Bismarck and Iowa

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Re: Bismarck and Iowa

Postby alecsandros » Wed Jan 18, 2017 10:19 am

RF wrote:
alecsandros wrote:In terms of anti-torpedo protection, Bismarck had stronger defense.


But it still failed to stop the ship from being crippled - and ultimately sunk.

That's right,
the TDS of Bismarck covered 70% of the ship's length. The rest of 30% wasn't protected by the TDS... She also had a triple shaft arrangemetn (while most contemporaries had a quadruple shaft arrangement), and 2 parallel main rudders, very close to one another, making them vulnerable to ... single hits (most contemporaries had the same rudder arrangent. Thre are notable exceptions , such as Littorio class).

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Re: Bismarck and Iowa

Postby Iranon » Wed Jan 18, 2017 8:49 pm

Byron Angel wrote:Re comparison of shell effects, it can also be argued that optimizing the number and velocity of projectile fragments may not be as important as ensuring that a projectile whose detonation can produce a sufficient number of effective fragments is physically able reach a critical location within the target ship.

In other words, a case of the optimal being the enemy of the sufficient.

B


There is probably a compromise somewhere between "range band of likely penetration in a state fit to burst" and "likely amount of damage if such penetration occurs".
The British cared about the latter, did some rather in-depth research on it, and decided on a larger burster than other nations. I see reasons for disagreeing with their choice, but not to dismiss their findings and hold that they probably sacrificed penetration for no gain.
I consider it more likely that the US and Germany had different priorities and were willing to sacrifice some damage potential for better penetration (focus on long-range deck hits for the US, overall performance over a wide range of conditions for Germany).

*

Regarding TDS... their purpose is to prevent/limit flooding, and that's what they should be measured by. Screws/rudders can't be protected adequately (a bit can be done about redundancy, as mentioned for Vittorio Veneto... desirable, but this is something else). The crippling hits on Bismarck and Prince of Wales have nothing to do with the merits of their respective TDS, that would be akin to "helmet faulty, didn't prevent kneecapping (when worn on head)".

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Re: Bismarck and Iowa

Postby RF » Thu Jan 19, 2017 9:49 am

Iranon wrote:
The crippling hits on Bismarck and Prince of Wales have nothing to do with the merits of their respective TDS, that would be akin to "helmet faulty, didn't prevent kneecapping (when worn on head)".


Torpedo defence has to consider the entire below waterline part of the ship and as such isn't just the armour plating. Provision for rudder and screw damage can be made although it is limited.

Regarding faulty helmets - well that has been an issue in international cricket, not just with the death of Australian cricketer Phil Hughes.
Your quote about knee-capping while wearing a helmet isn't an irrelevant throw away. The issue there is restriction of vision which leads to injuries elsewhere, that it is safer not wearing helmets. The great West Indian cricketer Viv Richards refused to wear a helmet because it restricted his field of vision and made it more likely to be hit by the ball as a result.
Today he wouldn't be allowed to play cricket because the ICC has made the wearing of helmets compulsory.

Similar thinking can be applied to a ships torpedo defence - all indirect matters need to be considered.
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Rick Rather
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Re: Bismarck and Iowa

Postby Rick Rather » Mon Feb 06, 2017 10:22 am

Dave Saxton wrote:The German 38cm gun could penetrate 130mm of Wh deck at 30,000 meters. The Iowa's decks protection is 140mm worth of, in my opinion, a slightly inferior material. Once past 30,000 meters the angle of fall of the 800kg projectile increases at rapid rate, due to it carrying less momentum down range than if it was heavier. This means that deck penetration increases quickly with greater range. By 32,000 meters it is exceeding 150mm deck penetration and by 36,000 meters it is exceeding 200mm deck penetration, according to one source.

For the same reason of the 12000kg 16" projectile carrying more momentum down range, steeper angles of fall are delayed until greater battle ranges, causing it have virtually the same deck penetration as the West Virginia's lighter 2240 lb 16" projectile per range. The penetration does not exceed 130mm (of in my opinion a slightly inferior material) until 30,000 yards, and does not exceed 150mm until 34,000 yards.

A Bismarck could certainly challenge an Iowa at long range.


That's assuming that they could hit the Iowa at long range. The consensus in this thread is that such hits were very, very unlikely. In it, you wrote,

Dave Saxton wrote:So max practical range late war in day light could be defined by the effective range that radar could range the target and spot the fall of shot. However, radar doesn't change the low probability of scoring hits at such ranges due to ballistic reasons. In most cases I'd say the max practical range in excellent conditions, late war, was about 30km (33,000 yards) for all combatants.


and

Dave Saxton wrote:It's probably not by tactical circumstances alone that BB59 did its shooting within that radius at Casablanca. The BB to BB range of its FC radars was also about 27,000 yards but since the radars were knocked out by gunfire shock right at the start of action that probably wasn't the reason. One notes that the 1945 BB59 gunnery doctrine reads 27,000 yards as extreme range.


OTOH, see my sig line (below). :wink:
Just because it's stupid, futile and doomed to failure, that doesn't mean some officer won't try it.
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Re: Bismarck and Iowa

Postby Thorsten Wahl » Mon Feb 06, 2017 1:22 pm

scoring hits at such ranges due to ballistic reasons


another problem is the flight time

at 25 km fligthtimes of shells are in the order of 40+ seconds
at 30 km round about 55+ seconds.

Ample of time for the target to change course.
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Re: Bismarck and Iowa

Postby Dave Saxton » Mon Feb 06, 2017 3:07 pm

Rick Rather wrote:
Dave Saxton wrote:The German 38cm gun could penetrate 130mm of Wh deck at 30,000 meters. The Iowa's decks protection is 140mm worth of, in my opinion, a slightly inferior material. Once past 30,000 meters the angle of fall of the 800kg projectile increases at rapid rate, due to it carrying less momentum down range than if it was heavier. This means that deck penetration increases quickly with greater range. By 32,000 meters it is exceeding 150mm deck penetration and by 36,000 meters it is exceeding 200mm deck penetration, according to one source.

For the same reason of the 12000kg 16" projectile carrying more momentum down range, steeper angles of fall are delayed until greater battle ranges, causing it have virtually the same deck penetration as the West Virginia's lighter 2240 lb 16" projectile per range. The penetration does not exceed 130mm (of in my opinion a slightly inferior material) until 30,000 yards, and does not exceed 150mm until 34,000 yards.

A Bismarck could certainly challenge an Iowa at long range.


That's assuming that they could hit the Iowa at long range. The consensus in this thread is that such hits were very, very unlikely. In it, you wrote,

Dave Saxton wrote:So max practical range late war in day light could be defined by the effective range that radar could range the target and spot the fall of shot. However, radar doesn't change the low probability of scoring hits at such ranges due to ballistic reasons. In most cases I'd say the max practical range in excellent conditions, late war, was about 30km (33,000 yards) for all combatants.


and

Dave Saxton wrote:It's probably not by tactical circumstances alone that BB59 did its shooting within that radius at Casablanca. The BB to BB range of its FC radars was also about 27,000 yards but since the radars were knocked out by gunfire shock right at the start of action that probably wasn't the reason. One notes that the 1945 BB59 gunnery doctrine reads 27,000 yards as extreme range.


OTOH, see my sig line (below). :wink:


In the past I have been rather zealous in pointing out the improbability of consistently scoring hits at plus 30km range, not because it is not possible, as it is possible and the Germans proved it, but to counter the unrealistic, and impractical, fantasies that exist on the internet of such unlikely combat scenarios, at least for WWII.

Often, the underlying assumption is the Iowa class could, but their potential opponents could not.
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: Bismarck and Iowa

Postby Rick Rather » Tue Feb 07, 2017 3:42 pm

Dave Saxton wrote:In the past I have been rather zealous in pointing out the improbability of consistently scoring hits at plus 30km range, not because it is not possible, as it is possible and the Germans proved it...


The Germans were "consistently scoring hits at plus 30km range"? When?
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Re: Bismarck and Iowa

Postby Dave Saxton » Tue Feb 07, 2017 10:02 pm

June, 1941. However, it was an 11-inch shore battery under full radar control. :wink:
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: Bismarck and Iowa

Postby Thorsten Wahl » Wed Feb 08, 2017 11:07 am

im not sure about "consistently scoring hits" as the KTB from the Admiral Kanalküste mostly states "Erfolg nicht beobachtet" -"success not observed", except you have informations about gunfire damage on british ships available.

sample
0266.jpg
0266.jpg (78.52 KiB) Viewed 512 times


but as a result, these shootings led to ceasing of the british convoy traffic through the channel
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Re: Bismarck and Iowa

Postby Dave Saxton » Wed Feb 08, 2017 3:29 pm

Thorsten Wahl wrote:im not sure about "consistently scoring hits" as the KTB from the Admiral Kanalküste mostly states "Erfolg nicht beobachtet" -"success not observed", except you have informations about gunfire damage on british ships available.

sample
0266.jpg


but as a result, these shootings led to ceasing of the british convoy traffic through the channel


Yes, I have information from the British side that the long range shooting against these coastal convoys at night was effective.

In addition, one can see that the shooting was effective by the counter measures tried by the British.
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: Bismarck and Iowa

Postby Rick Rather » Thu Feb 09, 2017 3:46 pm

Can we agree that

A.) Coastal artillery is irrelevant to the discussion of extreme-range battleship-to-battleship engagements, and

B.) That there is no historical data to suggest that such ship-to-ship engagements beyond 30km were considered practical or advisable?
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Re: Bismarck and Iowa

Postby Dave Saxton » Thu Feb 09, 2017 6:52 pm

Rick Rather wrote:Can we agree that

A.) Coastal artillery is irrelevant to the discussion of extreme-range battleship-to-battleship engagements, and

B.) That there is no historical data to suggest that such ship-to-ship engagements beyond 30km were considered practical or advisable?


Yes, agreed.

Although I think the radar aspects of the Kriegsmarine coastal artillery is instructive about potential capabilities because it was essentially the same radar as used by German warships.
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: Bismarck and Iowa

Postby Rick Rather » Thu Feb 09, 2017 8:33 pm

:lol: The phrase "potential capabilities" pretty much sums it up for most German technologies in WWII.
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Re: Bismarck and Iowa

Postby Dave Saxton » Fri Feb 10, 2017 3:29 am

Rick Rather wrote::lol: The phrase "potential capabilities" pretty much sums it up for most German technologies in WWII.


I must agree with that for many cases. Much of the problem for the Germans wasn't their technology but rather their training. Here's something I wrote about a year ago:

viewtopic.php?f=1&t=6811&start=15




pgollin wrote:
.

Dave,

Do you know the dates when the German navy decided ;

1: That radar was sufficiently reliable to be depended upon as an ASSISTANT to optical range-finders ?

2: That radar was sufficiently mature that it would be the main input for range-finding ?

I ASSUME that radar was the preferred method for range taking at night and very poor weather from the time it was regarded as reliable - is that correct ????

Thanks.

.


Phil,

As far as Naval Ordnance was concerned, right from the beginning- Sept 1936. Fleet Command was another matter though. The Kriegesmarine's bureaucracy was organized into two main divisions; the NWA or Naval Waffen Authority (Naval Ordnance) and Fleet Command. Fleet Command included B-dienst, as a part of Naval Intel, and the MND (signals). The NWA which consisted of the various ordnance and testing commands such as the AVKS, the TVA, the NVA,..ect... was responsible for the research and development of weapons systems. Fleet on the other hand, was responsible for systems application and officer training. Communication between the bureaus was poor.

(circa 1936) Fleet had their own ideas. They had wide ranging thoughts and put considerable importance on naval tactics. By providing a way to see in the dark, radar forced all previous classical concepts of naval warfare to be rethought. For tactics on a large scale, ships had to be detected all the way to the horizon, a requirement that did not require great accuracy for bearing. Determination of range with the (precision ranging panel) to 100 meters was satisfactory.

But Naval Ordnance held opinions that were not in agreement with those of Fleet Command. They wanted above all to see radar made into a method of fire control for various weapons. They recognized in the demonstrations (of the Seetakt prototype) of the accurate determination of direction and range that it was within the domain of the possible not only to equal the accuracy of optical aiming systems but to even exceed them. The advantage of being able to aim independently of visibility spoke loudly for radar. Given a requirement for a universal method of fire control for artillery and torpedoes the range achieved so far of 20-40km was completely satisfactory. Naval ordnance pressed for a requirement of a directional accuracyof 0.2* (the prototype had already achieved an accuracy of 0.1*) and range accuracy of 50 meters.. (von Kroge)


Fleet won the argument and lobe switching was left dormant on the early sets. Thus it was named Seetakt (Sea tactical instead of Seeart (Sea Artillery). Naval Ordnance did not give a recommendation to employ radars for fire control because it lacked the accuracy in their opinion.

However, in practice radar was used for fire control ranging from the beginning. For example, Graf Spee used radar ranging up until it was knocked out by the 6" hit to the foretop during River Plate. Likewise, Gneisenau's use of radar ranging allowed it to accurately return fire with Renown, until the 15" hit through the foretop knocked it out. Scheer used radar for ranging and in one case blind fire against HX84. The documents read that although it was at one point knocked out by shock, it could be reset and used for additional shooting during Nov, 5, 1940, night action.

By May 1940 the radar design had advanced to the point that 50 meters range accuracy and a new lobing method was available. However, there is little evidence that this was recognized by Fleet or that gunnery officers were aware of these advanced capabilities. However, severe secrecy policies may play a role in that.

With Bismarck, the AVKS simply had the radar data stream hard wired directly to the fire control computers. So Bismarck practiced radar ranging by default.

................

But Fleet really dropped the ball in terms of providing training or directions to officers for the best applications of the radar systems provided. Right after the loss of Bismarck, a division of the Signals Establishment (MND) was set aside to develop radar application and officer training. But they were given no authority to issue instructions to officers until late 41. Then it got bogged down in bureaucratic red tape throughout 1942, and little if any instructions had been given by the Battle of Barents Sea. Official Instructions were finally issued by the fall of 1943, but Bey departed for Norway having received no training.


The German Navy of course wasn't unique in the need to overcome the incompetence of bureaucrats. This is a near universal problem of any time period. The USN Bureau of Ordinance could be considered a rouge department during the WWII era. If I get time, I might try to dig out an internal RN memo I have listing the criticisms and frustrations the RN had with the USN BuOrd. Among them was your point B in the previous post- which was the RN position- and BuOrd's preoccupation with plus 30k gunnery ideas.
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: Bismarck and Iowa

Postby Thorsten Wahl » Tue May 02, 2017 4:15 pm

@spicmart: Bismarck's torpedo defense system was rated to withstand 250kg of TNT, expectation was that damage inwards of the TDS from larger explosions would be contained rather than prevented - Bismarck featured extensive subdivision. The rating seems quite conservative; German assumptions of the time were generally pessimistic.


-Bismarcks TDS it was full size testet against 300 kg S1 (Schießwolle 36) wich was significantly stronger than TNT.
The TDS remained watertight.

Combat results
-the UW protection/TDS-Double bottom wasnt impaired by the 2 ton charges of the X-Crafts. despite beneath/nearby explosions Nevertheless the ship was rendered off duty due to massive shock damage.

-a bulls-eye-hit of a Tallboy through the forecastle with following Detonation below the keel in September 1944 destroyed the parts before the forward transversal bulkhead almost completely. Ship seaworthyness was gone but ship remained watertight and it's nominal combat capabilitiees and could proceed from own power to Tromsoe.

-Bismarck received several torpedohits. No damage of significance to the core citadel.
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