38 cm shells

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Billy
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38 cm shells

Postby Billy » Tue Apr 30, 2013 9:34 pm

I've done a lots research and have found out some very interesting details about the 38 cm shells used aboard Bismark. First of all, they used a much heavier armour piercing cap than anyone else (at least 50% heavier for their full armour piercing). This had some quite startling differences to the shells of other countrys. First of all it put alot of weight further forward in the nose of the shell. this would make it much more stable in flight and make it a much more accurate weapon. Evidence for this can be seen by examining the average dispersion of fall of shot compared with other navies. If I remeber correctly the data was something like 250 meters for Richelieu's guns at 25000 yards (after rectification of 0.04sec time delay of firing with two guns together to improve accuracy as the close proximity of the barrels caused interference of the shells in flight) , 180 for the American 16 inch guns, which was very good but only 125 for the German shells. The other implication of the heavier cap is that it excavated a much larger hole out of the armour plate before being destroyed, and by concentrating its force on a smaller area so that the shell itself had to penetrate only a small percentage of armour in comparison. The evidence for this is seen in the German documentation which was gathered from actual results so I will not doubt them. The failure to notice the exceptional performance of these shells is that they are often compared directly to American armour scales, which it still exceded even though German and British armour was at least 25% better in penetration resistance,(other sources quote 30%). The source of this data is from the authur D.K. Brown who worked for the Royal navy desighning ships so I think his facts should not be doubted. I just wanted to add that although American armour was less resistant does not mean it was useless. In fact their use of angled armour more than made up for any inefficiencys but was used better (not to mention their propulsion systems which were the best in the world by a fair margin, and all nations excelled in certain areas others not. That is the nature of the way things are.) I have heard that the cause of the armour problem was scalling because of the use of excessively thick face. However, the British but the cause of their enhanced resistance at directly thickening the face from 25 to 33 percent and the Germans aswell at abo 45 percent with composition refinement and heat treatments. The greatest resistance plate the Americans tested was a Japanese plate of lacklustre composition but using German hardening techniques that they had supplied them. Since the plate was only 7.21 inches ,it thereby makes nonsense of the scalling issue. The next topic I would like to raise is the percent elongation a metal has on armour penetration resistance. The idea being that the greater the elongation the greater the resistance, however this is not strictly true as there are many factors to take into account. Tensile strenth ,the heating effect of the metal under its impact will also change its properties as well as its resistance to brittle fracture and its heat treatments would play a big role as to its molecular structure. In fact the Germans found that aluminium alloy actually had the greatest resistance by weight, but it only had an elongation of only 11%. The same goes with modern ceramic armour which has no elongation to speak of but is about twice as effective as steel armours. The truth is that if you want good data you go to the people who made the best armour and then ask their opinion, not the other way around. The next topic I would like to raise is the value of a gun with a higher rate of fire. Well once salvoes have found the range the guns will go into rapid fire until the fall of shot is not near the target anymore. For this value it is usefull comparing how many shots Bismark got off compared to Prince of wales. Bismark got off 93 (8 guns) in comparison to a potential 76 (10 guns) from POW. If one compares the the rate of fire as percentages per gun to that of the amount of shells actually fired you will find a startling agreement. So even though finding the range may be a slow process the use of quicker firing guns when the range was found greatly increased the average firepower even though on average it was less than 1 round per minute due to the initial spotting and ranging. The last thing i would like to raise is the German use of alluminized explosives in their shells. As far as i know they were they only one to actually use it, but it effectively doubled the explosive power. This all put together means in my opinion that Bismarck was a very underated ship in my opinion especially as far as firepower was concerned, she could practically match the imense penetrative power of Yamato ( once a person has properly calibrated your armour penetration scale) with a shell about half the weight and then burst with even more power than it could, and do it at a rapid rate of fire accuratly! Lastly I would just like to point out that deck penetration in ships is only of value if the battle is fought at a range where it could actually penetrate the deck.(ie at about 25000Yards). As by far most battles are fought under this range a flat trajectory gun with a short flight time and therefore better accuracy due to enhanced danger space is far better to attack the side of the ship which is vulnerable at battle range and of far greater value.

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Rick Rather
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Re: 38 cm shells

Postby Rick Rather » Wed May 01, 2013 11:47 pm

Welcome to the board, Billy.

I'm sorry, but I could not read that wall-of-text.

Please-please use paragraphs.

:(
Just because it's stupid, futile and doomed to failure, that doesn't mean some officer won't try it.
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RNfanDan
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Re: 38 cm shells

Postby RNfanDan » Sat May 04, 2013 2:08 am

Paragraphs, punctuation, and PLEASE spell Bismarck with the "c", like the big title of this website you see on every forum page, upper left.

Thank you!

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Thorsten Wahl
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Re: 38 cm shells

Postby Thorsten Wahl » Sat May 04, 2013 7:17 pm

If you have done some more careful reading on this board before you would have seen that many of "your findings" has been adressed on this board on a much more substantiated basis.
to start with few questionable things

cap percentage american armor piercing projectiles had caps with roughly similar percentage values.

The last thing i would like to raise is the German use of alluminized explosives in their shells
wich shells and source please MDVs preferred

which it still exceded even though German and British armour was at least 25% better in penetration resistance,(other sources quote 30%).
british reports of the armour technical committee indicate that differences were much lesser then 25% ADM 281-127 ATC Meeting held at the E.S.C Ltd. Sheffield 22nd July 1948
"...we can only assert, that is appears possible, that britsh cemented armour(comment in thicknesses around 13") is slightly superior to its american counterpart ... "
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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tommy303
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Re: 38 cm shells

Postby tommy303 » Sun May 05, 2013 4:53 am

The last thing i would like to raise is the German use of alluminized explosives in their shells. As far as i know they were they only one to actually use it, but it effectively doubled the explosive power.


While it is true that the Germans made use of aluminized explosives in certain high brissance explosives (HBX), notably in some anti shipping bombs, torpedoes, mines, 15mm, 2cm, 3cm, and 3,7cm cannon shells. Aluminium powder was also used in certain economy explosives like amatol to increase splinter effect of shell bursts.

viewtopic.php?p=360

German naval APC and base fuzed HE shells generally used Fp5, 10, 15, or 20 frequently in combination together. These explosive charges were generally preformed TNT blocks desensitized with a certain percentage of wax (5, 10, 15, 20%). The highest percentage blocks were used in the forward part of the shell cavity, and the smallest at the base around the fuze gaine.

see:

http://www.freilassung.de/div/texte/spreng/lexikon.htm

Thomas

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And saved the sum of things for pay.

Billy
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Re: 38 cm shells

Postby Billy » Tue May 07, 2013 7:52 pm

Hello everyone, thanks for your input. I have to apologize for the bad punctuation and rather lengthy opening "paragraph". I would first like to just show a quick comparison between the penetrative capabilities of the German and British guns of equal caliber. Note that I'm not using the old 15 inch 42 caliber of the British but what a more modern gun could do. The British gun could penetrate 13 inches at 19400 yards. The German gun could penetrate about 17.63 inches at the same range! Again at 21700 yards the British gun could penetrate 12 inches, the German gun 16.37 inches.

The other thing I would like to mention is a note on the value of high rates of fire. It turns out that at the battle of the Denmark straits the German ships only started to open fire three minutes after the British started, but still got off more shots. I have checked the records to see that POW only got off 55 out of a potential 74 (due to breakdowns). The German ships started later, found the range quicker and scored more hits. As to prove beyond doubt as the the value of a high rate of fire weapon, Prinz Eugen got off 179 rounds during the same battle!

Billy
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Re: 38 cm shells

Postby Billy » Tue May 07, 2013 8:15 pm

Just like to show a quick comparison between armor piercing caps of different navies. The Bismarck had 112.5 kg cap weight for its armor piercing shells compared to 84 kg for that used by Richelieu.

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Dave Saxton
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Re: 38 cm shells

Postby Dave Saxton » Wed May 08, 2013 2:29 pm

Billy, enter terms such as caliber-radius, armor piercing caps, cap mass, ..ect... into the search function. You could be at it for days. :D
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: 38 cm shells

Postby Billy » Wed May 08, 2013 3:46 pm

Done a little more research as to the comparative armor resistance of American versus British and German armor. Post war tests of the British and 14 inch 1595 pound projectile versus the American 14 inch Mark 16 1500 pound projectile showed that the american shell was better at oblique impacts, but the British shell was slightly better at impacts closer to normal incidence due to its more pointy nose. This is at least good enough for a comparison of the relative resistances of armor plate published by each country made given the similarity in penetrative performance.

The British gun could pierce 14 inches of armor at 13700 yards, the american weapon could pierce 17.63 inches of American armor at the same range. Now if you divide 14 by 17.63 you get a ratio of 1.259, or 25.9 percent more resistance. Which is almost exactly the value given by authors such as D.K. Brown. It is therefore proved that British and German armor was superior by the stated amount of 25%.

It is worthy to note though that other navies did not make these changes as well. German accounts of French armor was that it was not as resistive and Japanese armor was not of the same resistance. A question mark still hangs over Italian armor but will do more research on this.

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Re: 38 cm shells

Postby tommy303 » Wed May 08, 2013 5:13 pm

Although a few years old, you may find this article helpful if you have not read it already:

http://www.navweaps.com/index_nathan/me ... pt2009.htm

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.

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Dave Saxton
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Re: 38 cm shells

Postby Dave Saxton » Wed May 08, 2013 6:59 pm

Billy wrote:.... and Japanese armor was not of the same resistance. A question mark still hangs over Italian armor but will do more research on this.


The Japanese copied British metalurgy. Their homogenous armour was of the same chemical composition as British non cemented armour and their face hardened armour was based on Vickers cemented armour.

The Italian Terni face hardened armour was also based on Vickers, but their homogenous armour types AOD and ER was very different from British homogenous armour.
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: 38 cm shells

Postby dunmunro » Wed May 08, 2013 8:56 pm

Billy wrote:Hello everyone, thanks for your input. I have to apologize for the bad punctuation and rather lengthy opening "paragraph". I would first like to just show a quick comparison between the penetrative capabilities of the German and British guns of equal caliber. Note that I'm not using the old 15 inch 42 caliber of the British but what a more modern gun could do. The British gun could penetrate 13 inches at 19400 yards. The German gun could penetrate about 17.63 inches at the same range! Again at 21700 yards the British gun could penetrate 12 inches, the German gun 16.37 inches.

The other thing I would like to mention is a note on the value of high rates of fire. It turns out that at the battle of the Denmark straits the German ships only started to open fire three minutes after the British started, but still got off more shots. I have checked the records to see that POW only got off 55 out of a potential 74 (due to breakdowns). The German ships started later, found the range quicker and scored more hits. As to prove beyond doubt as the the value of a high rate of fire weapon, Prinz Eugen got off 179 rounds during the same battle!


Your penetration figures seem to be drawn from different sources, using different methodologies, and are thus not valid for comparisons. The actual penetration abilities of the RN 15" Mk17B and the KM 38cm are fairly similar.

At Denmark Straits: "Bismarck and Prinz Eugen also suffered a loss of output. Bismarck had a total of 104 possible shots, but actually fired 93 for an 89% output. Prinz Eugen had a total of 184 possible shots but actually fired 157 for an 85% output.

http://www.bismarck-class.dk/bismarck/h ... attle.html


Bismarck and Prinz Eugen both used radar ranging to find the range. Hood, probably using radar, found the range fairly quickly but, of course, fired upon the wrong target. Prinz Eugen probably evaded being hit by making radical course changes. PoW took longer to find the range because her radar systems malfunctioned. Both German ships had the advantage of firing from all their main armament, where as Hood and PoW could only fire from their forward armament for about 1/2 the battle.

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Re: 38 cm shells

Postby Billy » Wed May 08, 2013 11:10 pm

Would like to point a few things out , but thankyou very much for your input. The Japanese did copy from British sources, but as I understand it that was circa ww1. I would find it highly unlikly that they would reveal or give top secret information away that would drastically improve their armor.

As to the comparison against both British and American shells it would be useful to note that the USA actually made 15in shells for the British by Crucible steel. The results were that the British thought that they were the equel to those made by Hadfield and Firth and Brown, but not equel to those made by Cardonald which were better. This is yet further evidence that British and American shells were comparable in performance. Yet when analyzing the armor penetrative values by each navy there is still a large discrepancy which usually adds up to our 25%.

Thanks for pointing out that the German ships also could have put out more rpm - thanks for the data. It is true that the British were only firing half of their armament for the start of the battle, but the German also ships did'nt fire for the first 3 minutes or the 4th salvo from the British. In the account given by axis battleships of world war two they point out that Bismarck fired a quick 8 gun 4th salvo (broadside) when they found the range was found. But the account makes says that they fired a 5th broadside quickly after this, before, the fourth had time to "land" and destroy the ship. This would meet the definition of rapid fire. Another account tells of her firing every 22 sec at one stage in the battle and that P.E. was firing at every 10.

As to armor piercing caps. I am finding it hard to get exact details, but this is what I've found so far. The cap shape of all navies was quite different as well as the actual point that it covered, leading to quite complex interactions. The details for the British 15in was around give or take a few kg 80kg (still cant find exact no). The French Richelieu was at 83 kg (exact). The American 16in cap was very heavy at 141,5 kg but still less than its German counterpart 16in weapon at 164,7 kg.

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paulcadogan
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Re: 38 cm shells

Postby paulcadogan » Thu May 09, 2013 3:29 am

Hi Billy,

Regarding the rates of fire in the Denmark Strait, it's not as simple as you're stating. You have to take into account the length of time each ship fired and how the salvoes were patterned.

PoW fired 18 centrally controlled salvoes from 5:53 to 6:02 (9 minutes) or 2 salvoes per minute. Each salvo consisted of half the guns that were bearing as was the standard RN practice for daytime shooting. Of course her output suffered a bit losing an average of about 1 gun per "half" salvo. After that she fired 3 more (of 2, 1 and 1 shell) from her aft turret in local control as she retreated.

Bismarck fired 93 shells out of a possible 104 - the equivalent of thirteen 8-gun salvoes - from 5:55 to 6:09 (14 minutes). That's just less than 1 full salvo per minute. When you look at it, she too lost a little less than 1 gun per salvo.

In other words PoW fired a half salvo about every 30 seconds, Bismarck fired on average a full salvo about every 60 seconds - roughly equal output - even though Bismarck was theoretically capable of a higher rate, she did not accomplish that in the DS. There are a number of factors affecting the rate of fire - pattern of salvo firing, course changes, spotting issues, corrections - all combine to produce the practical rate during the action.

Comparing Prinz Eugen's rate to PoW's or Bismarck's is not really appropriate since you would expect the cruiser's guns to have a much higher rate capability.

But (as if this needs to be said! :wink: )....Bismarck certainly did demonstrate the penetrative power of her 15-inch shells.....

Paul
Qui invidet minor est - He who envies is the lesser man

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Re: 38 cm shells

Postby tommy303 » Thu May 09, 2013 4:03 am

As others have said, Bismarck did not achieve her full possible output of shells during the Denmark Straits battle, possibly due to ammunition problems as had been experienced during the few practice shoots she participated in during her working up period. These problems were documented by the AVKS, though it is unclear if the faults were corrected before she sailed on her first and only operational mission.

Prinz Eugen's problems were another matter and were fully documented by her First Gunnery Officer, Korvettenkapitaen Jasper. According to Jasper, a technical fault occurred in B Turret, causing it to not fire in one salvo, and for another 13 salvos with only the left hand gun. A turret experienced operational errors (mistakes by the crew) which caused that turret to miss four salvoes during the action, while C and D turrets each missed one salvo.

I do not think too much should be made of Bismarck and Prinz Eugen not achieving their full output; like Prince of Wales, both were new and like the British battleship, not fully worked up. For that matter, it was rare for a battleship or heavy cruiser to actually have a 100% output during an action. As to the rates of fire, one might say both German ships were shooting in a deliberate manner.

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.


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