late 1943 Tirpitz instead of Bismarck in May 1941

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alecsandros
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late 1943 Tirpitz instead of Bismarck in May 1941

Post by alecsandros »

Completely hypothetical scenario:
What if the 1943 equiped Tirpitz would be sent back in time in may 1941 and woudl replace Bismarck.

The main improvements would be: Fumo26 radars, much more AA, better trained and experienced crew, new target tracking systems, giving the ship 360* turning
ability while still mantaining target lock.

What do you think ? Would these improvements be enough for a successfull Rheinubung ? (at least 1 convoy attacked and scattered)
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by RF »

Possibly. The key point if convoys are to be attacked is shaking off the RN pursuers.

My consideration would also apply to commander - do we have Lutjens or someone else, such as Marschall or Ciliax? And at the DS battle is Lindemann ordered to go after POW in an attempt to sink her?

More realistically if we have a fully worked up Tirpitz available in May 1941 I would send her out with Bismarck......
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Saltheart »

alecsandros wrote:Completely hypothetical scenario:
What if the 1943 equiped Tirpitz would be sent back in time in may 1941 and woudl replace Bismarck.

The main improvements would be: Fumo26 radars, much more AA, better trained and experienced crew, new target tracking systems, giving the ship 360* turning
ability while still mantaining target lock.

What do you think ? Would these improvements be enough for a successfull Rheinubung ? (at least 1 convoy attacked and scattered)
It would not be enough for a succesful operation. What it would do is give the ship a chance of making it home. After the Denmark Strait the Royal Navy relied on torpedoe bombers to attack the Bismarck. If it's Tirpitz with about 80x20mm cannons then they have a chance of shooting down planes and avoiding getting torpedoed. It's a big difference as it means the ship at least survives but the fundamental problem of no carriers for the Germans remains. Once they're shadowed how do they break contact? If the shadowers are scout planes from a carrier endlessly calling in cruisers then Tirpitz can never refuel and never replace anti-aircraft ammuntion. In the end it'll still just be trying to make it home or be sunk.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by lwd »

I would actually expect Tirpitz to do worse. The lucky hit that destroyed Hood early in the battle is unlikly to occur in another run through of Denmark straits. As a result while POW and Hood are both likely to suffer severe damage Tirpitz is likely to take worse damage as well. PE may also be damaged in the battle.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Karl Heidenreich »

lwd:
I would actually expect Tirpitz to do worse. The lucky hit that destroyed Hood early in the battle is unlikly to occur in another run through of Denmark straits. As a result while POW and Hood are both likely to suffer severe damage Tirpitz is likely to take worse damage as well. PE may also be damaged in the battle.
I do not agree at all with this statement but would like lwd to bring forth a more solid argument before discussing. Maybe you have a point we are all missing.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by alecsandros »

lwd wrote:I would actually expect Tirpitz to do worse. The lucky hit that destroyed Hood early in the battle is unlikly to occur in another run through of Denmark straits. As a result while POW and Hood are both likely to suffer severe damage Tirpitz is likely to take worse damage as well. PE may also be damaged in the battle.
I don't think so.

Tirpitz would start tracking at 30km, and open fire at 25. Hits may be obtained before 20km. Any part of Hood would be vulnerable to 38cm fire at that distance.

Additional points to take into consideration:

1) Remember that in the historical engagement, Hood was hit by at least 1 more shell from Bismarck, that went through the foreward spoting tower. Hood was in flames when it was destroyed; and was firing erraticaly.

2) PoW obtained hits only while Bismarck was concentrated on Hood. As soon as Bismarck opened on PoW, no more 356mm hits were obtained.

3) The false torpedo alarm at 6:01 forced Bismarck to change course and to lose its fire-control solution over PoW. That would not have been the case for Tirpitz, equiped with the latest in fire-control systems. Tirpitz would have been capable of mantaining target lock even while turning, and at that time the distance to PoW was 14km. At 14km, any part of a KGV class would be vulnerable to 38cm gunfire. Given the trajectories, rate of fire and accuracy pf the 4 x 2 38cm guns arrangement and fire control system, in the crucial 2 minutes of "evading torpedoes", PoW was likely to be hit by at least 4-6 shells before turning under smoke.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by lwd »

alecsandros wrote:
lwd wrote:I would actually expect Tirpitz to do worse. The lucky hit that destroyed Hood early in the battle is unlikly to occur in another run through of Denmark straits. As a result while POW and Hood are both likely to suffer severe damage Tirpitz is likely to take worse damage as well. PE may also be damaged in the battle.
I don't think so.
Tirpitz would start tracking at 30km, and open fire at 25. Hits may be obtained before 20km. Any part of Hood would be vulnerable to 38cm fire at that distance.
Bismarck was tracking the British battleships well before she opened fire. They were miss identified as cruisers. Of course this might not come into play as it's another pecularity of the Denmark strait battle. However the British ships could also open fire at that distance and again a catastrophic hit is unlikely.
Additional points to take into consideration:

1) Remember that in the historical engagement, Hood was hit by at least 1 more shell from Bismarck, that went through the foreward spoting tower. Hood was in flames when it was destroyed; and was firing erraticaly.

2) PoW obtained hits only while Bismarck was concentrated on Hood. As soon as Bismarck opened on PoW, no more 356mm hits were obtained.
I don't see any difference that this would introduce. Unless of course Hood correctly IDs Tirpitz or Tirpitz opens fire on POW. Neither of which are to her benefit.
3) The false torpedo alarm at 6:01 forced Bismarck to change course and to lose its fire-control solution over PoW. That would not have been the case for Tirpitz, equiped with the latest in fire-control systems. Tirpitz would have been capable of mantaining target lock even while turning, and at that time the distance to PoW was 14km. At 14km, any part of a KGV class would be vulnerable to 38cm gunfire. Given the trajectories, rate of fire and accuracy pf the 4 x 2 38cm guns arrangement and fire control system, in the crucial 2 minutes of "evading torpedoes", PoW was likely to be hit by at least 4-6 shells before turning under smoke.
Was Tirpitz really capable of maintaining a target lock? I haven't seen anything to indicate such. In any case the false torpedo alarm is another unlikely event especially as many here seem to consider it an artifact of Hood's demise.

Now I'm not saying that if you had an accurate simulation and ran it say 100 times each for Bismark and Tirpitz that Tirpitz wouldn't do better than Bismarck on average. Indeed I believe she would, however the historical result was so favorable to the Germans that it might well fit the definition of an outlier if it was produced by said simulation.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by alecsandros »

lwd wrote: Bismarck was tracking the British battleships well before she opened fire...
The Fumo26 radar could easily differentiate between various types of ships; it had a range of over 30km and very good range and bearing accuracy.
The systems on board Bismarck (especialy the main director) were only capable of detecting enemy ships at 25km maximum, while reliable tracking and ranging in battle conditions were around 20km.
I don't see any difference that this would introduce. Unless of course Hood correctly IDs Tirpitz or Tirpitz opens fire on POW. Neither of which are to her benefit.
It makes a huge difference: once Hood was out (either destroyed or dead in the water), teh PoW couldn't effectively return fire.

Was Tirpitz really capable of maintaining a target lock?
I believe she was. Prinz Eugen ran some tests in 1943, amongst which 360* turns while mantaining a proper firing solution. If I remember correctly, Tirpitz, Gneisenau, Scheer and Hipper were scheduled for a similar refit.
In any case the false torpedo alarm is another unlikely event especially as many here seem to consider it an artifact of Hood's demise.
Without the torpedo alarm to come just at the right time, PoW may also have been sunk in the historical battle against Bismarck.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Karl Heidenreich »

lwd:
I don't see any difference that this would introduce. Unless of course Hood correctly IDs Tirpitz or Tirpitz opens fire on POW. Neither of which are to her benefit.
That doens't change anything in reality. Hood was the first ship opening fire but by the moment she blew sky high she didn't hit anything. What would have made some people so sure she would have hit something by changes the ships it's still a matter of argument but there is no strong evidence, whatsoever, that something of the sort will happen.

Alex points have been my own for a long time: Hood opens fire first and hit nothing. Bismarck and PE open fire later but both find target pretty soon. Also PoW finds target soon but only, as Alex states, as the Germans do NOT fire back to her. Once PE and Bismarck fires to PoW then she hits nothing but is hit back several times and withdraws. Now: with TIrpitz and her more sophisticated FD (and given the same circumstances) there is a highly degree of certainty that Hood would have run a similar if not equal fate and that PoW's destruction would have been more likely.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by dunmunro »

Bismarck and PE were, in all probability, using radar ranging in the historical scenario, with optical control. The range accuracy of later radars is not much, if any better, so I wouldn't expect much difference in KM shooting.

PoW didn't score any hits after Hood was lost because she was manoeuvring constantly, initially to avoid hitting Hood, and not because she was under fire.

However, if PoW was given another few weeks to get all her radars functioning, then I would expect her shooting to greatly improve.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Karl Heidenreich »

dunmuro:
PoW didn't score any hits after Hood was lost because she was manoeuvring constantly, initially to avoid hitting Hood, and not because she was under fire.
If she is manouvering then is like evasives, which would have made also difficult for the Germans to hit it, which was not the case.
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by alecsandros »

dunmunro wrote:Bismarck and PE were, in all probability, using radar ranging in the historical scenario, with optical control. The range accuracy of later radars is not much, if any better, so I wouldn't expect much difference in KM shooting.
From another part of the forum:

Regarding the Bismarck's radar fit, the Bismarck was fitted with three Seetakt radars to the three main optical rangefinder assemblies (these were not directors as the directors were seperate equipment). More common practice was the fitting of two radar sets at the foretop and aft, or only one set at the foretop early war, so Bismarck being fitted with three sets, two forward, was a new practice.

It is puzzling that the Bismarck, the KM's newest and most powerful warship, would be fitted with the obsolete first generation models (FuMG39Gg only later designated FuMO23) that used the fragile TS1 transmitting triodes more than a year after they went out of production. The second generation Seetakt models, which began production in mid 1940, used, among other significant improvements, the more rugged TS6 triode that was specially designed to stand up to shock of heavy guns firing, which the TS1 had proven especially vulnerable to. The Prinz Eugen was fitted with two second generation Seetakt (FuMG40Gg or FuMO27 in a later designation) sets using the TS6 triodes in Aug 1940.


The Tirpitz was equipped with FuMO26 sets (as well as Hohentwiel and Wuerzburg) during the time it was laid up from the X craft attack from Sept 1943 to March 1944. The large antenna FuMO26 sets had 30% more range than the FuMO27 sets it had from 1941 until late 43. The FuMO27 had a BB to BB range of ~30km prior to 1943. The early models such as mounted on Graf Spee and Gneisenau could easly track large warships to 25km. In 1938 trials on Graf Spee it proved it could track another Panzerschiff to 25km. The Gniesenau's Seetakt picked up and tracked the Renown at 25km in brutal weather on April 9th 1940. The second generation in mid 1940 gave a 20% increase in range above that baseline. The FuMO27 on Luetzow picked up and tracked Burnettes light cruisers from 29km at Barents Sea in late 1942. In tests of large antenna versions of Seetakt it could track PT's to 15km. Late war the Germans standardized the size of the ship targets to a 2,000 ton warship for range comparison purposes.

More about Fumo 26:
viewtopic.php?f=1&t=3265&p=38003&hilit=fumo27#p38003

More about Fumo 23:
http://www.kbismarck.com/controltiri.html

Fumo23 max BB range: ~ 25.000m; range accuracy: ~ 100m
Fumo26 max BB range: ~ 33.000m, range accuracy: ~ 25m
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by dunmunro »

Karl Heidenreich wrote:dunmuro:
PoW didn't score any hits after Hood was lost because she was manoeuvring constantly, initially to avoid hitting Hood, and not because she was under fire.
If she is manouvering then is like evasives, which would have made also difficult for the Germans to hit it, which was not the case.
PoW was hit 7 times, including 3 38cm hits, but one of these was the UW dud hit, while the first hit was made just as PoW passed through where Hood would have been, resulting in the compass platform hit, which is not surprising since Bismarck already had a FC solution on Hood. The other 4 hits were from PE which fired 17 of her 23 salvos at PoW, and she scored 2 hits, again just as PoW passed through where Hood would have been. Given the close range (under 16000 yds) and the number of salvos fired, neither PE nor Bismarck showed particularly good gunnery especially as both had radar.
There's a good summary here:
http://www.hmshood.com/history/denmarks ... trait2.htm
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Karl Heidenreich »

And how many hits Hood made?
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Re: late 1943 Tirpitz instead of Bismarck in May 1941

Post by Dave Saxton »

alecsandros wrote:Regarding the Bismarck's radar fit, the Bismarck was fitted with three Seetakt radars to the three main optical rangefinder assemblies (these were not directors as the directors were seperate equipment). More common practice was the fitting of two radar sets at the foretop and aft, or only one set at the foretop early war, so Bismarck being fitted with three sets, two forward, was a new practice.

It is puzzling that the Bismarck, the KM's newest and most powerful warship, would be fitted with the obsolete first generation models (FuMG39Gg only later designated FuMO23) that used the fragile TS1 transmitting triodes more than a year after they went out of production. The second generation Seetakt models, which began production in mid 1940, used, among other significant improvements, the more rugged TS6 triode that was specially designed to stand up to shock of heavy guns firing, which the TS1 had proven especially vulnerable to. The Prinz Eugen was fitted with two second generation Seetakt (FuMG40Gg or FuMO27 in a later designation) sets using the TS6 triodes in Aug 1940.


There's new information guys: Bismarck's radars were tested before sailing and noted to have the following power output and pulse repetition rates. 9kw output and ~500 hz PRF.

FuMO23: output = 2kw, and PRF = 2000hz
FuMO27: output =8kw (min), and PRF =500.

Bismarck had FuMO27-not FuMO23.

One factor of significance beyond just the accuracy and range attainment improvement, was that FuMO27 could be more easily maintained and repaired at sea, and it was more durable to start with. Indeed the British Intel experts obtained indication from the prisioners, that the Bismarck's radar devices had a range to large ships of 30km and that the forward radars were brought back online by the late afternoon of May 24th.

This would have been too late for Denmark St. and immediately following.

At Denmark St., Bismarck fired a 400 meter bracket to start shooting at the Hood. In other words, one salvo was to be 200 meters too far and one 200 meters too short (200 meters was the likely range accuracy tolerance of the optical range finders at those battle ranges, and therefore confirming the accuracy of the firing solution) with the third to hit, followed by firing for effect. Which is exactly what happened. This was the standard procedure, especially without radar. Bismarck's shooting was excellent but not as good as PG's.

Prinz Eugen averaged radar ranges and optical ranges at the central fire control, and near-missed with salvo number 1 and hit with salvo number 2.
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