Bismarck vs USS Iowa

Why do you say the USN had better radar? Have any sources?

 

The following was written by a friend over on warships1.com. Now to be fair it uses an older form of facehard and that program has been attacked by Pro-Bismarck posters for various reasons also my opinion on facehard has also changed in the last year. However over on the same forum I have seen where South Dakota & Iowa designs have been attacked by the same Pro-Bismarck crowd as having a vulnerability to shells hitting right at the water-line ,then by passing the Class A face-hardened section of the Upper Main Belt thereby hitting only the Class B Homogenous Armored Lower Belt section totally ignoring the fact that this "flaw" was at most theoretical whilst ignoring the fact that Bismarck suffered an under the belt/under water trajectory hit whereby bypassing the main belt .

The Bismarck's seem to have a vulnerability to plunging fire but the Pro-Bismarck crowd always brings up that the longest hit ever achieved was at around 26K in either the case of Scharnhorst hitting Glorious or Warspite hitting Andrea Doria,which suits their argument because it removes one glaring weakness of the German ships. HOWEVER also being debated over there is some very convincing evidence that Yamato hit White Plains at like 34K during the Battle off of Samar during the Battle of Lyete Gulf. There was also a very fiercve debate over earlier this year that just maybe the Massachusetts may have hit a French DD at like 28K during the Battle of Casablanca ,and most certainly hit a DD at 22-23K.

In another theoretical vulnerability of Bismarck involving a batle with North Carolina is a hit from the latter's 16"/45 2700 lb shell hitting Bismarck's upper belt and still having enough power to penetrate her deck armor as close as 16-18K though again to be fair it's using Nathan Okun's programs which the Pro-Bismarck crowd have expressed serious issues with..



quote....

"""" Written by Michael Teucke at 13 Feb 2003 18:38:27:
Hello, here I present a text some person has posted recently on the
www.warships1.com battleships discussion forum. I guess no-one will even try
to give any argumentation against the text there, thus I present the text
here. Here it is:
„Oldie but a goodie here, North Carolina vs. Bismarck/Tripitz, using the
updated Facehard and the old M79APCLC programs. This is a simple raw armor
comparision. I like this because its a more fair comparision (Time wise etc)
then a lot of the matchups we like.
Simple but contrived situation here, opening range is 28000 yards, one on one
battle. I used M79APCLC for Deck armor, and Facehard 5.4 for all the other
stuff.
Immune zone comparisons.
Bismarck upper deck is 3.15in in some spots, 1.97in in others. I used Nathan
Okuns APC program to estimate penetration ranges for the NC’s 2700 pounds
shells. Disclaimer, the M79APCLC program somewhat understates the penetration
ability of US and Japanese shells. In addition, I’m using new gun velocity, so
penetration would actually be better with a slightly used liner, so these
estimates are conservative. (If you want to check these numbers, remember to
use 18% elongation for German Wh armor.)
At 20000 yards, the 2700 16in shells would strike at 72.1 degree obliquity at
1604 fps. This would penetrate the 3.15in deck, remaining velocity is 1314fps,
and obliquity is now 69.1 degrees, the shell is decapped. This reduces the
weight to 2352.5 pounds for subsequent decks, the second deck is ~.5in, after
penetrating it the remaining velocity is 1282fps and the angle is now 68.6.
This is insufficient to penetrate either the 3.74 deck of the Bismarck or the
3.94 deck of the Tripitz. Barely.
At 22000 yards the 2700 shell is now at 1581fps and 68.9 degrees obliquity.
The first deck decaps the shells (Bringing weight to 2352.5), slows it to
1312fps at 65.6 degree obliquity. Second decks brings it to 1285fps at 65.2
degree obliquity. This achieves a nose first penetration with a remaining
velocity of 769fps for Bismarck (3.74in deck) or 594fps for Triptz (3.94in
deck). Averaging the values I estimate that penetration of the Bismarck’s
magazines is possible at 21000 yards, still 22000 for Tripitz. Considering the
fact that the M79APCLC program is slightly inaccurate and that used liners
would improve penetration, it appears that North Carolina could penetrate the
Magazines of either German ship at about 21000 yards, perhaps a tad closer.
The question then becomes one if the fuze of the US shells is long enough for
it to detonate in the ship, anyone know? (Shatter can occur under certain
conditions for decaped projectiles against homogenous armor, but is
unlikely.).
For the 1.97in deck + .5+3.15 deck over the weaker portions of the ship, the
2700 shell at 1722fps and 76.5 degrees obliquity, penetrates at 16000 yards at
1593fps remaining velocity and 75.5 obliquity (Shell is now decaped, remaining
weight is 2352.50). This penetrates the .5 in second deck with remaining
velocity at 1562fps and 75.2 degrees. This will penetrate the 3.15 main deck
easily with 1190fps remaining velocity. The same analysis at 14000 yards the
shell just fails to penetrate. Averaging the values to approximate a 15000
yard range (Sloppy, but good enough for general comparisons.) gives a initial
obliquity of 77.65, initial FPS of 1752, this penetrates all the decks with a
remaining velocity of 1222fps. The weak portion of Bismarck/Triptz deck can
probably be penetrated at 15000 yards.
The side belt of Bismarck is 12.6 German improved type armor, over ~4in of
wood and a .6in backing plate (I used D steel as a aproximator for this.) For
amidships, this armor is not inclined. I used a 20 degree target angle for the
following calculations, and the 1939-1944 16in shell. Facehard gives complete
effective penetration out to 26000 yards (Angle of fall of the shell is 27.6,
total obliquity is 33.62. FPS is 1536.) and Partial ineffective penetration at
28000 yards. Of course, the slope behind the belt is theoretically
invulnerable, although it appears it was too stiff for this to be true over
much of the slope, at least that is the working theory. I’m not sure how much
that is worth.
The Magazine belt armor of the Bismarck follows the contour of the ship, and
is therefore sloped. I assumed a 5 degree angle, and although it presumable
moved the limits closer to the inner end of each break point, it didn’t
actually cause a shift. (That’s confusing, I man that at 24000 yards, the
total obliquity is 35.18 instead of 31.08, but its still a effective
penetration of the belt.) I don’t have D&G handy, I suspect the outer hull
sloped at more then 5 degrees, anybody know how much, generally?
As for the NC, She was a 1.45in bomb deck, and a 3.6in main deck laminated
with 1.4in STS backing. I used a .7 modifier and concluded the main deck was
worth 4.58in of STS. US STS and class B armor has 25% elongation and 1.0
quality. The 15in Bismarck shell will penetrate the 1.45in upper deck at 30000
yards at 62.5 degree obliquity and 1518 initial velocity. Post penetration
this is 60.8 degrees and 1408fps. This cannot penetrate the 4.58in main deck.
(NC has considerable splinter armor under the magazines, I didn’t use these
numbers for simplicities sake, and also note the German projectile is NOT
decapped.) Penetration at 32000 yards is assured. So NC’s decks are proof
closer then 30000 yards.
NC uses a 12in belt on .75STS backing (I assumed it had the same 2in of cement
backing as on the SD) at 15 degrees. At a 20 degree target angle the German
15in shell has ineffective penetration at 22000 yards (37.18 total Obliquity,
1670 fps), and cannot hole the belt at 24000 yards (39.29 total Obliquity,
1622fps).
As for turrets, I did a quick and dirty comparison, this is just meant as a
relative assessment, not definitive. I welcome any suggestions. NC’s turret
top is 7in, unlikely to be penetrated. The Top of the German turret, well,
some part of it is vulnerable at all ranges due to the facet design, but it
should be fairly safe. I wont bother with the turret faces because I don’t
know how to account for the holes in the plate etc. So I used the Barbettes as
a proxy. I know it’s overly simplistic, but I assumed the typical hit would be
at a 30 degree angle, i.e. the typical hit would strike the barbette as if it
was a flat plate at a 30 degree target angle. Then I calculated the total
obliquity with the decent of the shell, used Facehard using a curved surface
etc.
NC’s 2700lb shells would strike the 13.39in German armor at 34.5 degree
obliquity (30 degree “Barbette” angle, 17.9 descent angle.) at 20000 yards and
still get a effective penetration. Partial penetration occurs at 22000 and
24000 yards, the Barbette is proof at 26000 yards. Penetration could occur
much closer, or fail completely depending on how it strikes the Barbette.
Bismarck’s 15in shell strikes the 16in US Class A Armour of the North Carolina
at a 32.24 degrees obliquity at 18000 yards (30 degree barbette angle, 12.4
descent angle.) at 1816 fps and cannot hole the Barbette. Partial penetration
occurs at 16000 yards, again, penetration could occur much further if a better
part of the Barbette is struck.
Note, I was going to give the Bismarck’s barbettes a “bonus”, since being twin
turrets they should have sharper curves then the larger US ones. But I
understand the actual diameters are similar, so I didn’t bother, bear that in
mind.
So to summarize:
North Carolina, at a 20 degree target angle, has a 24000-30000 immune zone
against the 15in gun. The turrets are vulnerable with a typical hit inside of
18000. Turret tops are pretty much proof at all realistic ranges.
Citadel immune zone 24000-30000
Turret (Typical hit) 18000-Max
Bismarck/Tirpitz, at a 20 degree target angle has a complicated immune zone.
The belt is effectively penetrated out to 26000 yards. The weak deck is
vulnerable past 15000 yards, the strong deck over the magazines is vulnerable
past 21000/22000 yards for Bismarck/Tripitz respectively. Turrets are
vulnerable inside of 26000 yards for a typical hit. Slope should be
invulnerable, but can fail under certain circumstances.
Citadel, Machinery/Weak deck No immune zone, Belt penetration to 26000, Deck
past 15000 (!)
Citadel, Magazines/Machinery/Strong deck. No Immune zone, belt penetration to
~25000(Assuming a 5 degree slope to belt.), deck past 21000/22000 yards.
Turret, (Typical hit.) 26000-partial max (Sloped portion of Turret still
vulnerable.)
Immune zone with slope. Under 15000/~21000 yards, although Slope can fail.
Any thoughts, Ideas? Errors? In retrospect, I should have calculated
penetrating the magazine lower armor after going through the 1.97in deck,
which would be possible under certain circumstances. I didn’t include splinter
armor below the deck for NS since penetration was unlikely anyway. It does
appear the 18% elongation of German deck armor costs it quite a bit.
One thing I was shocked by was the deck performance of the 16in shells. Even
after being decapped, they still could penetrate the weak deck at around 15000
yards and the magazines at 21000! Remarkable.“
One – rather little – error I detected was an underestimation of the belt
slope
Questions:
- how valid are the assumptions on armour (18% German Wotan hard homogeneous
armour elongation limit vs 25% US?) and shell properties, influence of angle
etc. used for the penetration formulae used by the programs of Mr. Okun, e.g.
how important is shell yaw, are such influences considered in the formulae?
- Are the assumptions on Bismarck’s and the US ships‘ armour strength the same
as in the „Protection of the DKM Bismarck“ article (which included some errors
I guess) or have they changed.
- How much is the influence of immunity zones in a rating of a battleship’s
capability to fight opponents? Influences of other aspects than immunity zones
(protected hull volume and buoyancy etc.), how do they influence the scenarios
above?
- A special question on the supposed vulnerability of the slopes due to not
being elastic enough (think this stems from Okun’s article on Bismarck’s
protection): I would guess the same applies for all homogeneous deck armour
near the ends of ist extension at the side belt or transverse bulkheads but is
not taken into account normally for evaluation of IM zones?
Thanks for any answer, in a best case scenario I would like to see some
falsifications of assumptions in the cited text in defence of Bismarck.""""



end quote...

 

My only real source (I'm responding instead of "Gromit901") is Fleets of World War II by our own Richard Worth (Tiornu) where he credits the night defeat of Kirishima by the USS Washington in November of 1942 to its Mark 3 radar fire control (p.295). Both the North Carolina class ships had been fitted with the Mark 3 version of radar fire control in early 1941, among twenty ships so fitted and operational by early 1942. As the technology improved, each American ship got more and more accurate in its radar and computer fire control.

Whereas the main gun concussion of the Bismarck disabled its own radar (FuMO 23) gun control with its first shots on Hood, the two North Carolina class ships functioned at both long and short range. The German system appears to have been inferior to the American/allied systems in any number of areas including rugged construction/reliability.

The fire of the main and secondary batteries was directed from the command posts, which were located forward, astern, and above the foretop platform. Each of these three posts mounted a rotating dome with an optical rangefinder and a FuMO 23 radar instrument. The command posts were connected by armoured communication shafts to the computation rooms under the armour deck forward (section XV) and aft (section VII). The FuMO 23 antennae had a rectangular shape and measured approximately 2 m. high and 4 m. wide. They had a frequency of 368 MHz, and operated on an 81.5 cm wavelength with a power-output of 9 kW at 500 kHz. The maximum effective range of this device was about 25,000 m. However, the GermanFuMOs were not equipped with the PPI (Plan Position Indicator) display system that is so familiar in today’s radars, but a simple A-scope display instead. Therefore, they could hardly detect more than one target at the same time, and bearings were not very accurate either. The lack of PPI was one of the reasons German capital ships were so redundant and equipped with three sensors.

Goto:

Bismarck Fire Control - KBismarck.com

 

Thanks Clint. I had the knowledge, but not the references at hand. I had read years ago about German naval radar shortcomings, but couldn't lay my hands on it. Someone stole my copy of Battleship Bismarck by Baron V Mullenheim-Rech.

 

Too true, a person can remember reading and incorporating a "stat" into their old biological memory banks but not be able to "lay hands" on the dang thing. Thanks for the salute BTW!

 

Do mean this one?

Goto:

Battleship Comparison

 

what would happen if the Yamamoto was thrown in the mix, now that is something i would like to see

 

It says no such thing in the text.
Germany was not a signatory to the Washington treaty, nor subject to the limits of 35,000 tons since they couldn't build ANY battleships over 10,000 tons under versailles.
They did violate versailles treaty, but not WNT or AGNT

...Which makes no mention of the 35,000 tons.

The key phrase there is
may be arrived at in a future general treaty on naval limitation,

The treaty talks about tonnage limits in each category, this doesn't refer to the 10,000 & 35,000 limits in the WNT, what it's referring to (as per the text) are total limits in each category arrived at in the 35:100 ratio between British & German fleets.
So for example if the British had 300,000 tons of battleships, the Germans would be limited to 105,000 tons of BB's
What the treaty mentions is that they can exceed the 35% ratio in one or two categories as long as the total naval tonnage remains at 35% of UK/Commonwealth.
So if the British had 250,000 tons of BB's then Germany wouldn't be restricted to 87,500 tons of BB's, they could build 100,000 tons of BB' (for example) if they subtracted the extra 12,500 tons from another category.

No, not correct.
The AGNT uses the phrase "total tonnage of the German fleet" not "laid down" or "begin construction" so tonnage limits would only take effect upon completion. The WNT on the other hand DID use that exact language, and had further limits on when new construction could begin. (to replace older ships)

Again, the escalator clause was result of WNT and the 1930 London Naval treaty, which Germany wasn't a signatory of.
They were allowed to build whatever battleships they liked, provided that they were not more than 35% of the tonnage of existing British ships

 

Then read it again is all I can say. The "Future agreement" part pertains to the ratios. The previous relevant part says "that divide naval vessels into catergories,fixing the maximum tonnage and/or armaments in each catergory ,and allocates the tonnage to be allowed to each power by catergories of vessels." What you refer to is the following sentence which pertains to tonnage allocation to various catergories and then references section 2f which then references section 2g. Once again read it. The AGNT binds Germany to the same treaties as the UK period.

 

The escalator clause comes under 2nd London not WNT or the First London Treaty. The 2nd London was signed in March,1936 and as I've pointed out the 2 German BB's were laid down in July & October of that year. What matters is that the Germans agreed to follow the same treaties as the UK did and the WNT didn't expire till 12/31/1936. Don't you think it's just a bit funny that the RN & USN built their BB's to the 35K limit of the LNT2 ???? The escalator clause wasn't invoked(and by the US) till after 1938.
London Conference of 1936

 

Here's a good discussion right here ,you might also read a few pages before the one I linked to...You might also want to look at section 2g more carefully where it talks tonnage allocation divided by maximum allowed tonnage per vessel. I know it's(the 35K limit) hard to find but it's there.
Ideal Treaty BB in Battleship Vs Battleship Forum

 

I fail to understand why so many people are enamored with the Bismark, she wasn't really an exceptional ship. I guess it has to do with her sinking the Hood, which had been the pride of the Royal Navy.
The Bismark wasn't really impressive in any particular area nor was she groundbreaking in her design. Her armor layout was archaic, her main battery wasn't the biggest or even particularly impressive in it's performance. Her fire control systems weren't cutting edge like those on the Iowa's, SoDak's or North Carolina's. She was only two knots faster than the North Carolinas and Bismark's proponents cite this as a key advantage but ignore the fact that the Iowa's were 3 knots faster when comparing Bismark to that class. Her ammunition wasn't particularly reliable or of superior performance like the U.S. 16" 2700lb. Mk8 shell. So where's the superiority?

 

I'm well familiar with it.
The sentance you quote:
The German Government favour, in the matter of limitation of naval armaments, that system which divides naval vessels into categories, fixing the maximum tonnage and/or armament for vessels in each category, and allocates the tonnage to be allowed to each Power by categories of vessels.

It specifies that they "favour" such a system, (dividing ships into categories) not that they agree to abide by any particular previous agreement that they were not party to.

.

Then please cite the exact clause where the AGNT states "Germany sgrees to be bound by the terms of the WNT or LNT" or that they "agree to abide by the maximum tonnages set in the LNT"

Nowhere in the agreement do they agree to any such thing.

No, because they were still bound by a treaty that they had signed.

And you will note that despite the LNC of 1936 occurring after the Anglo-German agreement, Germany does not participate.

 

If you mean the Yamato the ship, and not Yamamoto the man, then that Battleship Comparison link I posted in #46 has the ship in the mix.

 

If you compare ships in the spring of '41 the Bismarck was arguably better than any Allied BB, superior to the KGV and better than the NC in the condition she was in. Certainly not a match for the Iowa, but obviously Iowa is many months away. In early 1941 the German ship was a major threat.

 

I can only speak for myself as i don´t know the reasons of the others. The "Bismarck" wasn´t a superior ship it is the myth around it. Yes. it may have no chance in a duell against the USS Iowa or other ones, but it isn´t right to know only the technical data´s and compare it to say" Yes there is a chance" or "No she has to sink after the first strike. It hasn´t anything to do that she´s a german ship and i´m a german guy, no i only want that all of the guys aren´t forget about other facts. Look at the "HMS Hood", she had enough power to beat the "Bismarck" but she sunk after a lucky hit. Why can´t this happen again? Or maybe the skipper isn´t that good or any other reason. So you can only say:" after comparing the technical datas, the "Bismarck" is the weaker ship with some disadvantages, but who knows how it had worked out in reallity?!" Nothing more, nothing less.

 

Good god why can't people do their own research???? The German themselves agreed the 35k limit applied to them and yes even before their 1937 agreement with the UK.. If you have an e-mail I'll send you a copy of the 1937 treaty where the Germans & UK agreed pertinent limits of the LNT1 & LNT2 applied to the 1935 Anglo-German Naval Treaty .The name of the treaty is....

AGREEMENT BETWEEN HIS MAJESTY'S GOVERNMENT IN THE UNITED KINGDOM AND THE GERMAN GOVERNMENT PROVIDING FOR THE LIMITATION OF NAVAL ARMAMENT AND THE EXCHANGE OF INFORMATIONCONCERNING NAVAL CONSTRUCTION , WITH DECLARATION PROTOCOL OF SIGNATURE AND EXCHANGE OF NOTES.

On the same day this was signed another treaty was signed obliging the SU to abide by certain treaty limitations.


edit...

Once more you bring the word being used as "favor" which doesn't bind them according to you BUT basically it does because to enter into the 1935 agreement then start building two BB's well over 35K limit pertaining to the 2nd LNT right after the latter was signed by the UK is surely in bad faith ,or actually just out & out breaking a treaty (all the same difference). Nevertheless the Germans agreed in 1937 the relevant 2nd LNT applied to the 1935 Anglo-German Naval Treaty whilst the Germans themselves consider the 35K limit to apply to them even before that. Now again I know you are going to bring up the 1937 agreement was signed after the Bismarck & Tirpitz were laid down but the 1937 agreement bound the 2nd LNT onto the 1935 agreement and for the Germans to continue building two BB's well in excess of the 35K limit was most certainly in bad faith,therefore basically breaking the treaty no matter how you cut it.

 

Well by all reasoning Kirishima shouldn't have had a chance against South Dakota at 2nd Guadalacanal but for Washington coming into save the day South Dakota might have been hurt real,real bad. In a naval engagement anything can happen,I mean Sprague in Taffy 1 shouldn't have had a chance against Kurita with just about the whole IJN battlefleet but every dog has it's day and sometimes an extreme under-dog does also.

 

Thank you for the reply Ulrich, I can understand being enamored with the myth. I admire the ship and it's crew because of her story, it was a heroic struggle. The Bismark against the entire might of the Royal Navy, it is a compelling odessey. I just don't see the need to give her attributes she didn't have, I actually think her story more heroic when she's not made out to be a super-ship. I also find the British side of the story compelling, the efforts that went into bringing the Bismark to bay. The Hood and the Bismark were both also beautiful ships, but Hood was 20+ years old and designed in WWI. Technology had advanced. When Hood was launched she could rightly claim to be one of the most powerful ships in the world, when she met Bismark she had the potential to sink Bismark but it was not the probable outcome. That she went down to a lucky shot so quickly was a shock, even more so to the British public that wasn't familiar to how much ship technology had advanced, to them she was the "Mighty Hood". I guess because Bismark killed the legend of the "Mighty Hood" she herself became a larger than life legend.

 

LOL. That is very true.