Lutjens' Intentions

Discussions about the history of the ship, technical details, etc.

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Herr Nilsson
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Re: *sigh*

Post by Herr Nilsson » Thu Jul 18, 2013 10:26 am

Pandora wrote:
Herr Nilsson wrote:Metric tons and cubic meters are different. The offical density of heating oil used in the Kriegsmarine for calculations was 0.927.
hello Mr. Herr Nilsson. in the scan you uploaded earlier it is written 0.97 density I think. Spez. Gewicht?

Image
Well observed. Bismarck's trials (or at least all I know where a density is mentioned) were done with oil with a density of 0.97. I took the figure from a memo about the wartime experiences with Bismarck and Tirpitz, which was made by Marineoberbaurat Krux after the sinking of Tirpitz . There is a simliar list included in this source. You'll notice, that the densitiy is again different.
Tirpitz.jpg
Tirpitz.jpg (73.11 KiB) Viewed 1022 times
The density of heating oil varied very much therefore the Germans standardized a certain value (0,927) for weight list and calculations.
Dichte.jpg
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Bismarck.jpg
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Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

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Re: *sigh*

Post by Herr Nilsson » Thu Jul 18, 2013 10:34 am

Bismarck2.jpg
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Gneisenau.jpg
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M-Boote 35.jpg
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Regards

Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

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Re: Lutjens' Intentions

Post by Vic Dale » Thu Jul 18, 2013 12:32 pm

Well thanks for all the wonderful information - it would be great if I could understand it. I doubt it makes a great deal of difference to Bismarck's endurance.

Last night I manged to locate the correct position of Grid Square AK55 on Google Earth and got a shock. I think we have all seen the chart in the Baron's book which shows how Lutjens evaded his shadowers and I don't doubt that everyone thought - as I did myself - that the ship made off to the southeast. The grid square is to the north of where I had thought. The southwestern corner of the square is located at; 57* 25' N by 35* 57' W.

AK55 therefore lies to the northeast of the position at which contact was lost at 0306. The track chart plots Lutjen's evasion maneuver over the following hour, heading to the west, north and North east and arriving at a position 10 miles to the north west of her position at 0306. Bismarck could only have made AK55 at her then maximum of 28 knots. She will have hit the southwestern corner at 0700 and that must have been what triggered the need to report her position to Group west. The shadowing report contained in that signal is of secondary importance and is not necessarily a strong expression of the tactical situation.

In order to make AK55, Bismarck's heading would have had to have been 48 degrees. Allowing for dead reckoning errors I would suggest that Lutjens set a course of 45 degrees - northeast - and on that heading the ship was pointing toward the Iceland Faroes exit from the Atlantic into the Arctic. I shall present graphic illustrations of my findings later.

The logic of the situation at 0306 was that Bismarck was heading south, though to the east of Prinz Eugen's track. Doubling back round to the north west between 0306 and 0400, had two advantages; firstly, the heading was opposite to that being followed by PG, secondly it was in the opposite direction to that taken by Wake Walker's squadron after contact was lost, though I am not certain that Lutjens was aware of their heading as they hunted for him.

I now have an alternative view of the purpose of the evasion maneuver. The shadowing force was stationed to the port side of Bismarck's track, with Suffolk closest, Norfolk to port of her and PoW farther still out to port. The reason for this pattern is; if Lutjens chose to break to the east, she would come into direct contact with PoW and an engagement would ensue. Keeping Suffolk closest allowed her to maintain radar contact - of sorts - and also offer a soft target which might tempt Lutjens to attack and draw him to the east and towards the C-in-C Home Fleet. The Zig Zag was set not only to avoid U-Boats, but to keep the squadron up to speed in case Lutjens tried to break away using high speed. Wake-Walker basically had the situation taped. Permitting Bismarck to go off the radar periodically whilst the squadron was on the outer leg of the zig zag prevented Lutjens from learning the true range capability of Suffolk's radar and it also kept Suffolk at a safer range. It also presented Lutjens with a possibility, if he knew the range capability of Suffolk's radar, but he didn't, so it seems Lutjens made his move simply to later his heading. Causing the enemy to lose contact was a happy accident.

In doubling back round to the west ,then north, Lutjens was able to make best use of the enemy's speed to get round behind him and head to the northeast and away from PG without the need to engage PoW. Then it was a case of increasing speed and making off to the northeast.

The above observations have opened yet another possibility and though I know this opens a can of worms and may feed those who wish to undermine my suggestions, I must pursue it.

During the past ten years, I have managed to show that the long message transmitted by Lutjens was sent in four segments at 0401, 0417, 0428 and 0443. The ship used teleprinters ship to shore and the send speed would have got each segment off in about 15 seconds, far to short a time for ships to make a DF fix, though if they were listening, they might get a heading.

With the above in mind and having regard to what the Radio Officer in PG says he heard over the radio; supposing Lutjens intended for the transmissions to be heard? He might insist that the signal was sent by morse key and by a man with a very slow hand in order to ensure the enemy could make a DF fix. This would have to be a very special arrangement and with a very special purpose in mind. It would only make sense if Lutjens intended to draw the enemy force away from PG, by giving his own position away. I am not the first to suggest that the signal was a ruse to draw the enemy away from PG, I believe Tommy first raised it many years ago. This is only a possibility and if it transpires that the need for WT security maintained, then the ship would still be safe making that transmission using her teleprinters.

Finally, heading northeast (45 deg.) to AK55 demonstrates beyond doubt that Bismarck was not anywhere near short of fuel and that there was no desperation to get to France. The alteration to 150 deg. sometime later that day shows again that France was not where Lutjens was headed at that time.

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Re: Lutjens' Intentions

Post by Herr Nilsson » Thu Jul 18, 2013 1:38 pm

Vic Dale wrote: The southwestern corner of the square is located at; 57* 25' N by 35* 57' W.
54°36'00"N, 034°00'00"W
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Marc

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Re: Lutjens' Intentions

Post by Vic Dale » Thu Jul 18, 2013 4:41 pm

Try and plot the position of Grid Sqaure AK55 using the lat' and long' as shown on Grid Map (54°36'00"N, 034°00'00"W) on Google. I did and it produces a grid square position so far south, Bismarck could not possibly reach it at 40+ knots.

It is necessary to find the actual geographical positions on the Grid map which the tops and sides of the AK55 square align to in Scotland and Labrador.

The base line of the grid square aligns with the southern headland of Maryport in Scotland and Holton Island to the north of Lake Melville in Labrador.

The top of the square aligns with Kidialuit Island in Labradour and the town of Ayr in Scotland.

The western edge aligns with Aliuarssik and the western edge aligns with Tikivigpik in Greenland

There is no place to align to in the south, so a simple north-south line will do for each side.

The error between the Grid Map and the globe is the reason Doenitz used the large globe for plotting his U-boats positions.

The latitude and longitude markings on the Grid Map, which is flat, cannot produce an accurate position on the globe, without a complicated set of calculations.

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Re: Lutjens' Intentions

Post by Herr Nilsson » Thu Jul 18, 2013 6:42 pm

I'm sorry, if it doesn't fit to your story, but the center of AK 55 is 55°03'00"N, 033°15'00"W.
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Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

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Re: Lutjens' Intentions

Post by Vic Dale » Thu Jul 18, 2013 7:28 pm

On the Grid map AK 55 is truly is; 55°03'00"N, 033°15'00"W as you say, but that won't work on the globe without serious correction.

Bismarck was sailing on the surface of the globe and it all looks very different in comparison to flat charts. This is why charts do not work on the large scale and are only really of any use in coastal areas.

The position at which contact was lost is clearly given as 56* 20' N by 36* 20' west and that is the position I have plotted on Google Earth and which I have been using since the start of this discussion. All ships involved, both British and German, managed to get a sun shot at noon on the 24th to establish their positions, so I don't think that can be greatly in dispute. Their dead reckoning would have to be about 100 miles out and the worst it ever was during the course of this operation was about 25 miles after three days without a sun shot.

Plotting the position you have given for AK55, Bismarck would have had to steam 178nm by 0700, or at 60 knots for 3 hours to reach it.

Better look at it again.

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Re: Lutjens' Intentions

Post by RNfanDan » Thu Jul 18, 2013 8:47 pm

I must ask:

What aim is served by transposing already-known, and fairly accurate, reported lat-long positions into grid squares? Properly, grid squares are estimators, helpful in the absence of precise global positions---not the other way 'round.

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Re: Lutjens' Intentions

Post by Wordy » Thu Jul 18, 2013 9:21 pm

RNfanDan wrote:I must ask:

What aim is served by transposing already-known, and fairly accurate, reported lat-long positions into grid squares?

Dan.
Unfortunately l think we all know, I just don't understand why he's going to such effort to troll a military history forum :?
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Re: Lutjens' Intentions

Post by Guest » Thu Jul 18, 2013 10:50 pm

The German grid charts are in Mercator projection and Google Earth is essentially gnomonic. These are only semi-compatible. If you confuse those two -- one gives a correct (constant) course from point 'a' to point 'b' but not necessarily the shortest distance, and the other presents the shortest distance (rhumb line) but cannot give, except by interpolation, the course(s) required to achive this. If you mix these up you will thoroughly confuse yourself (and, perhaps, others as well). It's my recollection, perhaps incorrect, that the British did exactly this at least once during the 'Bismarck' chase, sending British units off, for a while, in entirely the wrong direction...

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Re: Lutjens' Intentions

Post by Herr Nilsson » Fri Jul 19, 2013 2:58 pm

Vic Dale wrote:On the Grid map AK 55 is truly is; 55°03'00"N, 033°15'00"W as you say, but that won't work on the globe without serious correction.

Bismarck was sailing on the surface of the globe and it all looks very different in comparison to flat charts. This is why charts do not work on the large scale and are only really of any use in coastal areas.

The position at which contact was lost is clearly given as 56* 20' N by 36* 20' west and that is the position I have plotted on Google Earth and which I have been using since the start of this discussion. All ships involved, both British and German, managed to get a sun shot at noon on the 24th to establish their positions, so I don't think that can be greatly in dispute. Their dead reckoning would have to be about 100 miles out and the worst it ever was during the course of this operation was about 25 miles after three days without a sun shot.

Plotting the position you have given for AK55, Bismarck would have had to steam 178nm by 0700, or at 60 knots for 3 hours to reach it.

Better look at it again.
Vic, I'm pretty sure the Germans didn't use Google Earth.
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Marc

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Re: Lutjens' Intentions

Post by Vic Dale » Fri Jul 19, 2013 3:55 pm

But their ships did sail on a globe and not on a Mercators projection. The Grid Map is clearly a Mercator's projection and such a projection has limitations for navigation. The shortest distance between two points on a Mercator's projection is, as can be seen on the Grid Map, a straight line, whilst on a globe it is a curve.

I believe there must be an additional book for use with the grid Map which gives the Latitude and Longitude for the center of each Grid Square.

From the U-Boat Grid System http://www.convoyweb.org.uk/extras/inde ... htm~exmain;

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
"The U-boat Positional Grid System

U-boats had a novel method for reporting and receiving positional information based on a grid system. This was easier to use than the conventional latitude/ longitude fix and less liable to error in transmission. Each area of the world was divided into sectors which were given a 2 letter designation. For example, the sinking of SS Port Hunter (dispersed from OS.33) was reported as grid reference DG6397, referring to the sector designated DG on the main chart (below). Each sector was divided into a 3x3 grid which was further divided into another 3x3 grid to produce 81 sub-sectors which were given a logical 2 digit number (bottom left). Thus, the position of the Port Hunter is seen as DG63. The sub-sectors were similarly further divided (bottom right) to identify the final position of DG6397."
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

From this we can see that conventional navigation was side stepped in order to find a quick and certain way of transmitting a U-Boat's position. AK55 is much quicker to send than; 56* 20' N by 36* 20' W. The grid system is not about navigation but is a method of reporting. So if the actual position of a grid square is needed then the lines between physical locations on an actual globe are needed.

I am going to attempt to plot all positions by Latitude and Longitude which were reported in War Diaries, Sighting Reports and from Personal Diaries, during the life of this operation. This may take some time, but it may tie up the loose ends. Then possibly we'll get a clearer picture of what went on.

Doenitz and his U-Boats may not have use Google Earth, but Doenitz most certainly used a globe at U-Boat Headquarters, so as to be able to make sense of U-Boat reports.

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Re: Lutjens' Intentions

Post by Herr Nilsson » Fri Jul 19, 2013 4:14 pm

Vic Dale wrote:The grid system is not about navigation but is a method of reporting.
:clap: That was a difficult birth.
Regards

Marc

"Thank God we blow up and sink more easily." (unknown officer from HMS Norfolk)

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Re: Lutjens' Intentions

Post by Guest » Fri Jul 19, 2013 6:47 pm

A one meter diameter globe would have a natural scale of about 1:13,000,000, which is really too small to make useful navigational measurements on, which is -- of course -- one reason why navigators never took big globe models to sea for navigational purposes. Those with navigational experience are perfectly happy with, and get very good results from, conventional charts. I'm sure that if such a globe were indeed used, its purpose would have been more decorative than functional. I'm highly skeptical that Adm. Doenitz needed to look at a globe to help him understand things...

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Re: Lutjens' Intentions

Post by tommy303 » Fri Jul 19, 2013 7:08 pm

Vic,

This might speed things up for you:

http://grid.nylle.de/

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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