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Author Topic: Sinking of Bismark  (Read 8475 times)

farrow

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Sinking of Bismark
« on: January 20, 2010, 10:30:04 pm »

There seems so much interest in the Bismark, I thought this US Navy intelligence site may be of interest to you all. Some interesting facts here, especially on how her main armenent shells travelled some distance under water, could explain Hoods eruption with a shell in her torpedo storage between mainmast and aft funnel.

http://www.history.navy.mil/faqs/faq118-1.htm
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Colin Bishop

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Re: Sinking of Bismark
« Reply #1 on: January 20, 2010, 11:03:34 pm »

Yes, interesting. This was discussed on here a while back.

I am inclined to agree with the view that the Bismarck was actually overrated as a fighting ship. Her main assets were her sheer size and watertight subdivision which made her very hard to sink. However, her basic design was taken from the WW1 battleship Baden (a contemporary of the Revenge class) as the Germans had no other experience to draw upon. Her armour belt was relatively light compared with her contemporaries abroad and many of the critical fighting and communication links were run above the main armour deck which left them vulnerable to shellfire. She also had an old fashioned three tier primary, secondary and tertiary (AA) armament at a time when most other battleships of the time had dual purpose secondary armament, which wasted a lot of weight.

She was clearly superior to Hood, as she should have been, but it was said that she would have been considerably technically inferior to the earlier G3 British design had that been built. As it was the Rodney, which was essentially a diminutive of the G3 battlecruiser, wasted no time in taking Bismarck apart with relatively minimal help from King George V.

Another thing about Bismarck was that, like several other German warships, the stern was structurally weak. Examination of the wreck showed that it detached from the rest of the ship during the sinking.

Colin
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Wasyl

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Re: Sinking of Bismark
« Reply #2 on: January 21, 2010, 12:03:29 am »

Whilst I have an ongoing love of the Bismarck and almost every other German warship,I am of the opinion,that they were just Dinosaurs,..they were built for Prestige,but in reality served no purpose,and as aircraft of the day has shown they were very vulnareable,and as for the German strategy of them hunting alone,they were useless when confronted with a pack of warships,Had AH,taken Doenitz advice and built only U-boots,then history might have been different,
you just have to look at the early stages of the war,to realise how useless they were,..Graf Spee,Bismarck,Hipper class kreuzer, Blucher all gone in less than two years,and the rest were either holed up in harbours or Fjords,the only one in my opinion that gave a good account of herself was the Scharnhorst,her sister ship Gneisenau achieved little as did the Deutschland/Lutzow,...beautiful,.Dinosaurs, all of them

Wullie,
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tweety777

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Re: Sinking of Bismark
« Reply #3 on: January 21, 2010, 07:41:47 am »

A 381mm shell travelling underwatre?
That myth is completly busted, Mythbusters have tested this with far smaller weapons, and it turned out that the lighter the weapon the deeper it comes in the watre.
When they fired a large 50calibre sniper-rifle into the watre it didn't come any further then the surface of the watre.
There is no way a 381mm shell would had been able to come under watre, and therefore the Hood hasn't been sunk by Bismarck, but by Prinz Eugen, which managed to hit AA munition.

Greetings Josse
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Wasyl

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Re: Sinking of Bismark
« Reply #4 on: January 21, 2010, 09:43:46 am »

Hi Josse,methnks you have a slight prob with your R,s and E,s....water,....watre {:-{

Wullie
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steve pickstock

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Re: Sinking of Bismark
« Reply #5 on: January 21, 2010, 10:06:37 am »

I have no wish to upset any American mayhemmers - but I'm a bit disconcerted by the inference that there was American assistance in sinking the Bismark.

I understand the statement about the American commitment to patrol the western Atlantic but RN resources were so heavily committed anyway that is an irrelevancy. 
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Colin Bishop

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Re: Sinking of Bismark
« Reply #6 on: January 21, 2010, 10:34:08 am »

Quote
Whilst I have an ongoing love of the Bismarck and almost every other German warship,I am of the opinion,that they were just Dinosaurs

Yes, true up to a point but if the war had come when the Germans expected it to, in the mid 1940s, they would have had a more balanced surface fleet although it seems doubtful if the really big battleship designs would have actually been built.

In fact the Kriegsmarine surface fleet suffered from a lot of inherent constructional problems, partly from trying to push the envelope too much. Sterns had a propensity to drop off, Scharnhorst and Gneisenau had to have their bows rebuilt to improve seakeeping and treaty restrictions meant that they were undergunned for their size, the intended conversion to six 15inch main armament never happened. The light cruisers were built too light and some were never battleworthy. There were engineering problems too, the diesels of the Pocket Battleships proved to be unreliable while the high pressure steam plants of the big destroyers were a bit of a disaster area.

The U boats were initially very successful but once Allied airpower, radar and ahead throwing weapons got the measure of them their position was hopeless. The Walther prototypes were touted as a solution but British post war experience suggested that hydrogen peroxide as a fuel made the vessels more dangerous to their crews that to the enemy.

Colin
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dreadnought72

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Re: Sinking of Bismark
« Reply #7 on: January 21, 2010, 11:35:30 am »

A 381mm shell travelling underwatre?

You're trying to tell me that an 800kg shell travelling at ~800 m/s just bounces off the surface? That's ridiculous. It appears from a pile of evidence that even ricochets of large calibre shells include a path under the surface whose greatest depths can be several calibres. Furthermore, I suspect that a shell (with a quarter gigajoule of kinetic energy in it) hitting a wavefront at the right angle can and will travel for some considerable distance underwater at high speed.

Andy
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Re: Sinking of Bismark
« Reply #8 on: January 21, 2010, 11:49:21 am »

I agree that one of the biggest challenges the Kriegsmarine had to face was Hitler.  Colin has it spot on that the war started too early for the navy and had it started in 1940 as planned the Bismarck and Tirpitz would have been able to sail together.

Looking at the capabilities of all the vessels involved does not take into account the very high proportion of luck involed in any engagement, which tends to even that side of things out a bit.  There were significant deficiencies in vessels on both sides and a great number were pushed into service before they were ready.  Had the Bismarck sailed with the Tirpitz, things could have been quite different but Hitler insisted on sending the ships out as soon as they became available rather than waiting for a better tactical opportunity.  The Tirpitz ended up on her own and to spend the war tying up Royal navy ships is of questionably value for a ship of her capabilities.

None of the German ships were deployed anywhere near as effectively as they could have been and the only person with any sound judgement in naval warefare was Donitz and Hitler ignored him as much as he ignored anyone else. 

I used to actually think that Hitler was an army man rather than a naval man but a very good Discovery Channel documentary about Kursk, that I watched only last night changed my opinion of that.  Once again he had huge numbers of extreemly capable machinery but insisted on wasting it by throwing it at the enemy against the advice of all his generals.  I think he expected the whole of the war to be as easy as his early Blitzkrieg successes, which were never against a very strong opposition.
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tweety777

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Re: Sinking of Bismark
« Reply #9 on: January 21, 2010, 04:39:01 pm »

You're trying to tell me that an 800kg shell travelling at ~800 m/s just bounces off the surface? That's ridiculous. It appears from a pile of evidence that even ricochets of large calibre shells include a path under the surface whose greatest depths can be several calibres. Furthermore, I suspect that a shell (with a quarter gigajoule of kinetic energy in it) hitting a wavefront at the right angle can and will travel for some considerable distance underwater at high speed.

Andy

I'm not telling you it i'll bounce off, it will simply explode.
Even if there's no explosive inside it, it won't penetrate the water in one piece, it will smash apart.

Greetings Josse
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around

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Re: Sinking of Bismark
« Reply #10 on: January 21, 2010, 06:46:12 pm »

WWII naval AP rounds were designed to penetrate the armour of the target before detonating.  The fuze was typically located at the rear of the projectile ("base detonating" to use the correct terminology) and incorporated a delay to allow for the transit of the armour.   Crushing nose caps provided the required aerodynamic form and helped ease the initial impact forces.

As far as the shell is concerned, hitting the water would be no more stressful than impacting the armour belt of a target.   To state that the round would shatter on impact is incorrect.  Far more likely is that the round would become unstable on entering the water and the trajectory would be seriously compromised. 

As far as the Mythbuster’s show was concerned, they tested normal jacketed rifle ammunition for its ability to penetrate water.  Comparing apples to oranges.

Cheers,

Adrian (ret’d Gunnery Officer)
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tweety777

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Re: Sinking of Bismark
« Reply #11 on: January 21, 2010, 06:52:49 pm »

Even if the shell would have travelled through the water there is no way it could have sunk the Hood.
The Hood has torpedo-armour that is designed to make sure that no explosive could get inside the ships vitals in one time.
A torpedo can't reach the ships vitals on it's own, why would a none-purposebuild 381mm shell be able to penetrate through it?
I think this story can't be enything else then a myth.
A 381mm shell can't do that much damage below the surface.

Greetings Josse
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Colin Bishop

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Re: Sinking of Bismark
« Reply #12 on: January 21, 2010, 07:08:11 pm »

It does seem unlikely that a shell from a gun could do significant underwater damage. A base fused AP round carried a relatively small bursting charge which would have been very small compared with the torpedo warhead which the hull was designed to withstand.

However, experience in the First World War did show that it was possible for a shell to hit the hull below the armour belt if the target ship was rolling significantlly. Nevertheless that does seem to be an unlikely scenario for Hood which had a vertical armour belt of roughly equal thickness to Bismarck. It was in horizontal armour that Hood was deficient and her loss was most likely due to either a plunging shot from Bismarck or a chain reaction from hits from Prinz Eugen which had the effect of detonating her after main magazines.

Colin
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John W E

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Re: Sinking of Bismark
« Reply #13 on: January 21, 2010, 07:48:24 pm »

hi ya there

I think Tweety if you look at the weblink I have put on, this is the Bismark as she is today

http://www.bismarck-class.dk/bismarck/wreck/bismarck_wreck_2.html

just have a look at the damage an unexploded 16" shell has done to the bridge area - and note this shell just didnt explode.   If a shell is close to a ship - it will no doubt do a lot of damage to the underside of a ship if it comes into contact.   

To go back to an earlier part of this topic where it mentions the effectiveness and also the advances in the design; what we have to remember is that in 1939 we didnt have the technology for spying as we do today - and we had to rely on the human element/word of mouth which is very unreliable - so things did get a bit distorted about design claims etc. 

In one sense they were very effective, the German surface fleet, even though the Turpitz never left the Norweigan Fjords just think how much resources it tied up in both finances and manpower - and how many attempts there were to try and sink her.   So with the ship sitting doing nothing in the Fjords it was doing a lot of damage psychologically to the Allied forces.

aye
john e
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dreadnought72

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Re: Sinking of Bismark
« Reply #14 on: January 21, 2010, 08:19:10 pm »

However, experience in the First World War did show that it was possible for a shell to hit the hull below the armour belt if the target ship was rolling significantlly.

And don't forget the Lion was hit below the waterline at Dogger Bank, for example, due to the hull's high-speed waveform in such shallow water. Not the case here, of course.

But - once again - the charge on a slow moving torpedo compared to the kinetic energy and explosive force of (as Adrian pointed out) base-fused rounds of the period make the point mute. Apples are NOT oranges, and it is certainly possible that the Hood was sunk as the result of an underwater shell hit.

Here's a then-sceret report from the Prince of Wales after being dry-docked after the confrontation:



The damage sustained in PRINCE OF WALES in her recent action has now been examined by D.N.C's representative.
SECRET
Subject.. Unexploded Enemy Shell
From .. The Commanding Officer, H.M.S. PRINCE OF WALES
Date .. 8th June, 1941 No. 001.A/1
To .. THE COMMANDER IN CHIEF, HOME FLEET.
(Copies to The Secretary of the Admiralty.
The Commander-in-Chief, Rosyth
During the early morning action on May 24th a heavy hit was felt abreast the Starboard Diesel Room. It was found that the outer air space 184-196, the outer oil fuel tank 184-206, the inner air space 184-194, the starboard diesel tank 184-206 were fill to the crown with oil and water.
2. On Friday 6th June, on pumping out the dry dock a clean hole in the side about 15" diameter was found, a foot above the bilge keel at 187 starboard.
Holes were also found in the light plating forming the sides of the outer oil fuel tank 184-206.
Heavy marking was found on the protective bulkhead but there were no signs of explosion.
3. When the ship's bottom was visible it became apparent that there was no exit hole and a search was made for the shell.



TV - even Mythbusters (!) - is not necessarily the truth, Josse.

Andy
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Re: Sinking of Bismark
« Reply #15 on: January 21, 2010, 08:38:57 pm »

Isn't it often the case that in theory it should not happen but in actuality often things which should not happen Do happen.. %%  and often with no reasonable explanation.
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Colin Bishop

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Re: Sinking of Bismark
« Reply #16 on: January 21, 2010, 08:46:48 pm »

Quote
Isn't it often the case that in theory it should not happen but in actuality often things which should not happen Do happen..   and often with no reasonable explanation.

Yes, that is very true, you can't altogether discount the unlikely. When you look at the analysis of the battle damage at Jutland the effects of hits varied enormously for no apparent reason.

Colin
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farrow

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Re: Sinking of Bismark
« Reply #17 on: January 25, 2010, 08:30:58 pm »

I think you will find, that Hoods 8" armour belt only went as far as the torpedo blisters then it was a bundle of steel pipes within the bulge. The pipes where designed to crush and absorb the kinetic energy of a torpedo warhead. I just mused it was a low entry below the armour belt which entered the torpedo magazine, as that is the area which witness's saw the explosion develop on Hood. But we will never know as there was no survivors who really knew, so it is all conjecture!! to what really7 happened to her violently with virtually all hands.
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Geoff

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Re: Sinking of Bismark
« Reply #18 on: January 26, 2010, 01:55:44 pm »

I'd just like to add some comments about a diving shell from Bismark causing the destruction of Hood. In my view this is entirely possible given the range at which the action occurred which was at the limit of Hoods imunity zone.

A large calibre armour piercing shell hitting the water does not explode on impact. As has been previously commented the fuse is in the base not the nose. A 15" AP shell is designed to penetrate up to 15" of armour and metal is harder than water.

We need to look at the construction of an AP shell. From the outside (front) in. First there is a light wind shield to improve the balistic qualities in the air and thus enhance range. Second there is a soft iron nose (capped) followed by the shell proper. If one looks at shells there is the nomenclature APC = Armour Piercing Capped. The capped part prestressed the armour it hits allowing the true AP to penetrate through.

In practice once a large calibre APC hits the water it can and does travel 30 to 40 feet but it does rapidly loose stability and velocity.

There also seems to be some confusion between how side armour works and a torpedo protection systems. The former is basically designed to resist a massive impact and either defeat the shell or cause it to break up in penetrating. The APC itself only has about 2%-5% of its weight as a burster (going from memory here) and does not of itself do a lot of damage - the large splinters do the damage. The fuses in APC were delayed action and needed to hit armour in the region of 4" to trigger the fuse as otherwise they just went right through without exploding.

Torpedo protection systems were entirely different and were a layerd defense against 500/600 pounds of torpex which would utterly destroy the ships outer shell, the splinters then being slowed by crushing tubes which also absorbed the blast and/or layers or void and liqid filled compartments all designed to reduce the velocity of splinters and keep the gas bubble caused by the explosion out side the vitals of the ship i.e make sure it vents outboard and not inboard.

The requirements for a torpedo protection were completely different to shell protection and the typically thin torpedo bulkhead of 1" to 2" was designed to be flexible and was therfore little protection against an APC even after diving through the water.

A hit in line with X or Y turrets say 20 feet from the ships side could easily dive under the armour belt which on Hood was  a maximum of 12" albeit not for all of its depth (don't have the books in front of me).

The detonation of a shell near or in the after magazines would produce the effect seen.

Magazines don't explode as such, they burn rather like a match head and the pressure builds up until there is an explosion. In Hoods case the magazine pressure would build until either the turrets were blown off and the sides destroyed or the aft engine room bulkhead would collapse inwards giving release to the pressure and a large column of fire just before the mainmast as it vented upwards, all of which generally tracks what was seen. The other explanation appears to be that the 4" magazine was ignited which in turn set of the 15" but the effect was the same.

General comment on thick armour. It has a very tough face but a softer back so in tests armour that could not be pierced from the front could be pierced from the rear and hence the development of capped shell to effectivly place a layer of softer metal on the hard face which aloowed the shell to pierce previously unpiereable armour.

Hope this of interest

Regards

Geoff

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farrow

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Re: Sinking of Bismark
« Reply #19 on: February 03, 2010, 08:38:27 pm »

Most interesting reply yet, thanks.
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Colin Bishop

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Re: Sinking of Bismark
« Reply #20 on: February 03, 2010, 08:53:37 pm »

Yes Geoff, an interesting analysis. Which would also explain the reported effect of the forward magazines blowing up as the ship sank which was attributed to a blowtorch pressure effect from the after magazines spreading forward through the vessel.

Colin
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John @ WEM

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Re: Sinking of Bismark
« Reply #21 on: February 05, 2010, 05:49:49 pm »

To add to Geoff's post--which was spot-on--the Imperial Japanese Navy had shells for both their battleships' and cruisers' main batteries that were specifically designed to dive and strike the underwater hull of their target. And there is now evidence that USN 16" projectiles from USS Washington did the same thing to the Kirishima during the engagement off Guadalcanal.
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dodgy geezer

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Re: Sinking of Bismark
« Reply #22 on: February 05, 2010, 06:40:50 pm »

I seem to remember a diagram of shell behaviour under water which suggested that they could rotate and travel rear-first. In this attitude they resembled a teardrop, which is a stable shape for high-speed underwater travel, so they would continue on the inverse of the trajectory they had when they struck the water, and with not much diminution in speed....

Everyone was trying to find a way of getting high explosive underneath a ship's armour. Even the Barnes Wallis bouncing bomb was adapted to be dropped from an attacking aeroplane, skip over the surface and tunnel underneath a hull, but it only worked in a flat calm... 
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