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#1 Chris Lane

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Posted 11 November 2012 - 04:31 PM

Hi all.

With the H class being included in the German Deluxe Ships logs I was wondering what would be best to use for the 16" guns.

a) the German 15"

B) the British 16"

Cheers

#2 Cpt M

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Posted 11 November 2012 - 09:15 PM

Hi all.

With the H class being included in the German Deluxe Ships logs I was wondering what would be best to use for the 16" guns.

a) the German 15"

B) the British 16"

Cheers

Good question. Unfortunately, the author of the first batch of the Deluxe Ship Logs (UK and German) developed the logs for the unbuilt ships (Lion and the 'H' class) without reference to the CRTs. So we don't have a CRT for either the British late 16" (which was never built) or German 16" (which was built but never ship mounted). The best that can be done is to use a known gun with similar characteristics (which is an imperfect solution). For the German 16", a close match (in terms of shell weight, muzzle velocity and performance) isn't really available due to its unique characteristics (medium weight shell with high velocity), but a fairly close match in terms of performance would be the USN 16" CRT.

#3 Chris Lane

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Posted 12 November 2012 - 05:09 PM

Ideal thanks for that coastal.

Likewise if or when I use my Lion classes I take it the older British 16" gun is best to use?

Cheers

Chris

#4 Cpt M

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Posted 22 November 2012 - 06:46 PM

Ideal thanks for that coastal.

Likewise if or when I use my Lion classes I take it the older British 16" gun is best to use?

Cheers

Chris

The British 16" might be the best option (or not. Read on). The problem is that the British never built the guns in question. I say guns, because there were 2 different designs in the works. The first (16" Mk II and Mk III) were the original guns intended. Later, the 16" Mk IV was substituted (which would have fired a heavier shell). Neither design was ever built, so all performance data is theoritical (which can have serious errors). According to the limited theoritical data on hand, the Mk II's performance would have fallen roughly between that of the British 16" Mk I (carried by the Nelson class) and the US WWII 16" Mark 6 (carried by the North Carolinas). What the 16" Mk IV would have done is unknown. So you can err on the conservative side and use the British 16" CRT (probably the best option ) or assume the later Mk IV is mounted and use the USN 16" CRT.

#5 glenn_simpson

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Posted 30 August 2016 - 02:44 AM

I was looking at the German 11"+ (28cm SK) gun on the GQ 3.3 CRT, carried by the Scharnhorst class, to see what effect in game terms the planned regunning to 38cm/15" would have had, and noticed that the 11" gun seems very weak in penetrative ability, given that its armour penetration, as given by Garzke & Dulin, and other sources, is very close to the British 14" in the KGV Class. Yet the British CRT gives the British 14" the ability to penetrate BA up to 18,000 yds while the German CRT gives the 11"+ the ability to penetrate BA only up to 9,000 yds. Is there a reason for this?
Also, the German 38cm/15" 1934 model penetrates BA up to 18,000 yards, the same as the British 14" 1936 model, although the published figures for armour penetration at 20,000 yds are 11.2" for the British 14" (and 11.47" for the German 28cm/11" 1934 model) and 16.5" (or 14.33") for the German 38cm.
I don't want to be a nitpicker but these values in the CRTs seem substantially at variance with reality.

#6 Cpt M

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Posted 31 August 2016 - 04:14 PM

"I was looking at the German 11"+ (28cm SK) gun on the GQ 3.3 CRT, carried by the Scharnhorst class, to see what effect in game terms the planned regunning to 38cm/15" would have had, and noticed that the 11" gun seems very weak in penetrative ability, given that its armour penetration, as given by Garzke & Dulin, and other sources, is very close to the British 14" in the KGV Class. Yet the British CRT gives the British 14" the ability to penetrate BA up to 18,000 yds while the German CRT gives the 11"+ the ability to penetrate BA only up to 9,000 yds. Is there a reason for this?"

 

 

First, determining the penetration values for any gun can be more art than science. This is due to the seeming contradictions in data or the outright lack of data.  You'll often see values derived empirically from set formulas, or the results of proving ground tests, or the results derived from combat results.  Of the the three, the last are generally the most reliable since these account for actual service conditions as opposed to the perfect conditions of proof firing or the results derived from formulas (which tend to be the least reliable and can either understate or overstate the performance of a gun.  The best example of this is the case of the RN’s 16” MK I.  The formula results proved to be highly overstated when compared to either proving ground or service results).  Finally, when using proving ground results, a certain amount of reduction is required to reflect actual service conditions.

 

In reality, the Garzke/Dulin data (based on a formula used by the USN) overstates the penetration of the 28cm/54.5 SKC/34 when compared with the data from pre-war test firings performed by Krupps.  As an example, the Garzke/Dulin penetration value at 20000yds is 11.67" while the Krupps value at 21000yds is 8.86" (both assume penetration at 90 degrees).  Given that preference is always given to actual firing results (preferably service results as oppose to test results), the CRT as written better represents the actual performance of this gun.

 

As for the British 14”/45 MK VII, the penetration data was derived from actual service firing results that the author obtained from a noted authority on the subject and are somewhat higher than the Garzke/Dulin formula results.  Once again, preference is given to actual sevice results.

 

 

“Also, the German 38cm/15" 1934 model penetrates BA up to 18,000 yards, the same as the British 14" 1936 model, although the published figures for armour penetration at 20,000 yds are 11.2" for the British 14" (and 11.47" for the German 28cm/11" 1934 model) and 16.5" (or 14.33") for the German 38cm.”

 

 

The same situation that applied to the German 28cm/54.5 SKC/34 applies here as well.  The Garzke/Dulin formula data overstates the penetration of the German 38cm/45 SKC/34 when compared with the data from pre-war test firings performed by Krupps.  As an example, the Garzke/Dulin penetration value at 19685yds is 16.5" while the Krupps value at 21872yds is 14.33".  The CRT as written, based on the Krupps results and adjusted for service conditions, is consistent with actual performance.



#7 glenn_simpson

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Posted 06 September 2016 - 12:58 AM

Thank you very much for this explanation.  I note that the German 11"/56 SK36 in S&G was significantly downrated from the GQ3 to GQ3.3 tables, making the planned 15" upgrade for these ships even more useful in game terms.   I do not have access to the Krupps data to which you refer - perhaps you can tell me if and where it was published?  

 

I note that Garzke et al state that their data is theoretical and should be used to rank the guns comparatively rather than apply the figures to assess actual armour plate penetration, but the figures they give for the British 14" 1936 and a few other guns is the actual RN service data, as stated in Raven & Roberts; likewise their US data is in-service data, so they are certainly not comparing like with like in every case.  And their ranking of the Italian 15" as equal to or better than the US 16"/50 with 2700 pound shell is plainly absurd. 

 

I  quite agree that forming judgments on gun performance and armour penetration is an art, and a dark one at that - I am dimly ware of the work done over many years by Nathan Okun (?) in relation to the resistance of different types of armour plate from different navies, so not only must one look at the actual service figures for penetration of vertical KC armour at various ranges, and the type and weight of shell used, but assess the quality of the relevant KC armour that was penetrated in the test.  And then consider gun accuracy and sloppy manufacturing tolerances for some navies' shells leading to dispersion and failure!  Plus wear in the gun barrel!

 

I also appreciate that there must inevitably be simplifications in a playable game of this sort (grouping in a single category both the US 16" /45 and /50 model guns and various weight 16" shells, for example) which in many cases far outweighs minor technical differences. 

 

Perhaps I should just get on with the game and enjoy it.   Once again, my thanks for the explanations.



#8 Cpt M

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Posted 06 September 2016 - 05:18 PM

" I note that the German 11"/56 SK36 in S&G was significantly downrated from the GQ3 to GQ3.3 tables, making the planned 15" upgrade for these ships even more useful in game terms.   I do not have access to the Krupps data to which you refer - perhaps you can tell me if and where it was published?  "

 

The 11" was at a definite disadvantage compared to the guns mounted on similar ships of the same tonnage (such as HMS Renown).  The main problem was Germany really had no other option at the time the ships were constructed, the 11" being their only big gun available.

 

The Krupps results are from an article that, IIRC, appeared in Warship (can't say for sure since most of my library is currently packed up awaiting a move).  IIRC, the same information appears in Whitley's "German Capital Ships of World War Two" (but I may be wrong).

 

" And their ranking of the Italian 15" as equal to or better than the US 16"/50 with 2700 pound shell is plainly absurd." 

 

Interesting enough, the performance of the US 2700 lb shell when fired from the 16"/45 Mk 6 (as mounted on the North Carolina and South Dakota classes) is not that far from that of the Italian 381mm/50 Model 1934 and Model 1939 guns.  The reason is that the Italian gun, with a smaller shell (1951 lbs), had a significant higher muzzle velocity (2887 fps).  The US 16"/45 Mk 6 fire the 2700 lb shell at a much lower muzzle velocity of 2300 fps.  So the penetration performance evened out.  Of course, the rub was in barrel life.  The Italian guns were rated for only 110-130 rounds while the US guns were rated for 395 rounds.  BTW, the German guns had the same low barrel life because of the same reason.

 

BTW, the US 16" data on the GQ3.3 CRT is based on the 16"/45 Mk 6.  This is due to it actually seeing combat (the Mk 7 being shipped aboard the Iowas did not, save for one action against a IJN patrol boat!).

 

 

 

 

 



#9 glenn_simpson

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Posted 18 September 2016 - 07:10 PM

Thanks for this explanation - I have some of the Warship magazines and annuals, as well as Whitley, and will have a look.  I had always understood that the choice of the 28cm / 11" gun for Deutschland was to conform with the 10,000t/28cm limits in the Versailles Treaty, and retaining that caliber for S&G (freed from the Versailles limits by the Anglo-German Naval Agreement) was primarily to avoid rousing the British from their pacifist torpor, with the option of replacing the 11" with 15" later.   Certainly the Germans had a 38cm / 15" gun and twin turret design from WW1, and Krupp and Rheinmetall would have been pleased to run up a new design if they were asked.  I guess, as you suggest, it was a matter of timing and availability as well as political and technical risk for the German decision-makers in 1933-4, and a gamble that paid off - certainly S&G would have not done any better historically with 6x15" than they did with 9x11".   

 

So far as the Italian 15" is concerned, I guess you can't  argue with exterior ballistics and their shells might have been effective if they hit, but as I understand it the Italian industry's manufacturing quality control in the areas of metallurgy, explosives and propellants was well below US and British standards, leading to high dispersion of shells and a higher proportion of duds/failures.  So I understand that the British and especially the French 15" guns were considered substantially better in practice, let alone the US 16"/50.

 

I also appreciate your explanation of the US 16" gun in the GQ3.3 CRT - I wondered why all the US 16" were in the same column, as there was such a big jump in performance with the 16"/50 and 2700 pound shell.  You will permit me to  observe that the explanation you give, that the 16"/50 was not actually used in ship-on -ship combat, does not make entire sense to me in a game premised on hypothetical ship encounters, let alone encounters between hypothetical ships with hypothetical guns such as the German H42 BBs (I have an impressive Alnavco model of H42 in 1/1200 to duel with my hypothetical Lion and actual Vanguard).   Never having been good at envisaging numbers, I have graphed the penetration at range figures in the GQ3.3 CRTs for these guns, and the Japanese 18" is clearly a standout.  However, Garzke et al, and others in various internet fora, have argued that the Iowa's 16"/50 was a good match.  If, as you say,  the US 16"/50 is not represented in the GQ3.3 CRT, then as a fudge, I think I will use the Yamato's CRT column for Iowa, and the US 16"/45 CRT for H35 and Lion (1940) as you suggested earlier in this thread.   

 

Thank you once again for this very informative discussion.

Glenn Simpson

Gold Coast, Australia



#10 Cpt M

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Posted 18 September 2016 - 10:24 PM

"So far as the Italian 15" is concerned, I guess you can't  argue with exterior ballistics and their shells might have been effective if they hit, but as I understand it the Italian industry's manufacturing quality control in the areas of metallurgy, explosives and propellants was well below US and British standards, leading to high dispersion of shells and a higher proportion of duds/failures.  So I understand that the British and especially the French 15" guns were considered substantially better in practice, let alone the US 16"/50."

 

According to what I've read, the problem with the Italian's gunnery was principally with their shells (sourcing from several manufacturers had led to quality control problems).  As far as the guns themselves, those were considered on par with the rest of the major powers (of course, if your ammo sucks, it doesn't really matter how good your gun is!).  The Italians weren't the only ones to have problems with dispersion.  The US early triple 14" turrets had severe dispersion problems due to the guns being too close together.  This was resolved during the '20s by staggering the firing of adjacent guns.  The Italians had the same problem with their twin 8" turrets and used the same solution.       

 

 

"I also appreciate your explanation of the US 16" gun in the GQ3.3 CRT - I wondered why all the US 16" were in the same column, as there was such a big jump in performance with the 16"/50 and 2700 pound shell.  You will permit me to  observe that the explanation you give, that the 16"/50 was not actually used in ship-on -ship combat, does not make entire sense to me in a game premised on hypothetical ship encounters, let alone encounters between hypothetical ships with hypothetical guns such as the German H42 BBs (I have an impressive Alnavco model of H42 in 1/1200 to duel with my hypothetical Lion and actual Vanguard).   Never having been good at envisaging numbers, I have graphed the penetration at range figures in the GQ3.3 CRTs for these guns, and the Japanese 18" is clearly a standout.  However, Garzke et al, and others in various internet fora, have argued that the Iowa's 16"/50 was a good match.  If, as you say,  the US 16"/50 is not represented in the GQ3.3 CRT, then as a fudge, I think I will use the Yamato's CRT column for Iowa, and the US 16"/45 CRT for H35 and Lion (1940) as you suggested earlier in this thread."   

 

The problem of providing of a separate column for the 16"/50 is one of space.  The CRT can only accommodate so many guns.  And while we would've liked to included every Mark (and, in come cases, sub Marks) of each nation's guns, that would've led to either an awfully cramped CRT or one with a very small font; neither of which would've been legible.  For example under the US 16" guns, you could have the 16"/50 heavy shell, 16"/45 heavy shell, and 16"/45 standard shell, just for starters.  As for the hypothetical guns (some of which were never built), the issue becomes one of data (or lack of) to base a CRT on.

 

As for the Japanese 46cm/45 (which the IJN designated "40cm/45 to hide their actual size), the data is, once again, variable.  Some sources give a slightly better penetration than the US 16"/50 while others rate the guns the same.  In game terms, the difference is minimal (at best), so using the Japanese 18" table for the US 16"/50 would be a "good enough" solution.   



#11 Dave Franklin

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Posted 19 September 2016 - 06:24 PM

There is a thread somewhere on the forum - I think it starts asking about the 12" column on the US Gunfire CRT and the Alaska class ships.  IIRC, the answer WRT the 12" is the table represents the guns on USS Arkansas.  Recommended modifications are provided for the Alaska class.

 

There is a further discussion in the thread WRT the 16" column.  Again IIRC, the answer for the 16" column is that it represents the guns on the Colorado class, North Carolina class and South Dakota class BBs.  Recommended modifications are provided for the 16"/50s on the Iowa class, and would have been on the Montana class.

 

You could take a look at that and possibly use the latter for the German "H" class.

 

Dave



#12 glenn_simpson

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Posted 06 April 2017 - 06:57 PM

What CRT would be appropriate for British 9.2 inch coastal guns?  These were old WW1 guns commonly used around the world by the British Empire as coastal artillery against raids by CAs and smaller - they were not expected to defeat BBs, but could do a lot of damage to one if they scored a deck hit at long range.  The one from Gibraltar is now at IWM Duxford, but some still exist in their original emplacements, such as at Rottnest Island Western Australia.  

We are going to do a Channel Dash 1942 scenario and there were 4 x 9.2" radar controlled coastal guns at Dover which did fire at the German squadron.  These guns had been modernised with 30 degree elevation and could fire out to 36,000 yds.  There is a 9.2" GCRT in the Balkan Navies supplement covering the guns of Averoff, but that seems unsuitable, at least as far as range and accuracy is concerned, although the penetration categories for belt armour are probably OK.



#13 Cpt M

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Posted 11 April 2017 - 10:40 PM

Sorry about the late reply (bad case of 'real life' intervening...).

 

This a tough one.  By WWII, the coastal artillery 9.2" Mk X was generally using a larger charge (or Supercharge) than that used in WWI or that used by the Greeks.  So its overall performance was better in range and penetration.  Given the overall performance, a usable stand-in would be the Italian 10" (it has the range and better penetration).  However, the penetration may be too high.  You could use the range and 'to hit' numbers of the Italian gun and the penetration numbers of the Greek gun (with the longer range extrapolated).  But given that the WWII gun was superior in penetration to the 'standard' WWI gun, I might go with just using the Italian 10" unmodified.        



#14 Lonnie Gill

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Posted 15 April 2017 - 04:35 PM

G' Day all,

 

As several of you have stated, all this penetration data is indeed rather a black art.  I consulted many sources during the development of GQ and FAI and found the data all over the place.   Calculated results and real results varied widely as did which type of shell,  ballistic cap  and armor piercing cap was used - especially important for AP shells.  Given all this, I did give considerable weight to the Nathan Okan data available on the Navweaps site.   Nathan has spent many years developing his data base and refining it as better data becomes available.   It's his passion and he's probably the closest thing to an expert there is.  He's also been kind enough to answer a few questions over the years.  

 

Penetration is, of course, a continuum.  Selecting specific results on the CRTs for the defined armor bands in GQ and FAI was a judgement call in a few cases where the data was "on the cusp" between two alternatives.  Further, penetration is greatly affected by the angle of impact, which can vary tremendously during an engagement.   All this can become an extremely complex and time consuming simulation all its own - as several other game systems have tried.  I think you will find that once you expend all that time going through the calculations and tables, the results are not as precise as you may have expected.  In addition to the type of shell and caps, you must account for the angle of fall, deviation due to wind and atmospherics at the upper reaches of the trajectory, the type and slope of the target's armor and relative aspect of the target to the line of fire.  And don't forget, the target is continually rolling in a seaway which can change all the angles from one shot to the next.  There's more, but you get the picture.  The GQ and FAI CRTs provide a reasonable alternative with results applicable for the majority of cases as a captain can't depend on getting an optimum hit with a perfect 90° impact during an engagement.

 

 For the various hypothetical guns and those not shown on the CRTs due to space limitations, I suggest consulting Nathan's data or using comparable guns as suggested by Capt M.

 

Cheers,

 

LONNIE 






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