GHG and the related warnings

Discussions about the history of the ship, technical details, etc.
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Antonio Bonomi
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GHG and the related warnings

Postby Antonio Bonomi » Mon Mar 09, 2015 3:24 pm

Hello everybody,

the Gruppen Horch Gerät ( GHG ) installed on both Prinz Eugen and Bismarck had a very critical role.

It helped the enemy interception as well as it caused some alarms.

A Prinz Eugen survivor I interviewed time ago told me that it was a key equipment they were utilizing during the Op. Rheinubung.

What is your opinion about it and it's role during the various operation events.

Bye Antonio :D
In order to honor a soldier, we have to tell the truth about what happened over there. The whole, hard, cold truth. And until we do that, we dishonor her and every soldier who died, who gave their life for their country. ( Courage Under Fire )

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Re: GHG and the related warnings

Postby alecsandros » Mon Mar 09, 2015 4:53 pm

Antonio Bonomi wrote:Hello everybody,

the Gruppen Horch Gerät ( GHG ) installed on both Prinz Eugen and Bismarck had a very critical role.

It helped the enemy interception as well as it caused some alarms.

A Prinz Eugen survivor I interviewed time ago told me that it was a key equipment they were utilizing during the Op. Rheinubung.

What is your opinion about it and it's role during the various operation events.

Bye Antonio :D


For me, the key element brough by the GHG during the main battle phase was the detection of "2 more enemy vessels" [Hood and Prince of Wales], at 5:35 or so, implying that range TO Hood and Prince of Wales at that moment was ~ 30km or so. [the Prinz eugen log also tells us that the battleship detection range was about 30km]

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Re: GHG and the related warnings

Postby Steve Crandell » Mon Mar 09, 2015 5:03 pm

The sonar from the Prinz Eugene was installed on a US submarine post war. It was studied and formed the basis for one of several sonars installed on US submarines. We called it the "conformal array". It had a large number of transducers wrapped around the bow and a short distance down the sides of the submarine. This sonar was called the BQR-1. I served on US submarines for nine years, in the late sixties and early seventies. By that time it had been considerably refined with advanced transducers and electronic signal processing, and it was called the BQR-7.

I was not a sonar operator, but spent a fair amount of time in the sonar room and a lot of time in the control room while tracking various contacts. The conformal array was used when we were looking for a very faint contact, possibly at very long range. It was not the preferred sonar when tracking something at medium to close range for a fire control solution. Because of the possibility of a very long range contact, it could take quite a while to determine how close it was and whether it was worth prosecuting. Like all sonars, it worked best on a very quiet platform moving at low speed.

Was Prinz Eugene very quiet? Obviously not. She would have had a large amount of self noise as well as a large amount of flow noise when travelling at high speed. Of course, a large target surface ship travelling at high speed is also very noisy and she could and did track them.

With respect to the torpedo report at DS ... have you ever been under water listening to a ski boat? That is similar to what a torpedo sounds like. In my opinion, that same sort of sound could be caused by equipment on one of the British ships; possibly even a "runaway" motor of some kind on Hood, sinking into the depths. Could it have been one of Hood's torpedoes started by the shock of her death throes? Who knows?

Currently large USN ships like carriers do not carry sonars. They did at one time, but it just isn't considered worth it today.

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Re: GHG and the related warnings

Postby alecsandros » Mon Mar 09, 2015 8:49 pm

:clap:

I would like to ask what does "flow noise" mean ? Is it the water rushing sideways and under the ship ?

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Re: GHG and the related warnings

Postby Antonio Bonomi » Mon Mar 09, 2015 9:30 pm

Hello everybody,

on the Baron book he wrote that just after 05.00 that morning the Prinz Eugen hydrophones picked up noise on the port ( left ) side of the German formation.

Than Group North at 05.09 informed them that the Suffolk was again radio communicating their position ....

Now my question to you is very simple.

Do you think that it was because of that warning that Adm Lutjens ordered this manoeuvre of the German formation from 220° to 170° and back to 220 ° again ?

BS-PG_0520-0535_manoeuvre.jpg
BS-PG_0520-0535_manoeuvre.jpg (58.09 KiB) Viewed 1145 times


Opinions welcome ...

Bye Antonio :D
In order to honor a soldier, we have to tell the truth about what happened over there. The whole, hard, cold truth. And until we do that, we dishonor her and every soldier who died, who gave their life for their country. ( Courage Under Fire )

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Re: GHG and the related warnings

Postby Steve Crandell » Mon Mar 09, 2015 10:48 pm

alecsandros wrote::clap:

I would like to ask what does "flow noise" mean ? Is it the water rushing sideways and under the ship ?


Yes. It interferes with the efficiency of the transducers. Any imperfections or protrusions can also cause cavitation, which is a noise source. Part of preparation to submerge after leaving port involves folding all cleats and other topside protrusions under so the hull becomes as smooth as possible and water can flow around it with as little irregularity as possible.

Of course a large ship with screws designed for high speed and efficiency (not silence) cavitates a great deal and causes noise that can be heard from a great distance. Modern submarine screws are designed as a compromise between propulsive efficiency and the reduction of cavitation. Also, the deeper you go the faster the screws can turn without cavitating.

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Re: GHG and the related warnings

Postby alecsandros » Tue Mar 10, 2015 7:18 am

Antonio Bonomi wrote:
on the Baron book he wrote that just after 05.00 that morning the Prinz Eugen hydrophones picked up noise on the port ( left ) side of the German formation.


... Is it certain it was Prince of Wales and Hood ?
Because we know the limitations of the GHG, and tracking them at 05:00 would imply a range of ~ 30km. This begs the question of why didn't the 2 forces interact much, much sooner then 05:52.

ALso, Prinz Eugen's log mentions a detection of 2 new contacts at around 5:30, not 05:00...

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Re: GHG and the related warnings

Postby paulcadogan » Tue Mar 10, 2015 7:57 pm

alecsandros wrote:ALso, Prinz Eugen's log mentions a detection of 2 new contacts at around 5:30, not 05:00...


Hmmm... Prinz Eugen's KTB is very confusing:

Brinkmann notes this in sequence:

At 0407, noises were heard by the GHG bearing 286 degrees. (If that is "true" that would be on the starboard bow if the ship was on 220 which makes no sense). Then at 0425 the GHG reported torpedo noises bearing 195 degrees (just fwd of the port beam) which were attributed by Brinkmann to a mistaken bearing caused by the ships to port. THEN almost an hour later at 0521 the two ships turn to port to 170.

(Note - this can't be a mix up of time conversion since the 0425 entry comes ahead of the 0521. So 0425 is not really 0525. :?: )

Schmalenbach reports something completely different:

At estimated 0425 (which has 0525 GMT in brackets) the listening room reported propeller noises bearing 242 or 252 degrees, specifying two targets and after a few minutes smoke was seen from the foretop in that direction and all this was duly reported to Brinkmann.

So Brinkmann writes torpedo noises at 0425 (0525??), Schmalenbach specifies propeller noises from two contacts at about 0525, then smoke.

But at 0525, if that time is accurate, the ships are already on course 170.

What gives?? :?
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Re: GHG and the related warnings

Postby alecsandros » Tue Mar 10, 2015 8:49 pm

paulcadogan wrote:At 0407, noises were heard by the GHG bearing 286 degrees. (If that is "true" that would be on the starboard bow if the ship was on 220 which makes no sense). Then at 0425 the GHG reported torpedo noises bearing 195 degrees (just fwd of the port beam) which were attributed by Brinkmann to a mistaken bearing caused by the ships to port. THEN almost an hour later at 0521 the two ships turn to port to 170.

... But Brinkmann doesn't say (perhaps he didn't know) wether the noises at 4:07 were new or not. Maybe they were made by Norfolk, Suffolk or both, or none of them, but other ships in the vicinity, or was simply a false echo.

Torpedo noises were reported by the GHG on at least 3 separate occasions, all on May 24th. And all of them proved to be unfounded...

The turn to 170 could be a result of the existing ice masses floating around the ships in the strait...

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Re: GHG and the related warnings

Postby Dave Saxton » Wed Mar 11, 2015 2:52 am

paulcadogan wrote:Hmmm... Prinz Eugen's KTB is very confusing:

Brinkmann notes this in sequence:

At 0407, noises were heard by the GHG bearing 286 degrees. (If that is "true" that would be on the starboard bow if the ship was on 220 which makes no sense). Then at 0425 the GHG reported torpedo noises bearing 195 degrees (just fwd of the port beam) which were attributed by Brinkmann to a mistaken bearing caused by the ships to port. THEN almost an hour later at 0521 the two ships turn to port to 170.


Relative bearings might work better. 286* relative would be just ahead the port beam instead of off the starboard bow..ect...
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: GHG and the related warnings

Postby Dave Saxton » Wed Mar 11, 2015 3:11 am

paulcadogan wrote:Schmalenbach reports something completely different:

At estimated 0425 (which has 0525 GMT in brackets) the listening room reported propeller noises bearing 242 or 252 degrees, specifying two targets and after a few minutes smoke was seen from the foretop in that direction and all this was duly reported to Brinkmann.


In Unter Drie Flaggen, Schmalenbach quotes his own watch officer's record: that the 286* GHG contact was at 0440 hours (PG time), which is 0540 hours by our reckoning. 286* relative would have been Hood and Prince of Wales, and 0540 hours would have put them about 31 km away. And that makes sense.

What time was the false torpedo report during the battle?
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: GHG and the related warnings

Postby paulcadogan » Wed Mar 11, 2015 4:59 am

Dave Saxton wrote:Relative bearings might work better. 286* relative would be just ahead the port beam instead of off the starboard bow..ect...


But then 195 deg at 0525 while on course 170 wound be astern to port- i.e. to the north!

Dave Saxton wrote:In Unter Drie Flaggen, Schmalenbach quotes his own watch officer's record: that the 286* GHG contact was at 0440 hours (PG time), which is 0540 hours by our reckoning. 286* relative would have been Hood and Prince of Wales, and 0540 hours would have put them about 31 km away. And that makes sense.


Makes sense yes, but throws some more conflicting data into the mix! Was there another Brinkmann "boo boo" then??

The false torpedo alarm was at about 0603 during the battle. The GHG probably picked up the noises generated by the sinking Hood. An upward rush of air bubbles would have been streaming out of the hull as it plunged to the depths. Probably sounded like nearby torpedoes would - the direction was right too. The power of suggestion then made Brinkmann and others see what they expected to see...
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Re: GHG and the related warnings

Postby alecsandros » Wed Mar 11, 2015 7:11 am

paulcadogan wrote:
The false torpedo alarm was at about 0603 during the battle. The GHG probably picked up the noises generated by the sinking Hood. An upward rush of air bubbles would have been streaming out of the hull as it plunged to the depths. Probably sounded like nearby torpedoes would - the direction was right too. The power of suggestion then made Brinkmann and others see what they expected to see...

... Possibly, but let's not forget the GHG provided false torpedo data on several more situations during the day, so the equipment was either to new , and the crew to inexperienced to properly use it, or it imply provided inaccurate data from time to time.

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Re: GHG and the related warnings

Postby Dave Saxton » Wed Mar 11, 2015 2:08 pm

paulcadogan wrote:
Dave Saxton wrote:In Unter Drie Flaggen, Schmalenbach quotes his own watch officer's record: that the 286* GHG contact was at 0440 hours (PG time), which is 0540 hours by our reckoning. 286* relative would have been Hood and Prince of Wales, and 0540 hours would have put them about 31 km away. And that makes sense.


Makes sense yes, but throws some more conflicting data into the mix! Was there another Brinkmann "boo boo" then??
...


The ship's KTB is for the most part typed up by clerks as it is compiled by the ships command after the fact. It is a mistake if we take it as exclusively a running record in chronological order as it happened. The watch officer's personal log is primary to the main KTB and should be given more weight.
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: GHG and the related warnings

Postby Antonio Bonomi » Wed Mar 11, 2015 3:03 pm

Hello everybody,

those may be of some help understanding ... :wink:

The GHG bearings while on course 220° :

PG_GHG_ref_013_220.jpg
PG_GHG_ref_013_220.jpg (18.49 KiB) Viewed 1016 times


The GHG bearings while on course 170° :


PG_GHG_ref_012_170.jpg
PG_GHG_ref_012_170.jpg (15.85 KiB) Viewed 1016 times


Bye Antonio :D
In order to honor a soldier, we have to tell the truth about what happened over there. The whole, hard, cold truth. And until we do that, we dishonor her and every soldier who died, who gave their life for their country. ( Courage Under Fire )


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