Poorly trained AA crews on Bismarck?

[TTTT]

Is it true that Bismarcks gun crews, and especially the AA crews, had not been trained to highest possible standard before her (his) first and final sortie?

[TTTT]

I found this on Quora. I know, normally Quora makes Wikipedia look like the mother of all primary documents, but I thought this one was well written and sourced. The datas are pulled from two main documents:

Kriegstagesbuch des Schlachtschiffes “Bismarck”, RM 92/5100 held in the Naval Archives in Freiburg, Germany. This covers the period from commissioning on 24.08.40 to 30.04.41; the war diary covering Operation Rhein was of course lost with the Bismarck, although a reconstruction was made based on submitted reports prior to sailing and subsequent signals between Bismarck and Prinz Eugen and signals between Bismarck and Groups North and West.

The other main source is the Artillery Testing Command for Ships, AVKS No. 700/41 aboard Battleship Bismarck.

How did the fire control for the Bismarck's anti-aircraft guns fail to track the attacking Swordfish torpedo bombers?

One of the aspects of the Bismarck narrative is that the ship is almost always presented in common literature and film as being fully worked up with a highly trained crew ready for action. This is actually against the reality of the situation. In some ways, Bismarck went into action with more similarity to the readiness of Prince of Wales than the usual presentation depicts. In reality, Bismarck was, in Lindemann’s own evaulation, ready in all respects for a peace time cruise. The rush by the naval high command to get Bismarck into action had caused problems that limited Bismarck’s effectiveness. These fall into two basic categories, training and technical.

Technical:
Bismarck’s heavy Flak was of mixed mountings—four twin mounts of newer faster traversing and elevating design fully integrated with the heavy Flak fire control computers, and four twin mounts of an older design which were incapable of being integrated into the latest Flak fire control system installed on the ship. The split had been necessitated by Germany having sent the USSR four modern ones to complete the cruiser Luetzow which had been sold, incomplete to Russia.
Bismarck’s heavy Flak were supposed to be directed by four triaxle directors, normally each one directing a pair of twin mounts against the most dangerous attacking aircraft. However, at the time of Bismarck’s sortie, only the two forward ones had been installed, as the other two had been allocated to the USSR as part of the Russo-German trade agreements. In their place two simple rangefinders had been installed. The plan was to replace them with the proper Flak directors which were being manufactured once Bismarck returned from her first cruise. Prinz Eugen was in similar condition, as her two forward triaxle directors had also been sold to the USSR leaving her with just the two after ones.
Bismarck’s medium and light Flak were sufficient in numbers, but the medium 3,7cm twin Flak were not automatic and had a low rate of fire. The 2cm was better, but fields of fire for both were often poor and they lacked directors to control target selection.

Training:
While Bismarck had conducted several trial and practice shoots with the main and secondary low angle armament, there had only been one practice session with the Flak guns, due in part to Bismarck having to return to the shipyard during exercises to correct technical faults, particularly severe winter weather which kept her in port longer due to the freezing over of the Kiel Canal and ice in the Elbe River blocking the route from Hamburg, and lack of cooperation from the Luftwaffe in providing drogue towing aircraft.
Such practice as could be done in the meantime was mostly while at anchor and consisted of pointing and tracking under conditions that did not simulate what would be encountered at sea.

All in all, it is somewhat remarkable that, though unable to break up attacks by the Swordfish, the Flak gunners were able to damage a number of the attackers.

[marcelo_malara]

I would rather say that the medium range AA guns onboard were poor. Instead of the automatic 40mm Bofors then available, the KM used an obsolete single shot 3.7cm gun.

[wadinga]

Hi TTTT,

The archive section of this very site (thanks to Mr Rico) includes these documents helpfully translated. These and other vital source materials are a terrific resource to further your understanding.

The shortcomings of Bismarck's light AA have been addressed before:

I posted:

Ploughing through the complex nomenclature of the German 37mm gun in Skiwiot's German Naval Guns I think the retention of the SK C/30 model, which was really a "quick firing gun" (Schnell Kanone) rather than an automatic cannon was because the Kriegsmarine was convinced of the overwhelming virtue of a triaxial gyro stabilised mount carrying all the crew as well. Redesigning the complex package to incorporate the Flak 36 or 37 which did feature a multi-round loading clip was evidently not considered feasible. Hence in 1940/41 Bismarck and Prinz Eugen were outfitted with the slower firing, manually loaded gun on the Dopp L C/30 mount.

While the Reichsmarine, later Kriegsmarine, was convinced of the requirement for 37mm stabilisation from 1930 onwards, in the Royal Navy such complex gyro-stabilised mounts were only developed after 1940 when Dutch warships with the Hazemeyer Bofors mount were evaluated. Even when the British STAAG mount was produced, the majority of light AA mounts were simpler, relying on the trainer and layer's co-ordination to compensate for vessel motion as well as target motion.

In German ships, later, when the Bofors-derived 4cm Flak 28 was introduced, largely replacing the SK C/30 model, they seem to be fitted without the complex gyro-stabilised mount.

and

there was an archive clip which I have never seen before of the single shot 37mm in action. One simple method of maintaining a higher rate of fire was shown. A luckless seaman had a heavy-looking satchel slung across his chest with something like 10 37mm shells stuffed nose down into it, which he pulled out and passed to the loader. Depending on how many satchel carriers there were, this low tech transport method would determine how long a higher rate of fire could be maintained.

The complexities of WWII AA directors (or gun mounts), their ability or otherwise to "take-out" vessel motion and avoid gyro-induced hysteresis effects degrading their performance has been addressed several times on the forum. The Swordfish attacks took place in very stormy Atlantic conditions when even the wide beamed and high metacentric height Bismarck would have quite jerky wave-induced motion aside from the high speed evasive turns she was making. Her AA gunners may have had experience in other vessels before joining Bismarck, but conditions on this mission were difficult.

All the best

wadinga

[RF]

Is it not the case that up to the commencement of Rheinubung there were hardly any cases of German capital ships facing serious air attack whilst at sea? So air defence may not have been taken as seriously as hindsight suggests?

I am aware of KM light cruisers being attacked by the Fleet Air Arm during the Norwegian campaign and of course the raid on Taranto sinking Italian battleships, but there wasn't anything to suggest that Bismarck would be in serious danger of air attack in the Atlantic?

[paul.mercer]

Gentlemen,
I'm sure that I read somewhere that the AA crews om Bismarck had difficulty hitting the Swordfish because they had been trained by firing at faster moving drone targets and the aircraft were approaching them were travelling much at a slower speed and were dancing about in the strong winds, whether that is true or not I don't know, although it seems unlikely.
Also, as some of the Swordfish were only damaged but not shot down, I worder if it was because of their design that the shells and bullets were going straight through rather than exploding?

[Thorsten Wahl]

Its been said that Swordfish aircraft used a unusual approach tactics
Typically they used low overcast to approach unseen, using a spotter plane out of AA range. Then they let the airplane trundle out of the clouds (distance 1.5 -2 km) and were going into a deep approach to the target.

In contrast to the royal navy the Kriegsmarine had a extremely small personnel before the war. Practically all Bismarck crew members were previously civilians. With absolutely no experience in the use of any navy/firecontrol equipment or guns etc pp. They simply had no available personnel from older ships.

As training they had only "few" simulated enemy approaches during their training. They had no battle experience with real enemy behavior and/or under difficult wheather conditions. Maybe northatlantic swell played a role.

With regard to reported deficiencies in gun depression during excercises according AVKS report. These were no problems of maximum depression of the guns (All AA guns could be depressed to at least-9 degrees). It was a problem of allowed tolerances for use in full RPC.
This problem was applicable to all german captitalship firecontrol facilities and could be bypassed.

You can be sure, that such problems were solved immediately after detection, if the ressources allowed for. Or, if the problem could not be solved in RPC mode, the gun would use another method of firecontrol. In case of the other german capitalships certain parts of "unnecessary firecontrol gimmicks" were permantly switched off. with no effect to overall efficency.

with regard to fusing AA shells. the light structure of Swordfish aircraft require extremly sensitive fuzes in contrast to aircraft made from metal.
Here the use of "overly" sensitive fuzes would reduce damage caused. This may have played a role also.

3,7 cm AA armament.
it was planned that the German battleships should receive a very strong anti-aircraft gun suite.

In the course of the first two years of war, it turned out that the fire volume in the close-up area in particular could not be considered sufficient. So Bismarck received two or so 20 mm Vierlings as compensation. But in the 3,7 cm sector the equipment was not changed, despite -in theory- they had a fast firing triaxially stabilised 3,7 cm AA gun(3,7 cm Flak C/36) that could be used on warships. But this gun was not available in numbers nor reliable enough for mass use. The Kriegsmarine tries to surpass the fire volume problem by operating within aircraft remote areas.

[Herr Nilsson]

... In reality, Bismarck was, in Lindemann’s own evaulation, ready in all respects for a peace time cruise.
The rush by the naval high command to get Bismarck into action had caused problems that limited Bismarck’s effectiveness.

Actually:
"The state of training that has been reached compares favorably with that of a capital ship's readiness for a full scale battle inspection in the good years of peace".
That means the combat readiness compares to the highest grade achievable without combat experience.

Bismarck’s heavy Flak was of mixed mountings—four twin mounts of newer faster traversing and elevating design fully integrated with the heavy Flak fire control computers, and four twin mounts of an older design which were incapable of being integrated into the latest Flak fire control system installed on the ship.

Actually, only the older mountings could use all features of the fire control. The newer C/37 were incompatible to a certain degree and allegedly (according Cordes) that was never solved during wartime. However, Tirpitz' C/37 apparently worked sufficiently.

However, at the time of Bismarck’s sortie, only the two forward ones had been installed, as the other two had been allocated to the USSR as part of the Russo-German trade agreements. In their place two simple rangefinders had been installed. The plan was to replace them with the proper Flak directors which were being manufactured once Bismarck returned from her first cruise.

So? Certainly not ideal, but also not decisive.

Bismarck’s medium and light Flak were sufficient in numbers, but the medium 3,7cm twin Flak were not automatic and had a low rate of fire. The 2cm was better, but fields of fire for both were often poor and they lacked directors to control target selection.

The 3,7cm had a comparatively low rate of fire, but was - and this is always ignored - a very precise and powerfull weapon.
What directors?

While Bismarck had conducted several trial and practice shoots with the main and secondary low angle armament, there had only been one practice session with the Flak guns...

There were practice sessions (confirmed!) at least on:

March 28th
April 1st
April 2nd
April 3rd
April 7th
April 18th
April 19th
April 29th
May 14th

[TTTT]

There were practice sessions (confirmed!) at least on:

March 28th
April 1st
April 2nd
April 3rd
April 7th
April 18th
April 19th
April 29th
May 14th

But how many of these were out in the open sea with the ship moving?

[Herr Nilsson]

All of them. I addition to these dates there was at least one more while anchored at Pillau-roadstead on March 25th for heavy Flak.

Edit: I stand corrected, March 25th was also at sea.

[TTTT]

Where did you find this info?

[Herr Nilsson]

Bismarck, Kriegstagebuch, Bordfliegerstaffel 1/196, 14.03.- 29.04.1941

[Byron Angel]

There are some other curious sidelights to the Swordfish attack upon Bismarck. Apparently, on their run-in to torpedo launch point, they were flying into a gale force head wind blowing from 45deg to port. This, as was explained to me, reduced their speed over the ground to less than 60 knots and also introduced a pronounced lateral drift to starboard - which would have made any AA fire prediction efforts challenging indeed.

Another story I have heard is that the decision to rely upon the old but proven contact fuze on the torpedoes rather than the theoretically more destructive but highly unreliable magnetic exploder, was made only at the last minute after rather heated argument.

Upon such minutiae is history sometimes made. FWIW.

Byron

[dunmunro]

There are some other curious sidelights to the Swordfish attack upon Bismarck. Apparently, on their run-in to torpedo launch point, they were flying into a gale force head wind blowing from 45deg to port. This, as was explained to me, reduced their speed over the ground to less than 60 knots and also introduced a pronounced lateral drift to starboard - which would have made any AA fire prediction efforts challenging indeed.

Another story I have heard is that the decision to rely upon the old but proven contact fuze on the torpedoes rather than the theoretically more destructive but highly unreliable magnetic exploder, was made only at the last minute after rather heated argument.

Upon such minutiae is history sometimes made. FWIW.

Byron

The Swordfish attacks on Bismarck are recounted here:

http://www.kbismarck.com/article2.html

[Byron Angel]

There are some other curious sidelights to the Swordfish attack upon Bismarck. Apparently, on their run-in to torpedo launch point, they were flying into a gale force head wind blowing from 45deg to port. This, as was explained to me, reduced their speed over the ground to less than 60 knots and also introduced a pronounced lateral drift to starboard - which would have made any AA fire prediction efforts challenging indeed.

Another story I have heard is that the decision to rely upon the old but proven contact fuze on the torpedoes rather than the theoretically more destructive but highly unreliable magnetic exploder, was made only at the last minute after rather heated argument.

Upon such minutiae is history sometimes made. FWIW.

Byron

The Swordfish attacks on Bismarck are recounted here:

http://www.kbismarck.com/article2.html

Mark and I are acquainted, but I was unaware that he had provided his essay to the KBismarck forum. I can think of no better site to host it.

Byron