The loss of the Hood video

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dunmunro
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The loss of the Hood video

Post by dunmunro »

An in-depth review of the various theories regarding Hood's loss:

[youtube]https://youtu.be/CLPeC7LRqIY[/youtube]
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Re: The loss of the Hood video

Post by gcogger »

The conclusion as the the most likely scenario is interesting, and not a theory that I've seen before. I'm no expert, but it seems to fit what was observed, and appears plausible given the photo at 34:20mins (taken with Hood en route to the Denmark Strait). It suggests that no improvement to Hood's deck armour would have helped.
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Re: The loss of the Hood video

Post by HMSVF »

dunmunro wrote: Thu Dec 17, 2020 9:27 pm An in-depth review of the various theories regarding Hood's loss:

[youtube]https://youtu.be/CLPeC7LRqIY[/youtube]

I watched it the other day. I bow down to those more knowledgable than I, but I thought it made perfect sense and the most likely reason for Hood's demise (especially when looking at the picture of her sailing on her way to the Battle Of Denmark Strait).

Best wishes


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wadinga
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Re: The loss of the Hood video

Post by wadinga »

Fellow Contributors,

It is in my opinion a very well-presented video, and the credit duly given to Bill Jurens as the source of much of the technical material and conclusions is gratifying. His authoritative paper can be read on the INRO section of the Navweaps website. The presenter speaks clearly and confidently and the script is a model presentation of complex matters in a concise and comprehensible manner.

However I must take issue with the assumption expressed that Hood fired torpedoes during the engagement which the presenter uses as a partial explanation for the dismissal of stored torpedoes being part of the explosive explanation. I am personally convinced that Bill Jurens' explanation of deflagration of the cordite stores in the main magazines as the result of a "lucky low blow" shell strike is the real reason, and we know the Director of Naval Construction had a bee in his bonnet about the vulnerability of these above water tubes, had sought to have them removed and was keen to pin the blame on their retention.

The only evidence from any source whatsoever that Hood fired torpedoes are the IMHO highly unreliable reports from the German side. The passive hydrophone GHG system reported torpedo noise in the water and Captain Brinkmann said he had seen tracks. However there are three very strong negative factors to be considered.

Nowhere in any of the PoW eye witness reports is there any mention of torpedoes leaping from Hood's side and splashing into the water. Witnesses saw many fine details but they never saw this.

Firing torpedoes, delicate and often unreliable pieces of dangerous ordnance, into the water only a few hundred yard in front of a sister vessel would be extremely unwise. There were several cases where stuck rudders resulted in a circle back towards the firing vessel or even a tumbleturn and return down the reciprocal course, eg HMS Trinidad. Firing Hood's torpedoes, with PoW in such close proximity, would have been foolhardy in the extreme.

Lastly there would have been no point. Hood was steering a course, before the turns to port, were made which was not far off a collision course with the German ships. Any torpedo fired by Hood would have to turn 90 degrees to port to head towards an interception point and given the extreme range setting would have only slowly overtaken the launching vessel. The selection of a gyro course for the torpedo different to the orientation of the tube at launch time was not often used in British ships at all, and more often than not the whole ship was turned, with the tube being fired as the"sights came on" momentarily.

The idea that PG's GHG system actually detected torpedoes from Hood which was never closer than about 16-18,000yds, and because of the relatively slow speed of torpedoes would have had to launch them far, far earlier at much greater range in order to be in detection range by the time the intership range had dropped to 16-18,000 yds, is IMHO ludicrous. The PG KTB is littered with spurious GHG warnings and the occasions when it failed to detect British ships or even Bismarck's movements when she attempted to escape are many. Its performance was highly questionable. What the operators heard, and what Brinkmann saw is unknown. It should certainly not be stated in any account hoping to be considered reasonable, that "Hood fired torpedoes".

Brinkmann may have considered he had to react with a violent course change to a torpedo threat, but a moment's reflection should have assured him it could not have come from Hood. Maybe he imagined a submarine trap, maybe he imagined it could have been dropped from an enormous height by the shadowing Sunderland. His extreme turn out of the firing line, at the moment of victory is one of the unexplained mysteries of Denmark Straits.

I too wish the resources put into some TV documentaries on naval history might do as good a job as this you tube video.

All the best

wadinga
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Re: The loss of the Hood video

Post by HMSVF »

wadinga wrote: Sun Dec 20, 2020 4:36 pm Fellow Contributors,

It is in my opinion a very well-presented video, and the credit duly given to Bill Jurens as the source of much of the technical material and conclusions is gratifying. His authoritative paper can be read on the INRO section of the Navweaps website. The presenter speaks clearly and confidently and the script is a model presentation of complex matters in a concise and comprehensible manner.

However I must take issue with the assumption expressed that Hood fired torpedoes during the engagement which the presenter uses as a partial explanation for the dismissal of stored torpedoes being part of the explosive explanation. I am personally convinced that Bill Jurens' explanation of deflagration of the cordite stores in the main magazines as the result of a "lucky low blow" shell strike is the real reason, and we know the Director of Naval Construction had a bee in his bonnet about the vulnerability of these above water tubes, had sought to have them removed and was keen to pin the blame on their retention.

The only evidence from any source whatsoever that Hood fired torpedoes are the IMHO highly unreliable reports from the German side. The passive hydrophone GHG system reported torpedo noise in the water and Captain Brinkmann said he had seen tracks. However there are three very strong negative factors to be considered.

Nowhere in any of the PoW eye witness reports is there any mention of torpedoes leaping from Hood's side and splashing into the water. Witnesses saw many fine details but they never saw this.

Firing torpedoes, delicate and often unreliable pieces of dangerous ordnance, into the water only a few hundred yard in front of a sister vessel would be extremely unwise. There were several cases where stuck rudders resulted in a circle back towards the firing vessel or even a tumbleturn and return down the reciprocal course, eg HMS Trinidad. Firing Hood's torpedoes, with PoW in such close proximity, would have been foolhardy in the extreme.

Lastly there would have been no point. Hood was steering a course, before the turns to port, were made which was not far off a collision course with the German ships. Any torpedo fired by Hood would have to turn 90 degrees to port to head towards an interception point and given the extreme range setting would have only slowly overtaken the launching vessel. The selection of a gyro course for the torpedo different to the orientation of the tube at launch time was not often used in British ships at all, and more often than not the whole ship was turned, with the tube being fired as the"sights came on" momentarily.

The idea that PG's GHG system actually detected torpedoes from Hood which was never closer than about 16-18,000yds, and because of the relatively slow speed of torpedoes would have had to launch them far, far earlier at much greater range in order to be in detection range by the time the intership range had dropped to 16-18,000 yds, is IMHO ludicrous. The PG KTB is littered with spurious GHG warnings and the occasions when it failed to detect British ships or even Bismarck's movements when she attempted to escape are many. Its performance was highly questionable. What the operators heard, and what Brinkmann saw is unknown. It should certainly not be stated in any account hoping to be considered reasonable, that "Hood fired torpedoes".

Brinkmann may have considered he had to react with a violent course change to a torpedo threat, but a moment's reflection should have assured him it could not have come from Hood. Maybe he imagined a submarine trap, maybe he imagined it could have been dropped from an enormous height by the shadowing Sunderland. His extreme turn out of the firing line, at the moment of victory is one of the unexplained mysteries of Denmark Straits.

I too wish the resources put into some TV documentaries on naval history might do as good a job as this you tube video.

All the best

wadinga
Wadinga,

What did you make of the wave profile thesis? To me it fitted like a glove and would explain how HMS Hood's demise came about. When the video showed that picture of her on her way in 1941 my first thought was "christ, thats a lot of exposed hull". From what I have learned on this site from other posters it would explain how a shell managed to penetrate all of the Hoods defences at an angle that, by all rights should have been dealt with.

It's such a simple thesis, but then I suppose in retrospect these things always are.

That picture. So much exposed below waterline hull. Makes you wonder whether she had been doing 25 or 26 kots what would have happened.



Hope you have a good Christmas


BW


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Re: The loss of the Hood video

Post by wadinga »

Hi HMSVF,

The "wave profile" thesis is attractive, which why both the 1941 enquiry and Bill's definitive studies consider it. It is indeed the most probable explanation. However even here I would like to raise a couple of points.

There are indeed a number of excellent and rarely seen photos displayed in the video including Hood digging her nose into long period ocean swells, which because of their shape mean their "leading face" exposes more of Hood's side than might normally be the case. They make a good photo and induce the photographer to record that moment with the shutter. This would be a short duration phenomenon as moments later, Hood's bow would have a large freeboard and the passing swell would cover up that previously exposed area of the after hull.

Also, one of the earlier shots shows Hood heeling in a sharp turn and since the rudder evidence from the wreck shows just such a turn was underway at the moment of her destruction, we may assume that heel submerged more of her starboard side, and put the lower edge of the belt deeper under the water surface. This heel might change some of those estimates of the angle at which any incoming projectile might strike an element of Hood's complex armouring.

All in all, since these factors affecting Hood's protection were changing almost by the second, it is entirely fair to conclude it was indeed a "lucky hit" that destroyed the ship.

A wider question is: who agrees with me that the story of Hood firing torpedoes should be consigned to the extremely unlikely/impossible segment?

All the best to all at the end of a grizzly year in hope of a better one

wadinga
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Re: The loss of the Hood video

Post by Herr Nilsson »

wadinga wrote: Mon Dec 21, 2020 10:44 am Also, one of the earlier shots shows Hood heeling in a sharp turn and since the rudder evidence from the wreck shows just such a turn was underway at the moment of her destruction, we may assume that heel submerged more of her starboard side, and put the lower edge of the belt deeper under the water surface. This heel might change some of those estimates of the angle at which any incoming projectile might strike an element of Hood's complex armouring.
But in the first seconds of the turn the heel is to the port side, which exposes the lower edge of the belt even more.
Regards

Marc

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Re: The loss of the Hood video

Post by wadinga »

Hi Herr Nilsson,

I presume you are suggesting that the rudder being low down in the ship somehow, because its centre of effort, creates an opposite heelinging moment because it is below the C of G/ C o Buoyancy, before the massive real heel gets underway ?

Film of USS Harry Truman on You Tube carrying out extreme turns shows no tendency to initially lean in to the turn before the greatly larger lean out. Methods for calculating amount of heel make no mention of any initial opposite effect. The Spruance shows nothing similat either. Is there any evidence of "initial heel? BTW Sailing boats are different , they have a centre of effort up in the sail plan.

All the best

wadinga
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Re: The loss of the Hood video

Post by Herr Nilsson »

According Schmalenbach Prinz Eugen had an initial heel.
Regards

Marc

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Re: The loss of the Hood video

Post by paul.mercer »

Gentlemen,
Re the Hood launching torpedoes, would they have launched them in the general direction of the German ships just to get rid of them as they could prove to be a hazard to the ship from enemy shells?
Also, I believe one of the survivors described seeing the bow "planing away", and film of the wreck shows just part of the bow remaining intact and the rest of the ship disintegrated with just part of the stern remaining, so if the explosion occurred in the aft magazines would the explosion have torn out all the internals of the ship and detonated the forward magazines as well?
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Re: The loss of the Hood video

Post by Bill Jurens »

While it's possible that Hood jettisoned torpedoes, that's unlikely, particularly since we found one close to the main hull section in the debris field.

I am unaware of any film of the wreck showing '... part of the bow... with just the stern remaining...' as you mentioned. So far as I know there is no really useful film or photographs of the explosion at all.

If you look at other wrecks where magazine explosions occurred you will find -- again, at least so far as I know -- no cases whatsoever that demonstrate any significant for-and-aft propagation of the explosion. I published some equations on this, which demonstrated how, and I think also explained why, such explosive events rarely extend more than 1.5 ship beams in any direction from the center of the blast.

Perhaps slightly premature Best Wishes to all over the Holiday season, and my thanks for making the moderator's job so easy of late...

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Re: The loss of the Hood video

Post by wadinga »

Hello All and especially Bill,

Firstly I have to accept there may be something in what Herr Nilsson says. :oops: There are marine engineering discussion papers on the web speculating on the idea of using repeated rudder motion under autopilot control to damp out rolling by applying rudder briefly to create an opposing heeling motion without changing heading much. This seems to be "cheap and cheerful" alternative to proper active stabilizers. However how much this is "real world" applied and how fast it wears out the steering gear and creates expensive drag and whether this would scale up to a 42,000 ton battlecruiser I have no idea. Conventional bilge keels are supposed to damp rolling and heeling until they are overcome by a massive heeling effect caused by high speed hard rudder manoeuvring. If Schmalenbach says there was an initial heel into the turn before the major heel outwards, well I have to accept that but I suspect it was so small and short lived that it would not expose "under the belt" for long. Also it may only have been noticeable with gunnery optics on the horizon. Geoffrey Brookes in Alarm Starboard gives no hint that rudder motion turning away from the enemy would initially give a brief heel away.......... He does describe gunnery optics seeing only sea as PoW heeled hard toward the enemy as she turned away.

Hood's heeling in the video at about 4 minutes in is most noticeable, and would definitely have submerged more belt. The diagram used to show a 15" shell at the angle of fall Bill determined passing over the Main Belt after penetrating the thinner Upper Belt, but then skittering across the armoured deck having hit it at a very shallow angle would surely find a different path if Hood were heeled say 10 degrees toward the enemy. Would it hit that turtleback at something much more like orthogonal?

Once again, no eye witness saw Hood's torpedoes being fired/jettisoned so I reiterate, I believe it is incorrect to state "Hood fired torpedoes". The German evidence is flimsy and circumstantial. There is also no evidence that cordite deflagration at the after end of the vessel did anything to the forward end. The Barham film and the survival of so many of her crew show that magazine destruction can be quite localized.

All the best

wadinga
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Re: The loss of the Hood video

Post by paul.mercer »

Gentlemen,
As always, many thanks for your replies, may I take this opportunity to wish you all a very Happy Christmas and let us all hope for a better New Year
Paul
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