Comparisons of Axis vs Allied Combat Vessels

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Mostlyharmless
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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Mostlyharmless » Sat Dec 13, 2014 4:40 pm

I am not sure that all your figures, especially those for Yamato, are correct. Tim Thornton's article
“Yamato: The Achilles Heel” from Warship Magazine 1987 http://www.spacecruiseryamato.com/ijn/a ... /heel.html has

“The width of this around her machinery spaces was on average 5.lm, and was narrower than that of almost all her contemporaries in other navies despite her displacing considerably more. Two examples will suffice to illustrate this. The American North Carolina, on a displacement calculated in a comparable manner at 45,298 tons, had a system 5.6m deep, while the German Scharnhorst on only 35,398 tons still managed a depth of 5.4m.”

I agree that the Littorios had a very wide side protection system, which may have been why they took on so much water from a torpedo hit as they flooded as far in as the inner bulkhead. The con to that was that the machinery space was narrow and therefore went up to the main deck leaving no route for going fore and aft under the main armour deck without opening doors between compartments low in the ship. The King George V class have a compromise with “sacrificial” compartments containing generators etc. between the inner bulkhead and the main machinery.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Sat Dec 13, 2014 5:14 pm

My information was from here:

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

It appears that they conflict with each other.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Mostlyharmless » Sat Dec 13, 2014 6:23 pm

I am dubious about your best battleship pages because there are no references or diagrams.

The KGV Class must have been hard for the author to classify because I suspect that the RN's 1000 lb. of TNT rating allows flooding of the auxiliary machinery compartments. Wikipedia's article http://en.wikipedia.org/wiki/King_Georg ... %281939%29 has

“If this final inner bulkhead was penetrated a further set of subdivided compartments would contain any leaks; inboard of the holding bulkhead the ship was highly subdivided into small compartments containing auxiliary machinery spaces. The SPS void-liquid-void layer was generally about 13 feet wide, and the auxiliary machinery spaces added approximately another 8 feet of space from the outer hull plating to the major machinery spaces. The only exception to this was abreast A and B Engine Rooms, where the auxiliary machinery spaces were omitted, but another void space, about three feet wide was substituted in its place."

Of course, loss of those compartments would degrade the ships capability with reduction in the available electrical and hydraulic power. However, I imagine that it would require hits on both sides to take away power to rotate the turrets etc.

There is a similar problem with Bismarck which had refrigerated food storage between the 45 mm bulkhead and the magazines, which were protected by their own 20 mm bulkhead. Thus a torpedo hit there would cost the crew all their sausages before flash could reach the magazines.

The page's suggestion that KGV's belt was “shallow” is misleading unless you are comparing with Yamato. KGV had a 23.75 ft. high belt compared to North Carolina's 16 ft. high belt which only covered about 15.5 ft. as it was at 15 degrees. Bismarck's belt was similar in depth to North Carolina.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Sun Dec 14, 2014 2:22 am

Garyt wrote:
The Japanese battleship Hiei was also badly damaged topside by a combinafion of 5 and 8" hits, leaving her burning and with heavy casualties. She was later crippled by 1 or 2 x 8" shells that flooded part of her machinery.


She was indeed rather vulnerable to 8" shells piercing her armor, which is why I think of her more as a battle cruiser.

Just real quick, The Hiei had 9" turrets, 10" barbettes, and an 8-11" belt.

South Dakota had 18" turret faces, 11-17" Barbettes, and a 12.2" Belt. Plus the south Dakota has better quality armor, multiply the Hiei's armor by about .95 to get a comparative number.

These ships were nowhere close in armor. The Hiei could indeed take serious damage in her armored areas from 8" shells - Can't say the same for the South Dakota.



Indeed, the Kongo class were originally designed and built as battle cruisers, designed and at least the first of the class built by the British.

South Dakota had 18" turret faces, 11-17" Barbettes, and a 12.2" Belt. Plus the south Dakota has better quality armor, multiply the Hiei's armor by about .95 to get a comparative number.


American WWII Class A (face hardened) armour was of rather poor quality. Indeed Mr Okun quantifies it about 25% less penetration resistance vs large caliber shells than standard. This was one reason that the turret faces were made of Class B (homogenous armour) as a substitute. American homoguous armour was pretty good but there remains a physics problem when using homogenuous armour at such thickness. The interiors of such thick plates don't cool at the same rate as the outer portions and so they become more brittle. Such thick homogenous plates had about 85% the standard ballistic resistance. If I recall Thorsten calculated these face plates were about equal to 13" KCnA. The fact that they still used homogenous plates here speaks to the poor quality of the Class A plates.

There's also a point of diminishing returns in terms plate thickness of face hardened armour. Its about 13".
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: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Sun Dec 14, 2014 3:07 am

Garyt wrote:and it also proves that 14" Guns are not a match for 16" guns..

This is an interesting sub topic. 14" guns were considered. Alternative North Carolina designs called for 12x14" and another with 9x14" and 30 knots speed. 16" guns on 37,000 tons standard meant compromises had to be made in protection or speed or both. In the case of North Carolina it was really both.



It is well known that the NC class IZ was 18,000 yards to 28,000 yards vs 14" shell fire.

The 16" NC design originally called for a max speed of 24 knots. Then in 1938 intercepts of Japanese messages proved that Nagato and Mutsu regulary exceeded 26 knots. So efforts were made to boost power output over the design power so that 27 knots could be made using excess power. During trials the greater shaft rpm created vibration problems. Eventually 26.8 knots was obtained.

A 14" gun would have still sunk Kirishima and a 14" gun was still plenty powerful for short and medium battle ranges. Admiral Lee made some interesting comments following GCII:

our battleships are neither designed nor armed for close range night actions with enemy light forces.


But these were the kind of surface fights that were fought for the most part through out the war. After 1941 90% of all naval surface battles would be fought at night and never at long range at night. The American 16" gun battleships were the wrong designs for WWII. It's a classic case of designing weapons and tactics for the previous war. Perhaps 14" guns would have allowed other aspects of the design to be better suited to the times?
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: Comparisons of Axis vs Allied Combat Vessels

Postby aurora » Sun Dec 14, 2014 9:24 am

Is this statement TRUE or FALSE ???

At 11:30 am, two torpedoes launched from Grumman TBF Avenger torpedo-bombers struck Hiei. After suffering several more torpedo and dive-bomber attacks throughout the day, the order was given for her crew to abandon ship before her escorting destroyers scuttled her.
Hiei sank sometime in the evening on 14 November with the loss of 188 of her crew, the first battleship ever lost in action by Japan
. She was removed from the Navy List on 20 December 1942.
Quo Fata Vocant-Whither the Fates call

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Steve Crandell » Sun Dec 14, 2014 1:45 pm

aurora wrote:Is this statement TRUE or FALSE ???

At 11:30 am, two torpedoes launched from Grumman TBF Avenger torpedo-bombers struck Hiei. After suffering several more torpedo and dive-bomber attacks throughout the day, the order was given for her crew to abandon ship before her escorting destroyers scuttled her.
Hiei sank sometime in the evening on 14 November with the loss of 188 of her crew, the first battleship ever lost in action by Japan
. She was removed from the Navy List on 20 December 1942.


I don't know. Apparently something similar did happen. Is that a trick question?

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby aurora » Sun Dec 14, 2014 2:08 pm

Not at all Steve-the actual manner in which Hiei went to the bottom did seem to me to be in some doubt-I appreciate that this thread deals mainly with the effects of gunfire on her- without specifying where and how she sank.The Hiei, according to my research,had three causes for her eventual demise 1) USN gunfire 2)USAAF bombs and torpedoes 3) Scuttling. Tough old Bird!!
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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Mon Dec 15, 2014 7:42 pm

Mostlyharmelss wrote:

I am dubious about your best battleship pages because there are no references or diagrams.


Well, the author of the page is certainly respected, Jonathan Parshall, author of "Shattered Sword". I would think he had charts and diagrams as well, and did not come up with it off the top of his head. There does seem to be a bit pro US bias is the only thing I see. For that matter, Okun's earlier calculations or wrok seemed to be a bit US biased as well, though he revised some of his estimates later.

Dave Saxton wrote:

American WWII Class A (face hardened) armour was of rather poor quality. Indeed Mr Okun quantifies it about 25% less penetration resistance vs large caliber shells than standard. This was one reason that the turret faces were made of Class B (homogenous armour) as a substitute.


I've heard of that, though I have not heard the armor quantified in that way. I did not think it was Okun though that came to this conclusion - We have Garzke and Dulin stating in reference to English Battleship armor “The side armor was of excellent quality, providing resistance equal to that of U.S. class “A” armor of 25percent greater thickness". Then another report, I forget the name other than the authors name was Horner stating US class A armor was flawed before 1943, to about 85% on average of post 1943 armor.

As far as what Okun says, hereis how he rates US A face hardened:

AVERAGE WWII-ERA CLASS "A" ARMOR
USAGE: Vertical armor from 5" (12.7cm) up except for 16" (40.64cm) & up turret face (port) plates. ARMOR QUALITY: Q=1.00


He does state there were some issues with it, but gives it a rating of 1.0, which is a bit inferior to German and British armor, though superior to Japanese.

One of my concerns with fully "believing" any author/expert by themselves is the bit of disagreement we have among the "experts". I try to look at them all as being right and wrong to some point, with perhaps the truth being in the middle until proven by testing, which will likey never happen.

But these were the kind of surface fights that were fought for the most part through out the war. After 1941 90% of all naval surface battles would be fought at night and never at long range at night. The American 16" gun battleships were the wrong designs for WWII. It's a classic case of designing weapons and tactics for the previous war. Perhaps 14" guns would have allowed other aspects of the design to be better suited to the times?


Well, if we knew before the wat that we will fight mostly the Kongo class in battleship engagments, the 14" guns make sense. But we had no idea if it would be the Kingo class, the Nagato class, or even the Yamato.

I'd hate to go up against the Yamato with 14" guns!

One aspect though of preparing for a long range daytime battle - the deck armor is going to be thicker. Which means the battleship designed this way have better protection against bombs, another major threat for battleships. Perhaps not armored for bombs by intent, but it still works out that way.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Mon Dec 15, 2014 9:37 pm

Garyt wrote:Well, if we knew before the wat that we will fight mostly the Kongo class in battleship engagments, the 14" guns make sense. But we had no idea if it would be the Kingo class, the Nagato class, or even the Yamato.

I'd hate to go up against the Yamato with 14" guns!


14" guns could be effective against the Yamato. Inside of 21,000 yards they could defeat the Yamato's belt protection just as much as the Kirishima's belt. Also at ranges exceeding 25km the American 1500lb 14" shell was a good deck penetrator due to a steep angle of fall * and due to having a good head shape for oblique striking angles. The British 14" gun was a better belt penetrator short of extreme range than the Washington's 16" gun. These comments were made by Mr Okun in this forum a few years ago:


Also, shell weight does not matter very much as to penetration of face-hardened armor (it is only to the 0.2 power), though full weight effects occur against homogeneous armor. The homogeneous armor gives way slowly and the entire projectile momentum has time to get involved in punching a hole. Thus, projectile weight and the square of the velocity can be seen to balance the complete kinetic energy required to penetrate (a heavy projectile has a lower striking velocity to penetrate in accordance with the conservation of energy of the entire plate and projectile).

Face-hardened armor, however, is rigid and does not give until the force gets too great to resist, at which point the hard face caves in suddenly and the pressure can then tear through the soft, ductile rear of the armor. Usually, the face breaks prior to the full weight of the projectile getting involved ...This is why the use of 2700-lb 16" shells (US final Mark 8 AP design) does not buy you much compared to 2100-lb 16" shells (WWI Mark 3 AP design) -- a 29% weight increase -- against the same face-hardened armor plate, assuming equal damage to both projectiles from the impact. You only can reduce the impact velocity with the heavy shell here to 94% of what you need for the light shell; hardly worth the effort to make the heavy shell here.



Actually the 14" gun KGV was better suited to the historical Guadalcanal battle (Kirishima or Yamato) than the 16" gun Washington and South Dakota because the 14" gun is good enough and the belt armour of KGV is miles better. Better yet would be a scarp triangle protection scheme.

*The lighter weight results in a greater loss of velocity with range and therefore a steeper angle of fall at very long range compared to a heavier shell.
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: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Mon Dec 15, 2014 10:24 pm

I can't get facehard to run on my computer anymore for some reason. But per Navweaps, the 14" POW gun Penetrates 15.6" at 10,000 yards. And that's for a dead on hit, we are looking at least at a at a 20 degree incline, plus the descent angle of any shot.

I'd think it would be tough to penetrate until about 7,000 yards are so, if the Navweap numbers are correct.

Per Navweaps:

Armor Penetration with 1,590 lbs. (721 kg) AP Shell
.
Range
Side Armor
Deck Armor
0 yards (0 m)
26.9" (668 mm)
---
10,000 yards (9,144 m)
15.6" (396 mm)
1.15" (29 mm)
15,000 yards (13,716 m)
13.2" (335 mm)
1.95" (50 mm)
20,000 yards (18,288 m)
11.2" (285 mm)
2.85" (73 mm)
25,000 yards (22,860 m)
9.5" (241 mm)
4.00" (102 mm)
28,000 yards (25,603 m)
---
4.75" (121 mm)
Note: This data is from "Battleships: Allied Battleships in World War II" for a muzzle velocity of 2,400 fps (732 mps) and is partly based upon the USN Empirical Formula for Armor Penetration and partly based upon official data.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Tue Dec 16, 2014 1:57 am

Aurora wrote:

Not at all Steve-the actual manner in which Hiei went to the bottom did seem to me to be in some doubt-I appreciate that this thread deals mainly with the effects of gunfire on her- without specifying where and how she sank.The Hiei, according to my research,had three causes for her eventual demise 1) USN gunfire 2)USAAF bombs and torpedoes 3) Scuttling. Tough old Bird!!


What I've pretty well seen with most WW2 Era battleships - Gunfire generally does not sink them, unless in combination with something else, OR if the gunfire hits a magazine or starts a fire which gets to the magazines before they can be flooded. Bombs really don't sink them either, other than with the specific cases mentioned for shelling. And when I say "bombs" I mean those normally carried by strike aircraft - usually 500 or 1000 pounds, no heavier than about 1760 pound bombs.

Battlecruisers are a bit different, a bit more vulnerable to shells and bombs, though still not the best way to sink them.

BUT, is there a big difference for instance between sinking the Bismarck and somehow her shattered hulk being towed into port by the Germans? Or if a couple of the carriers lost and Midway were not scuttled but towed back to Japan? A lot of work if they could be brought back to functionality. Given Japans limited repair facilities, this might mena they are knocked out of the war anyway.

The Hiei was not completely destroyed by the shelling, but was useless until extensive repairs were done.

The US of course was a bit different with it's huge repair capability, but I recall reading somewhere where the Navy thought that when the Bunker Hill surviving the kamikaze that caused intense fires to rage and extensive fire damage it almost would have been better had she sunk due to the huge cost to repair her.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Dave Saxton » Tue Dec 16, 2014 3:26 pm

Garyt wrote:Per Navweaps:

Armor Penetration with 1,590 lbs. (721 kg) AP Shell
.
Range
Side Armor
Deck Armor
0 yards (0 m)
26.9" (668 mm)
---
10,000 yards (9,144 m)
15.6" (396 mm)
1.15" (29 mm)
15,000 yards (13,716 m)
13.2" (335 mm)
1.95" (50 mm)
20,000 yards (18,288 m)
11.2" (285 mm)
.


According to an online data set based on Facehard, the POW 14" penetrates 17.3" of Japanese belt armour at 20,000 yards. The Washington's 16" penetrates 17.1" the same armour at the same range. For kicks I also looked up the German 15" and it penetrates ~19" of Japanese belt at that range according to this data set.

But I'm sceptical that Japanese armour was worse than US Class A. According to the Technical Mission to Japan, Japanese armour (both homogenous and face hardened) was virtually identical to the latest British armour. Indeed MNC was chemically identical to British NCA, VH was very similar to CA. But 16" of belt doesn't provide the full 16" worth of protection either.

Nonetheless, the leathal belt penetration of modern naval guns with modern shells by the mid 1930s had fundementally changed the necessary design considerations of battleships since the early 1920s regardless of the armour quality differences. It is certainly something to consider when talking about comparative design for what kind of battle scenarios the design might enccounter. A wider IZ was needed, but the 1920s based designs didn't provide a wider IZ.

The Italians went for the de-capping belt system design to deal with this new reality and to extend the IZ.

The Germans in, if recall Bericht 66, detail the design rationales of their protection scheme. Because of bombs, much armour weight had to be taken from vertical protection and added to horizontal protection. Given the belt penetration power of the most modern guns this created a design problem. Hence the scarp triangle arangement where the weight of the main armour deck provides both horizontal and vertical protection.
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: Comparisons of Axis vs Allied Combat Vessels

Postby Steve Crandell » Tue Dec 16, 2014 6:44 pm

The thing is, the Yamato belt armor was inclined, so that would tend to reduce the penetration. Also, in post war US testing against an Iowa size faceplate the British 14" shell tended to deform and ricochet off of thick armor because of the thin walls they accepted in order to get the large (for the caliber) explosive filler.

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Re: Comparisons of Axis vs Allied Combat Vessels

Postby Garyt » Tue Dec 16, 2014 7:23 pm

Also, in post war US testing against an Iowa size faceplate the British 14" shell tended to deform and ricochet off of thick armor because of the thin walls they accepted in order to get the large (for the caliber) explosive filler.


Interesting. In comparison to the US 16"/45 the British 14" had some good penetration numbers per Navweaps, but I was thinking it's bursting charge would be proportionately smaller. I was surprised to see that it actually had a larger bursting charge than the 16"/45 shell, so the above makes sense.

Reminds me a bit of the US 16"/50. It can penetrate very close to the Yamato's 18.1" shell's - but pays the price when it comes to it's bursting charge, as the Yamato's shell has about twice the bursting charge.

14" shell tended to deform and ricochet


One important issue here for any projectile that deforms or shatters - Any energy that goes into deforming or shattering the projectile is energy wasted that cannot be applied to penetration.

This is similar to how a carbon-fiber arrow, being more rigid than wood loses less of the bows imparted energy than a wood arrow does, meaning more energy transferred to the arrows forward velocity, meaning if shot from the same bow the carbon fiber arrow will launch at higher speed than a wooden arrow, even if both are the same weight.


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