What if Bismarck hit Rodney early on?

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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Wed Sep 05, 2018 5:26 pm

RF wrote:
Tue Sep 04, 2018 8:07 am
Dave Saxton wrote:
Sun Sep 02, 2018 2:44 pm

Bismarck was simply overwhelmed by the combined volume of fire, unable to maneuver, and greatly affected by the sea state, and I don't see any other likely outcome to the battle.
Correct.

However the key at the start was that Rodney provided the bulk of the volume of fire with the heaviest shells. If some or most of that was taken out initially then Bismarck's guns stay in action longer with the prospect of more hits before they will eventually be silenced.
KGV fired more 14in shells than Rodney fired 16in up to 0920 and her radar equipped FC was more modern than Rodney's. The idea that KGV shot poorly or the bulk of the early hits were made by Rodney is not true and it not supported by either Rodney or KGV's gunnery record. The fact is that 14in and 16in salvos appeared almost identical to observers aboard KGV and Rodney and it is doubtful that observers elsewhere could tell them apart either.

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Re: What if Bismarck hit Rodney early on?

Post by swpz » Fri Sep 07, 2018 1:16 am

Thanks for the replies guys, quite interesting so far. I'm going to add some comments and a few more questions.

With regards to the 14" gun; the wreck shows pretty much no penetration of the vitals from the side KGV was firing from - so regardless of paper specs and post war testing, the gun did not do the lions share of the damage. A possible reason for this is how much Bismarck was rolling; perhaps the shells hit when she was angled from a roll and thus had higher effective armor - or vice versa. Post war testing on Tirpitz's armor is likely under perfect conditions of impact angles and range. So while I agree the 14" in theory could damage, it simply did not that day and the random angles from the sea might be the very reason why they did not. Or perhaps the shell were of an inferior quality? Allied munitions only improved as the war progressed after all.

Rodney is attributed to have gotten the range from KGV's radar and that's what allowed her to land the first shots. Bismarck likely too had the range as her first few salvos were rather well placed based on the Baron's accounts. Splinters can come from AP shells too unless I'm mistaken, Hood had fired AP at PE and we have a video shot of Brinkmann inspecting a splinter after the battle.

Bismarck's FC being taken out was almost like a foreshadowing of what happened to Scharnhorst, same thing exactly; radar taken out, FC taken out minutes into the battle. However, when the Baron took over only aft circuit responded, so whatever Rodney did at 09:02, it took out both turrets and severed all communications with aft control.

Why they didn't blow Norfolk out of the water is a complete mystery; it's conceivable that they opted not to as they later (according to some accounts) tried to hoist both cease fire and parley flags? The British simply ignored them and kept shooting though. I'm not sure how accurate this is - if indeed it happened.

What sort of protection did Rodney have in the bows? What if say a shell hit the bow and penetrated downwards? Was the A barbette thick enough to absorb the hit? Was the bow profile even armored enough to withstand a hit that dove deeper? If a shell hit, penetrated and subsequently exploded what might have happened? In fact with a bow on profile, isn't a magazine hit a very distinct and dangerous possibility? What sort of result could be expected if say a shell hit B barbette right behind A? Would it have conceivably disabled/destroyed A/B?

In his Book the Baron said he received an order to take over fire control but that Albrecht was still directing the secondary armament - how was he able to do that if the FC position was hit?

--

I'm somewhat of the opinion, that if Rodney was disabled early on in the battle; Tovey might actually have broken off the attack as alone KGV might not have been enough. Without the Rodney hits, their command functions would have remained intact and it's possible that they could have even gotten the forward guns working again as A turret was recorded to have fired another salvo at around 09:20 but without directed FC. So we'd be talking about Bismarck with 6(8) guns working against KGV and 2 8" gun CA. The Baron also noted in his book that he was wondering when the order to split fire would have come, when he was asked to take over he only had the aft guns; if he had the forward guns too it's possible he would have split half the armament to fire on the cruisers or perhaps even shift from Rodney to the cruisers immediately as those might have been closer than even KGV?

With Bismarck shooting at the cruisers, what actions would Tovey have taken? Immediately withdraw them?

Basically I find it very interesting that this battle - like the one at DS was dictated almost entirely by luck. By the numbers, Bismarck and PE should have been sunk at DS but they weren't. However, the second time round Bismarck did not have luck favor her.

The survival of Bismarck - even if she had to be scuttled later - would perhaps amount to a lifting of Hitler's idiotic "no capital ship" order. That would have likely had some significant implications towards how the war at sea would turn out. The USA still hadn't joined and a potential task force with Tirpitz and twins sortieing could have caused quite a lot of damage.

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Re: What if Bismarck hit Rodney early on?

Post by RF » Fri Sep 07, 2018 9:12 am

swpz wrote:
Fri Sep 07, 2018 1:16 am

I'm somewhat of the opinion, that if Rodney was disabled early on in the battle; Tovey might actually have broken off the attack as alone KGV might not have been enough. .
This was not an option because of the KGV fuel situation, and with Churchill in the background wanting action. KGV would have to engage with the two cruisers in support and whatever firepower Rodney had.
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Re: What if Bismarck hit Rodney early on?

Post by Dave Saxton » Fri Sep 07, 2018 3:23 pm

swpz wrote:
Fri Sep 07, 2018 1:16 am


In his Book the Baron said he received an order to take over fire control but that Albrecht was still directing the secondary armament - how was he able to do that if the FC position was hit?
I dug out my von Muellenheim book which is the revised 1990 edition. I need to make a few corrections to some of my previous comments. First, the Baron only speculates that Albrecht was directing the middle artillery, and he further speculates that Albrecht's station may have been disabled. I did not recall correctly when I stated that Albrecht was the one that ordered the Baron to take over fire control duties. That person was Cardinal, who was the second gunnery officer and stationed in the forward computer room below the armoured deck. Cardinal told the Baron that he could not get through to the foretop fire control position and that turrets A and B were out of action. He told the Baron nothing about Albrecht's station. If the forward station was not disabled, then apparently Cardinal wanted Albrecht to conduct fire of the MA battery while the Baron conducted fire of the remaining heavy artillery (SA battery). Albrecht did phone the Baron later on to tell him he was abandoning the forward fire control station because of smoke and fumes.

The forward FC station was inside the heavily armoured conning tower. As far as I know the conning tower was not penetrated, but a non penetrating hit can knock out equipment inside through shock and possible plug ejection. A heavy hit adjacent could also possibly take it out of action.
Bismarck's FC being taken out was almost like a foreshadowing of what happened to Scharnhorst, same thing exactly; radar taken out, FC taken out minutes into the battle. However, when the Baron took over only aft circuit responded, so whatever Rodney did at 09:02, it took out both turrets and severed all communications with aft control.
Cardinal did not tell the Baron that he could not get through to the forward main battery but that it was out of action. This implies that he could communicate with the forward battery. He only told the baron that he could not get through to the foretop. There was no point in directing the forward battery from the aft position if it was out of action.

Indeed, a hit to the foretop was also the case with the Scharnhorst at N. Cape. I have mentioned before that this was most unlucky. However, it was not really uncommon. Besides the Bismarck, it also happened to South Dakota. Kirishima hit the SD's foretop fire control station with a 6" round from 10,000 meters with its first salvo. A 14" round passed through Washington's SK radar antenna in the same battle. A few meters lower and it would have hit Washington's main fire control position. A 6" round passed through Graf Spee's foretop below the fire control station. It severed electrical power and communications to the position and the radar. This turned the battle. A 15" round passed through Gneisenau's foretop on April 9th 1940, knocking out the radar and causing Luetjen's to seek to disengage. Not uncommon.
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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Sat Sep 08, 2018 7:35 pm

swpz wrote:
Fri Sep 07, 2018 1:16 am
Thanks for the replies guys, quite interesting so far. I'm going to add some comments and a few more questions.

With regards to the 14" gun; the wreck shows pretty much no penetration of the vitals from the side KGV was firing from - so regardless of paper specs and post war testing, the gun did not do the lions share of the damage. A possible reason for this is how much Bismarck was rolling; perhaps the shells hit when she was angled from a roll and thus had higher effective armor - or vice versa. Post war testing on Tirpitz's armor is likely under perfect conditions of impact angles and range. So while I agree the 14" in theory could damage, it simply did not that day and the random angles from the sea might be the very reason why they did not. Or perhaps the shell were of an inferior quality? Allied munitions only improved as the war progressed after all.

Rodney is attributed to have gotten the range from KGV's radar and that's what allowed her to land the first shots. Bismarck likely too had the range as her first few salvos were rather well placed based on the Baron's accounts. Splinters can come from AP shells too unless I'm mistaken, Hood had fired AP at PE and we have a video shot of Brinkmann inspecting a splinter after the battle.

Bismarck's FC being taken out was almost like a foreshadowing of what happened to Scharnhorst, same thing exactly; radar taken out, FC taken out minutes into the battle. However, when the Baron took over only aft circuit responded, so whatever Rodney did at 09:02, it took out both turrets and severed all communications with aft control.

Why they didn't blow Norfolk out of the water is a complete mystery; it's conceivable that they opted not to as they later (according to some accounts) tried to hoist both cease fire and parley flags? The British simply ignored them and kept shooting though. I'm not sure how accurate this is - if indeed it happened.

What sort of protection did Rodney have in the bows? What if say a shell hit the bow and penetrated downwards? Was the A barbette thick enough to absorb the hit? Was the bow profile even armored enough to withstand a hit that dove deeper? If a shell hit, penetrated and subsequently exploded what might have happened? In fact with a bow on profile, isn't a magazine hit a very distinct and dangerous possibility? What sort of result could be expected if say a shell hit B barbette right behind A? Would it have conceivably disabled/destroyed A/B?

In his Book the Baron said he received an order to take over fire control but that Albrecht was still directing the secondary armament - how was he able to do that if the FC position was hit?

--

I'm somewhat of the opinion, that if Rodney was disabled early on in the battle; Tovey might actually have broken off the attack as alone KGV might not have been enough. Without the Rodney hits, their command functions would have remained intact and it's possible that they could have even gotten the forward guns working again as A turret was recorded to have fired another salvo at around 09:20 but without directed FC. So we'd be talking about Bismarck with 6(8) guns working against KGV and 2 8" gun CA. The Baron also noted in his book that he was wondering when the order to split fire would have come, when he was asked to take over he only had the aft guns; if he had the forward guns too it's possible he would have split half the armament to fire on the cruisers or perhaps even shift from Rodney to the cruisers immediately as those might have been closer than even KGV?

With Bismarck shooting at the cruisers, what actions would Tovey have taken? Immediately withdraw them?

Basically I find it very interesting that this battle - like the one at DS was dictated almost entirely by luck. By the numbers, Bismarck and PE should have been sunk at DS but they weren't. However, the second time round Bismarck did not have luck favor her.

The survival of Bismarck - even if she had to be scuttled later - would perhaps amount to a lifting of Hitler's idiotic "no capital ship" order. That would have likely had some significant implications towards how the war at sea would turn out. The USA still hadn't joined and a potential task force with Tirpitz and twins sortieing could have caused quite a lot of damage.
Both ships primarily engaged Bismarck's port side. Rodney (and to lesser extent KGV) briefly engaged Bismarck's starboard side. Rodney's salvo record is clear and it states that she opened fire with an incorrect range and it took her some time before she straddled. Bismarck's 13in side armour was largely submerged due to previous battle damage and in the high swells prevalent during the battle was largely shielded from being hit.

Anything you may have read from any source that attributes specific hits to Rodney or KGV (or any other ship) is wrong. This was all pure speculation. There was no observer who could distinguish 14in salvos or hits from 16in salvos or hits, except for when KGV and Rodney closed to near point blank range and even then, when hits could be seen through the smoke and flame onboard Bismarck, there is no way to correlate the hits on the wreck to specific shots fired. KGV and Rodney could only tell a 14in salvo from a 16in salvo by means of a horn that would sound when their salvo was expected to land. External observers could not possibly identify a 14in or 16in salvo because they had no means of precisely timing the salvos to identify their ship of origin. The only way another ship could positively indentify a salvo's origin would be to communicate with that ship via a dedicated FC radio link, and we know that neither KGV or Rodney did this.

What we do know is that KGV had much more modern FC equipment than Rodney and FC radar, which Rodney lacked. It is a mathematical certainty that KGV was scoring, by far, the greater number of hits from 0848-0920. Testing against armour plate, including some from Tirpitz showed that 14in AP rounds could penetrate any armour that Bismarck possessed. At inclinations over 40 degrees 14in and 16in AP would begin to fail to penetrate. Any 14in hit with an inclination of 30 degrees or less would penetrate any armour on Bismarck. There is a very narrow band of inclinations maybe ~5-10 degrees wide, where a 16in shell would penetrate when a 14in wouldn't. Unfortunately there has been a tendency for writers to attribute any penetrating hit identified on Bismarck to a 16in shell when this is simply not possible to do.
Last edited by dunmunro on Sat Sep 08, 2018 7:51 pm, edited 1 time in total.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sat Sep 08, 2018 7:50 pm

Rodney's forward bulkhead was 12" thick , so ~305mm of 1920s vintage armor, tapering down to 6" (150mm) towards the bottom of the hull:
http://i.imgur.com/uQldjFr.jpg

At the ~20km range and less then 30deg target obliquity at which the initial phase of the battle was fought, the 380mm L52 gun had no trouble perforating such armor thickness.

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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Sat Sep 08, 2018 7:57 pm

alecsandros wrote:
Sat Sep 08, 2018 7:50 pm
Rodney's forward bulkhead was 12" thick , so ~305mm of 1920s vintage armor, tapering down to 6" (150mm) towards the bottom of the hull:
http://i.imgur.com/uQldjFr.jpg

At the ~20km range and less then 30deg target obliquity at which the initial phase of the battle was fought, the 380mm L52 gun had no trouble perforating such armor thickness.
To hit the bulkhead required penetrating hull structure of sufficient thickness to impair penetration.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sat Sep 08, 2018 8:26 pm

dunmunro wrote:
Sat Sep 08, 2018 7:57 pm
To hit the bulkhead required penetrating hull structure of sufficient thickness to impair penetration.
the only armor grade steel in way of the projectile was the forward armored bulkhead.
I don't see how it would impair penetration in a statistically significant way.

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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Sat Sep 08, 2018 8:36 pm

alecsandros wrote:
Sat Sep 08, 2018 8:26 pm
dunmunro wrote:
Sat Sep 08, 2018 7:57 pm
To hit the bulkhead required penetrating hull structure of sufficient thickness to impair penetration.
the only armor grade steel in way of the projectile was the forward armored bulkhead.
I don't see how it would impair penetration in a statistically significant way.
it would required the projectile to either penetrate the hull side or weather deck which are ~1.5in D steel, IIRC, at a fairly steep inclination, which would probably decap and/or yaw the shell and it would probably have to pass through a number of other decks and bulkheads before hitting the armoured bulkhead, so the odds of it hitting in an ideal condition for penetration is minimal. Once it hits the armoured bulkhead the path from there to the magazines makes it unlikely to reach them, even if it penetrates.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sun Sep 09, 2018 5:12 am

Of course not,
the projectile would need to perforate the forecastle from the front , and travel towards the armored bulkhead.

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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Sun Sep 09, 2018 11:16 am

alecsandros wrote:
Sun Sep 09, 2018 5:12 am
Of course not,
the projectile would need to perforate the forecastle from the front , and travel towards the armored bulkhead.
The forward armoured bulkhead runs from the top of the 6 1/4in armoured deck (the dashed line on the forward barbette) down about two decks at full thickness and then gradually reduces in thickness as it reaches the bottom of the ship.

If Rodney is steaming directly at Bismarck, the shell must pass through the weather deck or the hull sides, both of which are 1.5in D steel which will probably decap the shell, and will certainly activate the fuze. After it passes through the outer hull it will then have to pass through multiple decks and bulkheads to reach the armoured bulkhead. At 25000 yds the angle of fall of a 38cm shell is about 20 degs and at 22k yds it is only 16 degrees. To reach the armoured bulkhead the shell must pass through the ships structure for a considerable distance which I estimate to be about ~65 ft, this implies a high probability that the shell will detonate before it even reaches the armoured bulkhead.

It is virtually impossible for a 38cm shell to reach a magazine via the bow. A 38cm hit could probably penetrate a barbette but Rodney had extensive anti-flash arrangements to prevent such a hit from endangering a magazine and/or another turret.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sun Sep 09, 2018 11:57 am

dunmunro wrote:
Sun Sep 09, 2018 11:16 am
It is virtually impossible for a 38cm shell to reach a magazine via the bow. A 38cm hit could probably penetrate a barbette but Rodney had extensive anti-flash arrangements to prevent such a hit from endangering a magazine and/or another turret.
If you observe the picture I linked above, you will see that at numbers "4", Rodney had the main magazines.
You can easily draw trajectories towards the main magazines, and then measure distance between the point of entry in the forecastle and the point at which the magazine is located.

As for distance travelled by the AP shell before exploding, when passing through lightly armored structures, you can observe the trajectories of historical shells fired at River Plate , where 283mm German shells with the same fuze length (0.05sec) as the German 380mm shell , travelled up to 75feet within the cruisers, before finally exploding.

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Re: What if Bismarck hit Rodney early on?

Post by dunmunro » Sun Sep 09, 2018 12:27 pm

alecsandros wrote:
Sun Sep 09, 2018 11:57 am
dunmunro wrote:
Sun Sep 09, 2018 11:16 am
It is virtually impossible for a 38cm shell to reach a magazine via the bow. A 38cm hit could probably penetrate a barbette but Rodney had extensive anti-flash arrangements to prevent such a hit from endangering a magazine and/or another turret.
If you observe the picture I linked above, you will see that at numbers "4", Rodney had the main magazines.
You can easily draw trajectories towards the main magazines, and then measure distance between the point of entry in the forecastle and the point at which the magazine is located.

As for distance travelled by the AP shell before exploding, when passing through lightly armored structures, you can observe the trajectories of historical shells fired at River Plate , where 283mm German shells with the same fuze length (0.05sec) as the German 380mm shell , travelled up to 75feet within the cruisers, before finally exploding.
Bow on, at 20deg descent a 38cm shell must travel ~60ft to reach the very upper edge of the armoured bulkhead, if it strikes the weather deck.


The hull and weather deck of a battleship is thicker than a light cruiser's hull and the 28cm hits were at much closer distance and higher SV. The nominal delay for KM 38cm AP was .035 seconds.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sun Sep 09, 2018 1:13 pm

dunmunro wrote:
Sun Sep 09, 2018 12:27 pm
Bow on, at 20deg descent a 38cm shell must travel ~60ft to reach the very upper edge of the armoured bulkhead, if it strikes the weather deck.
And if it strikes the side of the forecastle it requires 30ft before striking the forward armored bulkhead (at a point at which it is not full thickness), and 30ft more before reaching the upper forward edge of the main magazines.

The 283mm/L52 fired at 910m/s, and the shell had 407m/s at 20.000meters. The 380mm/L52 fired at 820m/s, and the shell retained 510m/s at 20.000meters.

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Re: What if Bismarck hit Rodney early on?

Post by alecsandros » Sun Sep 09, 2018 1:15 pm

dunmunro wrote:
Sun Sep 09, 2018 12:27 pm
The hull and weather deck of a battleship is thicker than a light cruiser's hull and the 28cm hits were at much closer distance and higher SV. The nominal delay for KM 38cm AP was .035 seconds.
The range at which Graf Spee hit Exeter and Ajax with the deep penetrating hits was probably between 12 to 17km. At this range band, the 283mm/L52 had 10 to 20% less striking velocity then the 380mm/L52.

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