Hit on Bismarck's turret

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paul.mercer
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Hit on Bismarck's turret

Post by paul.mercer » Sat Feb 23, 2019 10:32 am

Gentlemen,
I believe that towards the end of the final battle a hit blew the back off 'B' turret (I think it was this one). Bearing in mind the thickness of battleship turrets I wonder how this could have happened unless a shell penetrated and exploded some cordite about to be loaded?

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Re: Hit on Bismarck's turret

Post by Bill Jurens » Sat Feb 23, 2019 5:26 pm

My examinations of the wreckage, which included the turrets, and (as below) probably the backing plate as well, suggest that some sort of internal explosion must have occurred. It probably didn't 'blow the back off' -- the plates there were too heavy for that, but probably did vent through the relatively thin plating under the turret overhang near the loading mechanisms. This left the heavy backing plating unsupported from below, at which point it fell down vertically down onto the deck below. Later, as the ship capsized and sank, the plate further dislodged and ended up in the debris field. I can recall seeing it, or seeing something that certainly looked like a turret backing plate.

The precise mechanisms surrounding the likely internal explosion(s) remain, and probably always will remain, obscure...

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Re: Hit on Bismarck's turret

Post by paul.mercer » Sun Feb 24, 2019 10:33 am

Thanks Bill,
Would it have been possible for a 14" or 16" shell to penetrate the turret and cause that damage? Also, if it did would it be likely to set off any cordite that was waiting to be loaded - shades of Jutland perhaps ?

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Re: Hit on Bismarck's turret

Post by Bill Jurens » Mon Feb 25, 2019 5:35 am

I see no particular reason why penetration of the turret might have been impossible, particularly later in the action when the British were fully capable of attacking the sides and even the backs of turrets that were no longer capable of training towards the enemy. The ignition mechanism for a deflagration are really entirely speculative, but assuming a loading accident of some sort could be ruled out, it would seem likely that the burns that did occur were in some way initiated by British projectiles, perhaps in locations quite remote from the gunhouse itself.

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Re: Hit on Bismarck's turret

Post by spicmart » Mon Apr 08, 2019 3:01 pm

Bill. What about the splinters from that backing plate which are said to have killed the staff on the bridge?

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Re: Hit on Bismarck's turret

Post by Bill Jurens » Tue Apr 09, 2019 3:42 pm

I am not certain why these splinters -- if they existed at all -- might be of any particular significance, i.e. I don't think I quite understand the question. Might you elaborate or rephrase, please?

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Re: Hit on Bismarck's turret

Post by spicmart » Mon Apr 22, 2019 9:53 am

Bill Jurens wrote:
Tue Apr 09, 2019 3:42 pm
I am not certain why these splinters -- if they existed at all -- might be of any particular significance, i.e. I don't think I quite understand the question. Might you elaborate or rephrase, please?

Bill Jurens
Hello Bill,

sorry for answering this late. I'v been away and simply forgot. I read it in Brennecke's book. It said the hit blew parts off the turret which killed the people in the bridge.

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Re: Hit on Bismarck's turret

Post by Bill Jurens » Mon Apr 22, 2019 3:02 pm

You will read a lot of literary extension in secondary sources. A lot of the apparent detail in these books is quite imaginative, and of little actual historical vale — a writer’s elaboration of what was already somewhat of a sea-story...

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Re: Hit on Bismarck's turret

Post by paul.mercer » Fri May 24, 2019 9:08 am

Gentlemen,
Forgive me for re-opening this subject but it has been said in other posts that hits with AP shells do not always register as they explode after entering a ship.What was described as a 'spectacular hit,'occurred on Bismarck's fore deck at 9.02 which disabled one or both of A and B turrets, presumably both KGV and Rodney were using AP shells,' so as this hit was actually observed would it mean that the shell exploded on impact or very shortly after without penetrating very far and is it likely that it was the one that hit the barbette?
Finally, this hit has always been attributed to Rodney's 16",as there has been some discussion on other threads as to who actually fired it, would a 14" shell have done the same amount of damage?

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Re: Hit on Bismarck's turret

Post by alecsandros » Fri May 24, 2019 9:50 am

British APC projectiles of the time had average fuze length of 0.025sec. Impact velocity at 20.000meters for 16" shells was 470m/s (data for firing velocity of 770m/s), and 460m/s for 14" guns (data for firing velocity of 730m/s).

That means that, on average, the fuzed fuze would permit travel of projectile (if still in one piece and functioning after the initial impact) , for a distance of some 0.025 x 470 = 11,75 meters.

However, after the initial impact, remaining velocity of shell would be greatly reduced, and therefore the space travel until detonation would be smaller then 11,75 meters (I would expect about half of that).

===

There is at least one secondary source that I've read detailing a hit on turret Dora at around 9:20, coming from KGV's 14inch guns, that impacted at un unfavourable angle directly against the 360mm face plate of the turret. The shell was reportedly deviated in the air, and expoded high-order some distance above the Bismarck. The hit nonetheless produced internal shock damage to the turret Dora, which lost hydraulic pressure to her guns.

Such a mechanism could be imagined for the hit(s) of 9:02 as well. HMS Rodney's report mentions a 4-gun salvo fired at ~9:01, of which only 2 columns of water were seen at 9:02, coinciding with the spectacular hit(s) on Bismarck's forecastle. This doesn't necessarily mean the hit(s) came from Rodney, however.

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Re: Hit on Bismarck's turret

Post by Alberto Virtuani » Fri May 24, 2019 10:10 am

Hi Alec,
looking at the KGV GAR and at the Rodney Salvo Plot, distance at 9:02 was already quite shorter than 20000 meters for both Rodney (around 17000-18000 yards, residual velocity slightly less than 500m/sec) and KGV (around 15000 yards, residual velocity 520 m/sec).

This does not change much to conclusions, I admit.


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Re: Hit on Bismarck's turret

Post by alecsandros » Fri May 24, 2019 10:31 am

You're right,
that would put max travel distance with average fuze length at ~ 13 meters, and maybe 6-7 meters applying the speed reduction (for remaining velocity).

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Re: Hit on Bismarck's turret

Post by Bill Jurens » Fri May 24, 2019 3:39 pm

The descriptions of this event are, as usual, often somewhat vague and contradictory, so it's difficult to do other than speculate. Rather than an exploding shell, I suspect that if any large flash or flame was seen it was more likely due to the venting of deflagrating propellant, i.e. some evidence of an internal burn in the gunhouse or barbette.

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Re: Hit on Bismarck's turret

Post by Alberto Virtuani » Fri May 24, 2019 5:00 pm

@all,
I agree with Mr.Jurens possible explanation of what was seen from distance.

This is possibly a way to explain why 2 turrets were put out of action together (possibly due to the flooding of the fore magazines following the penetration of a barbette/turret in order to avoid worse consequences), and why after some time a turret could open fire again, once water was pumped out of magazine.

However, from that distance, I would say that the penetration of a 360 mm turret face, of a 340mm barbette or a 50mm deck+220mm barbette (under the deck) means the hit was quite "lucky", hitting with an extremely favorable angle (the 16" was capable of penetrating only 330mm of armor at 18000 yards and the 14" was capable of 330mm armor from 15000 yards at normal impact angle)...


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Last edited by Alberto Virtuani on Fri May 24, 2019 5:10 pm, edited 4 times in total.
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

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Re: Hit on Bismarck's turret

Post by alecsandros » Fri May 24, 2019 5:05 pm

While theoretically possible,
I have never read about such an internal deflagration being produced in any shell vs turret or shell vs barbette impacts of capital ships. Instances are numerous - Massachussets vs Jean Bart*, Kirishima vs South Dakota**, Hood vs Richelieu***, Renown vs Gneisenau****, etc.

Vague memories of records of battle of Jutland come to mind, including numerous impacts against main turrets/barbettes, none of which apparently triggering "internal deflagrations".

Of note is also that such an event (involving a perforating hit of either the turret or barbette) would not explain the initial loss of both forward turrets (Anton and Bruno), nor the apparent coming back online of Anton , after some 25 minutes. It would also not explain Norfolk's report , indicating Bruno's guns were raised at apparently max elevation, and Anton's depressed at minimum elevation, some time after the "spectacular hit " occured.

* Direct 16inch hit against face plate of main turret, causing shell to shatter, with components being thrown out to hundreds of meters, and turret to remain jammed for 5 hours.
** Glancing hit on face plate of main turret , causing shell to ricochet in ther air and explode low order.
*** Glancing hit on roof of main turret, causing internal spalling inside the turret, and breaking up of the shell.
**** direct hit on side of main turret, causing turret to jam.


I have purposefully refrained from exmplifying with further accounts from Bismarck's last battle (such as one main turret being blown off by 1 x 16inch shot, from 3000meters, and another turret being put out of action from 12000meters by a non-penetrating hit)

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