GHG and the related warnings

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Alberto Virtuani
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Re: GHG and the related warnings

Post by Alberto Virtuani »

@all: does anybody have an idea at which approximate distance (in open waters, like Atlantic ocean) the 1941 GHG could detect a big ship sailing at full speed ?

Bye, Alberto

P.S. of course I mean a 1941 GHG installed on a big ship speeding as well (like the ones on board PG and BS on May 24 morning...... and not a GHG installed on a more "silent" submerged and possibly slow-moving U-Boat.....
Last edited by Alberto Virtuani on Wed Mar 11, 2015 5:37 pm, edited 3 times in total.
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Steve Crandell
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Re: GHG and the related warnings

Post by Steve Crandell »

That would depend on a lot of factors. I would say anywhere from 5,000 yards to 50 miles. It's very unpredictable. Water temperature, what own ship is doing, presence or absence of biologics (noise from marine animals) on the contact bearing, sea conditions, and so on. You could gain contact at 50 miles and then lose it at 45 miles. You might not have any idea how far away the contact is. It could be fairly loud at 40 miles and very faint at 20 miles.
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Re: GHG and the related warnings

Post by alecsandros »

Alberto Virtuani wrote:@all: does anybody have an idea at which approximate distance (in open waters, like Atlantic ocean) the 1941 GHG could detect a big ship sailing at full speed ?

Bye, Alberto

P.S. of course I mean a 1941 GHG installed on a big ship speeding as well (like the ones on board PG and BS on May 24 morning...... and not a GHG installed on a more "silent" submerged and possibly slow-moving U-Boat.....
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Alberto Virtuani
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Re: GHG and the related warnings

Post by Alberto Virtuani »

Thanks Steve and Alecsandros for all the info !

@Steve Crandell: as you mentioned, the sensitivity of the GHG varied a lot also in relation with the bearing of the target: on BS and PG I guess it was very limited in the aft sector (due to own propeller and water turbulence) while do you have an idea whether (with the sensors put on both sides relatively close to the bows.....) it was better in the bow sector (like in modern submarines) or abeam (while the extreme bow sector was a bit "blinded") ?

Bye, Alberto
"It takes three years to build a ship; it takes three centuries to build a tradition" (Adm.A.B.Cunningham)

"There's always a danger running in the enemy at close range" (Adm.W.F.Wake-Walker)
Steve Crandell
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Re: GHG and the related warnings

Post by Steve Crandell »

Alberto Virtuani wrote:Thanks Steve and Alecsandros for all the info !

@Steve Crandell: as you mentioned, the sensitivity of the GHG varied a lot also in relation with the bearing of the target: on BS and PG I guess it was very limited in the aft sector (due to own propeller and water turbulence) while do you have an idea whether (with the sensors put on both sides relatively close to the bows.....) it was better in the bow sector (like in modern submarines) or abeam (while the extreme bow sector was a bit "blinded") ?

Bye, Alberto
All ships I'm aware of have a sonar blind spot astern. It is referred to as the "baffles", and periodically you turn to "clear" the baffles. I am not sure about ships with sonars that they trail behind them with a cable, also known as "variable depth sonar". I think those are much more sensitive out to the sides than astern or forward, but I don't have any personal experience with them. Today's submarines use those, as well as surface ASW ships. They have the drawback that they significantly reduce the ship's maneuvering ability while they are deployed.
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Antonio Bonomi
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Re: GHG and the related warnings

Post by Antonio Bonomi »

Hello everybody,

@ Steve Crandell,

you wrote :
I think those are much more sensitive out to the sides than astern or forward, ...
I think I would agree about it given the position those equipment were located ... :wink:

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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Antonio Bonomi
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Re: GHG and the related warnings

Post by Antonio Bonomi »

Hello everybody,

if I recap briefly, ... here we have :

Prinz Eugen war diary - KTB

At 04.07 ( battle time ), noises were heard by the GHG bearing 286 degrees.
At 04.25 ( battle time ) the GHG reported torpedo noises bearing 195 degrees

Schmalenbach Report attached to PG KTB

At estimated 04.25 ( MEZ= Mittle Europe Zeit; which was 05.25 battle time ) the listening room reported propeller noises bearing 242 or 252 degrees

Prinz Eugen Unter Drie Flaggen - Paul Schmalenbach

He quotes his own watch officer's record: that the 286* GHG contact was at 04.40 hours (PG time=MEZ), which is 05.40 hours by our reckoning.

The story of Prince Eugen - Fritz Otto Busch

He wrote that the 280 GHG contact was at 04.35 hours (PG time=MEZ), which is 05.35 hours battle time.

Hans Henning von Schulz document

At 04.00 ( MEZ = PG time ) so at 05.00 battle time the 286 degrees GHG warning.

Than I agree with Dave Saxton when he wrote :
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.
Now the Prinz Eugen KTB time and bearing was confirmed by Brinkmann on some documents to the Kriegsmarine Admiralty later on.

Paul Schmalenbach was the Watch Officer, ... but Hans Henning von Schulz was the GHG equipment responsible Officer.

Now what do we have to believe here ... as far as time, including potential errors on base assumptions, ... and bearings ... :think:

Opinions welcome ... as usual ... :wink:

NOTE : Battle time is assumed being British Midsummer Time = Zone - 2, while the MEZ= Mittle Europe Zeit is one hour less than that.

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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wadinga
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Re: GHG and the related warnings

Post by wadinga »

Hello Antonio and all,

Surely Kapitanleutnant Hans-Henning von Schulze was the chief Wireless officer of PG as described by the Baron.He seems to have been involved also with the B-Dienst decoding operation ie intelligence. As an electrical sensor system I expect H-H v S was ultimately responsible for GHG but surely not closely involved with the system.
the Baron's book has: "I still remember the report from the Prinz Eugen, our companion on our Atlantic sortie, on 24th May 1941 before the battle off Iceland. It was made by Leutnant zur See Karlotto Flindt, a technically proficient and talented listening officer, who was sitting at the hydrophones when around 04:40 he picked up turbine noise and reported to the ship's bridge:' Noise of two fast moving turbine ships at 280 degrees relative bearing.' The ships proved to be the Hood and Prince of Wales.
There were a profusion of false propeller and torpedo warnings from the GHG throughout the mission. It also apparently displayed an inability to warn of the cruisers initial approach, detect the difference between icebergs and patrolling warships or even keep track of the mighty (noisy) Bismarck when he/she/it made the first attempt to seperate from the Prinz in poor visibility.

In fact significant mention of GHG detecting Hood and PoW's approach is made retrospectively in an analysis by Brinkmann of the difficulty of losing Suffolk and Norfolk. Brinkmann starts speculating about imaginary British passive sonar which is so much better than the GHG. Why, because they can't lose Wake Walker, and they only know where he is from B-Dienst intercepts, not because they can see three ships on GHG.It just doesn't work very well.

These meanderings are recorded some time after he personally has initiated a series of wild manoeuvrings requiring similar evasive actions by the Flagship, on the basis of a spurious GHG torpedo warning. One of many that day, but this one wrecking both German ships' fire control solutions on a faltering British battleship and terminating the chances of sinking two British capital ships in the same action. Additionally where does the figure of 320 hectometers come from? Passive sonar ranges are difficult to determine. How does he know how far away Holland was?

I have always thought this one, isolated, atypical instance of stellar performance by PG's GHG is very difficult to confirm. I have seen nothing in any other operation to match this claim.

All the best

wadinga
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Antonio Bonomi
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Re: GHG and the related warnings

Post by Antonio Bonomi »

Hello everybody,

@ Wadinga

you reported the Baron's book has: :
" I still remember the report from the Prinz Eugen, our companion on our Atlantic sortie, on 24th May 1941 before the battle off Iceland. It was made by Leutnant zur See Karl Otto Flindt, a technically proficient and talented listening officer, who was sitting at the hydrophones when around 04:40 he picked up turbine noise and reported to the ship's bridge:' Noise of two fast moving turbine ships at 280 degrees relative bearing.' The ships proved to be the Hood and Prince of Wales.
Thanks for that English version Sean, since in my Italian translation there are not all those information on page 66, it missed the Officer name and the time recorded.

Now we have for that 280 ... or 286° bearing, ... several times to be evaluated, even if I think that like on several other evidence the Baron was using Paul Schmalenbach help and information.

That immediately bring out the question : was that 04.40 a German time MEZ or the usual battle time so one hour after it ?

Schmalenbach declared on his book 04.40 hours (PG time=MEZ) being 05.40 hours battle time ... and similiarly he used 04.25 MEZ on his report for the 242-252° one. So always MEZ by Paul Schmalenbach ... :wink:

Still that 286° at 04.07 battle time on PG KTB is something interesting too ... :think:

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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Antonio Bonomi
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Re: GHG and the related warnings

Post by Antonio Bonomi »

Hello everybody,

some more food for thoughts from Fritz Otto Busch book on 1958 : "The story of the Prinz Eugen ".
As you can read it is confirmed that Paul Schmalenbach became Officer of the Watch at 04.00 (MEZ) so, at 05.00 battle time for our evaluations, and it is similarly confirmed that the GHG listing Officer was Leutnant zur See Karl Otto Flindt.
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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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wadinga
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Re: GHG and the related warnings

Post by wadinga »

Hello Antonio,

Once again things are somewhat garbled.

The Chapter heading 180 degrees makes no sense. Nothing bears 180. Just a typo.

Then we go to the two turbine ships at 280 degrees at 04:35 and "a little later" smoke on 281 degrees. Brinkmann is called to the Bridge.

Then a completely irrelevant message to the Flagship is sent about smoke at "96 and 157 degrees"? Not a report on the new contacts, which are important, but apparently something to do with the cruisers.

The ship goes to Action Stations.

What I find interesting is the claim that GHG has been tracking Norfolk "all night" on the port quarter. Presumably at ranges up to 15 miles.

All the best

wadinga
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Antonio Bonomi
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Re: GHG and the related warnings

Post by Antonio Bonomi »

Hello everybody,

so lets see how the real data looks like ... on the German side this time ... :think:
PG_GHG_bearings_02.jpg
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Hoping nobody will tell me now that I have something personal against Brinkmann, Schmalenbach, F.O. Busch, Von Schulz, ... or somebody else, ... in order to sustain VizeAdm Schmundt , Adm Schniewind or Adm Raeder ...

Just joking of course ... :wink:

For me the same methodology here as well, ... same fair approach ... and no discounts ... :negative:

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

Post by Paul L »

Franz Kohlauf T-23 Torpedoboot utilised its GHG scouting for British cruiser destroyer forces employing the "Tunnel" tactics on Oct 23 1943. Reportedly 15 minute before the British got radar contact at 14,000 yards , Kohlauf's boat got a GHG contact near the key waypoint of "The Tunnel" route. The distance between this point and Kohlauf's ships is hard to determine as there was 10nm approximate distance to the Islands , while Voeleker's force was strung out along a 4,000 yard line.

Between Voeleker's radar contact and Kohlauf's GHG contact 15 minutes before , the British were 'sweeping at 13Knots', which means they advanced 6500 yards [total 20,500 yards?]. If we knew Kohlauf's speed we could approximate the net distance between the two groups , when GHG contact was obtained. If the cruise speeds were similar it suggests GHG contact was at 27,000 yards.

Above was from OHaras 'German Fleet at War 1939-1945'. Looking at Peter Smith's 'Hold the Narrow Seas'; The map on pp193 seems to suggest a range of over 12-14nm [column length ] distance between the two groups at 0117 ; minutes after the GHG contact. This GHG contact could have been 15nm or 30,000yards.
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Re: GHG and the related warnings

Post by A Raven »

Admiralty Document dated 1939.

"The maximum range at which surface craft can be detected by hydrophone effect depends to a great extent on how close to their highest speed they are steaming.

It may be stated generally, that if approaching at high speeds , detection by hydrophone effect will be at longer range than by echo method, while if approaching at slow speeds the reverse may be the case."

The bottom line for the tactical use of passive detection of surface craft by hydrophone by late 1941, was that it had been supplanted by the much more efficient 10cm radar, but still used for the detection of approaching torpedoes.
A Raven

Re: GHG and the related warnings

Post by A Raven »

PS to my prior message,
"As a listening instrument the Asdic is efficient as any known type of hydrophone, sets with low frequency oscillators being better in this respect than those fitted with high frequency ones. The efficiency of any such listening device is dependant however, not only upon the speed of the target but upon the speed of the A/S vessel because when the latter is proceeding fast the "water noises" will drown the sounds emanating from the submarine. "

From official Admiralty documents.
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