Who won?

Guns, torpedoes, mines, bombs, missiles, ammunition, fire control, radars, and electronic warfare.
paul.mercer
Senior Member
Posts: 904
Joined: Fri Mar 26, 2010 10:25 pm

Who won?

Post by paul.mercer » Sat Feb 29, 2020 6:45 pm

Gentlemen,
There have been many discussions on this Forum about battleship armour and the penetration of shells, but it seem that these discussions have been going on far longer than that. i was reading a book the other day which told about the increase in protection via oak planks and eventually Iron cladding versus the size of gun and the weight of its projectile, leading up to the 34 pounder on HMS Victory up to the 64 pound carronade carried on specially designed ships.
Of course we all end up with the Yamoto class ships, 18" guns and very thick armour, but was this armour truly impenetrable by any shell (including an 18"), in other words, in the shell v armour debate, who eventually won?

User avatar
Dave Saxton
Supporter
Posts: 3093
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Who won?

Post by Dave Saxton » Mon Mar 02, 2020 5:45 pm

This is a vast and complex topic!

Who won? Neither completely won and neither completely lost. In the case of WW2 designs, it came down to the concept of immunity zone. The concept recognized the reality that no armour could defeat any shell at any battle range. However, it could defeat a given shell, in the case of vertical armour, once the range increased to certain values.

In the case of vertical protection (striking the vertical surfaces of the target) there would come a point after travelling through the air a given distance where the striking velocity of the projectile would fall below that which was necessary to penetrate the belt armour of the target. Additionally, as the range increased the striking angle also became less favorable to achieve penetration. In most cases by WW2, the range that a given battleship caliber shell could no longer defeat the belt of a target battleship was about 20,000 meters battle range. This, however, did not mean that once the range was beyond 20,000 meters that the target battleship was safe.

As the range increases beyond 20,000 meters the angle of fall of the shell means it strikes decks at a more and more favorable angle. Thus more and more of the amour weights budget had to be diverted to deck armour. Deck protection can consume enormous amounts of armour weight. In most cases it was possible to provide enough deck armour to protect a battleship from battleship caliber shells out to about 30,000 meters battle range. Thus it was possible to build a WW2 battleship that had protection against ww2 battleship caliber shells between the battle ranges of 20,000 meters to about 30,000 meters. At those ranges the armour would likely win. Beyond the range of 30,000 or at less than 20,000 meters battle ranges the shell would likely win.

Extending the range that the battleship deck protection could be effective to beyond 30,000 meters was not practical. This is because deck penetration increases exponentially beyond about 30,000 meters range. Even doubling the weight of the deck protection would only buy a little more range that the deck protection could be effective.

Compounding the problem was a dramatic increase in penetration power by new gun designs during the 1920s and 1930s. For example, during WW1 the British 15" gun could only defeat a 12" face hardened belt of the highest possible quality out to about 16,500 meters given a broadsides on target angle. However, the new German 15" gun of the 1930's, mounted aboard the Bismarck, could defeat that same belt out to about 27,000 meters given a broadsides on target angle. Moreover, the Bismarck's 15" gun could defeat the typical deck protection of the older generation of capital ships down to about 13,000 meters battle range.

I need to run for now but there is much, much, more to talk about pertaining to this topic if we want to discuss it more thoroughly.
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.

Mostlyharmless
Member
Posts: 170
Joined: Wed Jul 22, 2009 10:45 pm

Re: Who won?

Post by Mostlyharmless » Mon Mar 02, 2020 5:56 pm

Battleship, as opposed to battlecruiser, armour won at Jutland but by WW2 the evidence suggests that the shells were winning up to when the fight was stopped. However, there were only a limited number of times when battleship calibre shells hit battleships.

It is fairly clear that shells from the last generation of battleships could destroy older unmodified battleships with examples such as Bretagne, Hood and Kirishima. Modern "mini" battleships were also vulnerable as seen when Dunkerque was hit.

Jean Bart suffered hits at rather long range which suggested that her deck armour was vulnerable to the 16" guns of Massachusetts despite it being 150 mm thick. However, the Germans believed that French armour was low quality because of sulphur contamination.

Germans might find it harder to explain how Bismarck's armament was knocked out because the 360 mm face plates were relatively high quality. We know that one turret was disabled by a non penetrating hit to the face, showing that simply using thicker armour might not have solved all the problems. The hit on South Dakota's barbette suggests that very thick modern armour could get a draw against an older 14" gun even at close range. The shell did not penetrate but the turret was disabled.

Bismark's last battle (or Scharnhorst's) suggested that magazines and machinery could be protected against short and medium range shell fire by two layers of armour, which might have helped in a Jutland style battle but did not help an isolated ship once the armament was disabled.

ps. wrote this before Dave posted, so may need changes

User avatar
Dave Saxton
Supporter
Posts: 3093
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Who won?

Post by Dave Saxton » Mon Mar 02, 2020 10:06 pm

There were two basic concepts in play about how armour could defeat shells. One was that armour could destroy the shell or render it inert. The other was based on preventing effective penetration of a shell.

The advent of Krupps Cemented Armour or face hardened armour meant that a shell would shatter upon impact against the hard face of the armour if it was going fast enough. This lead to the practice of fitting a hard cap on the nose of the shell (but under the windscreen.) The cap's primary purpose was to protect the shell upon impact and prevent it from shattering.

An extension of the destroy the shell concept was the use of a de-capping array for a belt protection system. If a de-capping plate could remove the cap of the incoming shell, then the shell would not be protected by a cap when it struck the main face hardened armour plate behind it. This was the concept of the Italian belt system used on the Littorios. The advantage of this system was that it could expand the immunity zone of the vitals to less than 20,000 meters battle range-which was still likely to occur. The main plate did not need to be exceptionally thick to shatter an uncapped projectile. In fact the greater the kinetic energy of the uncapped projectile the more likely it would shatter.

This was the concept employed on the Bismarck for barbet protection below decks. ( For the exposed barbets this concept could not be employed, so the only option was to make the armour as thick as practical.) This concept was in play, perhaps unintended, in the case of the 14" shell that hit the South Dakota's number three barbet at short range. The shell would have been de-capped by striking and penetrating first the 38mm upper deck at an oblique angle before shattering against the heavy barbet armour.

The Bismarck's belt system employed a combination of the two concepts. In the Bismarck's system the main belt was placed externally but backed up by heavy scarps that presented a very unfavorable striking angle in turn. The necessary velocity required to penetrate the entire system was so high that the shell would be destroyed or rendered inert during the process. Lower kinetic energy hits would have insufficient energy to penetrate the system. This essentially expanded the vitals IZ from very short range to ~30,000 meters battle range. The system also provided the vitals protection from plug ejections and plate debris.

However, such a system could not be provided for the turrets.
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.

User avatar
Dave Saxton
Supporter
Posts: 3093
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Who won?

Post by Dave Saxton » Mon Mar 02, 2020 10:40 pm

Another method to shift the balance from favoring the shell winning, and battleships having virtually no IZ at likely combat battle ranges, was to manipulate the striking angle.* Simply increasing armour thickness was not practical in most cases, so manipulating the striking angle could improve the protection to incoming projectiles. About 13" was not only the max practical thickness of belt armour (and also homogeneous armour) because of weight concerns in many cases, but it was also the Approx. thickness that was the point of diminishing returns in terms of effectively resisting penetration. By sloping the belt, a 13" belt could provide the protection of about a 15" un-sloped belt.

However, a sloped belt also protects less area of a ship's sides. The sloped belt can be made taller and deeper or divided into upper and lower belts but that is not very weight efficient. It may require a limit to thickness to control weight. It also complicates and usually makes less effective torpedo defense arrangements.

Striking angle can also have profound ramifications for horizontal protection. Although it is true that the Germans were not impressed by the quality of French armour, in the case of the Jean Bart, the battleship listing presented incoming 16" shells with favorable striking angles as well.

*Most wrote into their fighting instructions to present an oblique target angle to the enemy if at all possible.
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.

paul.mercer
Senior Member
Posts: 904
Joined: Fri Mar 26, 2010 10:25 pm

Re: Who won?

Post by paul.mercer » Tue Mar 03, 2020 10:25 am

Gentlemen
Many thanks once again for all your replies, it is indeed a complex subject, compounded perhaps with a bit of luck that a shell hits at exactly the right angle on the weakest part of the armour, but returning to the Yamoto class ships which were considerably heavier in armament and armour than anything else at the time, would they really have been invulnerable to any battleship shell except perhaps an 18" from a similar sized ship (if one had existed on the allied side)? I realise we have had the Iowa class v Yamoto discussion before, and as far as i can remember it was suggested that the superior range finding of the US ships would have meant more hits which would perhaps have degraded the Japanese ship fighting capability without necessarily penetrating her armour except perhaps in certain less armoured places.
PS. I am talking about shell penetrations of armour rather than bombs.

User avatar
Dave Saxton
Supporter
Posts: 3093
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Who won?

Post by Dave Saxton » Tue Mar 03, 2020 3:47 pm

paul.mercer wrote:
Tue Mar 03, 2020 10:25 am
but returning to the Yamoto class ships which were considerably heavier in armament and armour than anything else at the time, would they really have been invulnerable to any battleship shell except perhaps an 18" from a similar sized ship (if one had existed on the allied side)?
I just got through examining some penetration tables, and Yamato would still have been vulnerable to shell hits from 14" guns beyond about 32 km battle range and below about 18 km battle range.
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.

HMSVF
Member
Posts: 236
Joined: Sun Jun 17, 2018 10:15 am

Re: Who won?

Post by HMSVF » Sat May 02, 2020 12:58 pm

Neither?

The whole line of battle premise was made obsolete once you could drop sufficiently powerful ordnance accurately from the air or break the back of a ship with torpedoes that bypassed any previous ideas of defence.

Isn’t the whole game plan these days not to be hit at all?

Post Reply