Bismarck vs. Iowa

Historical what if discussions, hypothetical operations, battleship vs. battleship engagements, design your own warship, etc.
dunmunro
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Re:

Post by dunmunro » Thu Mar 11, 2010 9:03 am

Karl Heidenreich wrote:Just for the record, a previous posting in which I stand to classified Hood as a Fast Battleship instead of a Battlecruiser. In that same thread there is some consensus about it. This is to support the idea that Hood + PoW were, on paper, a mighty match to the "poorly designed Baden heir" Bismarck and a cruiser. Just for the record.
There is another data that supports the idea of the reclassification of Hood as a Fast Battleship instead of Battlecruiser:

Armour comparison with other British Warships:

Hood
Main Belt: 305 mm (upper belts 5in and 7in)
Upper Deck: 32 mm
Armoured Deck: 50 mm
Turrets: 130-380 mm
Protected lenght: 65%
Speed: 31 knots (~29.5 in May 1941)

KGV Class
Main Belt: 350-375 mm
Upper Deck: no! (Yes weatherdeck- 31mm)
Armoured Deck: 150 mm (124 + 12.5 over machinery, 149.5 + 12.5 over magazines + 38mm splinter deck directly over magazines)
Turrets: 150-324 mm
Protected lenght: 60% (plus belt extensions forward and aft of the citadel - total about 75%)
Speed: 28 knots (29+ knots in 1941)

Nelson Class
Main Belt: 355 mm
Upper Deck: no! (Yes weather deck- ~31mm)
Armoured Deck: 160 mm (+ 12mm over magazine, 82mm + 12mm over machinery)
Turrets: 185-405 mm
Protected lenght: 50%
Speed: 23 knots
I made some comments, in red, above.

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Re: Re:

Post by alecsandros » Thu Mar 11, 2010 9:59 am

dunmunro wrote:
I made some comments, in red, above.
So you also consider Hood to be a Battleship?
I thought about it also, and, compared to the QE class, the Hood is better protected and faster.

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Re: Re:

Post by dunmunro » Thu Mar 11, 2010 10:17 am

alecsandros wrote:
dunmunro wrote:
I made some comments, in red, above.
So you also consider Hood to be a Battleship?
I thought about it also, and, compared to the QE class, the Hood is better protected and faster.
The RN did not think that Hood was better protected than the QE class

see table 5:

http://www.admirals.org.uk/records/adm/ ... 39-268.php

I don't really know how to classify Hood, but IIRC the RN called her a BC.

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Re: Re:

Post by alecsandros » Thu Mar 11, 2010 11:48 am

dunmunro wrote:
alecsandros wrote:
dunmunro wrote:
I made some comments, in red, above.
The RN did not think that Hood was better protected than the QE class

see table 5:

http://www.admirals.org.uk/records/adm/ ... 39-268.php
" This pamphlet is designed as a rough guide to the relative protection afforded by the armour of British and foreign capital ships and cruisers against gunfire from various calibres of guns.

The information contained herein should be treated with caution. It is based on the assumption that the penetrative power of foreign shells and the resistance of foreign armour to shell perforation are the same as the British. Calculations of the maximum or minimum ranges at which perforation of armour takes place have been based on the most recent information available at the time of publication of this pamphlet
.
"

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Re: Bismarck vs. Iowa

Post by yellowtail3 » Fri Mar 12, 2010 12:21 am

Mejis19 wrote:A comment on the hypothetical cruiser battle above: (Baltimore v. Admiral Hipper) Yes Baltimore could likely defeat Hipper in a gun battle due to superior armor. But that isnt necessarily the whole story. Gun duels are battleship thinking, and Hipper, like WWII Japanese cruisers, wasnt meant to be a miniature battleship. Hipper had 12 torpedo tubes (to Baltimore's none) and a stout secondary battery. A torpedo attack from Hipper would be a more appealing tactic than gunfighting Baltimore. For the results of a battle like that to a WWII U.S. cruiser, look to Savo Island or Tassafaronga


IF the Kraut Kruzer is carrying oxygen-powered Jap torpedoes, and Baltimore is unaware of their capabilities.... and if she can surprise Baltimore at night... then maybe she'll manage something like the Japanese managed, in the battles referenced above. Not likely, though, for a couple reasons. By the time the Baltimores were in combat, the USN was aware of the capabilities of Japan's type 93 - and Hipper didn't have any of those. And by the time the Baltimore was in service... her radar equipment far outpaced anything going to sea with the Kriegsmarine, so getting surprised at torpedo range isn't at all likely.

but you use what you've got...
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Re: Bismarck vs. Iowa

Post by lwd » Fri Mar 12, 2010 2:49 pm

Note also that torpedoes can be a hazard in a gun battle.

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Re: Bismarck vs. Iowa

Post by Dave Saxton » Fri Mar 12, 2010 3:11 pm

Interesting that Tassafaronga should be brought up in contrast with Hipper. Tassafaronga and Hipper's skirmish in the Barents Sea occured within weeks of each other. Both battles involved cruisers against destroyers in virtually blind conditions.

Barents Sea went badly for the Germans because the Luetzow battle group failed to excute its portion of the battle plan. The same canot be said of the Hipper battle group. Indeed Hipper had excuted its portion of the battle plan quite well. It had suceeded in drawing away the convoy's close escort and turning the convoy directly into the Luetzow battle group. In doing so Hipper demonstrated some exceptional long range radar directed shooting, scoring first salvo straddles and hits at least twice, and sinking one destroyer and damaging others. Adm Kummetz had done this while keeping his command out of the enemy's effective torpedo range. Kummetz had recalled his destroyers to prevent his gunners from confusing his destroyers with the British destroyers, and allowed his ship to bring its 8" longer range gunnery to bear using radar.

In constrast to Kummetz, Adm Wright could not have demonstrated more reckless and irresponsable command of cruisers. Wright did not seem to understand the complexities of using radar in a night action with big gun ships. He first sent his destroyers in to make a torpedo attack against the IJN destroyers, but only after hestitating. This made determining friend from foe electronically more difficult for the cruisers. The American cruisers often fired on the same targets, while ignoring other targets, because these targets stood out better on the radars. The American cruisers failure to keep the IJN destroyers out of effective torpedo launching range is the main factor in the disaster. The IJN destroyers closed range to less than 10,000 yards. The American cruisers did not maintain enough range to maintain their chief asset against destroyers. Which was longer range heavier guns.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Re:

Post by dunmunro » Fri Mar 12, 2010 8:10 pm

alecsandros wrote:
" This pamphlet is designed as a rough guide to the relative protection afforded by the armour of British and foreign capital ships and cruisers against gunfire from various calibres of guns.

The information contained herein should be treated with caution. It is based on the assumption that the penetrative power of foreign shells and the resistance of foreign armour to shell perforation are the same as the British. Calculations of the maximum or minimum ranges at which perforation of armour takes place have been based on the most recent information available at the time of publication of this pamphlet
.
"
I just wanted to point out that the RN did not consider Hood superior to QE in protection. The caveats you quote are worth noting, but at the same time, there really isn't a whole lot of difference between the RN 15" with the Mk 17B (1938lb) shell and the KM 38cm.

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Re: Bismarck vs. Iowa

Post by Karl Heidenreich » Sat Mar 13, 2010 2:14 am

The post that dunmuro used yesterday I wrote a long time ago, before reading and studying a lot of material that make that opinion superseeded by others.
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Re: Re:

Post by Bgile » Sat Mar 13, 2010 3:13 am

dunmunro wrote: KGV Class
Main Belt: 350-375 mm
Upper Deck: no! (Yes weatherdeck- 31mm)
Armoured Deck: 150 mm (124 + 12.5 over machinery, 149.5 + 12.5 over magazines + 38mm splinter deck directly over magazines)
Turrets: 150-324 mm
Protected lenght: 60% (plus belt extensions forward and aft of the citadel - total about 75%)
Speed: 28 knots (29+ knots in 1941)

I made some comments, in red, above.
I just re read Raven & Roberts and they go into great detail about the armor arrangements on the KGV class. There is no mention of 31mm of armor on the weather deck.

They also describe the TDS in great detail and there is no mention of the spaces above it being intended to contain pressure by having a thin deck which gives way. In fact, part of the after action analysis of the PoW declares that the space above the underwater protection compartments was found to represent a weakness in the system and so the protection system bulkheads on Vanguard were continued up to the middle deck.

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Re: Bismarck vs. Iowa

Post by yellowtail3 » Sat Mar 13, 2010 5:39 am

Dave Saxton wrote:In constrast to Kummetz, Adm Wright could not have demonstrated more reckless and irresponsable command of cruisers. Wright did not seem to understand the complexities of using radar in a night action with big gun ships. He first sent his destroyers in to make a torpedo attack against the IJN destroyers, but only after hestitating. This made determining friend from foe electronically more difficult for the cruisers. The American cruisers often fired on the same targets, while ignoring other targets, because these targets stood out better on the radars. The American cruisers failure to keep the IJN destroyers out of effective torpedo launching range is the main factor in the disaster. The IJN destroyers closed range to less than 10,000 yards. The American cruisers did not maintain enough range to maintain their chief asset against destroyers. Which was longer range heavier guns.
All true, but - to be fair - Wright's ships had crappy torpedoes (they did shoot them) and much more importantly, and Wright (USN, generally) was unaware of the capabilities of the Type 93. If he'd known the Japs had torpedoes running fifty knots for 20,000 yards, it's unlikely he'd have fought the same way.

Good info on Hipper.
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Re: Re:

Post by Dave Saxton » Sat Mar 13, 2010 2:59 pm

Bgile wrote:
dunmunro wrote: KGV Class
Main Belt: 350-375 mm
Upper Deck: no! (Yes weatherdeck- 31mm)
Armoured Deck: 150 mm (124 + 12.5 over machinery, 149.5 + 12.5 over magazines + 38mm splinter deck directly over magazines)
Turrets: 150-324 mm
Protected lenght: 60% (plus belt extensions forward and aft of the citadel - total about 75%)
Speed: 28 knots (29+ knots in 1941)

I made some comments, in red, above.
I just re read Raven & Roberts and they go into great detail about the armor arrangements on the KGV class. There is no mention of 31mm of armor on the weather deck.

...
I believe, the weather deck on KGV was a 12mm and 19mm laminate of D structural steel. It was not an amour grade material. Its contribution to the ballistic protection would have been rather minor, especially as a laminate. The British recognized this and usually excluded the D steel laminate and structural componants from their effective thickness calculations.

By the way I have some questions on the Hood data too, based on a cross sectional drawing I have of the Hood. I think I'll start a new thread on this question in the Naval technology forum ^^^ though.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Bismarck vs. Iowa

Post by Dave Saxton » Sat Mar 13, 2010 3:06 pm

yellowtail3 wrote:All true, but - to be fair - Wright's ships had crappy torpedoes (they did shoot them) and much more importantly, and Wright (USN, generally) was unaware of the capabilities of the Type 93. If he'd known the Japs had torpedoes running fifty knots for 20,000 yards, it's unlikely he'd have fought the same way.

Good info on Hipper.
But Wright allowed the IJN destroyers to get into position where they could have done the same with regular torpedoes.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Re:

Post by dunmunro » Sat Mar 13, 2010 8:05 pm

I just re read Raven & Roberts and they go into great detail about the armor arrangements on the KGV class. There is no mention of 31mm of armor on the weather deck.

They also describe the TDS in great detail and there is no mention of the spaces above it being intended to contain pressure by having a thin deck which gives way. In fact, part of the after action analysis of the PoW declares that the space above the underwater protection compartments was found to represent a weakness in the system and so the protection system bulkheads on Vanguard were continued up to the middle deck.

I believe, the weather deck on KGV was a 12mm and 19mm laminate of D structural steel. It was not an amour grade material. Its contribution to the ballistic protection would have been rather minor, especially as a laminate. The British recognized this and usually excluded the D steel laminate and structural componants from their effective thickness calculations.
D steel has good armour qualities but can also be used as a structural material, which is why it was usually excluded from total armour weights.

Nathan Okun states:

RELATIVE AVERAGE ARMOR QUALITY OF TYPICAL IRON-BASED ARMORS AND STEELS

Ballistic Quality
Homogeneous Metal Type

POST-WWI Homogeneous Krupp-Type Armor (Except Japanese NVNC & 1.00
CNC)*

Homogeneous Krupp-Type Armor Through WWI & Japanese NVNC & CNC 0.95

British-Type 'DUCOL' ("D" OR "D.1") Improved High-Tensile 0.9
Steel


http://www.combinedfleet.com/okun_biz.htm

Regarding the SPS, again, the criticisms of the SPS were predicated upon the assumption that it failed on PoW, which we now know is not true. The presence of only a 7mm deck capping the SPS Void-Liquid-Void layer shows that it was unmistakably designed to allow upward venting. The deck over the V-L-V layer is thinner than the longitudinal bulkheads that make up the lower portions of the V-L-V layer.

In R&R (p364) they go on to state: "It was also suggested the deck armour be terminated at the protective (armoured SPS holding bulkhead-dm) bulkhead to allow an underwater explosion to vent itself upwards and outside of the citadel proper..." So upward venting is recognized as vital to the SPS design. Unfortunately, there was a lot of mistaken speculation that the SPS failed at frame 206 on the port side due to a torpedo hit or hits in that area, when in fact this did not happen, and there was no torpedo hit in this area of the hull.[edit: I should go on to state that there were concerns that said hit at frame 206 contributed to flooding above the SPS, over the protective bulkhead, presumably from upward venting from the V-L-V layer, but since the hit never occurred such flooding was more likely due to the destruction of the WT integrity of the ship in that area from the flailing prop shaft and from poor damage control.] Vanguard's SPS is identical to KGV's except that the V-L-V layer has the upward venting space removed from ship's company use and that compartment is further subdivided, rather than being one large space.
Last edited by dunmunro on Sat Mar 13, 2010 9:02 pm, edited 1 time in total.

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Re: Bismarck vs. Iowa

Post by Dave Saxton » Sat Mar 13, 2010 8:33 pm

I know the properties of D-steel and must disagree that it had good armour properties. Certainly not 90% of NCA. D Steel was typically 80ksi tensile at which point it was at ~17% elongation. At ~24% elongation NCA would have been at 117ksi tensile. It would be a stretch to assume it had 80% the ballistic resistance of NCA.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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