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HMS Nelson vs Bismarck

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25 minutes ago, mofton said:

The fact that a 14 year newer, 7,000t greater displacement battleship is even being compared to Nelson says something...

There's a running theme I've seen in historical comparisons, the idea that superior firepower will often trump new technologies.

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9 hours ago, Phoenix_jz said:

To a degree - since the propellant hoists can't managed more than 2.5 rpm, you have a 'hard' limit at a 2.5 rpm/24 sec reload, but that's still significantly better than what you'd have otherwise - the shell hoists can theoretically do 2.3 rpm, but that puts the system at great risk of failure, so you're unlikely to ever see such a rate of fire in combat unless it's coming from the ready racks - which was, iirc, 5 rounds per turret?

There's disagreement on how many shells were stored in the rear of the turrets. At least five, could be as high as ten. And then obv no one seems to know what shells were stored there, if it was the APC, base fused HE, nose fused HE or for Tirpitz time fuzed HE, and if it was a mix how many of which were stored.

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On 6/22/2019 at 6:01 PM, Royeaux said:

That actually doomed the Bismarck in her final fight.  Captain Lindemann kept making small course adjustments in between incoming salvos in an attempt to dodge them, however this constantly threw off the aim of her guns and caused the Bismarck to fail to score a single hit.

This is great for the people that want "Realism" in WoWS as they will be somewhat surprised with what they will actually get :Smile_trollface:

 

 

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On 6/23/2019 at 3:01 AM, Royeaux said:

That actually doomed the Bismarck in her final fight.  Captain Lindemann kept making small course adjustments in between incoming salvos in an attempt to dodge them, however this constantly threw off the aim of her guns and caused the Bismarck to fail to score a single hit.

Not like Bismarck was doomed already.

Before her final battle she was reported to barely make any speed, and her crew reported a heavy list that resulted in some of her 15cm turrets to touch the waterline. On top of that her crew was exhausted by the constant engagements, demoralized after Lütjens told them that they were doomed and that he decided to not surrender and possibly drunk after the captain permitted the crew to help themselves at the ship's storage rooms, which like any ship back then had sizable amounts of alcohol stored (in the German case liquor).

She still managed to score close hits, which given the circumstances is quite incredible if you think of it.

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7 hours ago, SireneRacker said:

Not like Bismarck was doomed already.

Before her final battle she was reported to barely make any speed, and her crew reported a heavy list that resulted in some of her 15cm turrets to touch the waterline. On top of that her crew was exhausted by the constant engagements, demoralized after Lütjens told them that they were doomed and that he decided to not surrender and possibly drunk after the captain permitted the crew to help themselves at the ship's storage rooms, which like any ship back then had sizable amounts of alcohol stored (in the German case liquor).

She still managed to score close hits, which given the circumstances is quite incredible if you think of it.

I think Bismarck did have a chance to survive and that would have been to fire accurately at HMS Rodney in an attempt to blow it up to create a repeat of the Denmark Strait.  I know this is monday-morning Quarterbacking, but Bismarck's greatest asset was her accurate firepower.  If the ship is going to be blown up anyway, then there's no practical point in trying to dodge.  They were suppose to go down fighting anyway, otherwise they'd have evacuated the crew from the very start and scuttled the ship.  Captain Lindemann was a rookie so I can see why he'd make the decision to try and dodge, he reacted without orders to engage the Hood earlier because his ship was under fire.

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I would give the match to Nelson 6 times out of 10.

Nelson has a 14 inch belt and a 12 inch forward bulkhead. It should approach Bismarck at 25 degrees from head-on to marginally increase effective armour presented and bring all guns to bear on the approach, as per this informative thread.

The angle should swing wider to 50 degrees off from where the Bismarck is as it becomes very clear that the German is looking to close for a brawl and maximizing LOS armour thickness becomes more important to survival (i..e range has closed so the angled forward bulkhead is no longer theoretically immune to Bismarck's shells). Meanwhile, one or both torpedoes should be fired at the approaching German once they are within range (set gyros to steer in the right direction, just make sure you don't hit yourself with the torpedo that's further from the foe as those fish are only 35 knots at 15,000 yards range or 30 at 20,000... might want to set it to pass astern of yourself to prevent torpedoing yourself lol), and the tube(s) reloaded for another shot up close if need be.

https://en.wikipedia.org/wiki/British_24.5-inch_torpedo

If Bismarck keeps to its vector for fire control reasons it may encounter an unpleasant surprise or at least be forced to evade at an inopportune moment.

This approach vector will give Nelson a MUCH better immunity zone than expected on paper.

As I understand it from searches, Tirpitz in-game has rear turrets firing 35 degrees either side of dead ahead. The Bismarck's third turret can only fire at 40 degrees.

So if the Bismarck wants to close the range faster, it will only be able to reply with 4 guns (and show its 9 inch forward bulkhead nearly flat on--if Wikipedia's idea of a bulkhead is what is called an athwartship in WoWS--which Nelson's 16 inch shells will lol through trivially) while Nelson batters it with 9 guns. If Bismarck wants to trade full salvos, it will be MUCH slower getting into fully effective range while Nelson bludgeons against and perhaps through its deck armour, makes a charnel house of all levels above the panzerdeck through its upper belt--cutting wiring and systems to pieces does pretty well in incapacitating a warship--and perhaps even punch through parts of the turtleback due to the angle of descent.

Bismarck's above-citadel spaces are huge and rather crucial to keeping the ship fighting compared to Nelson's roomier and RELATIVELY more independent citadel. And since Nelson is in theoretical perfect mechanical condition like Bismarck to begin the battle, Nelson will be firing at better than the 1 RPM of its real service.

So 6 times out of 10, if Nelson was in factory fresh mechanical condition with her experienced crew, engaging Bismarck in a 1v1 God-mandated slugfest in the North Sea and both sides had full knowledge of the other's penetration tables, I believe Nelson should prevail.

If not mandated by God or Alien Space Bats, Bismarck RUNS AWAY.

Edited by Guardian54

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13 hours ago, Guardian54 said:

I would give the match to Nelson 6 times out of 10.

Nelson has a 14 inch belt and a 12 inch forward bulkhead. It should approach Bismarck at 25 degrees from head-on to marginally increase effective armour presented and bring all guns to bear on the approach, as per this informative thread.

I'm not sure I agree with this.

If Nelson insists on charging in against Bismarck, she trades away her major advantages - the heavy deck armor, the incline on her armor belt, and her main battery protection. It also plays to cover a major weakness of Bismarck, her poor deck armor.

An approach at an angle of 25º from head on also gives Bismarck a number of benefits aside from a closer-ranged fight. Not only does it force Nelson to allow Bismarck to cross her T, but the head-on-approach makes her more vulnerable to hits due to how shells tend to disperse (in range rather than horizontally). It also exposes the weaker frontal bulkhead, which even at such an angle Bismarck can plow through at ranges out to 30,000 yards. This offers overall inferior protection than if Nelson simply sits broadside and maintains range, which, again, plays more to Nelson's advantage. The only real benefit of adopting such an angle of approach is to reduce the chances of the secondary battery barbettes and magazines from being hit or set off by a near-miss.

If Nelson insists on approaching in such a manner, it's going to have a very bad time of it. 

 

13 hours ago, Guardian54 said:

The angle should swing wider to 50 degrees off from where the Bismarck is as it becomes very clear that the German is looking to close for a brawl and maximizing LOS armour thickness becomes more important to survival (i..e range has closed so the angled forward bulkhead is no longer theoretically immune to Bismarck's shells). Meanwhile, one or both torpedoes should be fired at the approaching German once they are within range (set gyros to steer in the right direction, just make sure you don't hit yourself with the torpedo that's further from the foe as those fish are only 35 knots at 15,000 yards range or 30 at 20,000... might want to set it to pass astern of yourself to prevent torpedoing yourself lol), and the tube(s) reloaded for another shot up close if need be.

https://en.wikipedia.org/wiki/British_24.5-inch_torpedo

If Bismarck keeps to its vector for fire control reasons it may encounter an unpleasant surprise or at least be forced to evade at an inopportune moment.

This approach vector will give Nelson a MUCH better immunity zone than expected on paper.

A 50º angle would do very well for Nelson, as this would probably shrink the range of penetration down to around 17,000 yards for the main armor belt (magazines) and 19,000 yards for the machinery - although this doesn't help the barbettes and turret faces. 

That being said, I doubt that Bismarck would be torpedoed unless Nelson was trying to finish off an already crippled foe - German underwater listening systems were good, so they'd probably just hear it coming and shift course.

This would probably be a good course to adopt from the beginning, rather than the initial 25º angle - in the North Sea, you're unlikely to be firing past 30,000 yards, and it's only outside of 30,000 yards that the frontal bulkhead will stop anything.

 

14 hours ago, Guardian54 said:

As I understand it from searches, Tirpitz in-game has rear turrets firing 35 degrees either side of dead ahead. The Bismarck's third turret can only fire at 40 degrees.

So if the Bismarck wants to close the range faster, it will only be able to reply with 4 guns (and show its 9 inch forward bulkhead nearly flat on--if Wikipedia's idea of a bulkhead is what is called an athwartship in WoWS--which Nelson's 16 inch shells will lol through trivially) while Nelson batters it with 9 guns. If Bismarck wants to trade full salvos, it will be MUCH slower getting into fully effective range while Nelson bludgeons against and perhaps through its deck armour, makes a charnel house of all levels above the panzerdeck through its upper belt--cutting wiring and systems to pieces does pretty well in incapacitating a warship--and perhaps even punch through parts of the turtleback due to the angle of descent.

Against the Nelson-class, the preferred angle of engagement was 30º (from the bow), which reduces the range of penetration for the armor belt about around 5,000 yards (Going by the past numbers, that could be anywhere from 15,000 to 26,000 yards, depending on the source - although the turtleback is still immune). All the main battery would still be brought to bear at such an angle. In order to penetrate the deck armor, Nelson would want to stick at range (which would favor the immune zone), as once you pass by 24-25,000 yards she probably can't get into Bismarck's citadel. 

It would essentially be this span that Nelson would be best placed to try and fight Bismarck, due to the heavy armor advantage. However, North Sea conditions usually aren't very cooperative in this regard - for example, the opening salvoes of the Battle of the Denmark Strait were Hood against Prinz Eugen at 25,000 yards, and Prince of Wales against Bismarck at 26,000 yards. When the Germans responded, the range from Bismarck to Hood was 21,000 yards, and Prinz Eugen to Hood as 23,000 yards.

This is essentially an action starting at a point where deck armor keeps both combatants fairly safe from the other, and will quickly close to more decisive range.

15 hours ago, Guardian54 said:

Bismarck's above-citadel spaces are huge and rather crucial to keeping the ship fighting compared to Nelson's roomier and RELATIVELY more independent citadel. And since Nelson is in theoretical perfect mechanical condition like Bismarck to begin the battle, Nelson will be firing at better than the 1 RPM of its real service.

So 6 times out of 10, if Nelson was in factory fresh mechanical condition with her experienced crew, engaging Bismarck in a 1v1 God-mandated slugfest in the North Sea and both sides had full knowledge of the other's penetration tables, I believe Nelson should prevail.

If not mandated by God or Alien Space Bats, Bismarck RUNS AWAY.

Agreed on the inherent weakness of Bismarck's small citadel volume. 

That being said, Nelson's guns were plagued by design issues, not so much wear & tear issues or operator error. Due to the handling arrangements, it wasn't possible to fire a single gun faster than once every 50 seconds (1.2 rpm), and even less in practice due to the need to compensate for dispersion issues. Inherent faults in the system would still cause a significant failure rate, although if we hand-wave away drill errors it won't be quite as bad as it was historically. 

Regardless, Bismarck still has a considerably higher shell output. 

 

For much the reasons as I stated originally, I don't think that Nelson is more likely to come out on top - rather the inverse. Nelson's citadel is well protected, but not as well as Bismarck's - once her opponent gets close enough, it will get penetrated. Her shell output is considerably lower, and her fire control isn't as good. All that stacks on top of the massive Achilles heel that is the essentially unprotected 152mm batteries, which could easily cripple the ship.

The 50º approach significantly increases her durability - I'd be curious if the Royal Navy did list preferred angles of approach - but likely isn't enough to turn the tide. The 25º angle of approach, however, would be disastrous.

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19 hours ago, Phoenix_jz said:

If Nelson insists on charging in against Bismarck, she trades away her major advantages - the heavy deck armor, the incline on her armor belt, and her main battery protection. It also plays to cover a major weakness of Bismarck, her poor deck armor.

The problem is that Nelson cannot kite away without getting lolrekt in the steering gear and other important stern bits, plus the stern bulkhead is 10 inches down to the steering and gearing armoured deck. At the very end of that it's only 4 inches. Compared to the forward 12 inch bulkhead...

Nelson_class_battleship_armour_layout.sv

Bismarck has the speed advantage. So Nelson will have to push in at some angle.

The lower parts under that 12 inch bullkhead can be pretty much ignored as the region where the 8-inch bulkhead is potentially pennable after the Bismarck's shell hits water and slips under the deck is so tiny in the target profile it would be pure RNGesus.

19 hours ago, Phoenix_jz said:

An approach at an angle of 25º from head on also gives Bismarck a number of benefits aside from a closer-ranged fight. Not only does it force Nelson to allow Bismarck to cross her T

Nelson's third turret can fire 25 degrees off dead ahead. That's why I used it for the max theoretical closing rate.

19 hours ago, Phoenix_jz said:

Against the Nelson-class, the preferred angle of engagement was 30º (from the bow), which reduces the range of penetration for the armor belt about around 5,000 yards (Going by the past numbers, that could be anywhere from 15,000 to 26,000 yards, depending on the source - although the turtleback is still immune). All the main battery would still be brought to bear at such an angle.

Impossible.

https://www.kbismarck.com/armament.html

Bismarck has to be at 35 degrees for all turrets to fire.

However, at 35 degrees the Bismarck's 9-inch forward bulkhead is a lolpen to Nelson's shells. A single hit punching into Bismarck's citadel there would immediately tip the scales even if it did not detonate a magazine.

19 hours ago, Phoenix_jz said:

I doubt that Bismarck would be torpedoed unless Nelson was trying to finish off an already crippled foe - German underwater listening systems were good, so they'd probably just hear it coming and shift course.

And how many minutes will it cost the Bismarck after each evasion to reacquire a firing solution? More importantly, if she turns her bow toward the incoming torpedoes, as is standard, are the two ships on converging courses or spiralling inward toward each other (i.e. near anti-parallel and both ships seeming to head toward the other's stern)?

If the ships are on converging courses (so both seem to be travelling toward the other's bow) then Nelson has a critical advantage: Bismarck lacks torpedoes.

When Nelson fires her torpedoes, even with gamble/distraction shots at extreme range, she can force Bismarck to either turn her bow toward the torpedoes and thus take her rear turrets temporarily offline, not to mention having to regain a firing solution or potentially blunder into them if the Germans do not think they are in torpedo range.

Suppose both ships are running at top speed (30 knots vs 23), which has the angle difference cancelling out much of the lateral speed difference in the diagram below. The % signs are roughly Nelson's course, \ is for Bismarck, and both ships are firing basically directly up/down the page (hard to show given the constant row spacing, the Bismarck has 4 markers but is only covering a little more distance than Nelson). X is where they would otherwise cross (RAM AND BOARDING ACTION IN THEORY :P). The two ship vectors have 95 degrees between them, almost exactly perpendicular.

------------------%
------------%
------%
X
----\
--------\
------------\
----------------\

If the Nelson correctly deploys its submerged torpedo tubes using long-range shots (20,000 yards at 30 knots) she can force Bismarck to evade several times, pointing its bow toward Nelson and increasing hit probability--Enjoy being razed to the Panzerdeck!--as well as making Bismarck's forward bulkhead even easier to LOL through.

By the time Bismarck closes to within the range where it can actually have a chance of penetrating Nelson's citadel, it will have been face-punched enough times and its superstructure blasted enough (many layers of splinter plating would still be enough to overall cause an AP shell to fuse and go off if it's hitting the superstructure almost from front to back) to be noticeably punch-drunk at best and most likely very severely aflame.

The closing rate in the Nelson at 50 degrees from Bismarck and Bismarck at 35 degrees from Nelson, both at full rated speed,  is just over 39 knots in theory. That's about 70 KPH or a bit over 1km per minute. In reality Nelson at least would probably go a bit slower than that to keep range open for a bit longer, so operating on a 1 kilometer per minute closing rate, Nelson can start firing torpedoes at the future position long before Bismarck is within nominal range.

Given Nelson's low speed (for some reason I thought she went 25 knots) and the relative positions and headings, for a long range pair of torpedo shots Nelson's far side torpedo might not even need to cross astern, depending on the turning arcs involved.

http://www.navweaps.com/Weapons/WTBR_PreWWII.php

I spot at least 4 torpedoes in that image and that's one side's torpedoes. So Nelson could force Bismarck to halve its firepower for harder face-punching at least 4 times.

Notice that unlike Tirpitz, Bismarck has no torpedo tubes to reply at Nelson with. So Nelson can repeatedly cross its T and lol through its forward bulkhead, or perhaps even get a heavyweight torpedo hit in!

By the time Bismarck can penetrate Nelson's turrets or anywhere else (about 20,000 yards), I expect Bismarck will have suffered at least one turret or barbette penetration, probably Anton, if not a forward bulkhead holing, lost its bridge, and lost or damaged the forward main fire director (most likely in the same hit as the bridge damage). That's assuming smashing through the front of the citadel doesn't set off a forward magazine, simply by probability and the armour there being an easy pen.

If the two ships are spiraling toward each other...

The range closes much slower, giving Nelson more time in that window when it has a serious advantage in holing Bismarck's incremental armour scheme while itself having its citadel stay intact.

If the spiralling becomes obvious and predictable enough, Nelson can fire torpedoes at Bismarck and force it to alter course. Of course, neither should be spiralling too actively for fire control reasons, but the point remains that they would overall be spiralling slowly toward each other, and that gives Nelson the advantage.

ALSO, Bismarck only carried 353 AP shells (plus 338 base fused HE, 313 nose fused HE), or 44 per gun plus 1, while Nelson carried 95 AP and 10 training shells per gun on NavWeaps--it didn't need to raid merchantmen unlike Bismarck, and the HE shell was introduced sometime in the 1930s.

While ranging, Bismarck would be firing the forward turrets at 1 salvo per minute. The ammunition supply would be quite limited in a capital ship slugfest, while Nelson don't give a fig about ammo consumption.

19 hours ago, Phoenix_jz said:

That being said, Nelson's guns were plagued by design issues, not so much wear & tear issues or operator error. Due to the handling arrangements, it wasn't possible to fire a single gun faster than once every 50 seconds (1.2 rpm), and even less in practice due to the need to compensate for dispersion issues. Inherent faults in the system would still cause a significant failure rate, although if we hand-wave away drill errors it won't be quite as bad as it was historically. 

Regardless, Bismarck still has a considerably higher shell output. 

I give above my way  way of negating Bismarck's ROF advantage using Nelson's torpedoes.

If Nelson can manage 9 guns per 50 seconds and Bismarck takes 25 seconds to reload, then as long as Nelson forces Bismarck to shadow its aft turrets and lose firing solution repeatedly using torpedos to force course changes, Nelson still has an advantage for a couple minutes at a time.

The fear of torpedoes is strong indeed, and that will give Nelson the chance to either raze Bismarck down to the armoured deck if the ships are spiralling, or lol through its forward bulkhead and punch its citadel full of holes. Thus I gave the Nelson a 60% chance of victory with fully trained and experienced crews compared to Bismarck's less experienced crew, assuming both ships were in ideal mechanical condition to begin with.

Edited by Guardian54

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19 hours ago, Guardian54 said:

The problem is that Nelson cannot kite away without getting lolrekt in the steering gear and other important stern bits, plus the stern bulkhead is 10 inches down to the steering and gearing armoured deck. At the very end of that it's only 4 inches. Compared to the forward 12 inch bulkhead...

Nelson_class_battleship_armour_layout.sv

Bismarck has the speed advantage. So Nelson will have to push in at some angle.

The lower parts under that 12 inch bullkhead can be pretty much ignored as the region where the 8-inch bulkhead is potentially pennable after the Bismarck's shell hits water and slips under the deck is so tiny in the target profile it would be pure RNGesus.

Not closing doesn't mean that Nelson has to kite - that generally wasn't a tactic unless you wanted to escape, or draw the enemy towards friendly guns - but simply neglecting to close means the Bismarck is forced to come to you. How long that takes depends on how much protection and firepower the German ship is willing to give up.

 

19 hours ago, Guardian54 said:

Nelson's third turret can fire 25 degrees off dead ahead. That's why I used it for the max theoretical closing rate.

Fair enough, I was just pointing out why it doesn't really work. The angle of approach would have to be about 35° from the bow for the thicknesses to be equal, ignoring the angle of impact of the shell itself on the inclined bulkhead - which means you'd need to be angled significantly further than 35° off the bow for that frontal bulkhead to be close to the strength of the armor belt abreast the magazines. Unless the angle is greater than 45° off the bow... I don't think it's worth it.

 

19 hours ago, Guardian54 said:

Impossible.

https://www.kbismarck.com/armament.html

Bismarck has to be at 35 degrees for all turrets to fire.

However, at 35 degrees the Bismarck's 9-inch forward bulkhead is a lolpen to Nelson's shells. A single hit punching into Bismarck's citadel there would immediately tip the scales even if it did not detonate a magazine.

Apologies, that was a typo on my part. That should read as 30° off the broadside, or 60° off the bow. I doubt Bismarck would adopt such a steep angle of approach at any point.

That being said - the 220mm bulkhead protects the space above the citadel, not the citadel itself. The part of the transverse bulkhead that protects the citadel is below the waterline, but only 180mm thick. Penetrations here would reach the citadel, but anything penetrating the 220mm portion would have to content with the main armor deck. It's a less likely hit location, but even easier to penetrate.

20 hours ago, Guardian54 said:

And how many minutes will it cost the Bismarck after each evasion to reacquire a firing solution? More importantly, if she turns her bow toward the incoming torpedoes, as is standard, are the two ships on converging courses or spiralling inward toward each other (i.e. near anti-parallel and both ships seeming to head toward the other's stern)?

If the ships are on converging courses (so both seem to be travelling toward the other's bow) then Nelson has a critical advantage: Bismarck lacks torpedoes.

When Nelson fires her torpedoes, even with gamble/distraction shots at extreme range, she can force Bismarck to either turn her bow toward the torpedoes and thus take her rear turrets temporarily offline, not to mention having to regain a firing solution or potentially blunder into them if the Germans do not think they are in torpedo range.

Suppose both ships are running at top speed (30 knots vs 23), which has the angle difference cancelling out much of the lateral speed difference in the diagram below. The % signs are roughly Nelson's course, \ is for Bismarck, and both ships are firing basically directly up/down the page (hard to show given the constant row spacing, the Bismarck has 4 markers but is only covering a little more distance than Nelson). X is where they would otherwise cross (RAM AND BOARDING ACTION IN THEORY :P). The two ship vectors have 95 degrees between them, almost exactly perpendicular.

------------------%
------------%
------%
X
----\
--------\
------------\
----------------\

If the Nelson correctly deploys its submerged torpedo tubes using long-range shots (20,000 yards at 30 knots) she can force Bismarck to evade several times, pointing its bow toward Nelson and increasing hit probability--Enjoy being razed to the Panzerdeck!--as well as making Bismarck's forward bulkhead even easier to LOL through.

By the time Bismarck closes to within the range where it can actually have a chance of penetrating Nelson's citadel, it will have been face-punched enough times and its superstructure blasted enough (many layers of splinter plating would still be enough to overall cause an AP shell to fuse and go off if it's hitting the superstructure almost from front to back) to be noticeably punch-drunk at best and most likely very severely aflame.

The closing rate in the Nelson at 50 degrees from Bismarck and Bismarck at 35 degrees from Nelson, both at full rated speed,  is just over 39 knots in theory. That's about 70 KPH or a bit over 1km per minute. In reality Nelson at least would probably go a bit slower than that to keep range open for a bit longer, so operating on a 1 kilometer per minute closing rate, Nelson can start firing torpedoes at the future position long before Bismarck is within nominal range.

Given Nelson's low speed (for some reason I thought she went 25 knots) and the relative positions and headings, for a long range pair of torpedo shots Nelson's far side torpedo might not even need to cross astern, depending on the turning arcs involved.

http://www.navweaps.com/Weapons/WTBR_PreWWII.php

I spot at least 4 torpedoes in that image and that's one side's torpedoes. So Nelson could force Bismarck to halve its firepower for harder face-punching at least 4 times.

Notice that unlike Tirpitz, Bismarck has no torpedo tubes to reply at Nelson with. So Nelson can repeatedly cross its T and lol through its forward bulkhead, or perhaps even get a heavyweight torpedo hit in!

By the time Bismarck can penetrate Nelson's turrets or anywhere else (about 20,000 yards), I expect Bismarck will have suffered at least one turret or barbette penetration, probably Anton, if not a forward bulkhead holing, lost its bridge, and lost or damaged the forward main fire director (most likely in the same hit as the bridge damage). That's assuming smashing through the front of the citadel doesn't set off a forward magazine, simply by probability and the armour there being an easy pen.

If the two ships are spiraling toward each other...

The range closes much slower, giving Nelson more time in that window when it has a serious advantage in holing Bismarck's incremental armour scheme while itself having its citadel stay intact.

If the spiralling becomes obvious and predictable enough, Nelson can fire torpedoes at Bismarck and force it to alter course. Of course, neither should be spiralling too actively for fire control reasons, but the point remains that they would overall be spiralling slowly toward each other, and that gives Nelson the advantage.

ALSO, Bismarck only carried 353 AP shells (plus 338 base fused HE, 313 nose fused HE), or 44 per gun plus 1, while Nelson carried 95 AP and 10 training shells per gun on NavWeaps--it didn't need to raid merchantmen unlike Bismarck, and the HE shell was introduced sometime in the 1930s.

While ranging, Bismarck would be firing the forward turrets at 1 salvo per minute. The ammunition supply would be quite limited in a capital ship slugfest, while Nelson don't give a fig about ammo consumption.

Bismarck's fire control computer is a modern one, that would be plenty capable of maintaining plot even after it's own maneuvers (ex, Denmark Strait) - the only thing it couldn't do is firing while maneuvering, due to the lack of RPC in train.  That, combined with the fact that only minor course adjustments are needed to avoid torpedoes at such a range, means that Bismarck probably isn't adjusting course by more than 5-10° to avoid shots, and isn't likely to need to re-acquire her target every time she does so. Furthermore, she's likely only going to need a few minutes before she's on targets - even with Hood sprinting in (to the point where Hood's fire control couldn't handle her own course), she was able to straddle within a few salvos. Likely, against a far easier target like Nelson (who isn't trying to sprint to close range), Bismarck would be going into fire for effect within five minutes (heck, she straddled Rodney after three salvos in her final battle, causing the Rodney to adjust course and lose the range).

Assuming, with a starting range of 30,000 yards, they close with  Nelson's bow angled 50° off from Bismarck, making 20 knots, and Bismarck's bow angled off 60° from Nelson, making 25 knots, after about five minutes the range drops to around 25,500 yards. After 10 minutes, 21,300 yards. 15 minutes, and you're at 17,500 yards. The issue is, unless Nelson keeps turning away, it makes it inevitable that Bismarck will cross her T. Assuming both ships open fire at around 25,500 yards (similar to Denmark Strait) and maintain course (at which point the angle of Bismarck to Nelson's guns is 45° off the port bow, and can penetrate Nelson's frontal bulkhead).

 

Bismarck can quite comfortably maintain course with minor adjustments to throw off torpedo solutions, while Nelson would have to be the one maneuvering more to avoid having her T crossed (and to over her frontal bulkhead). And again - both ships are quite capable of penetrating each other's turret faces, barrettes, and conning towers, at these combat ranges - if we're being generous to Nelson (she may not actually be capable of doing so). But, fire control abilities and rate of fire both favor Bismarck. She is more likely to get on target first, and once she does, will have a higher shell output - and that's not even docking Nelson for her dispersion issues. When those rounds hit, Nelson's just as if not more likely to lose her primary command spaces and main battery turrets as Bismarck, and again - as soon as any shells land near her secondary battery, she's going to be suffering from massive secondary explosions. They're not protected. 

 

Ammunition consumption is a fair point - although I doubt the action will last long enough for it to matter. It took Bismarck five four-gun salvos to sink Hood, six if you count the salvo in air when she went up - 20, 24 shells. I don't expect the same thing to happen to Nelson, but at the same time, that's only about 7% of her APC allocation. I don't expect her to exhaust her ammunition before either Nelson is done for or she has been defeated by Nelson.

 

21 hours ago, Guardian54 said:

I give above my way  way of negating Bismarck's ROF advantage using Nelson's torpedoes.

If Nelson can manage 9 guns per 50 seconds and Bismarck takes 25 seconds to reload, then as long as Nelson forces Bismarck to shadow its aft turrets and lose firing solution repeatedly using torpedos to force course changes, Nelson still has an advantage for a couple minutes at a time.

The fear of torpedoes is strong indeed, and that will give Nelson the chance to either raze Bismarck down to the armoured deck if the ships are spiralling, or lol through its forward bulkhead and punch its citadel full of holes. Thus I gave the Nelson a 60% chance of victory with fully trained and experienced crews compared to Bismarck's less experienced crew, assuming both ships were in ideal mechanical condition to begin with.

Again, the torpedoes aren't going to alter Bismarck's course by anywhere near that amount, and I don't expect it to hamper rate of fire that much - especially since Nelson herself will have to be constantly have to be adjusting her course if she wishes to avoid having her T crossed (unless she turns away, but as you said, that would be suicide).

I think you're way over-valuing the torpedoes in this scenario - if we look at Denmark Strait, where Bismarck was a sitting duck, Rodney fired off her torpedoes (six) at 11,000 yards, and despite Bismarck's lack of evasion - missed with all of them. When Bismarck was a drifting, blazing wreck, she fired four from a few thousand yards, and hit with one. The threat from these fish... is pretty low.

As far as mechanical condition - as I said before - there's a difference between faults from lack of training or wear and tear, and faults from design. Even in ideal condition, Nelson's guns are very prone to jamming and were unreliable. If we hand-wave those away, we might as well hand-wave all Bismarck's hoist issues away too.

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22 hours ago, Guardian54 said:

And how many minutes will it cost the Bismarck after each evasion to reacquire a firing solution? More importantly, if she turns her bow toward the incoming torpedoes, as is standard, are the two ships on converging courses or spiralling inward toward each other (i.e. near anti-parallel and both ships seeming to head toward the other's stern)? 

Not really. If you look at how both Bismarck and Prinz Eugen reacted to Hood firing her torpedoes you'll see that they turned away, not into them. The decision on how to maneuver was decided on the spot by the captain (which led to some heated discussions on Tirpitz in one case between Admiral and Captain).

image.png.88f6836b5f57ddc148d2e02a29a292e5.png

Also note that both torpedoes that Hood fired (which were confirmed by German crews which observed the trails) missed, and firing remained rather accurate throughout the engagement.

22 hours ago, Guardian54 said:

f the ships are on converging courses (so both seem to be travelling toward the other's bow) then Nelson has a critical advantage: Bismarck lacks torpedoes. 

When Nelson fires her torpedoes, even with gamble/distraction shots at extreme range, she can force Bismarck to either turn her bow toward the torpedoes and thus take her rear turrets temporarily offline, not to mention having to regain a firing solution or potentially blunder into them if the Germans do not think they are in torpedo range. 

If the Nelson correctly deploys its submerged torpedo tubes using long-range shots (20,000 yards at 30 knots) she can force Bismarck to evade several times, pointing its bow toward Nelson and increasing hit probability--Enjoy being razed to the Panzerdeck!--as well as making Bismarck's forward bulkhead even easier to LOL through.

Given Nelson's low speed (for some reason I thought she went 25 knots) and the relative positions and headings, for a long range pair of torpedo shots Nelson's far side torpedo might not even need to cross astern, depending on the turning arcs involved.

http://www.navweaps.com/Weapons/WTBR_PreWWII.php

I spot at least 4 torpedoes in that image and that's one side's torpedoes. So Nelson could force Bismarck to halve its firepower for harder face-punching at least 4 times.

Notice that unlike Tirpitz, Bismarck has no torpedo tubes to reply at Nelson with. So Nelson can repeatedly cross its T and lol through its forward bulkhead, or perhaps even get a heavyweight torpedo hit in!

You are seriously overestimating the effectiveness of Torpedoes in a BB vs BB engagement. As pointed out above Hood's torpedoes did practically nothing. The only time when a BB torpedo hit something that was not the ocean floor was when Rodney torpedoed a floating wreck. That's it.

You'll also find that Rodney fired a grand total of two torpedoes at Bismarck from point blank range. So thinking that Nelson would fire at least four torpedoes during an engagement is unrealistically optimistic on your part.

What strengthens the dubious usability of Torpedoes in BB vs BB combat is the fact that neither Tirpitz nor the Scharnhorst sisters ever carried a fire director for the torpedoes. Because they were not meant for combat, they were meant for merchant raiding. To the point where Tirpitz could not even deploy them without training the 15cm turret to a certain position. If Torpedoes were as crucial as you claim, why didn't the Germans attempt to use them for naval combat? Why didn't Scharnhorst dump six torps into DoY, if I may put it in a provocating manner?

22 hours ago, Guardian54 said:

ALSO, Bismarck only carried 353 AP shells (plus 338 base fused HE, 313 nose fused HE), or 44 per gun plus 1, while Nelson carried 95 AP and 10 training shells per gun on NavWeaps--it didn't need to raid merchantmen unlike Bismarck, and the HE shell was introduced sometime in the 1930s. 

Unless the British invented a way to bend time and space, or magically created more room elsewhere, the HE shells will come at the price of AP shells. In fact, when looking at how HMS Hood's ammunition count developed over the years you'll find an even more interesting trend:

  APC CPC Shrapnell Practice Total
Initial 672 289 30 82 1.073
Post Refit 640 160 48 96 944

She is losing more than 100 shells in total.

Since the only Battleship-esque ships with HE shells (according to navweaps) were the Renowns, which list 60% APC, 20% CPC and 20% HE, I'd say it's reasonable that Nelson would in total carry 20% HE. Applied to Nelson you'd end up with 74 APC rounds per gun, 21 HE rounds per gun and 10 training rounds per gun.

 

phoenix covers the rest of the points excellently.

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1 hour ago, Phoenix_jz said:

I think you're way over-valuing the torpedoes in this scenario

I think I'm using WoWS single-fire torp accuracy levels.:Smile_trollface:

1 hour ago, Phoenix_jz said:

Ammunition consumption is a fair point - although I doubt the action will last long enough for it to matter. It took Bismarck five four-gun salvos to sink Hood, six if you count the salvo in air when she went up - 20, 24 shells. I don't expect the same thing to happen to Nelson, but at the same time, that's only about 7% of her APC allocation. I don't expect her to exhaust her ammunition before either Nelson is done for or she has been defeated by Nelson.

You said the engagement would take 15 minutes to get from opening fire at 25,500 yards to 17,500 yards, below which Bismarck can pen Nelson reliably even at maximum armour presentation.

That's 8000 yards closed in 15 minutes, during which Bismarck can fire 30 salvos and Nelson fires about 15-18 (being generous here to Bismarck).

Nelson's captain knows he has more than enough AP stowed--likely over 70 rounds per gun as SireneRacker suggested --to last through any plausible engagement, so he can and should open fire at his maximum range hoping for a plunging Golden BB. Meanwhile, Bismarck has to either reply or close the range as quickly as possible (Let's say this brings the time down to 10 minutes i.e. 10 salvos for Nelson) and have its T crossed.

Both ships max out around 37,500-38,000 yards, and at any range down to 30,000 yards Bismarck's citadel can be penetrated with plunging fire, while the weather deck can be penetrated by plunging fire at any range over 15,000 yards, and below that range it's horizontal fire that matters (where Bismarck would win).

Nelson's engine deck can be penetrated by Bismarck's plunging fire down to about 22,000 yards, while its magazine armour deck holds up at any range to Bismarck's shells.

This is part of why I suggest a steep approach, to reduce the target profile of the engine deck for Nelson. However, if that's not going to be used, then Bismarck will take even longer to get into effective horizontal fire range, which benefits Nelson.

NELSON GUN: http://www.navweaps.com/Weapons/WNBR_16-45_mk1.php

BISMARCK GUN: http://www.navweaps.com/Weapons/WNGER_15-52_skc34.php

From opening up at max range of 38000 yards, it should take about 20 minutes for the parties to close to 25,500 since Bismarck will increase speed to close faster, Nelson can fire about 20 shells per gun before Bismarck's citadel is no longer reliably penetrable to plunging fire. 180 shells will likely yield two hits, and is very likely that something important should be knocked out. After that, and at every point during the engagement that matters, the space between the weather deck and armour deck on Bismarck will be a good impression of Hell because Nelson can chew up the critical systems there easily.

If Bismarck wants to open up with all guns in reply the closing rate is even slower.

Bismarck will want to close to have the advantage, whether allowing its T to be crossed (at least one citadel penetration is likely) or accepting a longer closing time (at least two citadel penetrations are likely).

If Bismarck replies during the run in from 38000 yards to 25,500 yards, it is in serious danger of running low on ammunition as 44 shells per gun will only last it about 22 minutes of rapid fire. Meanwhile Nelson can fire for 70 minutes (Or 50 at more theoretical firing rates).

Nelson can afford gambling shells away on wishful thinking. Bismarck really can't.

50 minutes ago, SireneRacker said:

If you look at how both Bismarck and Prinz Eugen reacted to Hood firing her torpedoes you'll see that they turned away

The Bismarck's rear bulkhead is even more lolpen than the forward... and making Bismarck turn broadside delays it closing, which is still useful for Nelson.

51 minutes ago, SireneRacker said:

Why didn't Scharnhorst dump six torps into DoY, if I may put it in a provocating manner?

Limited torpedo range, perhaps?

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6 hours ago, Guardian54 said:

Nelson's captain knows he has more than enough AP stowed--likely over 70 rounds per gun as SireneRacker suggested --to last through any plausible engagement, so he can and should open fire at his maximum range hoping for a plunging Golden BB. Meanwhile, Bismarck has to either reply or close the range as quickly as possible (Let's say this brings the time down to 10 minutes i.e. 10 salvos for Nelson) and have its T crossed.

 Both ships max out around 37,500-38,000 yards, and at any range down to 30,000 yards Bismarck's citadel can be penetrated with plunging fire, while the weather deck can be penetrated by plunging fire at any range over 15,000 yards, and below that range it's horizontal fire that matters (where Bismarck would win).

Considering how HMS Hood spotted Bismarck and PE from a range of 38k yds and would only open fire from a range of 25k yards, almost 20 minutes after the spotting, despite carrying more APC shells per gun than Nelson did, I hold serious doubts regarding Nelson opening up from max range. 

6 hours ago, Guardian54 said:

The Bismarck's rear bulkhead is even more lolpen than the forward... and making Bismarck turn broadside delays it closing, which is still useful for Nelson.

Not when you consider that there is a lot more armor in the aftship of Bismarck. There is more armor on a ship than just a belt, deck and bulkhead, especially German ships have a very complex system.

6 hours ago, Guardian54 said:

Limited torpedo range, perhaps?

Nope. The engagement ranges were as low as 11km. The G7a had a max range of 14km.

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11 hours ago, SireneRacker said:

Considering how HMS Hood spotted Bismarck and PE from a range of 38k yds and would only open fire from a range of 25k yards, almost 20 minutes after the spotting, despite carrying more APC shells per gun than Nelson did, I hold serious doubts regarding Nelson opening up from max range. 

I'm assuming both sides are perfectly informed about the other, which is, ahem, DUBIOUS.

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On 7/9/2019 at 6:02 PM, Guardian54 said:

I think I'm using WoWS single-fire torp accuracy levels.:Smile_trollface:

:Smile_teethhappy:

 

On 7/9/2019 at 6:02 PM, Guardian54 said:

You said the engagement would take 15 minutes to get from opening fire at 25,500 yards to 17,500 yards, below which Bismarck can pen Nelson reliably even at maximum armour presentation.

That's 8000 yards closed in 15 minutes, during which Bismarck can fire 30 salvos and Nelson fires about 15-18 (being generous here to Bismarck).

Nelson's captain knows he has more than enough AP stowed--likely over 70 rounds per gun as SireneRacker suggested --to last through any plausible engagement, so he can and should open fire at his maximum range hoping for a plunging Golden BB. Meanwhile, Bismarck has to either reply or close the range as quickly as possible (Let's say this brings the time down to 10 minutes i.e. 10 salvos for Nelson) and have its T crossed.

Both ships max out around 37,500-38,000 yards, and at any range down to 30,000 yards Bismarck's citadel can be penetrated with plunging fire, while the weather deck can be penetrated by plunging fire at any range over 15,000 yards, and below that range it's horizontal fire that matters (where Bismarck would win).

Nelson's engine deck can be penetrated by Bismarck's plunging fire down to about 22,000 yards, while its magazine armour deck holds up at any range to Bismarck's shells.

This is part of why I suggest a steep approach, to reduce the target profile of the engine deck for Nelson. However, if that's not going to be used, then Bismarck will take even longer to get into effective horizontal fire range, which benefits Nelson.

NELSON GUN: http://www.navweaps.com/Weapons/WNBR_16-45_mk1.php

BISMARCK GUN: http://www.navweaps.com/Weapons/WNGER_15-52_skc34.php

From opening up at max range of 38000 yards, it should take about 20 minutes for the parties to close to 25,500 since Bismarck will increase speed to close faster, Nelson can fire about 20 shells per gun before Bismarck's citadel is no longer reliably penetrable to plunging fire. 180 shells will likely yield two hits, and is very likely that something important should be knocked out. After that, and at every point during the engagement that matters, the space between the weather deck and armour deck on Bismarck will be a good impression of Hell because Nelson can chew up the critical systems there easily.

If Bismarck wants to open up with all guns in reply the closing rate is even slower.

Bismarck will want to close to have the advantage, whether allowing its T to be crossed (at least one citadel penetration is likely) or accepting a longer closing time (at least two citadel penetrations are likely).

If Bismarck replies during the run in from 38000 yards to 25,500 yards, it is in serious danger of running low on ammunition as 44 shells per gun will only last it about 22 minutes of rapid fire. Meanwhile Nelson can fire for 70 minutes (Or 50 at more theoretical firing rates).

Nelson can afford gambling shells away on wishful thinking. Bismarck really can't.

 

It's important to note that maximum ballistic range is not the same as maximum firing range. Even in a crystal-clear daylight confrontation in the Mediterranean or Pacific, the maximum effective range for battleship gunnery is about 35,000 yards. That's about the maximum range either ship would open up under ideal conditions - and as this is far from ideal conditions. If this is a clash of Nelson and Bismarck, then we're looking at either the North Atlantic or the North Sea, where even under ideal conditions the maximum effective gunnery range for a given caliber is limited - hence why I used around 25,000 yards as my maximum range. Typically that was the maximum range anyone was willing to open fire, with the exception of the Terrible Twins sinking Glorious (Scharnhorst opened fire at 28,400 yards).

 

I would expect, at the most, maybe for Nelson to open fire first at 26,000 yards with Bismarck's reply potentially delayed until 21,000 to 23,000 yards at the latest.

 

To keep things simple I'll use the same plot as before. For Bismarck, if we open fire at 25,500 yards, and take 5 minutes to secure straddles (1x 4-gun salvo/min) and go into rapid fire, and take another five minutes of rapid fire (3x 4-gun salvoes/min), that's 20 rounds for the first five minutes (2-3 rpg), 60 rounds for every next five minutes (7-8 rpg). That's 10 rpg burned for the first ten minutes, 15 over the next ten minutes, and another 15 for another ten minutes. At that point, each gun would have about 4 APC rounds left and Bismarck would be in trouble (assuming 353 rpg) - but that's also after 30 minutes of continuous firing, and assuming the same course I mentioned before, Bismarck crossed Nelson's T between the 20 and 25 minute marks.

 

I'll put Nelson though the same situation. The British tended to favor high rates of salvo fire before swapping to full broadsides, which makes things easy. Navweaps credits a rate of 1.6 rpm for salvo fire (4 & 5-gun salvoes) at Bismarck's last battle, so I'll use that. With that rate, you get 8 salvoes over five minutes, or 36 rounds (4 rpg), or 16 every ten minutes (72 rounds, 8 rpg). After 15 minutes range is down to only 13,500 yards, so I'll assume broadsides start rolling out then (thus over the first 15 minutes 24 salvoes are fired for 108 rounds, aka, 12 rpg). The next fifteen minutes of straight broadsides are Navweap's 1.1 rpm allows for 16 broadsides, or 144 rounds fired (16 rpg) - this assumes Nelson adjusts her course to keep all guns on target rather than allow her T to be crossed.

 

After 30 minutes of continuous gunnery, Bismarck will have fired off 320 APC rounds (40 rpg), almost every AP shell she carries (4 rpg + 1 are left).

Nelson will have fired off 252 APC rounds (28 rpg), which still leaves plenty of capacity. According to Campbell, the Nelson-class carried only APC, with HE only being carried specifically if there was to be a bombardment mission. In mid-1943 that changed to 95 rounds of APC & 5 time-fused HE (Unlike the older HE, these had a real nose fuse, not one buried inside the ballistic cap - so they would actually detonate). Either way, Nelson still has 67 APC per gun left after 30 minutes.

 

The big question, though, is what this actually means practically. It's great to have all that extra ammo, but that doesn't help in the short term. Does Nelson survive the first 30 minutes of combat? 

Honestly... It's a little unlikely she comes out better than Bismarck. Her opponent is already firing off about 27% more shells (9.35% more mass). The only way she can really make up for that is hitting more often... and Nelson is a bit screwed from that angle. She's using an older FC system with inferior limits, inferior rangefinders (the director rangefinder had not even half the base length of Bismarck's, 4.572 meters versus 10.5 meters). She's going to have a much harder time hitting than Bismarck, and it's extremely unlikely she hit first. The German battleship achieved a hit rate of 4.3% at Denmark strait - which implies, in our scenario, about 5-6 hits in ten minutes of rapid-fire before ranges drop below that of Denmark Strait (total 15 minutes firing time), and where Nelson can be penetrated pretty much anywhere by Bismarck's guns.

 

In the reverse... well, the Nelson is going to struggle to be hitting. In the same time period (15 min, just before we got to broadside firing), she'll have output 108 shells, and scored maybe 2-3 hits - about half as many as her opponent (I'm assuming a 2-3% hit rate). More likely than not, she's going to be in considerably worse condition than Bismarck by the time the range drops below 13,500 yards, and at that point the advantage is firmly in Bismarck's favor. The one close-range advantage for Nelson - her torpedoes -  while helpful, a hit would be far from devastating as Bismarck's TDS is likely to be able to handle it (the torpedoes had a warhead 337 kg TNT, the USN rated the Bismarck's system as proof against just over 400 kg).

 

No matter how you cut it, Nelson is more likely to be taking more damage than Bismarck as the range closes, and she's screwed once the range does get close. 

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4 hours ago, Phoenix_jz said:

At that point, each gun would have about 4 APC rounds left and Bismarck would be in trouble (assuming 353 rpg) - but that's also after 30 minutes of continuous firing, and assuming the same course I mentioned before, Bismarck crossed Nelson's T between the 20 and 25 minute marks.

If I may add, at some point Bismarck would actually fire nose fuzed HE as well. The firing tables clearly suggest the usage of nose fuzed HE given Nelson's large superstructure and foreship.

image.png.a82de986ad325618ffc74486b1b80be0.png

Translated into English:

"Ammo selection: For decisive impact APC, High Explosive Kz according to the regulations in Vol a. To note is, that "Nelson" has an unprotected foreship, a large upper ship [I assume upper casemate] and important, unprotected superstructure (battlemast)."

Nelson would not sink from such a hit, obviously, but it would certainly be critical for her to take such a shell especially around the main structure.

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8 hours ago, SireneRacker said:

If I may add, at some point Bismarck would actually fire nose fuzed HE as well. The firing tables clearly suggest the usage of nose fuzed HE given Nelson's large superstructure and foreship.

image.png.a82de986ad325618ffc74486b1b80be0.png

Translated into English:

"Ammo selection: For decisive impact APC, High Explosive Kz according to the regulations in Vol a. To note is, that "Nelson" has an unprotected foreship, a large upper ship [I assume upper casemate] and important, unprotected superstructure (battlemast)."

Nelson would not sink from such a hit, obviously, but it would certainly be critical for her to take such a shell especially around the main structure.

As I've mentioned previously, her Achilles heel is the nigh-unprotected 152mm battery & their magazines. A hit aft by an HE shell has plenty of potential to lead to a devastating secondary battery explosion..

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On 7/11/2019 at 11:56 PM, Phoenix_jz said:

The big question, though, is what this actually means practically. It's great to have all that extra ammo, but that doesn't help in the short term. Does Nelson survive the first 30 minutes of combat? 

Very well, I concede that I am working off entirely theoretical numbers and therefore cheesing the hell out of the situation to give Nelson a better chance of winning.

In a real match-up Bismarck should win 7 out of 10 times.

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On 7/13/2019 at 10:00 AM, Guardian54 said:

Very well, I concede that I am working off entirely theoretical numbers and therefore cheesing the hell out of the situation to give Nelson a better chance of winning.

In a real match-up Bismarck should win 7 out of 10 times.

Fair enough!

Thanks for the discussion, I enjoyed it.

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So I realized something important today for Nelson vs. Bismarck... It's not 7:3 in Bismarck's favour, it's 6:4 or less.

The 6-inch secondary magazines are UNDER that armoured deck in Nelson's rear.

Nelson_class_battleship_armour_layout.sv

What this means is that Nelson CAN kite away from Bismarck for... quite a while. Bismarck obviously wants this engagement, or it could have run away, which means it's going to try as hard as it can to kill Nelson, and that means closing the range quickly.

Nelson's A turret can fire up to 59 degrees back, B turret 75, and C turret 60.

That thin rudder room bulkhead is basically a negligibly small change of being hit compared to the rest. So Nelson kiting away at its best Parthian Shot angle (about 40 degrees away from perpendicular to Bismarck's position/incoming fire) gives 395mm effective on that 10-inch rear bulkhead, and factoring in hull curvature of about 5 degrees (so the side plate angles away at 35 degrees from perpendicular to the incoming shell), about 402mm. This is proof against Bismarck's AP out to about 19,000 meters, while going in at 50 degrees from straight toward Bismarck was proof to about 17,000-17,500 or so. Clearly, due to the huge engagement time differential, it's better to simply kite away all the time unless you can get the ship around between enemy half-salvos (like say by forcing them to occlude their own rear guns).

Bismarck can penetrate Nelson's engine space deck from outside roughly 27,000 meters by my estimate, according to its tables (http://www.navweaps.com/Weapons/WNGER_15-52_skc34.php says 120mm deck pen at 30km, when Nelson has 95+12.7 over the engines, the angle flattening cuts penetration FAST...).

Note that Nelson can turn broadside safely at down to 23,000 meters if it needs to adjust course to close, or if it initially closed to raise its firing accuracy and then turns away to make Bismarck have to slowly eat up the distance. Since Bismarck MUST close the range to hurt Nelson, it has to come toward Nelson. Nelson will just keep on turning away from an intercept course, so both ships will end up describing curves.

We have three realistic options here: Bismarck sails in the direction of Nelson's bow, (the curves will bend in the same direction on a map, like a single-armed swirl), toward Nelson's stern (two swirls locked on one another), or Bismarck bumrushes Nelson (and gets loled through the front of the citadel if it gets too close). We can approximate these as follows:

Bismarck sailing toward Nelson's stern:

Nelson making 23 knots sailing at 41 degrees away from Bismarck (so that incoming shells impact at about 40 degrees from Nelson's broadside) has a rate of change of 23*sin(41) = 15.089 knots away from Bismarck.

Bismarck making 30 knots at 34 degrees away from directly toward Nelson (it needs 35 to fire all its guns but Nelson is moving INTO its field of fire) has a rate of change of 30*cos(34) = 24.871 knots toward Nelson.

Total closing rate is 9.782 knots, or 5.0323 meters per second, or 301.9 meters per minute.

Bismarck sailing toward Nelson's bow:

Nelson making 23 knots sailing at 39 degrees away from Bismarck has 23*sin(39) = 14.474 knots away from Bismarck.

Bismarck making 30 knots at 36 degrees away from directly toward Nelson (it needs 35 to fire all its guns but Nelson is moving toward its bow) has a rate of change of 30*cos(36) = 24.271 knots toward Nelson.

Total closing rate is 9.796 knots (accounting for rounding issues), or 5.0395 meters per second, or 302.4 meters per minute.

Bismarck bumrushes bow-in toward Nelson (intercept course would not work as Nelson would just keep turning away)

Closing rate is 30 - 23*sin(40) = 15.216 knots, or 7.8278 meters per second, or 469.7 meters per minute.

Let's take a look at Bismarck's armour:

armourbismarcklarge.gif

At 35 degrees Bismarck's 220mm citadel bulkhead (just above the 20mm plate in the diagram) will be 269mm effective. This will withstand Nelson's guns down to about 20,000 meters if we extrapolate using Bismarck's guns' different numbers from German gun curves and USN Empirical Formula numbers. Of course if Bismarck bumrushes Nelson, the fore bulkheads will be penetrated at 25,000 meters.

The citadel deck is penetrated beyond about 27,000 meters. HOWEVER the weather deck armour is penned down to about 15,000 meters, and if the space between the decks is a mess, Bismarck will be thoroughly incapacitated.

XX

This tells us that unless both parties are firing at maximum range, Nelson is mostly immune to Bismarck (barring hitting the funnel trunking or steering) from 28,000 meters to 19,000 meters. Bismarck is citadel-proof to Nelson from 27,000 to 20,000 meters if Bismarck is being careful. HOWEVER, this would only close the range at 300m per minute.

Bismarck can close at 470m/min if it accepts immunity from only 27,000 to 25,000.

PROVIDED Bismarck and Nelson both have good information on the capabilities of the other, there will be no battle because Bismarck will not engage.

If the HAND OF GOD forced both sides to fight i.e. for Bismarck to attempt to sink Nelson, Nelson will begin firing as early as possible. This means firing commences at the Nelson's maximum range of about 34.75 km.

Let's assume Bismarck does a bow-in sprint toward Nelson from whenever Nelson starts firing, while shooting back, to 27km before swinging to be as immune as it can get while firing full broadsides back (with HE to erode Nelson's efficiency). At a closing rate of 470 meters per minute this takes 16.5 minutes. Bismarck's time to actually swing its bow to be toward Nelson's bow and start firing all its guns is 17 minutes after Nelson begins firing.

During this time Nelson can spend up to about 10 minutes (16 salvos, 8 RPG) getting a reasonable estimate of a firing solution (curving target paths SUCK HARD), then pound out 5 broadsides of AP, and still have 61 APC and 21 HE per gun left as per the earlier calc. 13 RPG on 9 guns is 117 shells being thrown at the Bismarck, which may damage something due to the forward three-quarters perspective the Bismarck would be presenting by the time the shells got there.

To finish Nelson off, Bismarck has to close from to 27 km to 19 km at a rate of about 300m/s, so 26.5 minutes, in the UNLIKELY EVENT that Nelson doesn't start slinging torpedoes to force Bismarck to either turn away (larger target, slower closing) or turn toward Nelson's previous location and Nelson itself (as the ship is slow, at long range going bow-in on torpedoes will make Bismarck shadowing its rear turrets momentarily).

In these 26.5 minutes, Nelson can get 29 broadsides in on Bismarck, and is at no risk of running short on ammunition. 261 shells at an increasingly close range (and thus increasing accuracy) will do SOMETHING unpleasant somewhere on Bismarck.

Nelson's superstructure will need to be reconstructed after this because it will have absorbed something like 45 broadsides of Bismarck's nose fused (Bismarck carried 39 RPG + 1 of these) and base fused HE shells (42 RPG + 2 carried) during this closing phase. So Nelson will be hurting very badly with 360 large HE shells flung its way. However, it will have inflicted critical damage on Bismarck in return even if it didn't penetrate the citadel yet (Ye gods Nelson's guns have awful stats).

Please note that 36.5 km is the Bismarck's max range, but Bismarck normally only carried 44 rounds per gun of APC. Technically it could fire a whole load of HE shells at Nelson to get the range, then switch to AP. So for 4 minutes before Nelson can fire, Bismarck can already fire. However, due to the shell flight time at such ranges (around 75 seconds) this amounts to 3 half-salvos from the forward guns for ranging purposes.

During the first 15 minutes after Nelson begins firing, Nelson can theoretically be citadelled by Bismarck's forward guns, firing about 12 RPG over that time before switching (back?) to HE. Due to the curving path the Nelson is taking, the full bumrush speed Bismarck is ploughing forward at, the lack of half-salvos to do ranging with, and the extreme range, I expect a small fraction of the Denmark Strait hit rate on either side, before both ships settle into the long pursuit from 27 km to 19 km.

During this pursuit, due to the curving path of both ships, experience and intuition may well count for much more in gunnery than any equipment short of fully computerized pattern-recognition-capable fire control of decades later.

Once the range closes to under 23,000m for the Germans and 23,500m for the British, the circa-6-inch secondary batteries start hammering away. By this point it is unlikely that all the secondaries have been silenced yet. The Germans can fire at 8 RPM, while the British can fire at 4 RPM. The problem is that the British are likely to be getting some worrying 16-inch hits on Bismarck by now so the 2ndary gunners would be altogether eager to fire as quickly as possible. Too bad the angle of approach only lets 6 guns fire while the British also have 6.

Yes, the British 2ndary turrets are far worse protected, but it's still quite possible that they haven't been blown up yet, and the German 2ndaries are hardly guaranteed to still be fully functioning either.

Bismarck has 311 base fuse HE and 333 nose fuse HE per side for the 3 twin 150mm secondaries on said side of the ship (so 52 RPG -1 and 55.5 RPG respectively). Nelson has 135 CPBC, 15 HE, and 24 practice rounds stowed per gun. Bismarck will run out of secondary ammunition (barring destroyed turrets) within 13 minutes of commencing fire, and will have to transfer ammunition across the ship from the other side's 2ndary magazines after that (or if the captain is creative and the range long enough to feel reasonably safe, he can swing the bow around to point toward Nelson's stern, it's not an appreciably slower closing rate but lets his other 2ndaries have a go at it, and his rear turrets can slew around really blazing fast by battleship standards at 5.4 degrees per second). Meanwhile Nelson's secondary gunners can (barring being shot to pieces) keep firing for 

But there's a problem here: Bismarck's secondaries have majority  pure HE (nose fuse) shells and minority semi-AP (base fuse HE). Meanwhile, CPBC was relabelled later as Semi-Armour Piercing, Ballistic Cap. So the secondary exchange will result in the German "use it or lose it" burning through their ammunition quickly, while the British MAY have 2ndaries still able to fire at rather less obscene ranges, where they can actually meaningfully blow deep holes into the Bismarck's superstructure.

There's another issue: the Nelson class carried 12 torpedoes with range up to 18km at 30 knots. If Kriegsmarine doctrine on torpedoes is indeed to turn away, then this all gets worse for Bismarck as its approach would be interrupted for whole kilometers at a time by Nelson just firing torpedoes into its expected path, alternating its tubes. Since Bismarck is closing it WILL run into the range of the torpedoes and WILL have to evade. Nelson is retreating at approximately 7.5-7.7 meters per second from Bismarck, which is in the neighbourhood of 450-460 meters per minute and by no means small, so if Bismarck turns AWAY from a torpedo for even a single minute ONCE, let alone maneuvering multiple times, you see where that's going (Bismarck at least loses some pursuit time, and at worst takes a hit somewhere on the TDS which slows it by quite a few knots). and if Bismarck turns TOWARD a torpedo, it will need to adjust its firing solution slightly, and heavens forbid may get a torpedo in the bow which would ruin its speed advantage... though I think it quite likely that Nelson shooting at Bismarck's approaching form should already have holed the bow enough that speed had to be reduced to not tear it apart.

The largest danger to Nelson if she takes this kiting strategy is the chance that Bismarck will either jam her rudder by penetrating the rudder spaces, or happen to penetrate one of her funnel trunkings and slow her down significantly. Given her path is curving though, I doubt it'll be that easy for Bismarck to actually hit her, and even if the rudder does jam in the very slight turn, it won't be obvious within the span of a few minutes, and Nelson will retain favourable engagement terms for quite a while.

Nelson has a reasonable chance of incapacitating the Bismarck's fire control or other faculties early enough to pound the bigger, newer battleship into scrap metal. So while Bismarck probably still manages to ultimately win, it will take a very irritatingly long time, and most likely exhaust Bismarck's ammunition to the point where a cruiser can waltz up and scuttle it.

And that's without considering this document which claims Rodney made 23.8 knots on trials. (https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1559-3584.1929.tb05019.x) which would extend the closing windows a bit further. In addition, due to the relative speeds and how air resistance works, Bismarck's shells will be slightly less powerful as much of their extra kinetic energy from sailing in that direction has been countered by air resistance, and Nelson sailing away removes some more of their impact velocity. Nelson's shells are boosted by air resistance not being so hard on them (air speed is lower as Nelson is sailing away) AND Bismarck charging into them at high velocity.

CONCLUSION?

I hereby revise my estimate of the match-up (from 7 in 10 to Bismarck) to 6 in 10, still in Bismarck's favour. Against a battleship so much older and lighter, this is a terrible showing. If the Nelson-class was refitted to operate more or less as the design intended (i.e. completely rebuilt with late 1930s materials, construction sciences, etc.), even discounting re-engineered guns, it drops to 5.5 in 10 in Bismarck's favour, which makes Bismarck a heap of terribad inefficiency considering the relative displacements.

I'd estimate two Bismarcks to cost as much as three Nelsons counting ships and crews, and that match-up would be "run away, run away..." for the Bismarcks because they'd get roflstomped in a deathmatch.

Edited by Guardian54
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On 6/21/2019 at 11:35 AM, Murotsu said:

Speed makes no difference tactically.  Once one is in range of the other, both are in range.  The Bismarck's higher speed is only valuable for running away from a fight, not getting into it.

This is incorrect since a higher speed increases distance traveled over a given time thereby increasing angular deviation.  This increase in angular deviation will magnify Target Location Error (TLE) caused by error in estimated heading.  For example if you are off in estimated heading by 2 degrees on a ship traveling 20kts it would be the same as being 3 degrees off on a ship traveling 30kts.

On 6/21/2019 at 11:35 AM, Murotsu said:

Armor.  Both are well protected, but I'd bet the Bismarck would take far more of a pounding than Nelson.

This is probably correct as even the point blank fire from Rodney did not compromise Bismarck's Citadel.  Bismarck sank either from the torpedoes or the scuttling charges not the gunfire.

On 6/21/2019 at 11:35 AM, Murotsu said:

Nelson has an advantage in firepower.  One more tube and 16" guns makes a difference.

I'd say in a one-on-one (almost zero chance of it happening as the RN, like the USN, recognized that you don't operate battleships singularly), it really comes down to who puts the first hurt on the other.  History shows that the side / ship that gets smacked hard first almost always loses the fight when it comes to WW 2 naval warfare.

This is also probably correct though I would add that such BB vs BB engagements tended to be decided not by firepower vs armor but by who got their guns on target first (or at all).  If IIRC it was South Dakota that got blasted by cruisers because its electrical system failed and it couldn't fight, one of the Kongos got deleted in the same engagement by a ship that had radar.  Fuso got blasted because the USN ships had radar and they didn't.  Scharnhorst got [edited] because its radar failed, and while everyone knows Hood's magazine blew up PoW's was also rendered helpless because her bridge got blown up and Bismarck herself was destroyed because her fire control and bridge was destroyed.

The salient point here being that BB engages didn't really seem to be determined by guns vs armor but by the first to get on target and destroy the vital bits of a ship like the Bridge/FCS and the like.  Or in the case of certain US vs Japan engagements and the Scharnhorst determined by who had crapthat was working in the first place.

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On 6/29/2019 at 12:41 PM, Royeaux said:

I think Bismarck did have a chance to survive and that would have been to fire accurately at HMS Rodney in an attempt to blow it up to create a repeat of the Denmark Strait.  I know this is monday-morning Quarterbacking, but Bismarck's greatest asset was her accurate firepower.  If the ship is going to be blown up anyway, then there's no practical point in trying to dodge.  They were suppose to go down fighting anyway, otherwise they'd have evacuated the crew from the very start and scuttled the ship.  Captain Lindemann was a rookie so I can see why he'd make the decision to try and dodge, he reacted without orders to engage the Hood earlier because his ship was under fire.

bismarck had no chance.

 

gotta remember, her rudder was jammed hard to starboard from the swordfish attack.  the entire reason she even fought that final battle was because she had lost all capacity to maneuver and literally turned around to go back at the brits.  hell, if it weren't for that hit bismarck would've been able to reach Brest before Tovey could catch her.

 

in that final battle bismarck could do nothing but turn in a circle, and did so at a reduced top speed due to the damage she had sustained in the denmark straits.  she couldn't make any evasive maneuvers or even attempt to control the engagement ranges.  there weren't any attempts to dodge, partly because it was impossible to do so, but also because the ship's commanding officer was killed very early on.

 

in spite of all that, james cameron's 2002 expedition did a thorough examination of the wreck.  bismarck suffered a brutal pounding, but zero belt armor penetrations.  this was partly due to the brits having closed to such close ranges that their shells literally skipped off the surface of the ocean and impacted the superstructure instead of the hull.  bismarck's gun director was knocked out in the first few minutes of the battle.  lindemann and lutjens were both killed early in the battle as well.  within a half hour all four of her main turrets had been knocked out.  moreover... an examination of the torpedo belt also showed zero penetrations.  bismarck sank at the hands of her own crew; she never suffered any fatal damage, even though the damage she did sustain reduced her to a floating wreck.

 

she was just too easy a target due to her speed and steerage both being crippled... but in spite of all that the brits could not sink her.

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On 1/19/2020 at 4:57 PM, Danyir_Amore said:

If IIRC it was South Dakota that got blasted by cruisers because its electrical system failed and it couldn't fight, one of the Kongos got deleted in the same engagement by a ship that had radar.

South Dakota's electrical failures started happening before receiving hits, kicked off by one of its own turrets.

44. Ordinarily, matters which are not the result of damage by enemy action are not included in damage reports. In this case, however, the fact that electrical failure initiated by the shock of gunfire was a handicap to SOUTH DAKOTA while in action warrants some comment. As a result of this failure, numerous control shifts had to be made and it was reported that all power on the after part of the ship was lost for about a minute. This occurred before receiving the first hit.

Paragraphs 45-47 go into the series of circuit breaker and bus transfer problems arising.

Then:

48. The source of these electrical failures was the unreliable operation of the automatic bus transfer switch. All of these switches have been replaced by a manual type transfer switch.

49. The power interruption on the after main switchboards was made more extensive by the failure of the feeder and the main generator circuit breakers to operate selectively under short-circuit conditions. As a result, instead of the feeder breaker operating alone to isolate the short-circuit, the generator breaker also tripped out at the same time. For proper operation, the generator circuit breakers should not open under fault conditions except when the fault is on the switchboard bus or between the generator and the switchboard. This means that the generator circuit breaker should have sufficient time delay at currents equal to the maximum short-circuit current of the generator to permit the feeder breakers only to trip. At the same time, the generator breakers must provide a reasonable amount of switchboard bus fault protection. After considerable study and development and subsequent to this casualty, improved circuit breaker performance was obtained by replacing the time delay dashpot trip devices on the main generator circuit breakers with a type PQ relay. The type PQ relays installed on the SOUTH DAKOTA were the first that became available. Nearly comparable improvement in selective breaker operation has been obtained on similar ships by the installation of special time delay dashpots on the generator breakers.

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On 6/21/2019 at 11:44 AM, lloyd1701 said:

The Nelson and Bismarck are both armed heavily enough that I'd say the winner of that engagement would be the first one to get a good hit in. 

This is always the correct answer.

All the talk of penetrating vitals and such really doesn't matter in most BB fights.   All the FC equipment is topside and subject to being knocked out....in fact, KM ships had an annoying tendency for just that very thing happening.  

Biz also has very suspect turret armor.   

If the fight is unavoidable, I'd put my money on Nelson, assuming she is in proper operating order.  Rodney was long overdue for serious overhaul and maintenance at the time of her encounter with Bismarck, but Biz was brand new.    Those are variables that have to be accounted for.  If both ships in good shape prior to the fight, it's close but I'm going with the one that has more, and bigger guns.  

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On 4/20/2020 at 3:58 PM, HazeGrayUnderway said:

South Dakota's electrical failures started happening before receiving hits, kicked off by one of its own turrets.

44. Ordinarily, matters which are not the result of damage by enemy action are not included in damage reports. In this case, however, the fact that electrical failure initiated by the shock of gunfire was a handicap to SOUTH DAKOTA while in action warrants some comment. As a result of this failure, numerous control shifts had to be made and it was reported that all power on the after part of the ship was lost for about a minute. This occurred before receiving the first hit.

Paragraphs 45-47 go into the series of circuit breaker and bus transfer problems arising.

Then:

48. The source of these electrical failures was the unreliable operation of the automatic bus transfer switch. All of these switches have been replaced by a manual type transfer switch.

49. The power interruption on the after main switchboards was made more extensive by the failure of the feeder and the main generator circuit breakers to operate selectively under short-circuit conditions. As a result, instead of the feeder breaker operating alone to isolate the short-circuit, the generator breaker also tripped out at the same time. For proper operation, the generator circuit breakers should not open under fault conditions except when the fault is on the switchboard bus or between the generator and the switchboard. This means that the generator circuit breaker should have sufficient time delay at currents equal to the maximum short-circuit current of the generator to permit the feeder breakers only to trip. At the same time, the generator breakers must provide a reasonable amount of switchboard bus fault protection. After considerable study and development and subsequent to this casualty, improved circuit breaker performance was obtained by replacing the time delay dashpot trip devices on the main generator circuit breakers with a type PQ relay. The type PQ relays installed on the SOUTH DAKOTA were the first that became available. Nearly comparable improvement in selective breaker operation has been obtained on similar ships by the installation of special time delay dashpots on the generator breakers.

Yep, that was an early "teething" issue that was corrected.  Thankfully for South Dakota, that issue didn't cost her more dearly at Guadalcanal before the issue could be addressed.   But addressed it was, and after that it wasn't a problem anymore.  

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On 4/17/2020 at 8:52 PM, Shadeylark said:

she was just too easy a target due to her speed and steerage both being crippled... but in spite of all that the brits could not sink her.

This really has to stop. 

Biz was sinking.  If the Germans had not scuttled, she's still going under that day, just slower.  All scuttling did was make it happen faster. 

And as I've said before, if your enemy pounds your ship to the point that you feel your only option is to scuttle and abandon it....They sank your Battleship.   Who let in the last bit of water is irrelevant.  

Battleships are tough to sink.  The US had some that survived a nuclear blast, then being used for target practice after that.  

Big ships are tough to sink, period.  The USS America endured munitions tests for WEEKS, including torp hits,  before they finally had to scuttle her.  

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