German battlecruisers and the Scharnhorst class

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Takao
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Re: German battlecruisers and the Scharnhorst class

Postby Takao » 02 Apr 2017 23:40

Well, the Scharnhorst mounted more armor tonnagewise - 14,006 metric tons to KGVs 12,612 metric tons. But, then again, the HMS Hood carried more armor tonnagewise than the KGV...

What mattered was the placement of the armor.

The IZ that I have seen for Scharnhorst was 16700 m to 17100 m (machinery) and 16700 m to 23300 m (magazines).
The IZ for the KGV..........................was 17831 m to 25603 m (machinery) and 15728 m to 29261 m (magazines).
Against a British 15"/42 gun firing a 1,938lb. shell.

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Takao
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Re: German battlecruisers and the Scharnhorst class

Postby Takao » 03 Apr 2017 00:04

genstab wrote:(Historical note- USS New Jersey was once clocked at 35 knots!- 212,000 horsepower is quite a lot but those ships needed it to keep up with the fast carrier task force in the Pacific.

35.2 knots at 207rpms just after completing her modernization for Vietnam...But, it is all relative. Also, the Iowa, after her '85 modernization, only slightly surpassed 32 knots at 205rpm.

In February, 1944, the Japanese destroyer Nowaki outraced the Iowa & New Jersey. With the throttles wide open, the battleships did not reach 33 knots, and the Nowaki eventually disappeared over the horizon. OF course, displacement & bottom fouling likely shaved off at least a knot from their top speed.

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Re: German battlecruisers and the Scharnhorst class

Postby Paul Lakowski » 03 Apr 2017 03:14

canceled
Last edited by Paul Lakowski on 03 Apr 2017 03:35, edited 1 time in total.

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Re: German battlecruisers and the Scharnhorst class

Postby Paul Lakowski » 03 Apr 2017 03:31

Vitals protection of the TWINS was 350mm outer belt followed by slopes 105mm thick @ 25o followed by 45mm torpedo bulk head. Combined against a 14"-15" shell this should offer 24-26" resistance , reducing 14" gun penetration to 4-6,000yards.

DECK protection was 50mm upper plate and 80mm main armor deck. However any plunging fire will also have to cut through the 30mm splinter belts. Combined this should offer deck protection of over 5".The British 14" gun cannot penetrate this amount of deck armor until it is greater than 29,000 yards.

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Re: German battlecruisers and the Scharnhorst class

Postby Takao » 03 Apr 2017 09:39

Paul Lakowski wrote:Vitals protection of the TWINS was 350mm outer belt followed by slopes 105mm thick @ 25o followed by 45mm torpedo bulk head. Combined against a 14"-15" shell this should offer 24-26" resistance , reducing 14" gun penetration to 4-6,000yards.

DECK protection was 50mm upper plate and 80mm main armor deck. However any plunging fire will also have to cut through the 30mm splinter belts. Combined this should offer deck protection of over 5".The British 14" gun cannot penetrate this amount of deck armor until it is greater than 29,000 yards.

In a perfect world.

However, the Duke of York put a 14-inch shell into her machinery spaces(boiler room #1) at a range of 18500-19500 meters.

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Re: German battlecruisers and the Scharnhorst class

Postby Paul Lakowski » 03 Apr 2017 20:07

Actually it didn't penetrate but its believed to have exploded in the wing tanks [between torpedo bulk head & slopes or main belt. That shock temporarily shut down boilers of a well known accident prone system.

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Re: German battlecruisers and the Scharnhorst class

Postby Terry Duncan » 12 Apr 2017 18:08

Not a single member of the Iowa class ever achieved the designed top speed, the best being 32.5kts - 32.8kts, both in WWII and for the Vietnam period trials. In service they were usually not much better than 32kts at best. There have been all sorts of fantastic figures cited for them, up to 50mph by one senator iirc, usually involving failed attempts at converting kts into mph, then using the resulting figure as a speed in kts before trying to convert the already inflated figure into mph yet again. Unexpected propeller cavitation at speeds above 30kts limited the total maximum the hull form was ever expected to achive, and even that was only 34.9kts.

http://www.navweaps.com/index_tech/tech-104.htm

When considering battlecruisers, the Iowas are effectively battlecruisers, both in their intended role of running down the Kongo class ships, and in their comparison to the contemporary Montana class ships.

The entire battlecruiser concept is simply a logical extension of the cruiser program in the dreadnought age. The all big gun requirement was there because Tsushima showed the heaviest guns were what counted at longer ranges, so the mass of intermediate caliber guns the cruisers of the time carried were barely effective compared to the same weight being used for a reduced number of big guns. Turbine technology allowed the weight saved to be put into extra speed above what the previous reciprocating engined cruisers had achieved. The armour of the Invincible was the same as the previous armoured cruisers she was effectively nothing but an evolution of.

Interestingly the same situation arose in WWII where the artificially limited 8" cruisers were being superceeded by 12" gunned designs in the US and Japan, and then for 18,000 ton cruisers armed with 9.2" guns in Britain. The design had gone full circle, we then had a design for a ship the tonnage of Invincible with the guns of the Minotaur class! The design was then shelved as it had become clear it would once again be more effective to fit 6 x 12" guns in place of the 9 x 9.2", not to forget their was neither the money or need for such a ship.

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Re: German battlecruisers and the Scharnhorst class

Postby Nautilus » 25 Apr 2017 14:38

genstab wrote:THE US Navy had two very interesting ships it chose to classify as Large Cruisers (CB)- USS Alaska and Guam. They were 30,000 tons (34,000 full load), 808 feet long, 91 foot beam and 31 foot draft with nine 12 inch guns, a new caliber for the modern US Navy, with 12 5-inch secondary in twin turrets. Her steam turbines were rated at 153,000 horsepower and she was good for 33 knots. Her belt armor was 9 inches, turrets 12.8 inches and deck 4 inches. It would have been an interesting battle between an Alaska and a Scharnhorst.


There's more in a warship's design that it meets the eye, and this has to be included when the ship is on the drawing board, before the first rivet had been hammered in.

Alaska was not designed from scratch as a battlecruiser - it wasn't expected for her to fight an equal enemy vessel, or withstand 2 or more enemies as WWI Imperial German battlecruisers were. Therefore they lacked the much needed survival features: underwater protection system, tight internal subdivision, with armoured bulkheads, and so on. The Alaskas were designed to smash one or more standard, Treaty cruiser enemies, as in the original idea of Fisher battlecruiser from 1905-1906.

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Re: German battlecruisers and the Scharnhorst class

Postby Thoddy » 08 Aug 2017 11:07

Not a single member of the Iowa class ever achieved the designed top speed, the best being 32.5kts - 32.8kts,


Did you possess informations on shaft RPM at this speed
According FTP 218
196 RPM were required for 30 kn at designed shaft horsepower (212,000 s.h.p.) and 56,600 tons mean displacement(~1945).

USS IOWA (BB 61) Standardization Trial data, 1985 showed 198 RPM for 31 kn - calibrated for range- ;(30,2kn speed as recorded from ships EM Log)

Conclusion from this trial "Extrapolating this data to full power indicates that IOWA
could reach a speed of 32.25 kn"

35.2 knots at 207rpms
is utterly nonsense.
"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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Re: German battlecruisers and the Scharnhorst class

Postby Pips » 09 Aug 2017 01:26

The discussion of whether the Twins were battleships or not is, to my mind, a moot point. The Germans built them as battleships, and battleships they be. Could they slug it out against British battleships a la Bismarck v Hood and Prince of Wales? Probably not.

I find it far more interesting to dwell on whether they were arguably more effective in their role as raiders than either of their two larger cousins the Bismarck or Tirpitz. Stats would have to say yes. Not only in ships sunk, but in longevity and mischief created. They certainly posed a greater threat for a longer period than did the Bismarck.

In those circumstances one could comfortably argue that they were successful ships, in that they achieved what they were designed for.

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Re: German battlecruisers and the Scharnhorst class

Postby Thoddy » 09 Aug 2017 07:30

Scharnhorst and Gneisenau were built as explicit counter against the french "light" battleships Dunkerque and Strasbourgh.
From the german naval command foreign WW1 battleships has been seen as equivalent opponents for the Scharnhorst- class (especially non modernised ones -based basically on firecontrol capabilites-, operational focus at long range (over 20-22 km)) as they expect better Hit% or at comparatively low distance of about 10-11 km to overcome the significantly lower firepower (penetration and explosive effect).

Whereby against modern battleships they were seen in general as inferior.

The raider role came into play in about 1938, when Great Britain became a potential opponent. They saw they were not able to achieve a superiority or at least parity as a naval power in the foreseable future. They only saw a chance for their navy in a supply war. The german naval command re-evaluated in this context all existing ships during 1938/39 including those in construction for the raider role and only the Scharnhorstclass was able to met(partially) the requirements of a raider, despite its sea endurance was somewhat limited.

The Panzerschiffe had to low speed but high endurance (required durable speed should be at least 30kn)
All smaller ships below this size had to low endurance and range.
Armament and protection of Bismarck class was justfied to fight other battlesips of same class and age but the use as a raider was expected to be inefficent.
"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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Re: German battlecruisers and the Scharnhorst class

Postby Terry Duncan » 09 Aug 2017 13:12

Pips wrote:I find it far more interesting to dwell on whether they were arguably more effective in their role as raiders than either of their two larger cousins the Bismarck or Tirpitz.


They were certainly more effective in the roles they were employed in, though all of the German capital ships were a massive waste of tonnage if a career in raiding was the main intent, and as a fleet in being any ship with a speed over 28 kts was a suitable threat. Converted merchant ships would have been a better use of resources, or even specific ships designed to look like or double as merchant ships - sort of an outgrowth of the Q ship idea.

Pips wrote:In those circumstances one could comfortably argue that they were successful ships, in that they achieved what they were designed for.


Not quite, but they did perform the roles they were assigned quite well. Sadly they could have been far more effective if the German high command had the slightest idea of how to use them and accept the risk of their loss in such an operation.

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Re: German battlecruisers and the Scharnhorst class

Postby Paul Lakowski » 09 Aug 2017 14:16

To be more risky in there usage the KM needed more of them...to be more expendable

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Re: German battlecruisers and the Scharnhorst class

Postby Pips » 10 Aug 2017 02:57

Terry Duncan wrote: Converted merchant ships would have been a better use of resources, or even specific ships designed to look like or double as merchant ships - sort of an outgrowth of the Q ship idea.


Quite right. The nine Hilfskreuzer's performed extremely well, sinking between them 130 merchant ships (885,433 tons), 1 light cruiser, 1 AMC and damaging a further 2 AMC's.

Terry Duncan wrote: Not quite, but they did perform the roles they were assigned quite well. Sadly they could have been far more effective if the German high command had the slightest idea of how to use them and accept the risk of their loss in such an operation.


Agree. Both the OKW and the OKM were the Achilles heel of effective employment of the Kriegsmarine. Although much is made of Hitler being loath to risk ships, Raeder et al also have to accept responsibility for the limited way the Kriegsmarine was employed.

PS: How best to effectively utilise the Kriegsmarine surface Navy would actually make for an interesting topic.

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Re: German battlecruisers and the Scharnhorst class

Postby Gorque » 10 Aug 2017 03:14

This is a very interesting thread. Thanks to all for their contributions to it.


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