Bismarck 150mm fire control

[alecsandros]

I was asking if C38 computers were capable of computing solutions for main battery guns. Are you saying that the ballistics cams in the C 38 computers could be replaced with 38cm cams while in action?

I took a look in the service regulation for weapon systems on board Bismarck class (TS131 - 22065 - B.B.V.-W- - Bauvorschrift für die Waffenanlagen),it state that ther were two C38 within each plotting room one associated to the main artillery and one associated to secondaries.

My additional information came from Paul Schmalenbach (History of german naval artillery), who state that ballistic cams were generally interchangeable.

Hi Thorsten,
It is relatively well known that the fire control calculators for German Bismarck and Hipper class ships were accurate and functioned well.

I would like to ask you, if it is possible to reply (and if the answer would not divulge secrets or information that are pending publication in print) , if you have knowledge on actual fire drills/testing shoots of Prinz Eugen/HIpper/Tirpitz from Oct 1941 onwards, that would serve in assessing their overall main battery shooting efficiency.
We all know the info on Marine Arsenal no. 6 about the 9 hits obtained on Hessen. However, I , and probably many other readers, would be very interested in learning if new evidence on German capital ships firing devices and firing efficiencies have surfaced in the previous years.

Thanks in advance,

[Dave Saxton]

I was asking if C38 computers were capable of computing solutions for main battery guns. Are you saying that the ballistics cams in the C 38 computers could be replaced with 38cm cams while in action?

I took a look in the service regulation for weapon systems on board Bismarck class (TS131 - 22065 - B.B.V.-W- - Bauvorschrift für die Waffenanlagen),it state that ther were two C38 within each plotting room one associated to the main artillery and one associated to secondaries.

My additional information came from Paul Schmalenbach (History of german naval artillery), who state that ballistic cams were generally interchangeable.

In addition the German schusswertrechner C/38 was largely electronic instead of mechanical, unlike calculaters used in other navies of the period. The solutions were presented graphically in real time on CRT screens. Several parameters were compenstated for automatically. These included: wind, air pressure, and the actual muzzle veocity, and as well as the temperature of the guns. Several solutions were run, including for cold or warm guns. Input for target range and bearing were continuous.

[Dave Saxton]

No one said there were more than 3, just that fire control solutions could still be calculated downstairs based on the inputs from other measuring instruments... And Bismarck had 12 rangefinders capable, in various degrees, to measure range to enemy ships. But the best one was the foretop one... 10.5m baselength with 31.5meters altitude... great field of view...

We do not know if they tried to use a 105mm director in the final minutes... who knows... were they still operational at least at 9:20 ?

One problem with using the flak directors as back up in the Bismarck's case, while possible to do so, was that they were put on to the target by the ZAGs. Target acqusition and designation of air targets were done by the ZAGs. The ZAGs sent the range and bearing/elevation to the flak firecontrol centers which then put the correct flak director on the selected target. Once on target they could have feed data to the firecontrol computers directing the main battery. However, the ZAGs were located on the the foretop and after firecontrol tower, both of which positions had already been destroyed. It's possible that a flak director might pickup one of the targets by accident without the aid of the ZAGs, but it wasn't the Baron's call to make such an assignment. It would have been the call of the second gunnery officer Hans Cardinal in the computor room to find a new data source. Perhaps he did, but the flak directors had been put out of action by then as well? At the time the Baron had his instruments destroyed it was already 20 minutes after the first hits. The top side damage would have been piling up quickly by that time. It didn't take that long for South Dakota in the words of Adm. Lee to be rendered : "Deaf, dumb, blind, and toothless." Why would BS be much different?

Another alternative would have been the night firecontrol directors. However, these were located on the wings of Admirals Bridge which we know had also been hit early.

[Thorsten Wahl]

We all know the info on Marine Arsenal no. 6 about the 9 hits obtained on Hessen. However, I , and probably many other readers, would be very interested in learning if new evidence on German capital ships firing devices and firing efficiencies have surfaced in the previous years.

I dont think that shooting records survived the war. Ther were only few pointwise observations and
summarized assessments by the Kriegsmarine leadership that allows for indication.

pointwise observation for instance
1)the nine hits of Tirpitz versus Hessen. these shooting trials had a very restricted time dilation say one hour and include different shooting attempts. The whole purpose was not to hit the Hessen but to assess hit probabilites under several different circumstances(parallel battle, encounter battle).

2)the shooting vs Hood the first half salvo was shot as a 400 m Gabelgruppe so 2 projectiles wer fired at calculated target distance and two projectiles at calculated target distance + 400m. POW observed an salvo spread of 400 yards with MPI over . MPI and salvo spread shouldnt measured on the artifical increased salvo spread. If one corrects the oberere Gabelgruppe by -400 m the result shows a very low deviation of the impacts from target for MPI and also salvo spread.

[alecsandros]

pointwise observation for instance
1)the nine hits of Tirpitz versus Hessen. these shooting trials had a very restricted time dilation say one hour and include different shooting attempts. The whole purpose was not to hit the Hessen but to assess hit probabilites under several different circumstances(parallel battle, encounter battle).

Do you think there were 9 hits ? I.E., are there other sources that hint towards, or even have written number of total hits over the Hessen ?

Do you think 250hm was the only range of firings, or was it one of the many ranges the firings were recorded ? Full caliber or sub-caliber shootings... ?

[Thorsten Wahl]

Do you think there were 9 hits ? I.E., are there other sources that hint towards, or even have written number of total hits over the Hessen ?

Ther is only one written source(protocol from memory) and few photos that shows damage to Hessen as far as I know.

Marineobebaurat Többicke "Die Panzerung deutscher Kriegsschiffe 1920-1945". Többicke was at a responsible position at the Marinewerft Wilhelmshaven. He explicitely mentioned that excercise ammunition had to be replaced by HE ammunition as excercise ammo had not the required ballistics for long range and it was normally not allowed to use combat ammo against target ships. The time periods of the shooting one can take from the war diary of Tirpitz.

The war game of the german naval command 1937/38 went from combat distances in the order of 25 km with fast convergence speeds for the Bismarck class vs the expected KGV class. In this war game they rated the horizontal protection as beeing 150mm for Bismarck class. Real training for the assumed distance is in my opinion the logical consequence

[alecsandros]

Do you think there were 9 hits ? I.E., are there other sources that hint towards, or even have written number of total hits over the Hessen ?

Ther is only one written source(protocol from memory) and few photos that shows damage to Hessen as far as I know.

Marineobebaurat Többicke "Die Panzerung deutscher Kriegsschiffe 1920-1945". Többicke was at a responsible position at the Marinewerft Wilhelmshaven. He explicitely mentioned that excercise ammunition had to be replaced by HE ammunition as excercise ammo had not the required ballistics for long range and it was normally not allowed to use combat ammo against target ships. The time periods of the shooting one can take from the war diary of Tirpitz.

The war game of the german naval command 1937/38 went from combat distances in the order of 25 km with fast convergence speeds for the Bismarck class vs the expected KGV class. In this war game they rated the horizontal protection as beeing 150mm for Bismarck class. Real training for the assumed distance is in my opinion the logical consequence

Are there speifications for the minimum distance of engagement ?
If the engagement starts at 25km, did they envisaged a certain minimum range for this battle ?

===
My issue is that Breyer praised KGM Hessen armor layout, but the firing trials he mentions were done with High Explosive ammo. Then what kind of armor protection did the Hessen prove ? Against HE shots... ?

[Byron Angel]

..... I would dearly love to locate any US report on the post-war gunnery shoot by Prinz Eugen off the NE US coast. I cannot believe that the shoot was authorized and undertaken without any US observer report having been produced. Secondary historical references suggest that the results were quite impressive.

B

[Thorsten Wahl]

My issue is that Breyer praised KGM Hessen armor layout, but the firing trials he mentions were done with High Explosive ammo. Then what kind of armor protection did the Hessen prove ? Against HE shots... ?

I think its inadmissible to draw conclusions from that trial on armor protection of Bismarck-class vs armor piercing projectiles. Its only confirmation of the knowledge that HE shells only make "superficial" damage, if they explode far enough from vital parts / if the armour prevents HE-shells from damaging the waterline.

Are there speifications for the minimum distance of engagement ?
If the engagement starts at 25km, did they envisaged a certain minimum range for this battle ?

The excercised scenario is remarkably similar to Denmark Strait including the timing of possible decisive hits.

[alecsandros]

My issue is that Breyer praised KGM Hessen armor layout, but the firing trials he mentions were done with High Explosive ammo. Then what kind of armor protection did the Hessen prove ? Against HE shots... ?

I think its inadmissible to draw conclusions from that trial on armor protection of Bismarck-class vs armor piercing projectiles. Its only confirmation of the knowledge that HE shells only make "superficial" damage, if they explode far enough from vital parts / if the armour prevents HE-shells from damaging the
If the engagement starts at 25km, did they envisaged a certain minimum range for this battle ?

The excercised scenario is remarkably similar to Denmark Strait including the timing of possible decisive hits.[/quote]
... I do not call into question the Bismarck armor array, but the conclusion pf Breywr/Tobicke, as ot is written in MA6. I do not understand how do they judge Hessen armor scheme (225mm belt of old type and 30-40 mm deck of Whotan hompgenous) if undrr attack only from HE shells...

[Dave Saxton]

As I recall, Toebicke only said that instrumentation confirmed the affect of a Wh upper deck on the energy of the projectiles. It could therefore be used to confirm the viability of the Bismarck system (the change of energy state is what causes yaw). The Luftwaffe also studied the effects of the German system on armour piercing bombs. These studies confirmed that the upper armoured deck would absorb about 10% of the energy of armour piercing bombs striking at the normal.

As far as records for shoots go, almost all of these were destroyed during the Allied bombings of Kiel. We know that the comprehensive blind fire trials of Scheer during 1943 were thus destroyed. The 1944 night shoot vs Hessen by Nuernburg was not destroyed however.

..... I would dearly love to locate any US report on the post-war gunnery shoot by Prinz Eugen off the NE US coast. I cannot believe that the shoot was authorized and undertaken without any US observer report having been produced. Secondary historical references suggest that the results were quite impressive.

B

If you ever find anything, let me know. I have not been able to find any USN official report on that. The Tech Mission exam of PG firecontrol at Bremerhafen is rather incomplete and said that a more thorough exam would be done later. A later more thorough exam was never actually done.

[alecsandros]

As I recall, Toebicke only said that instrumentation confirmed the affect of a Wh upper deck on the energy of the projectiles. It could therefore be used to confirm the viability of the Bismarck system (the change of energy state is what causes yaw).

Seems to me it wants to praise the Hessen armor scheme... which I find it peculiar. It is not the only peculiarity in M.A. no 6, that's why I was asking if there are other sources to confirm it.

[Dave Saxton]

I know I have read it many times. However, Toebicke is speaking in the context of the Hessen having been modified to mimick the Bismarck's horizontal spaced array by addition of its Wh upper deck. It is a comment on the effectiveness of the materials (Wh) and the arraingment used in that way.

[alecsandros]

I know I have read it many times. However, Toebicke is speaking in the context of the Hessen having been modified to mimick the Bismarck's horizontal spaced array by addition of its Wh upper deck. It is a comment on the effectiveness of the materials (Wh) and the arraingment used in that way.

I know... still the way it is written hints that the idea is a presentation of a good, well-shaped armor design which withstood several projectile attacks.
Especialy on the case of the 225mm KC armor, which was "only pushed back by a few centimeters", the impression is that of a well designed armor... But... in all fairness... who would expect anything else then superficial damage coming from 28 and 38cm HE shells hiting, and probably exploding against, such heavy armor plates ... ?

[Dave Saxton]

I know I have read it many times. However, Toebicke is speaking in the context of the Hessen having been modified to mimick the Bismarck's horizontal spaced array by addition of its Wh upper deck. It is a comment on the effectiveness of the materials (Wh) and the arraingment used in that way.

I know... still the way it is written hints that the idea is a presentation of a good, well-shaped armor design which withstood several projectile attacks.
Especialy on the case of the 225mm KC armor, which was "only pushed back by a few centimeters", the impression is that of a well designed armor... But... in all fairness... who would expect anything else then superficial damage coming from 28 and 38cm HE shells hiting, and probably exploding against, such heavy armor plates ... ?

You have to consider the overall context. The Russians were asking about the German practice of using a spaced deck protection system. Toebicke is only using the Hessen shoot as an example to show that the German horizontal protection scheme was proven valid. That it wasn't just theory. He's not really commenting on the Hessen's protection.