Intercepting Force H

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Matrose71
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Re: Intercepting Force H

Post by Matrose71 » Fri Jan 25, 2013 10:31 pm

@ dunmunro

1. What you have posted are the penetration datas of the 11"/52 gun of the Panzerschiffe.
SH and GS had the 11"/54 gun with 330 kg shell weight and the L 4.4 shell.

This is a very big difference.
The 11"/54 is credited to penetrate after GDokus something about 11 inch at 20000yards at right angle. Even after Facehard from Nathan Okun (which I didn't trust), this gun is credited for 10.5 effective limit against British WW2 facehardened armour at right angle.
If Thorsten will read this he can post the exact datas for 30 deg after GDokus for the 11"/54.
But for sure Renown will not have any immunity zone under 18000-19000yards.

2.
Ark Royal only added two 8 barrelled pom-poms during her time in service - no radars were ever fitted. She was last docked in Nov 1940, but AFAIK her machinery was in good shape, however S&G had machinery problems constantly - every time they tried to use overload power.
Only SH had continous problems, Gneisenaus machinary was much more reliable.

3.
Renown was outrun at Stromvaer because she suffered damage to her forward bulge, which had partially torn away in the heavy seas, and because she couldn't obtain ranges for her forward armament at such high speeds in the prevailing seas, so there was no point in trying for more speed. OTOH both S&G lost all their forward armament due to flooding. If they had found Glorious, in heavy seas, they probably wouldn't have been able to pursue her anyways, since they wouldn't be able to work their forward guns.
This issues were solved after the atlantic bow and and adding wave breaker ad Brest.
S and G had no problems at heavy weather to use their whole arnament after 1941.

4.
32 knots for S&G is fantasy
You should explain how SH could manage to run away 10000-12000yards in 1 and a half our from DoY in a force 9. DoY is credited with 29kn at overload.
So how could SH as smaler ship with a slight disadvantage in heavy weathe manage this, with only 1kn difference in speed after your claim/assumption?
Also Renown was clearly out run at Norway from SH and GS and both had not the new bows and other modification.

I think many of your claims are wrong and your penetration data to the gun and shell of SH/GS are totaly wrong!

5.
broken shells will be rejected by her scarf armour. Both the belt and scarf armour are backed by about 1in of HT steel. Here's the scarf (main deck slope thickness's: main deck (slope) : 4inch (2inch NCD + 1inch HT + 1 inch HT) over magazines, 3 inch and 1inch (1+1+1 or 1 inch HT) over machinery. So Renown was practically immune from the 28cm gun, through her main belt, at 30 deg target inclination.
As I pointed out, you are refering to the wrong gun, but at your claim is also one major failure, the scarfs had a very steep angle of 60 degrees and were only 60mm, that's nothing more then splinter protection, every shell that will punch through the main belt will go to such a thin scarf, which is also very bad laid back.

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Re: Intercepting Force H

Post by dunmunro » Sat Jan 26, 2013 12:04 am

Matrose71 wrote:@ dunmunro

1. What you have posted are the penetration datas of the 11"/52 gun of the Panzerschiffe.
SH and GS had the 11"/54 gun with 330 kg shell weight and the L 4.4 shell.

This is a very big difference.
The 11"/54 is credited to penetrate after GDokus something about 11 inch at 20000yards at right angle. Even after Facehard from Nathan Okun (which I didn't trust), this gun is credited for 10.5 effective limit against British WW2 facehardened armour at right angle.
If Thorsten will read this he can post the exact datas for 30 deg after GDokus for the 11"/54.
But for sure Renown will not have any immunity zone under 18000-19000yards.

2.
Ark Royal only added two 8 barrelled pom-poms during her time in service - no radars were ever fitted. She was last docked in Nov 1940, but AFAIK her machinery was in good shape, however S&G had machinery problems constantly - every time they tried to use overload power.
Only SH had continous problems, Gneisenaus machinary was much more reliable.

3.
Renown was outrun at Stromvaer because she suffered damage to her forward bulge, which had partially torn away in the heavy seas, and because she couldn't obtain ranges for her forward armament at such high speeds in the prevailing seas, so there was no point in trying for more speed. OTOH both S&G lost all their forward armament due to flooding. If they had found Glorious, in heavy seas, they probably wouldn't have been able to pursue her anyways, since they wouldn't be able to work their forward guns.
This issues were solved after the atlantic bow and and adding wave breaker ad Brest.
S and G had no problems at heavy weather to use their whole arnament after 1941.

4.
32 knots for S&G is fantasy
You should explain how SH could manage to run away 10000-12000yards in 1 and a half our from DoY in a force 9. DoY is credited with 29kn at overload.
So how could SH as smaler ship with a slight disadvantage in heavy weathe manage this, with only 1kn difference in speed after your claim/assumption?
Also Renown was clearly out run at Norway from SH and GS and both had not the new bows and other modification.

I think many of your claims are wrong and your penetration data to the gun and shell of SH/GS are totaly wrong!

5.
broken shells will be rejected by her scarf armour. Both the belt and scarf armour are backed by about 1in of HT steel. Here's the scarf (main deck slope thickness's: main deck (slope) : 4inch (2inch NCD + 1inch HT + 1 inch HT) over magazines, 3 inch and 1inch (1+1+1 or 1 inch HT) over machinery. So Renown was practically immune from the 28cm gun, through her main belt, at 30 deg target inclination.
As I pointed out, you are refering to the wrong gun, but at your claim is also one major failure, the scarfs had a very steep angle of 60 degrees and were only 60mm, that's nothing more then splinter protection, every shell that will punch through the main belt will go to such a thin scarf, which is also very bad laid back.
1) Yes, you are correct but in my defence this is from Whitley and he put it in the chapter for S&G. I should have noticed the shell weight. Whitely states that 225mm can be penetrated with the L54 gun at 20km at 20 deg obliquity. However, with a 10deg inclined belt, minimum obliquity would be ~28 degs even at 0degs target obliquity at 20km, so even at right angles, Renown's belt (with 1in HT backing) is immune at 20km and probably remains immune to about 18km, but even then the scarf would reject the decapped shell.

Right angle IZ should be about 13km for magazines and ~16km for machinery. However at 30 degs target inclination, and less than this would be unlikely, total obliquity with shell striking angle and belt inclination will be ~35 degs conferring immunity over the magazines at ~10km.

2) G was also slower

3) When was the Atlantic bow completed? Whitley states that it was done prewar, and so was not a success (obviously).

4) DoY never exceeded 24kn because she had to be able to fight her forward armament, she couldn't do that at faster speeds in the prevailing sea state.

5) I gave the main deck slope (scarf) armour thickness's after her 1926 reconstruction (from R&R). The scarf was inclined down about 40degs-45deg (depending on location) where horizontal = 0. Most sources don't give the increased armour over the magazine scarfs nor do they mention the HT plating under the scarf and belt plating.

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Ersatz Yorck
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Re: Intercepting Force H

Post by Ersatz Yorck » Sat Jan 26, 2013 9:27 am

A. Speed differences of 1 knot this way or that in theoretical maximum speeds cannot be used as a basis for deterministic predictions on who will outrun whom in an engagement. Weather, maintenance status, minor engineering failures, fouling etc etc will all change this in practice. And decisions by the commanders taken on the basis on incomplete data are far more important that a one or two knot advantage this way or that.

B. Same with theoretical penetration values and immunity zones. While penetration and armor thicknesses are of course not unimportant, discussions about theoretical immunity zones are largely purely academic IMHO. It is always location, location, location. There are so many lucky or soft kill possibilities that immunity zones are almost meaningless. The ship that will hit the enemy more with heavier shells will probably win, but a single lucky hit can and will decide many naval engagements.

C. Using the engagement at Stromvaer as a guideline for all future engagements between the same or similar ships is not really sustainable, considering that the engagement was decided by two extremely lucky hits. S&G landed the same number of hits but they were "unlucky" in that they didn't inflict any appreciable damage. Nobody "outshot" anyone. If the two hits on the Renown had been "lucky" and knocked out fire control and one main turret, would Renown had been "outshot" then.

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Re: Intercepting Force H

Post by alecsandros » Sat Jan 26, 2013 12:35 pm

dunmunro wrote: Renown was outrun at Stromvaer because she suffered damage to her forward bulge,
Renown was outrun because it was a slower ship.
Repulse also obtained 28-29kts in service in WW2
By maintaining a 30 deg inclination (very typical in combat and easy to do with an inclined belt), Renown has an immune zone from 28cm guns from about 11,000 yards or less:
GKDOS 100 figures consider a 20* obliquity.
Penetration of 28.3 cm L54 L4.4 AP shell is about 230mm at 22km according to GKDOS. Firings were conducted against Krupp new type armor, which was at least 6-7% more resistant to perforation than British 1919-1930 type cemented armor.
Thus penetration of British pre-1930 CA goes around 230mm at 23.5km (single sheet armor)

HT steel is not armor grade, the same way that German ST52 was not armor grade (they were both construction steels)

Thus, the internal armor of 2" is the only internal effective armor plate.
KM practise was to run trials with full overload power - so there is no way that KM ships can move faster then their trials speeds
Where are you getting this from ?
We have info on almost all German capital ships making trials at 60-70% of maximum power, and other tests with ships close to maximum power, and other tests at overload.
- 32 knots for S&G is fantasy. G made 30.7 knots on trials with full overload power and she will only be slower in service.
The fantasy is in your head.

Duke of York, rated at 28-29 kts, lagged behind Schar, with at least 3-4 kts speed differential.

Here's a weight breakdown:
note that with only 4900 tons of fuel that displacement is 38443 tons; full fuel = 6500 tonnes and max displacement is therefore about 40,000 tonnes. These ships used so much fuel that it is unlikely that they would a foray into the Atlantic without full tanks and that is why they had such a reputation as wet ships, they were constantly overloaded beyond their design displacements.
Those are , again, 1943 data. In 1940, maximum displaccement was around 37500 tons, and I don't have any indication on the ships being actualy lloaded at the max at any time whatsoever.

40.000 tons is madness for a very wet ship at 37000 tons.

If you have a source on Schar or Gneis loaded at anything higher than 37000 tons, I would realy like to see it.
Last edited by alecsandros on Sat Jan 26, 2013 12:44 pm, edited 4 times in total.

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Re: Intercepting Force H

Post by alecsandros » Sat Jan 26, 2013 12:38 pm

dunmunro wrote:
2) G was also slower
Against Glorious, Gneis went over 32kts. How is that "slower " ?
4) DoY never exceeded 24kn because she had to be able to fight her forward armament, she couldn't do that at faster speeds in the prevailing sea state.
Source pls?

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Dave Saxton
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Re: Intercepting Force H

Post by Dave Saxton » Sat Jan 26, 2013 3:06 pm

Fraser reported that 24 knots was the best speed the British cruisers could make into wind and seas. Doenitz also mentions this fact in his commentary on the battle and questions why Bey did not go directly into the wind and seas after 13:00 hours; since the British light forces could not follow the heavier Scharnhorst at speeds greater than about 24 knots going into the wind and seas. Bey could have alluded his shadowers this way.

However, the chase segment of the battle was with a following sea and the wind to their backs. Duke of York was low on fuel and running light. This may have meant that Duke of York was having problems maintaining speed with a following sea? Nonetheless, a Scharnhorst survivor noticed that the pitometer repeater at his station was registering 33 knots. Scharnhorst was making an average of 4.5 Knots more speed than Duke of York could.

At Stromvaer, Renown had to reduce speed two seperate times to keep it's forward battery in action following Luetjens initial turn away. It was able to catch back up to SH by 0640 because SH was having problems with two boilers. GU had left them both behind and Luetjens reduced to 20 knots to allow SH to catch up to GU. After 0644 SH had restored her speed, able to make 25 knots initially, and the Germans began to pull away once again. The Germans were soon lost from sight in a snow storm and Renown ceased fire. Renown increased speed to 25 knots with its turrets trained around backwards. Meanwhile, SH had another breakdown reducing its speed to 15 knots. At 0715 hours Renown re-engaged SH. SH turned to a North -North East course directly into the sea, and gradually was able to increase speed while chasing salvoes. SH fired intermittant salvoes from C turret, ceasing fire after the range increased to greater than 25km at 0754 hours. Renown also ceased fire so it could turn the forward turrets away from the seas yet again and inceased speed to 29 knots. However, SH continued to pull away, and by 0815 hours SH was beyond the range of the Renown's 15" guns. If Renown was making 29 knots as reported, then SH was making well better than that.

It should be noted that the problem of water swamping the forward turrets on SH & GU pre-1941 was only manifest when the turrets were trained around so that the backs of the turrets were facing spray coming over the bows and the forecastle breakwaters. The spent casing exits were exposed this way. Otherwise it was not a problem.
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: Intercepting Force H

Post by dunmunro » Sun Jan 27, 2013 12:08 am

The range between DoY and Scharnhorst opened mainly because the two ships were steaming diverging courses, as you can see on the official track chart:

Image

The range at open fire is ~51 pixels, and at 17:00 it is ~74 pixels and at 1800 it is ~89 pixels, so the range has opened less than 2nm (18 pixels) , therefore the speed differential is only ~1.5 knots, and after 1800 they are steering a diverging course, so the range opens rapidly.

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Dave Saxton
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Re: Intercepting Force H

Post by Dave Saxton » Sun Jan 27, 2013 3:04 pm

I wouldn"t put too much faith in a general track chart. Those things are usually not that exact, and in this case considering the conditions and all participants using dead reckoning navigation; it can't be very exact. Furthermore, it implies that the Royal Navy was allowing SH to escape by virtue of their own manovuering, when they were trying to prevent SH from escaping. It would imply that the speed differential only accounts for 2,778 meters in 90 minutes. It is reported by Jacobsen that at 17:17 hours the range was still only 12,500 meters but by 17:46 hours it was 16,500 meters. (4,000 meters in 29 minutes)
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: Intercepting Force H

Post by alecsandros » Sun Jan 27, 2013 5:00 pm

Dave Saxton wrote:I wouldn"t put too much faith in a general track chart. Those things are usually not that exact, and in this case considering the conditions and all participants using dead reckoning navigation; it can't be very exact. Furthermore, it implies that the Royal Navy was allowing SH to escape by virtue of their own manovuering, when they were trying to prevent SH from escaping. It would imply that the speed differential only accounts for 2,778 meters in 90 minutes. It is reported by Jacobsen that at 17:17 hours the range was still only 12,500 meters but by 17:46 hours it was 16,500 meters. (4,000 meters in 29 minutes)
And according to British radar plot, from DoY, distance was
13400y at 17:17
22000y+ at 18:24

that's 8600y in 67 minutes,

and that allthough Schar made several turns to the south to bring turret Bruno to bear, and then resumed course to the east.

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Re: Intercepting Force H

Post by dunmunro » Sun Jan 27, 2013 8:32 pm

alecsandros wrote:

And according to British radar plot, from DoY, distance was
13400y at 17:17
22000y+ at 18:24

that's 8600y in 67 minutes,

and that allthough Schar made several turns to the south to bring turret Bruno to bear, and then resumed course to the east.
As stated, and as the track chart clearly shows, Scharnhorst and DoY were on diverging courses from 18:00 onward.

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Re: Intercepting Force H

Post by dunmunro » Sun Jan 27, 2013 8:34 pm

Dave Saxton wrote: ...(4,000 meters in 29 minutes)
or about 4 knots/hr. So with DoY at 24 knots, that implies 28 knots for Scharnhorst.

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Re: Intercepting Force H

Post by alecsandros » Sun Jan 27, 2013 8:51 pm

dunmunro wrote:
alecsandros wrote:

And according to British radar plot, from DoY, distance was
13400y at 17:17
22000y+ at 18:24

that's 8600y in 67 minutes,

and that allthough Schar made several turns to the south to bring turret Bruno to bear, and then resumed course to the east.
As stated, and as the track chart clearly shows, Scharnhorst and DoY were on diverging courses from 18:00 onward.
I don't know if that's correct.

From a British report of the action:
"The minimum range in blind fire was 13400y, at 17:17, and opened until 18:24 at 22000y, when the Type284 developed a temporarily defect. One of the shots fired at 17-18000y had winged Scharnhorst at or near a propeller shaft and reduced her speed. the range was quickly closed and tracking had started once again at 22000y"
This seems the most logical thing - DoY closely following Scharnhorst. Any "divergent" course would imply some sort of motive for the British BB to allow Schar more time to escape, which is nonsense.

Also, this implies Schar was actualy over 22000y away at 18:24, so more than 8600y were put between the 2 ships in 67 minutes...

Slight changes of course by both heavy ships may have been over-marked on the map (btw, did DoY manouvre in order to bring her aft turret to bear ?)

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Re: Intercepting Force H

Post by dunmunro » Sun Jan 27, 2013 10:16 pm

alecsandros wrote:
dunmunro wrote:
alecsandros wrote:

And according to British radar plot, from DoY, distance was
13400y at 17:17
22000y+ at 18:24

that's 8600y in 67 minutes,

and that allthough Schar made several turns to the south to bring turret Bruno to bear, and then resumed course to the east.
As stated, and as the track chart clearly shows, Scharnhorst and DoY were on diverging courses from 18:00 onward.
I don't know if that's correct.

From a British report of the action:
"The minimum range in blind fire was 13400y, at 17:17, and opened until 18:24 at 22000y, when the Type284 developed a temporarily defect. One of the shots fired at 17-18000y had winged Scharnhorst at or near a propeller shaft and reduced her speed. the range was quickly closed and tracking had started once again at 22000y"
This seems the most logical thing - DoY closely following Scharnhorst. Any "divergent" course would imply some sort of motive for the British BB to allow Schar more time to escape, which is nonsense.

Also, this implies Schar was actualy over 22000y away at 18:24, so more than 8600y were put between the 2 ships in 67 minutes...

Slight changes of course by both heavy ships may have been over-marked on the map (btw, did DoY manouvre in order to bring her aft turret to bear ?)
Fraser was positioning DoY to cut Scharnhorst off, from escaping to the south but bringing Y turret into action may have played a role in the course change as well. Do you really think Fraser would not have noticed that the chart was incorrect, considering that the ranges were plotted by radar and the course via gyro compass, and this map was drawn from Fraser's official Action Report? Range at 18:00 was about 18k yds, so range at 1717 was 13400 yds, then the range opened about 4600 yds in 43 minutes or about 6k yds per hour.

The facts are pretty clear that Scharnhorst's speed was well under 30 knots during the chase until she was damaged at ~18:20

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Re: Intercepting Force H

Post by Dave Saxton » Mon Jan 28, 2013 7:31 pm

And what of the reported pitometer readings?

I didn't know the KGV class could only do 24 knots in a stern chase. :think:
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: Intercepting Force H

Post by dunmunro » Mon Jan 28, 2013 8:29 pm

Dave Saxton wrote:And what of the reported pitometer readings?

I didn't know the KGV class could only do 24 knots in a stern chase. :think:
Read Fraser's dispatch:
d) Force 2.
In position 71° 7' N. 10° 48' E.
steering 080 at 24 knots.
DUKE OF
YORK (Captain the Honourable G. H. E.
Russell, C.B.E., R.N., wearing the flag
of the Commander-in-Chief, Home Fleet),
JAMAICA (Captain J. Hdghes-HaDett,
D.S.O., R.N.), SAVAGE (Commander
M. D. G. Meyrick, R.N.), SCORPION
(Lieutenant-Commander W. S. Clouston,
R.N.), SAUMAREZ (Lieutenant-Commander
E. W. Walmsley, D.S.C., R.N.),
and STORD (Lieutenant-Commander S.
Storeheill, R.Nor.N.).
18. As J.W.55B. had been consistently
shadowed and reported by U-boats and aircraft
throughout its passage, and R.A.55A was
apparently undetected, I appreciated that
SCHARNHORST would make for the former
convoy.
19. While breaking W/T silence would give
away the fact that covering forces were in the
vicinity I decided that the safety of the convoy
must be the primary object.
20. The following action was therefore
taken: —
(a) The convoy was diverted to the north
in the hope that the change of course would
make it more difficult for the SCHARNHORST
to find it.
(b) C.S. 10* was ordered to report his
position and 0.17* that of the convoy.
(c) My position, course and speed was
indicated.
21. On the course and speed of Force 2
and in the following sea my destroyers had
much difficulty in avoiding broaching to and
the DUKE OF YORK'S bows were constantly
under water
.
DoY could probably steam faster but she would lose her gunnery effectiveness, and possibly risk structural damage. Force 2 was already moving as fast as it could when it encountered Scharnhorst.

Regarding Scharnhorst's recorded movements and speeds, these were all being accurately plotted via type 273 radar:

FIRST DESTROYER TORPEDO ATTACK BY
SCREEN OF FORCE 2.
60. At this time it seemed quite probable
that SCHARNHORST would escape and much
depended upon the four " S " class destroyers.
At 1713 they had 'been ordered to attack with
torpedoes and I could now see them on my
radar very slowly gaining bearing on SCHARNHORST
waiting for her to make an appreciable
lalteratiion of course to allow them to
attack. By 1820 they had closed in to 12,000
yards but were gaining little. At this time
they started to forge ahead and this must have
been due to the DUKE OF YORK's hit which
reduced SCHARNHORST'S speed and has
already been referred to. This was borne out
by the radar plot and the fact that she ceased
firing at this time.
61. As the effect of this was not apparent for
some time I had already decided to turn towards
the Norwegian coast, hoping the enemy would
also lead round and so give my destroyers
a chance to attack. When, however, I saw the
speed reduction I turned in straight at the
SCHARNHORST.

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