargo ships before turning back east to Brest. Its a lot more likely the Wasp would be the object of any hypothetical encounter. Its also hypothetical possible the Rangers TF is ordered to remain at sea. perhaps joining the Wasp, but that requires answering some logistics questions about fuel ect... IIRC the Wasp did have torpedo bombers in May 1941.

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Re: Bismarck vs USS Iowa coass

#68

Post by Carl Schwamberger » 07 May 2020, 15:12

T. A. Gardner wrote:
04 May 2020, 02:52
...

Well, a quick check on

https://www.history.navy.mil/research/h ... -1942.html ...
I've been unable to find any information on that site for 1941. Looks like nothing on this subject before January 1942.

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Re: Bismarck vs USS Iowa coass

#69

Post by Carl Schwamberger » 07 May 2020, 22:04

Here a graphic description of the Bismarcks armor, from this site: https://www.kbismarck.com/proteccioni.html
Bismarck Armor.png
At this point it appears certain the USN was not deploying AP bombs aboard the carriers. So, the Ranger or Wasp would be dropping bombs with limited ability to penetrate the protected decks. Here are photos of the French BB Jean Bart after struck by bombs & 40 cm naval canon AP projectiles, in November 1942. The visible damage seems to be from 500 & 1000 lb USN bombs. The secondary sources indicate the AP ammo exploded deep inside the ship. In one case in a empty magazine. Several hits seem to have failed to explode.
Jean Bart.png
Jean Bart.png (124.12 KiB) Viewed 926 times
JB 2.png
The a effects of 2-3 hits on the Bismarks superstructure & gunnery systems seem clear. The less clear effect is in the ships hull ability to resist stress and structural damage from shock to the internal below armor structure, and direct damage to the deck. Could this compromise the hulls ability to withstand the stress of heavy or average seas in the Atlantic? I'm not thinking of the ship losing a stern of bow, but the propellers shafts being twisted or stressed, or the turbines & boilers temporarily compromised

Golden Bullet Option
Note how the armor protects the rudder mount and rudder machinery. However 30-40% of the rudder is aft the last frame of armor bulkhead and deck. A lucky bomb could in theory detonate in the aft section so that damaged hull sections interfere with operation, hanging down on the rudders.

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Re: Bismarck vs USS Iowa coass

#70

Post by T. A. Gardner » 07 May 2020, 22:34

The damage on Jean Bart shown was done with 1000 lbs. GP bombs. The bow hit (top picture) would have caused major flooding of probably the entire bow section of the ship putting her down by the head if it had happened in a seaway. This in turn would have slowed the ship considerably to keep the pressure on whatever watertight bulkheads remained intact aft of the damage.

Another, not mentioned, effect of non-penetrating bomb hits amidships would be the partial destruction of the boiler air intake and smoke exhaust systems. These are critical to maintaining a pressurized, forced air flow into the boilers and an updraft pulling the smoke out. The loss of either will immediately result in a loss of boiler efficiency and in turn the amount of steam generated. These also repeatedly proved a source of smoke ingestion into the boiler spaces themselves even from the explosion alone, that frequently drove the crew out of those spaces causing a temporary loss of boiler steam.

Prop shaft loss is more likely with a near miss and underwater detonation of a large bomb near the shaft. In such a case it would be possible to cause a bearing to fail or for the shaft to get slightly misaligned reducing significantly the maximum rpm the shaft could take. But so long as the seals on the hull are reasonably intact and any flooding through them can be managed by pumping, the shaft could continue to operate. If it were bad enough, the shaft could be trailed and allowed to spin free slowly, or in the worst case it is locked and secured in place to prevent its movement.

Another danger is the amidships hangers and ship's boats. Both are sources of fuel for a major fire in one of the worst places to have a major fire--right over the machinery spaces. This could definitely affect ventilation to those spaces and cause them to be evacuated due to smoke ingestion.

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Re: Bismarck vs USS Iowa coass

#71

Post by Takao » 08 May 2020, 00:35

To the best of my knowledge the bow bomb hit caused no or minimal flooding. Garzke & Dulin mention only a few leaks. However, the flooding act did raise the bow up some, but there appears to have been no significant flooding.

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Re: Bismarck vs USS Iowa coass

#72

Post by T. A. Gardner » 08 May 2020, 01:54

Takao wrote:
08 May 2020, 00:35
To the best of my knowledge the bow bomb hit caused no or minimal flooding. Garzke & Dulin mention only a few leaks. However, the flooding act did raise the bow up some, but there appears to have been no significant flooding.
That's because the ship was in port. At sea wave action, bow wake, etc., would have very likely caused flooding to occur and that would have resulted in more flooding as the bow settled. The same goes aft. You can see the damage is very close to the waterline.

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Re: Bismarck vs USS Iowa coass

#73

Post by Carl Schwamberger » 09 May 2020, 19:20

Assuming the Bismarck takes a speed reducing hit what then? A hand full of US cruisers & destroyers are not going to make the kill unless its a really special circumstance. Were any of the USN Standards likely to be near enough? I agree the Brits won't be letting this one go & would be after the smell of blood. Could the Wasp/Ranger get in enough repeat strikes to finish the task?

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Re: Bismarck vs USS Iowa coass

#74

Post by Kingfish » 09 May 2020, 19:34

Carl Schwamberger wrote:
09 May 2020, 19:20
Could the Wasp/Ranger get in enough repeat strikes to finish the task?
Not to imply it would be easy, but three squadrons of strike aircraft vs an already damaged prey with no air cover...
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Re: Bismarck vs USS Iowa coass

#75

Post by Carl Schwamberger » 09 May 2020, 22:52

It has been suggested the additional battery of the Prinz Eugen would make things more difficult...

It also been raised in this & another thread how the carrier TF sinking the Bismarck would accelerate the change in attitudes of capitol ships and fleet operations.

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