Guns vs naval armour in ww1

Preliminary note:


I have been submerged for a while now and am now going to finish my study on major calibre impacts of naval guns versus naval armour (capital ship armour) in ww1.
Some of the results encountered have surprised me, so I will give only brief and preliminary notes at this time.


Sources:

Note that no attempts are made to deal with primary sources first hand. Altough I would be more than happy to get my hands on original docs!

Literature:
My primary source for this study is the comprehensive work of J. Campbell, Jutland. An analysis of the fighting. This work thoroughly goes through hit after hit in the major battle of Jutland. I also used other works (Sumida, Jones, Lambert, Massie, Marder) to complement informations gained by Campbell, esspeccially for non Jutland Combats.

Actions covered:
Falklands, Doggerbank, Jutland, Dardanelles, Black Sea engagements. For comparative reasons, I also included the post war firing trials on SMS BADEN with the improved APC shells.


Statistical background:
All in all over 400 major calibre impacts have been analysed for drawing conclusions. Statistical investigations are based on the statistical package of the social sciences (SPSS).


Intention of the study:
My primary intention of this study will be composed of the following aims:
A) Probability of hitting different parts of an ship. For saying so, I have run around comments like:

"...armour belts were virtually never hit in ww1 and ww2..." -Nathan Okun
or
"...deck armour is more important because the number of hits on armour belts are negliable" -I. Charles.

while reading these comments, I naturally asked myselfe (and the commentators) on what sources and statistics these comments are based on. I have never got any other answer than authoritative comments (...he said so), nor could I get statisfying informations in the books aviable on the matter. I believe, this justifies an investigation of this very question in detail with the help provided by the aforementioned authors and the sound statistical services provided by SPSS.

B) Relative performance of penetration from APC, CPC and base fuzed HE-rounds on their respective target plates. These are "REAL WORLD" -results, not the prooving ground results known from other studies. If a projectile pierces in a condition fit to burst a plate installed as it was on the ships structure, this is a very serious issue.

C) Stability of the filler to rapid deceleration.



I also would like to encourage as many as possible to comment and contribute to the problems outlined above. I run this thread in order to cover multiple problems associated with the big ´ol guns. From time to time I will submit results, starting with A) next week.

best reagrds,
delc

Definitely looking forward to your study delc. Think it will be most interesting. Especially the comments about deck armor being far more important than side armor. If your study confirms that perspective, it would give a whole new outlook to how warships SHOULD have been made.

Just briefly, it seems that side armor thickness is more of a throwback to the ways battles were fought in the previous century than a conscience design perspective. Designers built warships for fighting at 5,000 yards (or less) and the engagements ended up being fought at 10,000+ yards. Flat fire became irrelivent and plunging fire the threat.

Looking forward to it.

Del. I too am looking forward to your analysis. Tim raised an important factor about the fast moving trend toward gunfire at long ranges with plunging fire. A little like the revolution that needed to take place in infantry tactics with the advent of the rifled musket and Minie ball and the attendent increase in effective range.

Count me in. I admit that I was surprised by the comments on deck armour if only because most of the guns had limited elevation and the rangfinders were such that ranges were limited.

I look forward to it.

Campbell has written an exhaustive book on Naval weaopons of WWII. There are also some good general refernces for WWII in the 1944-5 Janes, and the Conways series. There is some discussion in the books about immune zones, which seems to indicate to me that deck hits became the predominant hit as the range increased, due to plunging fire. The protective zone appears to be the zone where the main belt is the major point of impact. and is expressed as a maximum and a mi9nimum. Below the minimum, the shell doing the hitting is assumed to be penetrating the belt.

I dont know much about WWI, except that engagement ranges appear to be generally less than those of WWII, where radar and better optics were probably a major factor.

I would be very interested to see the results of your study I do not consider myself any sort of expert in this area, but have some books that may be a help....

I have been thinking about doing a "best BB of WWII" poll. Or has that already been done

Parsifal, I think it was done. Bismark and North Carolinas came out on top. Not sure though, but I think it was 1941 as the year picked to measure.

: I thought it might have been. I have a back up suggestion..."Best prewar Battleship. " Would poll refurbished BBs like the Warspite, as well as the interwar construction completed before the outbreak of the war. that way the usual nominees get excluded from the poll, and we might get some intersting results.

All I gotta do is work out how to post new poll and everything will go just fiine

I have had problems with formatting the amount of datas in a form useful for this thread. I decided to submit describtive and analytical parts of statistics. For those who are interested in the datasource pm me and I will be happy to send You the spss-files for further research.

Here it goes. Part I deals with actions before Jutland. Only capital ship damage is actually considered for which the best datas exist.

I had to seperate these from Jutland because Campbells comprehensive view is much more detailed than most of the descriptions for prior actions.

We start with descriptive statistics and how the samples relate to actions generally:

...seems to have been a bit to large in size...

We can see that our samplesize is rather limited for actions prior to Jutland. They relate to their mean action distances as can be seen here:

-the mean distance for all hit´s is not to be misunderstood as true range. Reports for all actions are incomplete and the error in range for each hit, judging from conflicting sources appears to be pretty large for Falkland, the Dardanelles and Black Sea action. The following graph gives the range for each hit in direct comparison to the possible error in range for a more comprehensive overview:

Very interesting stuff. Some of it reinforces a logical approach (closer the range, the more likely the chance of a hit). However, there is one action that stands out. Doggerbank.

Why?

Is it the number of hits the Blucher took after she slowed and became the main target of the British BCs? Action was opened at extreme range and then worked it's way down due to speed differences. That may explain why the range is as high as it is but not really representative of when the majority of the hits took place.

It would be interesting to go into that further.

Is it the number of hits the Blucher took after she slowed and became the main target of the British BCs? Action was opened at extreme range and then worked it's way down due to speed differences. That may explain why the range is as high as it is but not really representative of when the majority of the hits took place.

Click to expand...

In addition to the selected hits, there have been major calibre hits on Scharnhorst and Gneisenau during Falklands and hits on Blücher on Doggerbank, which I had to reject for the principal reason that no detailed accounts on area of impact and effect of penetration exist. Surviving ships do offer comprehensive post action reports, which I had selected for compiling the informations. That´s why You will later not find information on destroyed britsh ACR´s in the Jutland part of this investigation.

Therefore, the mean distance chart for action is not representative for the action -exactly as You already recognized- but only representative for the selected 44 cases of major calibre impacts, which can be found in the attached SPSS file. Note that I cannot upload it here, I get the error:

ww1-hits-part1.sav invalid file

Click to expand...

.

Some overview over the action before engaging the anaylitcal part of the statistics:

compare:
Campbell 1978: Battlecruisers Warship special 1, Conway Maritime Press (1978).


Falklands:
The range was differing between 16,000 to less than 8,000 yards with most of the action taking place at over 12,000 yds. INVINCIBLE fired 128 APC, 259 CPC and 161 HE for a total of 513 rounds while IINFLEXIBLE retruned ammo expendeture figures totalling 661 rounds ( 157 APC, 343 CPC and 161 HE ).
The INVINCIBLE was hit 22 times of which 12 were 8.3in, 6 5.9in and 4 unidentified. There were 11 hits on the deck, 4 on the side armour, 4 on the unarmoured side, 1 on A turret and 1 on the foremast. INFLEXIBLE was hit 3 times with slight damage to the 4in guns on A and X turret.
In return, Scharnhorst and Gneisenau were hit for up to 40 times each, the correct number of hits is not recorded and the majority of the hits coming at the final stages of the encounter from closer ranges. There is evidence to suggest that much of the damage to the German ships was caused by hits below the waterline and penetrating the 1in battery roof.

Dardanelles:
INFLEXIBLE took part in the bombardment of the outer forts on 19th and the 25th February, firing 47 CP on the first and 10 CP ( 1 premature ) on the second. She returned to take part in the attack on the inner forts on March 18th. She engaged the forts at between 13,700 - 16,200 yds, the effective Turkish guns which would bear on the ships being 4 x 14in/35, 13 x 9.4in/35, 5 x 5.9in/40 and 32 x 5.9in howitzers. With 4crh shells the 14in could range out to 19,000 yds and the 9.4in to 15,800 yds. The INFLEXIBLE put the 2 x 14in in Rumeli Hamidieh out of action before they had fired a shot, by damage to the loading derrick in one and the traversing mechanism in the other. Only one 9.4in was knocked out by the rest of the fleet.

1) 14in burst close to hull port side aft driving in the plating for 33ft about 6ft below the waterline along the line of the armour deck, some compartments flooded giving a slight list to port. In return she ws hit six times:

1) 14in burst close to hull port side aft driving in the plating for 33ft about 6ft below the waterline along the line of the armour deck, some compartments flooded giving a slight list to port.

2) 9.4in burst on side above armour hole some 2ft diameter

3) 9.4in hit foremast at level of flying bridge causing fire which destroyed foretop fire control.

4) 5.9in howitzer hit left gun P turret, gun was considered out of action by cracks 17ft from muzzle.

5) 4in howitzer shell hit signalling yard, burst on foretop roof, nealy all complement casualties.

6) I small shell with minor damage, also minor splinter damage from 3 shrapnel bursts

In addition to these Inflexible also hit a mine, part of a field of 26 176lb Carbonite mines laid by the steamer Nusret. It exploded on the starboard bow by the after end of the fore torpedo flat just forward of A turret and at platform deck level 17ft above the keel. It made a hole 15ft x 15ft with damage extending along to a length of 36ft. The starboard side of the torpedo flat and the compartments below it were completely wrecked, and a locker of calcium phosphide Holme's lights caught fire. All 27 crew in the torpedo flat were killed, electirc light failed, ventilating fans stopped. The armour deck and magazine screen bulkhead in A turret prevented damage to the shell and magazine spaces, but water did enter the forward shell room and magazine, and later the lower conning tower. She shipped about 1600 tons of flood water.

Crimea

On the 18th Nov. 1914 GOEBEN encountered the Russian Black Sea fleet of 5 pre-dreadnoughts. In an action of scarcely 10 min at a range of 7-8,000 yds in fog she expended 19 x 11in APC and made 4 hits on the EVSTAFIJ (from which no detailed reports survived), and was hit once, by a 12in nose fused black powder filled shell, which holed the 6in armour of no. 3 port 5.9in and ignited 16 cartridges, gas smoke and flame entered the magazine but no charges caught fire.

Black Sea

This time in good visibility, GOEBEN engaged EVSATFIJ again for 22 mins. at ranges of 17,500 to 16,000 but made no hits. She was hit 3 times in return:

1) 12in far forward on forecastle deck

2) 12in on belt armour which sent up a water splash putting no. 2 port 5.9in out of action

3) One on net casing so nets hung down

The russian Pre Dreadnought was firing APC. It should be noted that russian APC projectiles by then were of a hard capped, delay fuzed type.

Doggerbank:

INDOMITABLE took part but was the slowest ship, and hampered by 2crh shells so she did not open fire until 113 minutes after Lion at a range of 16,250 yds. Her target was the already crippled Blucher expending 40 APC 15 CPC and 79 HE, as well as 2 shrapnel at the german airship L5. It is not recorded the number of hits she made on Blucher, but she was hit by 1 8.3in in return with little damage.

PRINCESS ROYAL expended 176 13.5in APC, 95 13.5in HE and also 2 13.5in shrapnel at airship L5. She reported to have made 5 hits, 2 on BLUCHER and 3 on DERFFLINGER, altough only one hit on DERFFLINGER can be linked with PRINCESS ROYAL and she was not hit herself in return.

Other than BLUCHER, the british Battlecruiser and flagship HMS LION suffered most in the action of Doggerbank and was in effect damaged critically enough to leave the line. Later she had to be taken in tow and the loss of the shipwas only prevented by a sea valave not giving way according to Campbell. In the action she expended 243 x 13.5 APC scoring one hit on BLUCHER, 1 on DERFFLINGER and 2 on SEYDLITZ at a range of 16,000 yds or more. Altogether she was hit by 16 11in or 12in shells and 1 x 8.3in.

1) 17-18ft below lwl one compartment flooded

2) As above with similar efect.

3) 8.3in from BLUCHER on 3.5in turret roof of A, roof dented and driven down a little, left gun out of action for 2 hours.

4) 11in from MOLTKE at about 18,000yds, struck water about 15ft from side ricocheted and pierced 5in armour aft 2ft above deep wl, passed through escapes and vent trunks of 4in magazines, through the 0.25in main deck, was deflected upwards and finally dropped unexploded on the main deck. The after low power switchboard compartment was flooded, eventually causing 2 of the ship's 3 dynamos to be shorted.

5) 11in from SEYDLITZ at about 16,000yds, one hit 5in armour forward, just below the main deck, drove in a piece 30ins x 24ins and burst 6ft from impact in a wing compartment abreats the torpedo body room, wrecking it, and flooding it up to the main deck, flooding the torpedo flat, the compartment below it, the port cable locker and the capstan compartment. A splinter hole in the exhaust pipe from the capstan engine filled the auxiliary condenser with salt water and the resultant salting of the boilers made it necessary to stop the starboard engine.

6) 11in from SEYDLITZ at about 16.000yds. This shell shell hit further aft, bursting on the 6in side armour, 3-4ft below full load wl. 2 armour plates were forced in 2ft, the outer and inner bottoms bulged over an area of 40ft x 7ft, the slope of the 1in armour deck forced in and some of the foremost bunkers flooded. Hit together with 5).

7) 11in amidships at 17,000yds. struck 6in side just below the upper deck and burst 8ft inboard, and the other

8 ) 11in amidships at 17.000 yds struck the junction of the 6in and 9in armour at main deck level and bursting 2ft inboard, much damage to light structures. Hit together with 7)

9) 11in went through forecastle skin plating and 1in upper deck bursting against 8in armour of A barbette, little damage done.

10) burst in bakery which was wrecked, part of shell passed through the armour gratings and holed the exhaust bend to the port inner condenser without damaging the tubes.

11) Hit 9in belt armour amidships, failed to penetrate.

12) Through no. 1 funnel and 1.25in forecastle deck, bursting 6ft beyond.

13) Through no. 2 funnel and burst on skylight.

14) Through no. 2 funnel and overboard.

15) Through forecastle deck and burst as it passed through ship's side.

16) Thought to be 12in from DERFFLINGER. Hit lower strake of 9in main belt armour abreast engine room and just below deep load wl and burst on the armour forcing in a 16ft x 5ft 9in plate at least 2ft inward (burst in holing). The outer and inner bottom plating and the 1in armour was much torn and distorted. The port feed tank was opened to the sea, overflowed into the reserve feed tank and thence into the port engine room. The feed tank bulkhead in the port engine room was badly bulged, 2 lower bunkers were flooded and the ship heeling 10 degrees to port and capable of only 15kts, shortly afterwards the remaining engine had to be stopped. The resultant rise in the water level shorted the remaining dynamo and the LION was out of action. This was a very serious hit, crippling Beattys flagship.

17) On starboard side 17-18ft below lwl.

In addition to these hits, the right gun of Q turret was out of action after 15 rounds from incorrectly diagnosed trouble with the firing mechanism, and 4 minutes before LION was overtaken by TIGER A magazine was erroneosly reported as on fire and flooded 2ft deep.

TIGER expended 355 13,5in rounds ( 249 APC 54 CPC 52 HE ) and scored 2 hits each on SEYDLITZ (one unconfirmed) and DERFFLINGER (one unconfirmed) and an unrecorded number on BLUZCHER. She also fired 268 6in HE at BLUCHER and destroyers and fired 2 x 21in torpedoes at BLUCHER, one of which was claimed as a hit.

HMS TIGER was hit 6 times by heavy shells;

1) 12in from Derfflinger burst on 9in main belt.

2) 11in on Q turret on 3.25in roof of Q turret at junction of 2 plates. Most of the shell deflected overboard but fragments entered the turret jamming the training gear and damaging the left gun breech mechanism.

3) 11in hit signal distributing office below CT bursting 6ft from impact in the intelligence office, all communcications between control top and connign tower destroyed. Above the burst the CT and the main and 6in gunnery control towers had 4in floors with access doors to all except the CT. These doors were open in the main and port 6in towers and all the occupants were casualties.

4) 11in hit 1.5in forecastle deck amidships severe damage to light structures.

5) 11in hit 9in belt below waterline no damage.

6) 11in on side armour forward, no details.

7) 8.3in went through the after funnel.


It was unlikely that MOLTKE was ever fired at, and no hits were made on her. She expended 276 x 11in at between 16,000 and 18,000 yds and 14 x 5.9in at btween 13,000 to 14,000 at destroyers. LION was hit by 16 shells and TIGER 6 and it is likely that MOLTKE scored 8 or 9 of these.

SEYDLITZ expended around 390 11in APC and made at least 8 of the 22 hits obtained. She recieved 3 hits.

1) 13.5in APC from TIGER, forward with little damage

2) 13.5in APC from LION, struck quarterdeck and burst in holing of the 9in barbette armour of sternmost turret. Shell and fragmentation was kept out but plugs of hot armour fragments entered, piercing the ring bulkhead, and ignited 11in main and fore charges in the working chamber. The flash ignited charges in the gunhouse, in the lower hoists and handling room, as well as some in the magazine. The ignition of these charges was comparitively slow until the crew of the handling room opened the bulkhead door to allow fumes to excape, at this moment the charges in the handling room ignited and flash passed into the superfiring turret, setting fire to charges in the gunhouse, magazine and handling room. Altogether some 62 charges were destroyed, Fumes and flames made the after part of the ship untenable, but it was possible to flood the after torpedo flat and magazines. This hit has to be considered as a very serious event and the loss of the ship must have followed had SEYDLITZ used cordite instead of RPC/12.

3) 13.5in APC from LION burst on 12in main belt with no effect.

DERFFLINGER expended 234 x 12in APC and 76 x base fused HE (effictively SAP), and scored 5 or six hits. She was hit 3 times in return:

1) 13.5in from LION, burst near hull and caused some leakage.

2) 13.5in from PRINCESS ROYAL, similar to no. 1 but after outer starboard shaft tunnel bent. A diving hit.

3) 13.5in from TIGER, burst on 12in main belt armour, at junction between two plates, plates forced in by 2-4in and caused some flooding of the adjacent wing compartements.

From the aforementioned hits we can see that MAIN BELT HITS were by far the most numerous hits of the pre-jutland incidents. This result appears to be contrary to general believe but I might add that the samplesize is rather small and -more importantly- incomplete. Compare the following graphs.


Note: the second graph shows superimposed points, significance is 65% out of N=44 investigated hits.

The following two graphs show how the hits relate to distance, armour thickness angaged and are of impact. Note that some datapoints are superimposed.

Definitions for effect:

A) unknown: No data avaiable

B) no effect: Projectile engaged armour, projectile rejected without serious damage to the plate and without any fractures behind

C) Burst on impact: Projectile burst on impact with all parts of the projectile kept out and no calibre sized hole punched out. Damage to the frames and fastenings my still be considerable and hot plugs of armour may be punched out.

D) Burst in holing: Projectile holed armour with at least a calibre sized hole. Blast fragmentation partly effective outside and inside with fragments of the projectile body / nose be found inside.

E) Pierced: complete Projectile pierces plate but either fails to fuse or is not in a condition fit to burst

F) pierced burst inside: complete Projectile pierced the plate and burst behind the plate (including low order bursts).

The following graph displays how the projectiles behave. The 8.3" and 11" projectile are german, the 9.3" and 14" are turkish, the 13.5" is british while the 12" projectile is either german or british, respectively.

Discriminance analysis:

This is the graphical display of an investigation of the areas of impact and how they relate to each other in terms of individual ship, weight of projectile, distance, error in distance, effect, result.

The aim of every discriminance analysis is to verify groupings. The groupings analysed are the areas of impact. It is a very interesting statistical approach to display meaningful korrelations...

The dominance of main belt hits as shown in this graph is notable!

rectangles show mathematically centroids for each group.