Comparisons of Axis vs Allied Combat Vessels

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
Garyt
Senior Member
Posts: 273
Joined: Tue Dec 09, 2014 9:31 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Tue Jan 27, 2015 5:47 am

Try this (Decapping Revisited): http://www.navweaps.com/index_tech/tech-085.htm


The one thing that escapes me is a list of projectiles determining if they are type 1 or type 2. But a 1.5" de-capping layer is rather useless against type 2 projectiles of a battleship size at most angles of obliquity.

GAryT - Re Japanese armor, it came up in private correspondence some years ago. I may have some related material/documentation filed away on this, but I would need to track it down. IIRC, it was part of a US postwar evaluation of Japanese versus US armor.


Would be interested in any info. Speaking with Chris Carlson, one of the designers of Command at Sea, Nathan revised his evaluation of Japanese armor to the better fairly recently, but I don't have specifics, though Chris said on Nathans's multiplier for armor values it went from about a .90 to a .95.

Steve Crandell
Senior Member
Posts: 630
Joined: Wed Feb 05, 2014 7:05 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Steve Crandell » Tue Jan 27, 2015 6:21 am

I quote the following in reference to the plate you were referring to:

"An experimental 7.21" (18.15cm) VH plate (#3133 at NPG, Dahlgren) seems to have been made from a German KC n/A (see above) specification added to an otherwise standard VH plate. It had a 535 Brinell maximum face hardness 3% into the plate, which is harder than all heavy VH production plate, though only by a small amount, with the hard point the closest to the face surface (about the same distance from the face surface (0.22" (0.55cm)) as with most cemented non-German KC-type plates), and a back hardness of 210-215 Brinell, which is slightly higher than production VH, but still well below average foreign World War II-era KC-type plates. The steel used was identical to the production VH plates that had been tested previously (rather dirty steel again of circa-1910 quality) and the hardness curve showed a typical VH-style pattern for the high-hardness portion. However, the major difference between this plate and all other VH plates was that the transition layer was much wider, extending to 43% into the plate (57% unhardened back), almost identical to German KC n/A, though with a higher average hardness than KC n/A in the decrementally hardened region. Since Germany and Japan were allies during World War II, it is not surprising that the Japanese may have obtained such information on German Krupp armor and made test plates to compare it with their own armor. The U.S. test personnel at the U.S. N.P.G. did not expect it to be much different from the production VH plates, especially due to its relatively poor steel quality. However, this plate was found to be the best face-hardened plate of its thickness ever tested at the U.S. N.P.G.! (The next best plate of similar thickness was also an experimental non-cemented face-hardened plate of 7.6" (19.3cm) thickness made by Carnegie-Illinois Steel Corporation during World War II, which was only slightly inferior to this VH plate.) It required the late-World War II, improved, super-hard-capped (650-680 Brinell all the way through) U.S. 8" (20.3cm) Mark 21 Mod 5 AP projectiles to completely penetrate this plate in "effective" condition at 30o obliquity (the standard U.S. armor test in World War II)--the older Mod 3 projectiles, similar but with a maximum cap hardness of 555-580 Brinell, were torn up badly even when they completely penetrated (a rare feat against these U.S. projectiles!) and needed a much higher striking velocity to do so. Against the Mod 5 projectile, my calculations indicate that this plate was 1% better on an equivalent thickness basis than an average KC n/A plate (probably because the VH plate does not lose any resistance due to the existance of the thin, but very brittle, cemented layer used in KC n/A armor), meaning that it would take an average 7.28" KC n/A plate to replace this 7.21" VH plate--a pretty big improvement from regular VH armor in a single step! The U.S. test personnel were at a loss to explain this, but to me it seems that the Japanese personnel used the face tempering process of KC n/A, possibly with some of their own expertise added, in addition to just increasing the chill thickness. Japanese metallurgists (and most other technical personnel) obviously were (and are still) just as good as anybody else when allowed to set their own standards of excellence, as the post-World War II world has discovered big-time! Also, a rather unusual 15" VH plate was obtained by Britain at the same time and when tested showed a very high quality, also. However, this plate also had a non-cemented surface hardness of 575 Brinell, which I did not know was possible, and the British could not duplicate this plate when they tried to make two 12" (30.5cm) scaled copies in two different manufacturing plants--the plates ended up rather like improved standard production VH armor in composition and ballistic results, with only about a 500 Brinell face layer in both cases, so the British could not figure out how such a face layer was made, either. "

This is from: http://www.navweaps.com/index_nathan/me ... pt2009.htm under the section titled: "JAPANESE VICKERS HARDENED NON-CEMENTED FACE-HARDENED ARMOR (VH) "

Thorsten Wahl
Senior Member
Posts: 643
Joined: Mon Apr 27, 2009 4:17 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Thorsten Wahl » Tue Jan 27, 2015 8:14 am

japanese 7,21 " plate
search at dtic .mil for
ADA955281 Ballistic Tests and Metallurgical Examination of Japanese Heavy Armor



Class A ;JE-50-3133
Gauge 7 1/4"


ballistics
100% of ord SK 78841 should be 1548 fs for this thickness (7 1/4 ")
projectile 8" Mk 21-3 at 30°(2 tests)
% of ord SK 78841 118% +-1 concluded

Comparison based on ord SK 78841
US average 112,8%
US plate 1G469A1 (7,6") non cemented 116%-117%
US plate RR324 (/,3") cemented 117% +-1

same japanese plate versus other projectile
8" MK 21-5 at 30" (3 tests)
% of ord SK 78841 110% - 111%

Comparison
US average 109,7%
german plate 33032 (8 1/2") 113 % +-1
so this german plate appears to be relatively better then the japanese plate above even considering the greater thickness
...and any american plate with approximate the same thicknesses testet until 1947

there are several german plates being better than all american plates ever tested and they covers thicknesses from approx
eight to sixteen inches
maybe the sample is to small to draw general assessments, but the same applies to the japanese plate and this is only one plate at one thickness wich performed better in ballistic tests
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

Byron Angel
Senior Member
Posts: 730
Joined: Sun Mar 06, 2011 1:06 am

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Byron Angel » Tue Jan 27, 2015 5:46 pm

..... Thanks for filling in, gentlemen. Over the many years I have corresponded with him, Nathan has never been a "flag waver". He doesn't care who made the stuff. It's really just about the science for him.

My opinion, FWIW.

B

Garyt
Senior Member
Posts: 273
Joined: Tue Dec 09, 2014 9:31 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Tue Jan 27, 2015 7:31 pm

Nathan has never been a "flag waver". He doesn't care who made the stuff. It's really just about the science for him.


Maybe I was premature instead of assuming the flag waving thing.

I guess my issue is there always seem to be some flag wavers that will refer to Nathan's earlier work and treat it as gospel when explaining how kick-arse American battleships were.

Then to see that Nathan has changed his opinion on some of this earlier research but the older numbers are still in use by flag wavers is frustrating.

But from what is being said, the real issue may have been lack of information, Nathan's research becoming more accurate as he acquires more data.

Kind of when using penetration data a flag waver will always use the US "super Heavy" 16" shell penetration numbers, when these shells were not used until towards the end of the war. And they also seem to not realize or forget that "super heavy" means more metals, less bursting charge, so they have penetration benefits but their shells will lose damage capability due to a smaller bursting charge.

Steve Crandell
Senior Member
Posts: 630
Joined: Wed Feb 05, 2014 7:05 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Steve Crandell » Tue Jan 27, 2015 9:57 pm

Garyt wrote:
Kind of when using penetration data a flag waver will always use the US "super Heavy" 16" shell penetration numbers, when these shells were not used until towards the end of the war. And they also seem to not realize or forget that "super heavy" means more metals, less bursting charge, so they have penetration benefits but their shells will lose damage capability due to a smaller bursting charge.


Yes, that was a given. Sacrifices were made in an attempt to produce a shell that would penetrate decks and remain in condition to burst properly after doing so. Do note, however, that the AP Mark 8 projectile was issued to all of the US Fast Battleships from the first day they were in service. Massachusettes was firing them at Jean Bart. Around the end of 1944 a new version was introduced, which is why Nathan gives two different penetration tables, one for early version and one for the "mod 6" version, which had improved performance.

User avatar
tommy303
Senior Member
Posts: 1526
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Comparisons of Axis vs Allied Combat Vessels

Postby tommy303 » Wed Jan 28, 2015 1:00 am

The weight of the bursting charge remained 1.5% in both the 16-in Mk 5 and Mk 8, which gave the Mk 8 a slightly heavier bursting charge than the 2240-lbs shell (34-lbs in the Mk5 and 40.9-lbs in the Mk 8). The Mk 8 Mod 8 had a blunter nose and heavier piercing cap. The blunter nose might have made the cap more difficult to attach and the the shell more easily decapped though.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

Mostlyharmless
Member
Posts: 146
Joined: Wed Jul 22, 2009 10:45 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Mostlyharmless » Wed Jan 28, 2015 3:07 am

Steve Crandell wrote:What I don't understand is when this topic was stated to include "combat vessels", but then the point is made that USN "battleships" didn't take a lot of damage so there was no indication of their ability to do so. What about all the cruisers and other ships that were heavily damaged and through good damage control survived to fight another day? Aren't those "Combat Vessels"?

This seems like a good idea but it looks as if it may be quite hard to reach comprehensive conclusions. I tried to look at large cruisers, roughly those above 8,500 tons standard displacement, which were hit by torpedoes. What I found was that cruisers from most navies seemed to be able to survive single torpedo hits although some were immobilized by single hits. A second torpedo hit was less clearly survivable but most cruisers survived at least for a time. All the cruisers hit by three or more torpedoes sank.

Naturally, I don't think that this data actually proves that such cruisers will survive single hits. For example, on 15th June 1942, Trento's magazine blew up when she was hit by a second torpedo. However, the same hit would presumably have sunk Trento if it had been the first hit. What may be significant is that both Pola and Trento were immobilized by single hits, suggesting that Italy should have chosen unit machinery for such two screw designs. For completeness, Trieste, Duca degli Abruzzi and Giuseppe Garibaldi survived single hits and Bolzano twice survived single hits.

Their RN opponents suffered torpedo hits mostly to light cruisers rather than to their heavy cruisers, except for HMS Exeter and HMAS Canberra, which were sunk by shells and torpedoes. Newcastle, Birmingham, Nigeria, Trinidad and Kenya all survived single hits although Trinidad was sunk after a further bomb hit. Liverpool twice survived single torpedo hits. Manchester was scuttled after two hits but could have been saved had the waters not been dominated by the Luftwaffe by day. Edinburgh survived two hits but sank after a third.

The IJN heavy cruisers which suffered one or two hits included Myoko, which was hit by one torpedo on 24th October 1944 and again hit by one torpedo on 13th December 1944, after which she needed to be towed. Nachi was hit by two torpedoes 5th November and immobilized. She was then sunk after several further hits. Takao survived two hits on 23rd October 1944 and Kumano was hit by one torpedo on 25th October 1944 and then by two torpedoes on 6th November 1944 after which she was towed to port. One could add that Chikuma was apparently in little danger of sinking after a single hit on 25th October 1944 but sank after further hits.

The USN experience was similar. During the Guadalcanal Campaign, Chicago survived a single hit at Savo Island, at Tassafaronga, Minneapolis, New Orleans, and Pensacola survived single hits while Northampton sank after two hits, and Chicago initially was immobilized by two hits off Rennell Island before being sunk by further hits. Later in the battles of Kula Gulf and Kolombangara, St. Louis and Honolulu (and Leander) survived single hits but Helena sank after three hits. Finally, off Formosa in 1944, the Cleveland class Houston and the Baltimore class Canberra survived single torpedo hits

User avatar
Dave Saxton
Supporter
Posts: 2882
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Wed Jan 28, 2015 3:23 am

The proximity of Tulagi skews the data of the US cruisers involved in the Solomons fighting. Had they not been able to limp into that near by base and effect temporary repairs would they have survived? In my opinion had they been far out in the open sea they would likely have eventually sank, or had to be scuttled.
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.

Steve Crandell
Senior Member
Posts: 630
Joined: Wed Feb 05, 2014 7:05 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Steve Crandell » Wed Jan 28, 2015 4:47 am

Dave Saxton wrote:The proximity of Tulagi skews the data of the US cruisers involved in the Solomons fighting. Had they not been able to limp into that near by base and effect temporary repairs would they have survived? In my opinion had they been far out in the open sea they would likely have eventually sank, or had to be scuttled.


So are you saying that USN cruisers are inherently vulnerable to torpedoes, whereas those of other navies are not? For example, a number of British cruisers survived torpedo hits on the open sea and you are apparently of the opinion that USN cruisers would not. Why is that? Inherently poor damage control? Poor US construction compared to that of other nations? While you are thinking of your answer, you might consider that almost (?) all of the USN cruisers in question were hit by Long Lance torpedoes.

dunmunro
Senior Member
Posts: 3096
Joined: Sat Oct 22, 2005 1:25 am
Location: Langley BC Canada

Re: Comparisons of Axis vs Allied Combat Vessels

Postby dunmunro » Wed Jan 28, 2015 10:13 am

Mostlyharmless wrote: Edinburgh survived two hits but sank after a third.



Edinburgh was stopped after the 3rd hit and scuttled by a 4th torpedo hit.

Mostlyharmless
Member
Posts: 146
Joined: Wed Jul 22, 2009 10:45 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Mostlyharmless » Wed Jan 28, 2015 11:32 am

I think that Edinburgh's performance was a spectacular demonstration of the quality of her design and her crew's determination. Alone of the cruisers that had been hit by two torpedoes, Edinburgh continued to fight effectively and inflicted crippling and eventually fatal damage on an enemy destroyer. This despite being unable to steer and after casting off her tow.

However, the captain correctly ordered abandon ship after the third hit and the fourth torpedo used to scuttle her merely hastened the inevitable.

Thorsten Wahl
Senior Member
Posts: 643
Joined: Mon Apr 27, 2009 4:17 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Thorsten Wahl » Wed Jan 28, 2015 12:35 pm

A comment to the deck penetration figures of US shells
The figures commonly used are based on penetration figures according ORD SK 78841 (F-Formula or US empirical).
These figures were completely calculated. It is noted in ballistic literature that F formula predicts to good penetration at oblique impacts stating with 20 degrees obliquity and the error increases as the obliquity increases.

At 60 degrees obliquity the formulae seemingly predicts a limit velocity to low in the order of 10-20percent (in the worst case ~30%)from comparison of real shell perfomance (for 3 inch projectiles). The error became smaller with increased % weight of cap, blunter shape of the projectile and increased hardening of the cap but even in the best case the error was in order of ~10% to low limit velocity then the real shell performance. In another case (for radar performance) someone had aptly noted that "The figures should be taken with a grain of salt".

Additionally one has to consider that for given shape of ogive the longer projectile has worser oblique performance (according german tests L 4 vs L5 projectile). This is caused by the different position of the center of gravity of the longer projectile compared to the direction of to the counterforces from the plate. The increased lever caused a larger sideways turning moment on the projectile during the pentration process.

In the german test the longer projectile completly loses the advantage of higher sectional density falling back to the same thickness penetrated as the shorter projectile at the same velocity despite larger mass at large angles of incidence.

Maybe these finding do not apply for the superheavy american shells.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

User avatar
Dave Saxton
Supporter
Posts: 2882
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Wed Jan 28, 2015 4:24 pm

Steve Crandell wrote:So are you saying that USN cruisers are inherently vulnerable to torpedoes, whereas those of other navies are not? For example, a number of British cruisers survived torpedo hits on the open sea and you are apparently of the opinion that USN cruisers would not. Why is that? Inherently poor damage control? Poor US construction compared to that of other nations? While you are thinking of your answer, you might consider that almost (?) all of the USN cruisers in question were hit by Long Lance torpedoes.

No, only that the damages were severe (because of the LL). Such severe damage would not likely be survivable, US or not, with out a nearby base to fall back on.
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.

Garyt
Senior Member
Posts: 273
Joined: Tue Dec 09, 2014 9:31 pm

Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Wed Jan 28, 2015 7:43 pm

Do note, however, that the AP Mark 8 projectile was issued to all of the US Fast Battleships from the first day they were in service. Massachusettes was firing them at Jean Bart. Around the end of 1944 a new version was introduced, which is why Nathan gives two different penetration tables, one for early version and one for the "mod 6" version, which had improved performance.


It's the later version that I was speaking in reference to. That later one is about is close to solid shot that I've seen :D

But getting hit by an 18.1" Shell with a about double the bursting charge of the 16" shell is going to cause more significant damage even if penetration is similar.


Return to “Naval Technology”

Who is online

Users browsing this forum: Google [Bot] and 2 guests