Intercepting Force H

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paul.mercer
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Re: Intercepting Force H

Post by paul.mercer » Mon Jan 28, 2013 10:13 pm

dunmunro wrote: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.

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.

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:

Image
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.

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 - 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. Here's a weight breakdown:

http://www.schlachtschiff.com/kriegsmar ... emein.html

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.
Gentlemen,
Quoting from the book 'Strike Hard Strike Sure' (HMS Renown 1916-1948) by Peter Smith one of the crew members states 'our own return fire from the 15" forward gunsshook the rivets off our starboard bulge forward that 30 feet of it stuck out at an angle of 90% causing a secornd terrible second bow wave'. Another witness states that 'it was apparent that the sea had damaged us more than the enemy, umteen feet of our bulges had torn off on both sides, and resembled giant scoops' It is not surprising therefore that Renown did not attain her full speed.
But surely these references to maximum speed both here and on other posts are all problematical and entirely dependant on conditions at the time. I presume that when a ship has her speed test over the 'measured mile' it will be when she is in top condition in as near perfect conditions as possible and is unlikely to achive the same results after months at sea and in foul weather. For instance, if the KGv class achieved 27.5, 27.6, 27.7, 28.5 or even 29.1 knots under different conditions really makes very little difference overall and this would also apply to any of the German ships who are generally quoted as being much faster than anything in the RN.
I have to repeat what I tried to say in another post, I really do not understand why it almost always seems to be assumed that German capital ships are so much better than those of the RN, i.e. faster, better armour, better guns, better shells, better range finders, etc. etc. I realise the Nelsons were old, but they were still very powerful well armoured ships and that the KGv's had their faults but were again powerful and well armoured and even the uprated QE's were a force to be reckoned with, it seems to be a shame that the RN appears to be so underated on this forum.

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Re: Intercepting Force H

Post by Dave Saxton » Tue Jan 29, 2013 4:27 am

Duncan,
The reference to Duke of York going to 24 knots has nothing to do with the stern chase. The time that going to 24 knots and ordering additional destroyers to close on the convoy alluded to was right after Fraser received the message: "Admiralty appreciates that Scharnhorst is at sea" at 0339 hours. This was about 13 hours prior to the interception that initiated the stern chase.
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 » Tue Jan 29, 2013 6:20 am

paul.mercer wrote: I have to repeat what I tried to say in another post, I really do not understand why it almost always seems to be assumed that German capital ships are so much better than those of the RN, i.e. faster, better armour, better guns, better shells, better range finders,
Because the body of evidence available thus far indicates that.

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Re: Intercepting Force H

Post by dunmunro » Tue Jan 29, 2013 6:22 am

Dave Saxton wrote:Duncan,
The reference to Duke of York going to 24 knots has nothing to do with the stern chase. The time that going to 24 knots and ordering additional destroyers to close on the convoy alluded to was right after Fraser received the message: "Admiralty appreciates that Scharnhorst is at sea" at 0339 hours. This was about 13 hours prior to the interception that initiated the stern chase.
Use the chart that I posted earlier and plot DoY's movement from 18:00 to 18:24 (it is mostly a straight line at that point) - it works out to exactly 24 knots.

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Re: Intercepting Force H

Post by dunmunro » Tue Jan 29, 2013 6:24 am

alecsandros wrote:
paul.mercer wrote: I have to repeat what I tried to say in another post, I really do not understand why it almost always seems to be assumed that German capital ships are so much better than those of the RN, i.e. faster, better armour, better guns, better shells, better range finders,
Because the body of evidence available thus far indicates that.
:lol: It only seems that way when you ignore all the evidence to the contrary...

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Re: Intercepting Force H

Post by alecsandros » Tue Jan 29, 2013 6:32 am

dunmunro wrote:
alecsandros wrote:
paul.mercer wrote: I have to repeat what I tried to say in another post, I really do not understand why it almost always seems to be assumed that German capital ships are so much better than those of the RN, i.e. faster, better armour, better guns, better shells, better range finders,
Because the body of evidence available thus far indicates that.
:lol: It only seems that way when you ignore all the evidence to the contrary...
:)

Give me an example :cool:

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Re: Intercepting Force H

Post by Dave Saxton » Tue Jan 29, 2013 3:06 pm

dunmunro wrote:Use the chart that I posted earlier and plot DoY's movement from 18:00 to 18:24 (it is mostly a straight line at that point) - it works out to exactly 24 knots.
Only using the chart would require ignoring all the other evidence to the contrary. Most telling is the accounts of the British destroyers involved. Early on the 26th Force 2 went to 24 knots as Fraser stated. Then shortly after Burnett lost radar contact with the Scharnhorst at 10:20 hours Fraser ordered a reduction in speed to 18 knots and actually reversed course to the west for awhile. Then after Burnett re-aquired radar contact with Scharnhorst, Fraser issued new orders.

At dawn (which in the artic on Dec 26th was about 12:30 hours), according to the Stords record, Fraser ordered an increase in speed to 25 knots followed shortly with a further increase in speed to 27 knots. The Stord's commander noted that this was despite the weather. It looks like Force 2 was making 27 knots in the following sea at the time of the interception. Then they decreased speed?

No, they in fact did not. According to the destroyers they increased speed. Fraser ordered the destroyers to: "take up the most advantageuos postion for a torpedo attack." Yet according to Commander Meyrick of the Savage despite working up to speeds exceeding 30 knots they could not close on the Scharnhorst. The Stord's account mentions that they were "coaxing the maximum out of the turbines" during this phase of the battle. Obviously the chart is wrong.


And we still have a the reported pitometer reading of 33 knots on Scharnhorst to consider. Perhaps the survivor misremembered? Or perhaps it was slightly inaccurate. But not by five knots.
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.

alecsandros2

Re: Intercepting Force H

Post by alecsandros2 » Tue Jan 29, 2013 6:13 pm

Do we have DoY's logs for the mission ?

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Re: Intercepting Force H

Post by dunmunro » Tue Jan 29, 2013 9:31 pm

Dave Saxton wrote:
dunmunro wrote:Use the chart that I posted earlier and plot DoY's movement from 18:00 to 18:24 (it is mostly a straight line at that point) - it works out to exactly 24 knots.
Only using the chart would require ignoring all the other evidence to the contrary. Most telling is the accounts of the British destroyers involved. Early on the 26th Force 2 went to 24 knots as Fraser stated. Then shortly after Burnett lost radar contact with the Scharnhorst at 10:20 hours Fraser ordered a reduction in speed to 18 knots and actually reversed course to the west for awhile. Then after Burnett re-aquired radar contact with Scharnhorst, Fraser issued new orders.

At dawn (which in the artic on Dec 26th was about 12:30 hours), according to the Stords record, Fraser ordered an increase in speed to 25 knots followed shortly with a further increase in speed to 27 knots. The Stord's commander noted that this was despite the weather. It looks like Force 2 was making 27 knots in the following sea at the time of the interception. Then they decreased speed?

No, they in fact did not. According to the destroyers they increased speed. Fraser ordered the destroyers to: "take up the most advantageuos postion for a torpedo attack." Yet according to Commander Meyrick of the Savage despite working up to speeds exceeding 30 knots they could not close on the Scharnhorst. The Stord's account mentions that they were "coaxing the maximum out of the turbines" during this phase of the battle. Obviously the chart is wrong.


And we still have a the reported pitometer reading of 33 knots on Scharnhorst to consider. Perhaps the survivor misremembered? Or perhaps it was slightly inaccurate. But not by five knots.
First off, Scharnhorst couldn't do 33 knots in flat calm conditions - that would require far more power than her engines were capable of. All ships gained weight as the war progressed, and Scharnhorst was no longer capable of her pre-war full overload trials speed of 31.65 knots, which was probably recorded at much less than full load, even then. Scharnhorst's full load (full fuel, feedwater, ammo, stores) was about 39600 tonnes in 1939, and the ship added considerable weight so that by Dec 1943, actual full load would have exceeded 40,000 tonnes by a considerable amount, consequently Scharnhorst was slower and wetter.

Using her speed-power chart, and given the prevailing sea state, Scharnhorst's maximum speed was probably about 28 knots - 30 knots depending on her course and these are the speeds reported in Fraser's despatch (simply look through it by searching for "knot" although mention of 30 knots are estimates). The RN destroyers were unable to gain appreciably on Scharnhorst because they simply couldn't drive themselves any faster in the prevailing conditions - even if they were using RPM for higher speeds, the sea state would slow them considerably. The S class destroyers ran trials with ~31.5 knots at full load, while the M class could only manage about 33 knots at deep load. In a 1/2 oil state both classes gained about 1-1.5 knots, but these were under trial conditions and reasonably calm seas. Running the same trials in the sea state at North Cape would have resulted in a dramatic reduction in speed. DoY made 28.6 knots on trials in a very calm seastate, yet Howe ran .9 knots slower with worse sea conditions and Force 4 winds, yet destroyers will slow far more than battleships, in heavy seas.

If the RN had an estimated speed for Scharnhorst of 32 or 33 knots, at North Cape, don't you think that Fraser would have mentioned this rather remarkable fact?

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Re: Intercepting Force H

Post by Dave Saxton » Wed Jan 30, 2013 2:25 am

That's more like it. Around 30 or slightly more knots for Scharnhorst and about 27 for Duke of York. BTW I'm not accepting the reported 33 knot reading at face value. I'm just pointing out that this was reported and thus it would seem to indicate that a 28 knot estimate is off base.

We do have some indication of what speeds Scharnhorst was capable of by late 1943, because Hintze and Koenig ran machinery trials in Stjern Sound during Nov 43. After SH topped off all fuel tanks (taking on 4,300 cubic meters) the SH attained 29.7 knots. Bey complained that this was less than SH had attained in 1940 at full load, but Koenig was happy considering SH ran these particular runs with 50cm more draught than in 1940. Scharnhorst ran several additional excersises in the Fjords in the following weeks but as far as I can tell it didn't take on more fuel. The SH was likely well less than full load by the time it sailed on Dec 25th, and certainly it had burned off significant fuel tonnage by the time the stern chase took place.
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 » Wed Jan 30, 2013 3:04 am

Dave Saxton wrote:That's more like it. Around 30 or slightly more knots for Scharnhorst and about 27 for Duke of York. BTW I'm not accepting the reported 33 knot reading at face value. I'm just pointing out that this was reported and thus it would seem to indicate that a 28 knot estimate is off base.

We do have some indication of what speeds Scharnhorst was capable of by late 1943, because Hintze and Koenig ran machinery trials in Stjern Sound during Nov 43. After SH topped off all fuel tanks (taking on 4,300 cubic meters) the SH attained 29.7 knots. Bey complained that this was less than SH had attained in 1940 at full load, but Koenig was happy considering SH ran these particular runs with 50cm more draught than in 1940. Scharnhorst ran several additional excersises in the Fjords in the following weeks but as far as I can tell it didn't take on more fuel. The SH was likely well less than full load by the time it sailed on Dec 25th, and certainly it had burned off significant fuel tonnage by the time the stern chase took place.
Thanks for the info. A couple of things to note; if Scharnhorst could make 29.7 knots in calm water, her full speed in a Force 8 gale and rough seas would be somewhat less, although it is possible that on some courses she would do better than on others. Also an increase in full load draft of 50cm implies an increase in full load displacement by ~2750 tonnes, which is about what I would expect, and about the same as similar RN BBs. Given the sea state and the need for accurate gunnery, I just don't see DoY making 27 knots from 16:50 to 18:24, and it is odd that Fraser would not mention an increase in speed. I may be able to get a better map, with higher resolution, and if so I will post it here.

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Re: Intercepting Force H

Post by alecsandros » Wed Jan 30, 2013 8:07 am

dunmunro wrote: Scharnhorst's full load (full fuel, feedwater, ammo, stores) was about 39600 tonnes in 1939,
Were are you taking this from ?

What kind of "tons" are they ? Metric or long ?

What draught would the ship have at ~40.000 tons, and what freeboard ?

G&D Axis BBs gives 38000 long tons maximum load for 1943, and 37000 long tons maximum load for 1939 (time of their comissioning).
[this considers maximum ammo load, full quantity of liquids on board, etc]

Actual displacement would be lower, as much fuel would have been expended before engagements (with Glorious, with DoY, etc)

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Re: Intercepting Force H

Post by MikeBrough » Wed Jan 30, 2013 8:37 am

I had a look at the link in the OP and the mention of the source, "the Kelly's", reminded me that the title contained a superfluous apostrophe. It annoyed me so much that I decided not to buy the book when it first came out.

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Re: Intercepting Force H

Post by dunmunro » Wed Jan 30, 2013 9:05 am

alecsandros wrote:
dunmunro wrote: Scharnhorst's full load (full fuel, feedwater, ammo, stores) was about 39600 tonnes in 1939,
Were are you taking this from ?

What kind of "tons" are they ? Metric or long ?

What draught would the ship have at ~40.000 tons, and what freeboard ?

G&D Axis BBs gives 38000 long tons maximum load for 1943, and 37000 long tons maximum load for 1939 (time of their comissioning).
[this considers maximum ammo load, full quantity of liquids on board, etc]

Actual displacement would be lower, as much fuel would have been expended before engagements (with Glorious, with DoY, etc)
Scharnhorst was designed with a standard displacement of 31.552 tonnes*; adding to this 7237 tonnes of fuel and water, we get a design full load of 38789 tonnes. Then we start adding in all the extra equipment added since the design was finalized up to Dec 1943 and a full load displacement well over 40,000 tonnes, is the end result.** By way of comparison the KGV class added ~5000 tons at full load over their designed full load.

Look at the weights here:
http://www.schlachtschiff.com/kriegsmar ... emein.html
Load displacement = 38,443 tonnes but full fuel would add 1400 tonnes to this figure

*and here:
http://www.scharnhorst-class.dk/technic ... tails.html

** Dave's data, above, implies a full load of ~41500 tonnes in Dec 1943

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Re: Intercepting Force H

Post by alecsandros » Wed Jan 30, 2013 1:03 pm

dunmunro wrote: Scharnhorst was designed with a standard displacement of 31.552 tonnes*; adding to this 7237 tonnes of fuel and water, we get a design full load of 38789 tonnes. Then we start adding in all the extra equipment added since the design was finalized up to Dec 1943 and a full load displacement well over 40,000 tonnes, is the end result.** By way of comparison the KGV class added ~5000 tons at full load over their designed full load.
What source are you using ?

G&D mention a standard displacement of ~ 30800 tons in 1939, and 31800 tons in 1943 for Scharnhorst.
Full load of 37224tons in 1939 for Scharnhorst, and a 9,93 meters draft, with 4,07 meters freeboard amidships.
War modifications modified full load displacement to 38100 tons in 1943.

This means roughly 7000 tons of difference between full load and standard load.

This makes sense, as BIsmarck had 41700tons standard displacement and 50900 tons full load, with 9200 tons in difference.

Bismarck was 15 meters longer, and had a 6meters wider beam than Schar.

Saying Scharnhorst had 41500 tons displacement (so 9700 tons diference from standard) would imply that they would carry more load than their larger cousins.

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