Ark Royal vs Bismark (1 Viewer)

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Yes, but another important component in a DB attack is momentum. Go too slow and the bomb will not have enough momentum to effect adequate penetration for the bomb type being used. Go too slow, and/or too shallow and you greatly increase vulnerability to AA defenses. Another important component is training. Training is critical when conducting a steep DB attack, more so against a moving target. If you don't have it, and practice it, it'll be a difficult maneuver to pull off, as was the case with the VMSB squadron at Midway flying SB2U's. Due to inexperience they conducted a GB attack vs a traditional full on DB attack.
Hi Nikademus

Actually aircraft speed has no impact on the maximum speed of an object, that's a function of the terminal velocity of the projectile. Only if the aircraft was travelling faster than the terminal velocity of the bomb would aircraft speed result in the bomb falling faster than its terminal velocity, and even then, only if the bomb was not dropped with sufficient altitude to decelerate back to terminal velocity before impact. An aircraft releasing a bomb at a speed less than a terminal velocity will reduce the time needed to reach terminal velocity, but in no way affect that maximum terminal velocity. The question therefore is whether either the Swordfish, or the Stuka are travelling at above terminal velocity.

A free-falling object achieves its terminal velocity when the downward force of gravity (Fg) equals the upward force of drag (Fd). This causes the net force on the object to be zero, resulting in an acceleration of zero.

I don't know what the terminal velocity for a bomb would be typically, but for a speed skydiver, its close to 650mph . All the delivery aircraft travelling at a speed less than this will do is enable the projectile to reach that terminal velocity faster, not that the projectile will actually travel faster

I think what this means is that a swordfish dropping a bomb, and wishing the bomb to reach its terminal velocity before impact, would need to release its bomb earlier than say a Ju-87/ if we assume the dive speed for a Ju-87 to be 200 knots and the dive speed of the Swordfish to be 100 knots, it will take the bomb released by the Swordfish an additional 4 seconds to reach terminal velocity. In that 4 seconds the Swordfish will have travelled 222 metres. That means the release altitude of the Swordfish is 222 metres above that of the Stuka. Given the greater accuracy that comes with a slower descent, I don't think that would make any difference to bombing accuracy, and absolutely no difference to the penetration capabilities of the bomb, since the bomb would hit the ground at the same speed

As far as training is concerned, the FAA swordfish sqdns did have some prcatice at divebombing, particularly the air groups working on the Ark Royal . Probably not as much as the SG crews operating with FKII, but enough to qualify as being proficient.
 
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Hi,

Bismarck's heavy belt armor covered 68% of her hull at the waterline which compared favorably to other designs (constrained by Treaty) at the time she was being built. It did not reflect any particular area of superiority however. .... Where things can vary more is depth of protection and in armor thickness. These were areas of strength of the KGV class for example, which had a deep and uniform belt of BB level protection topped by her primary armor deck (placed higher as was general practice except in the case Germany where the deck remained lower slung in order to reinforce the belt). ... Ultimately length of armor belt is irrelevant if the belt is vulnerable to the shellfire faced from a primary opponent type.

Hi Nik,

I gotta disagree at here somewhat since your example narrows the types of damage that can be suffered - to reverse your thesis, the belt is still valuable if it stops the enemy shellfire. The ca. 15% longer/larger belt/citadel of the Bismarck - compared to Treaty designs represented a protected box of some 36 meters in length and the same 30-36 meters in width worth of protected buoyancy, or an equivalent of 6500 tons of seawater that is NOT within the ship, quite an amount and explains why Bismarck was so damn hard to sink - she had massive reserves in her. I would not call that irrelevant. A

As this was an extra volume - compared to Treaty and post-Treaty BBs - which was completely safe from flooding from a large number of enemy guns at just about any range, and it could still keep out major caliber shells at long range. If that belt wouldn't have been there, the ship would have been considerably more vulnerable to flooding from any guns hitting her (pardon, him!) there - and that includes the literally thousends of secondary fired on her during her last battle.

Frankly I don't get why it would be more relaxing to have water pouring in from small caliber hits outside a rather small citadel - which is BTW just as unprotected in practice against flooding from heavy (14-16 inch) shells on even the KGV which as you note had rather thick belt at 356 mm. As per Okun's article which probably well-known to you, even that thick belt could be holed ("Navy Limit") out 23 800 yards - at the top of the battle ranges for a BB in WW2. Even at the magazines very it is extremely thick in comparison, we are still talking about vulnerability at 21 500 yards against the German (French, Italian etc.) 38cm guns. So what's the point? Thick belts might have worked during WW I, but by World War II, the guns were simply too powerful and belts no longer offered much protection anyway...

This is a basic concept of an All or Nothing protection scheme. The idea is to protect only the critical areas of a battleship and that with the thickest armor possible, leaving the non-critical areas unprotected. The ends of a BB, along with light superstructures, if damaged would not threaten the safety of the ship. Richelieu's citadel was intentionally concentrated in order to increase protection against heavy shellfire.

I am aware of the concept, but all I can say is because of the factors mentioned just above, it only works if the armor thickness is thick enough to keep shells out. And only Yamato had that, and she was a 70 000+ tons design.. so much about being displacement efficient. ;)

As for the safety of the ship due to its soft ends, yes it does not directly endangering the ship, if the ship otherwise have sufficient protected buoyancy, but Bismarck's (where the shell passed through the bow BTW!) as well as Lutzow's case demonstrates, it is a problem. The less the chance for that problem, the better.


Had Lutzow's bow area been unprotected, the shells would have had a greater chance of passing through the narrow hull section without detonation. Instead, the medium/light armors ensured detonation increasing structural damage and contributing to the loss of the ship. This makes Lutzow a case demonstrating how medium and light armors can be detrimental to a warship when struck by heavy shells.

Indeed I agree that light armor that cannot achieve anything else but to ensure the detonation of the shell inside the ship is useless and adds nothing to the protection of the ship. However the idea that the ends of the ships are sacrificial in their nature and need no protection at all does not seem to have been much accepted with designers - some splinter protection had to be provided, since for every shell hitting the ship's bow or stern there are probably ten that explode nearby, and their sizeable splinters can hole the ships normal plating - if it does not offer some ballistic protection at all - and cause flooding just the same.
 
I wouldn't agree with that. The weight of this multi belt system resulted in reduced thickness to the primary armor belt. Eliminate the middle/upper belt and one can maximize the primary belt protecting the ship's waterline and increase its depth.

There was no "middle" belt on the Bismarck (that was a feature of WW1 battleships). Roughly 800 tons of armor went into the top 145 mm belt, which as noted, alone allowed some 250 (one deck) to 500 tons of armor (two decks worth) saved on the barbettes (which thus could be shaved down from 340 mm to 220mm below the top deck, as opposed to the Scharnhorst class, where the barbettes were full thickness all the way down. As an added bonus, instead of the 13.4" thickness worth of ballistic protection, the barbettes below the deck offered a ballistic resistance equivalent to a 27" thick barbette(!!) due to the top belt's decapping effects, as seen on the Italian VV class's decapping plates. Further the top belt reinforced the main armor deck, made it unnecessary to heavily armor the barbettes/ammunition uptakes of the secondaries. Assuming these latter were of 4 meter diameter and would be armored to 145mm thickness instead of 20mm down for one deck height (assumed 2 meters height), we are talking about another 300 tons saved. I am not going to calculate the savings in the main armored deck.

And there's absolutely no doubt that the upper side belt on the Bismarck was major weight saver, which is why they decided to go that way, instead of repeating the Scharnhorst's thin 50mm top belt and thick barbettes.


The German designers compensated for this by keeping the armor deck low in a turtleback design reflecting their view that a typical North Sea engagement would be relatively close. The slopes reinforced the belt making the ship very resistant to veridical fire.

Yup!

The cost of the lower deck armor was more exposure of topside systems to damage and reduced protected buoyancy in the event of major flood damage.

I don't quite get this - how did the placing of the main belt reduce protected buoyancy?

Placing the main armored deck at the waterline instead at the top of belt did indeed expose one extra deck (the one behind the main belt) to enemy plunging fire - yes but there was nothing of vital importance to the ship's combat capability. The messing halls, crew quarters and laundry room might look messy if hits went there, but at the same time the vitals - magazines and machinery - were absolutely safe behind the main belt, if hits occured there, at any range. Any hit on the main belt would be rejected into the upper works, as you are well aware, and make mess of the laundry room but at least the ship doesn't go kaboom or to a full stop. But to me an equivalent weight of armor that is spent on the main deck is better spent if it performs triple function (1 as a simple main armored deck, 2 reinforcing the main belts protection 3 making seperate splinter protection for the magazines unnecessary), and protects against both short- and long range gunnery.

IF the main armor deck, on the other hand, would be placed on the top of the belt, the laundry room would be rather safe from high angle plunging fire, as are the magazines and machinery, but now additional splinter protection is neccessary for the magazines (as on the KGV), since once the belt is penetrated, or even pieces start to fly off it from the impact, the whole ship is endangered. Its again

Now, the sad part is, again that even the thickest belt couldn't hold projectiles out. Even if we would use the KGV's thick belt the magazines would be vulnerable to belt hits out to 21 000 yards or so. I would preserve that instead of the laundry, because of the magazines go, the laundry goes too.

The 145mm belt was employed to keep medium caliber shells from entering the spaces above the battery deck (protecting uptakes and ammunition handling spaces). The designers were convinced that potential close encounters with DD's and cruisers made this provision necessary (and thus absorbed critical weight that might have been put into the primary belt.)

That was probably a consideration too, but the change of the design from the Scharnhorst to the Bismarck shows that the weight saving potentional (see the most obvious barbette savings) was realized. They could keep just the same light top plating as on Scharnhorst if they wanted to (which was more or less proof against small caliber shells already), so the advantages of using triple the thickness must have been obvious, evidenced by the reduction in barbette thickness reduction.

The upper belt did not prove to be proof against UK 152mm and 203mm shellfire.
Don't be silly, a 145 mm armor plate is was certainly proof against UK (or anyone else's) 152mm shellfire.

As for 203mm shellfire, it was the equivalent, and in fact superior to the armored protection offered for heavy cruisers and was proof against their fire in the worst case scenario out to 15 000 yards. That's suicidal range for a heavy cruiser when an enemy battleship is that near, and the County class that was there had nothing but splinter protection as far as I am aware..:shock: The British CAs didn't try to get anywhere near Bismarck until she was silenced for a good reason.

Bismarck's protection scheme made her very resistant to close in vertical fire at the expense of greater vulnerability at expanded ranges to plunging fire and helps explain why she stayed defiantly afloat against the short range fire she was subjected too. An additional con of this was that close in fire deflecting off the lower armor deck slopes would increase topside damage and contribute to the ship being made combat ineffective, as occurred.

The primary armament proved suprisingly vulnerable to heavy BB shellfire; One 16in hit took out half of Bismarck's primary armament. .. Bismarck was disabled rather quickly by Rodney and KGV.

IMHO the nanny story about the one shell knocking out two turrets in a sort of miracle is utter nonsense, and any case, totally unproven. There's was no "surprising" vulnerability of the main armament - the turrets, unlike the rest of the ship, were entirely ordinary and average in their protection levels, but as noted, not in redundancy. They could be knocked out just as easy as any other battleship's main armament, and indeed if we place any other battleship in Bismarck's place, range and angle, those turrets would succumb to the same hits just as easy.

As for disabled "rather quickly", well its all relative, as it took "only" 45 minutes of firing from two battleships on an unmanouvering target at 8 knots while facing them with its bow and unable to use half its armement due to this position, and then about another half an hour to silence the smaller guns onboard.

As a class the ships proved very tough, but the tradeoffs were evident as well.

Of course there were tradeoffs, first and foremost in the horizontal protection, which however was still entirely satisfactory for the battle ranges expected and realized. Certainly while the hull was very well armored, the the turrets were completely ordinary in that regard, but German capital ship designers never seem to have cared too much about the turrets, as long as the ship survived. As Tirpitz said, its easier to repair ships than to build them - turrets were sacrificable. The front bulkheads were definietely weak by comparison, but I can't think of anything else that came as a compromise.

Overall, I think it was a very good blend of characteristics, and perfect from the German strategic point of view, as after all, she had speed, range, massive protection and good firepower, and being very difficult to sink, she could limp back to the dockyard even if the battle went bad - the German naval bases were usually close-by.

She proved difficult to sink however which has led to a long standing and silly argument about "Sunk vs Scuttled." To me it's irrelevant....the ship was stopped and wrecked.

Completely agree.
 
Part III.

Bismarck's armament was driven primary by what the Germans considered the optimal organizational effect a traditional four turret (2 guns each) offers. The penalty paid here was increased weight which resulted in a longer and heavier citadel. Had a three gun/three turret armament been opted for, weight would have been saved, an additional gun barrel would have been obtained and the primary belt armor could have been shortened, saving more weight allowing it to be thickened.

I disagree on that, it did not impose any weight penalty worth speaking of - using triple turrets would have meant less turrets yet, but at the same time much larger barbettes with heavier turrets on them. Three gun / three turret was not news to the Germans - they used them on the Deutschland and Scharnhorst already, and the thing goes back to WW1 Austo-Hungarian and Italian battleships. Three triple turrets were considered for the Bismarck, but lost in favour to four turrets, and I'd wager they had a good reason for that, and also for keeping this layout for the next class (H).

The citadel's length was determined not only by the number of turrets, but also size of the magazines underneath - and you certainly need a larger magazine to accommodate munition for nine guns rather than eight. Out of curiosity I did some calculation with this, comparing Bismarck's four turrets and barbettes with the three on the Vittorio Veneto (which has very similiar armouring characteristic, making it an ideal comparison). I don't recall there was any weight advantage. Either you opt for an extra gun, or you opt for an extra turret and better overall layout. Considering the rather high rate of fire of the Bismarck's guns (up to 3/minute is claimed, which might be a bit theoretical, but even if 1/8 higher rate was realized, there was no reduction in overall firepower), the layout was hardly disadvantageous from any point of view.

The "large hull" was a product of the rather bloated nature of the design which continually increased in size as requirements were piled onto it. The German designers could do this because they were not contrained by the Washington Treaty. The Italians were also guilty of flagerantly exceeding these limits.

Yes but at least they came up with good ships in the end. ;)
 
I dont know whether it was actually necessary to penetrate the hull to disable a ship. Many ships lost all or most of their command with a single hit to the bridge, it took very few hits to wreck any radar or radio transmitters.

Having been almost deafened in an empty oil container when a guy dropped a hammer I cant imagine what being in a steel structure being hit by tons of explosive would do to the men inside. I read an account of the Battle of the River Plate and although the Graf Spee wasnt seriously damaged the crew were shocked by the experience.
 
Part III.
The ca. 15% longer/larger belt/citadel of the Bismarck - compared to Treaty designs represented a protected box of some 36 meters in length and the same 30-36 meters in width worth of protected buoyancy, or an equivalent of 6500 tons of seawater that is NOT within the ship, quite an amount and explains why Bismarck was so damn hard to sink - she had massive reserves in her. I would not call that irrelevant.

As explained, belt armor alone does not equate to protected bouyancy. The longer belt represented a larger target of thinner armor that could be more easily penetrated. A belt that is penetrated does not protect bouyancy of any kind.

. So what's the point? Thick belts might have worked during WW I, but by World War II, the guns were simply too powerful and belts no longer offered much protection anyway...

If that is now your position then one can conclude that Bismarck's longer thinner belt armor was more wasteful than the stronger belts of certain other designs.


As for the safety of the ship due to its soft ends, yes it does not directly endangering the ship, if the ship otherwise have sufficient protected buoyancy, but Bismarck's (where the shell passed through the bow BTW!) as well as Lutzow's case demonstrates, it is a problem. The less the chance for that problem, the better.

Bismarck's bouyancy was not threatened by the bow hit. Lutzow's situation i've gone over already.

However the idea that the ends of the ships are sacrificial in their nature and need no protection at all does not seem to have been much accepted with designers

that is incorrect.

There was no "middle" belt on the Bismarck (that was a feature of WW1 battleships).

I never said there was a middle belt on Bismarck. Hood was used as an example demonstrating the weight penalties of having multiple belt's of varying thicknesses and the restrictions it imposes on primary belt armor depth and thickness, as well as demonstrating the added vulnerability to modern heavy shellfire. The designer's insistance on provisioning an upper belt of 145mm cost weight and took away displacement that might have been used to thicken the primary belt. This belt would be of no use against heavy shellfire and as mentioned the upper belt's function in keeping out medium caliber shellfire proved to be an overestimation as well. Reducing barbette thickness behind such a belt does not compensate for a singular thicker layer of armor. Seperate layers of armor thicknesses are weaker balistically than one single thickness. The same principle applies to deck armor. A single homogenous layer of deck armor is stronger than either two seperate decks who's thickness equals that of the single deck that consists of two layers of armor sandwiched together.

And there's absolutely no doubt that the upper side belt on the Bismarck was major weight saver, which is why they decided to go that way, instead of repeating the Scharnhorst's thin 50mm top belt and thick barbettes.

This is not supported by any research I have read including Garzke and Dunn's extensive study of the class (Axis Battleships of WWII) I would be interested in seeing evidence to support this declaration.


I don't quite get this - how did the placing of the main belt reduce protected buoyancy?

See D.K. Brown's "Grand Fleet" which goes into detail on "Protected Bouyancy" in relation to the placement of the primary armor deck. The danger of a low placed armor deck at the waterline level was that any amount of flooding might put the armor deck below the waterline allowing subsequent damage to flood areas above the primary area of armored protection.

Any hit on the main belt would be rejected into the upper works, as you are well aware, and make mess of the laundry room but at least the ship doesn't go kaboom or to a full stop.

Where data and power transmission systems are located as well.

IF the main armor deck, on the other hand, would be placed on the top of the belt, the laundry room would be rather safe from high angle plunging fire, as are the magazines and machinery, but now additional splinter protection is neccessary for the magazines (as on the KGV), since once the belt is penetrated, or even pieces start to fly off it from the impact, the whole ship is endangered. Its again

Placing the deck armor on top of the primarry belt increases the area of protected bouyancy against heavy shellfire. A splinter deck underneath the primary armor deck (as provisioned on USN battleships) was an integral part of the A/N system as it was meant to catch any fragments resulting from shell impacts on the primary armor deck...either shell fragments and/or deck armor fragments keeping the below spaces intact.

Don't be silly, a 145 mm armor plate is was certainly proof against UK (or anyone else's) 152mm shellfire.

See Garzke and Dunn (Axis Battleship of WWII) for more information.

IMHO the nanny story about the one shell knocking out two turrets in a sort of miracle is utter nonsense, and any case, totally unproven. There's was no "surprising" vulnerability of the main armament.

So you say. Myself, I have been skeptical and have participated in several discussions regarding it. While not airtight, the destruction of Bruno turret by a 16inch shell which caused an internal explosion powerful enough to blow off the entire turret's back armor plate could have accounted for Anton turret's disablement, even if temporary.

the turrets, unlike the rest of the ship, were entirely ordinary and average in their protection levelsbattleship's main armament, and indeed if we place any other battleship in Bismarck's place, range and angle, those turrets would succumb to the same hits just as easy.

That is incorrect.

I disagree on that, it did not impose any weight penalty worth speaking of - [3 tripple vs 4 twin]

See Garzke Dunn, Friedman, D.K Brown. for more details on the weight penalty imposed by this scheme.

The citadel's length was determined not only by the number of turrets, but also size of the magazines underneath - and you certainly need a larger magazine to accommodate munition for nine guns rather than eight.

Not necessarily as magazine size is also determined by overall hull size, gun shell size and the requirement # of rounds per barrel. the space savings from having a single magazine allows additional weight savings that more than compensates for the additional barrel, assuming the same rounds per barrell is a requirement.

Yes but at least they came up with good ships in the end.

Bismarck and her sister were good ships. Very strong and powerfully armed.
 
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Actually aircraft speed has no impact on the maximum speed of an object, that's a function of the terminal velocity of the projectile.

As far as training is concerned, the FAA swordfish sqdns did have some prcatice at divebombing, particularly the air groups working on the Ark Royal . Probably not as much as the SG crews operating with FKII, but enough to qualify as being proficient.


Hi,

I believe there was some influence as some calculations i've seen for DB delivered protectiles included both speed and height as a requirement to effect a set estimated penetration. Cambell's work on WW2 weapons includes these figures (300kt dive....release at at least 6500ft etc) Level bombers can only utilize height to influence potential penetration effect. I agree that in the SW case they'd probably have to release higher than a Val, Stuka or Dauntless to compensate for this.

I'm skeptical on the level of proficiency in regards full DB'ing on ships maneuvering at sea. All the examples i've seen have been against non-moving targets which, no offense to the FAA, but would not require as much proficiency as attacking a moving target. Given the light weight of the bombs used I have a hard time seeing the SW pilots spending any appreciable time practicing DB tactics, at least not till later in the war with the Barracuda arriving.
 
I dont know whether it was actually necessary to penetrate the hull to disable a ship. Many ships lost all or most of their command with a single hit to the bridge, it took very few hits to wreck any radar or radio transmitters.

Having been almost deafened in an empty oil container when a guy dropped a hammer I cant imagine what being in a steel structure being hit by tons of explosive would do to the men inside. I read an account of the Battle of the River Plate and although the Graf Spee wasnt seriously damaged the crew were shocked by the experience.

WW2 battleships were more vulnerable to "soft kill" (also called "mission kill") vs. earlier eras. New technology such as radar and electronic assisted fire control devices could at best only be given splinter protection. South Dakota was a good example of this. She was never seriously threatened by the damage received but was rendered deaf and blind by all the hits in the superstructure area.

Graf Spee was scuttled because her captain was tricked by the British into believing that a superior force awaited the ship just over the horizon from River Platte. (including the battlecruiser Renown) Rather than subject the crew to certain death, he chose to scuttle and spare the crew.
 
Actually, the Graf Spee had substantial damage and her captain probably made the correct decision to scuttle. Her system for fitering fuel and lubricants was wrecked as well as the system for obtaining fresh water. She had been hit by perhaps more than 30 shells and holed below the water line. A battle between Graf Spee and the two British CLs, seriously impaired and the CA, Cumberland, would have been truly between the "crippled and the arthritic" but the Graf Spee would almost certainly have not made it home with other Allied units speeding to the scene.

The electronic equipment in WW2 ships was subject to disablement by relatively light damage. The Salt Lake City, CA25, at the Komondorskis, lost much of her electronic capabilities from the concussion of her own ten gun eight inchers, firing the equivalent of eighty salvoes.
 
I agree, Spee had substantial damage. The point I was making was that her scuttling had more to do with Langsdorff's accessment of the situation vs. other factors. He was also ignorant of Exeter's damage which was equally substantial. If he'd known he was only facing the two CL's, I believe he would have tried breaking out. However with intel that substantial forces awaited him outside the harbor....he chose to scuttle.
 
I believe there was some influence as some calculations i've seen for DB delivered protectiles included both speed and height as a requirement to effect a set estimated penetration. Cambell's work on WW2 weapons includes these figures (300kt dive....release at at least 6500ft etc) Level bombers can only utilize height to influence potential penetration effect. I agree that in the SW case they'd probably have to release higher than a Val, Stuka or Dauntless to compensate for this.

In order for this to be true, there would have to be no actual or effective terminal velocity, or alternatively the aircraft dropping the bomb would need to have a dive speed greater than the terminal velocity. Doesnt matter who is trying to say it, its breaking the laws of physics to try and say otherwise. An inconvenient truth, but a truth nevertheless.

Put in its simplest form, a projectile free falling through the air reaches a point where the potential energy being converted to kinetic energy by the fall, is being matched perfectly by the drag of the falling object. Unless that falling object has access to additional energy, it cannot go faster than that. If an object is droped from already "falling" aircraft, but that aircraft is not travelling more than the terminal velocity of the bomb, then the terminal velocity of the bomb cannot be increased.

I'm skeptical on the level of proficiency in regards full DB'ing on ships maneuvering at sea. All the examples i've seen have been against non-moving targets which, no offense to the FAA, but would not require as much proficiency as attacking a moving target. Given the light weight of the bombs used I have a hard time seeing the SW pilots spending any appreciable time practicing DB tactics, at least not till later in the war with the Barracuda arriving.

The FAA undertook its first bombing missions with Swordfish in April 1940, in the Norwegian campaign. Ark Royal then continued to train, presumably this included bombing training, for a couple of months before being attached to Force H. I comparison, the aviators of the FAA had spent years training at dropping torpedoes. My opinion is that they were the best trained torpedo bomber squadrons in the weorld by May 1941. Not even the Japanese could match their profiiciency. They were so good, they could hit moving targets, in poor weather, at night, and not only that, could hit a specific part of that target, wityh a high degree of accuracy. I dont beleive there was anyone else in the world who could hope to match that skill .

Given that capability there is little wonder that they tened not to use bombing as a technique against ships. Though they did tend to so whilst based on Malta, and attacking Italians, agin at night.

The profiency of the Swordfish groups in divebombing really did not reveal itself fully until the swordfish began to be used in ASW operations. hitting a fast moving submarine, again often at night, demands skill far in excess of hitting a regular surface ship. The Swordfish groups were doing that quite regulalry, from about 1942 onwards. Whilst it would be a strech to say they were exceptional at D/B techiques, I think it can be convincingly argued that they were proficient.
 

In order for this to be true, there would have to be no actual or effective terminal velocity, or alternatively the aircraft dropping the bomb would need to have a dive speed greater than the terminal velocity. Doesnt matter who is trying to say it, its breaking the laws of physics to try and say otherwise. An inconvenient truth, but a truth nevertheless.

Put in its simplest form, a projectile free falling through the air reaches a point where the potential energy being converted to kinetic energy by the fall, is being matched perfectly by the drag of the falling object. Unless that falling object has access to additional energy, it cannot go faster than that. If an object is droped from already "falling" aircraft, but that aircraft is not travelling more than the terminal velocity of the bomb, then the terminal velocity of the bomb cannot be increased.


I'll concede the point as i'm not enough up on physics to sound halfway intelligent. :lol: Perhaps the speed and height calcs are included in order to ensure the bomb obtains terminal velocity just as a level bomber will bomb higher in order to ensure adequate velocity.


The FAA undertook its first bombing missions with Swordfish in April 1940, in the Norwegian campaign. Ark Royal then continued to train, presumably this included bombing training, for a couple of months before being attached to Force H. I comparison, the aviators of the FAA had spent years training at dropping torpedoes. My opinion is that they were the best trained torpedo bomber squadrons in the weorld by May 1941. Not even the Japanese could match their profiiciency. They were so good, they could hit moving targets, in poor weather, at night, and not only that, could hit a specific part of that target, wityh a high degree of accuracy. I dont beleive there was anyone else in the world who could hope to match that skill .

I'd argue the point on the Japanese matching it, at least in standard daylight ops given their track record. I don't doubt however that the FAA torepdo squadrons knew their jobs as well but torpedo bombing was their primary task after all which is my point. Dive Bombing, while the SW was technically capable of it to a degree was not the plane's primary attack role and the ASW examples I still believe are more a case of glide bombing vs. out and out dive bombing. A number of USN pilots were cross trained in regards fighters and dive bombers. Technically they were "proficient" but given the lack of practice in comparison i would not rate them as capable as full time DB pilots.

Clay Blair's books on the Uboat war are full of Air ASW examples and just last night again, while reading it i observed another instance where a plane (this time a Catalina) was described as "diving down" on a surfaced uboat and attacking with great skill and proficiency. The evidence based on ASW attacks is IMO not enough to warrent granting a swordfish squadron nor it's pilots full "Dive bomber" status in the same vein as a Ju-87/SBD/D3A.
 
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I really dislike the idea to sidetrap the discussion with quotes and responses, which doesn´t add anything than a spirited up discussion.
SO my response to the valididty of the BISMARCK´s TDS and the related other BB´s TDS is in part a summery of the problems, in part direct responses. I will try to avoid direct quotes and concentrate on the facts of the discussion in order to make reading and following up the development of the discussion easier.

Part of the discussion was the efficieny of the TDS with problems raised by myselfe to the effectiveness of other modern BB´s TDS and that of BISMARCK in comparison. Contrary to the opinion of Nikedamius, I rate BM´s TDS rather good and made a case out of this with reference to the three hits sustained by the ship before the final action.
NIKEDAMIUS referred to the TDS of LITTORIO and the Pugliese type of protection which was considered rather unorthodox (actually invented by a british designer in the dreadnought period but never implemented in BB design before the modernization of italien Dreadnoughts in the 20´s 30´s). It must be stressed here that the LITTORIO class was about the same tonnage as was BISMARCK, both nations didn´t designed their BB´s with congruence to the 35,000ts stand. limit.
I seriously doubt that the example of VITTORIO VENETO at MATAPAN from an british aerial torpedo is comparable to the experience of BISMARCK. At first, the hit occurred at a different spot. It´s true that the hit occurred at the stern (close to the rudders) but in BM´s case, the rudderengine was directly exposed to blast effects, in VITTORIO´s case it was not. Other than that, little flooding occurred in case of BISMARCK from the stern hit and the contemporary second torpedohit abreast the engine spaces (contained by the TDS), while VITTORIO VENETO soon shipped a total of ~4,000 ts of floodwater from this single torpedohit aft (including counterflooding). The high GM of BISMARCK didn´t made counterflooding necessary. Also, the machine room was temporarely affected in the italien case (speed limited to 19 kts), not so in BM´s case. Judging from this, the effect of an aerial torpedoe was much more pronounced in the VITTORIO VENETO than were two hits in case of BISMARCK, indicating a less effective torpedo damage containment system in the modern italien battleship, enforced by the lower design GM.
The wide stern of the italien BB allowed a three rudder system (one main flanked by two auxilary ones) instead of the twin arrengement of the BM but in the italien case, the rudder itselfe was not blocked in a turning position (only jammed) while in BM´s case, and according to wreckage analysis conducted by Ballard and Cameron, not only the rudder engines were jammed. There is a good reason to believe that also one of the rudders was blocked mechanically and turned by the blast effect. This has drastic consequences to the ability how to repair. And these conducts were endangered by the conditions of BISMARCK´s sortie. While the crew of VITTORIO was able to conduct repairs in calm water (allowing to use divers for repair) without beeing shadowed or engaged by enemy forces, BISMARCK´s crew had to deal with raising seas and a DD night attack. Finally, while VITTORIO returned under the air umbrella of italien and german airforces to Taranto ( a distcance of approx. 400 mls), the BM had to operate under enemy airspace (provided by VICTORIOUS ARK ROYAL) a good 700 mls away from Brest.
To sum up,
[A] The effect as a measure of flooding and interference with the propulsion machines of TT hits was more pronounced in the VITTORIO VENETO (and the sister ship LITTORIO grounded from only three hits at the air attack of TARANTO)
The effect as a measure of the ability to steer was more pronounced in the BM (but the hit was at a different spot as well).
[C] The conditions of repair are not comparable and conclusions cannot be drawn since BM had no opportunity to repair the damage before her final battle by means of it´s own (trials with divers were abandoned because of the seastate).

I would also liek to refer once more to the 2nd torpedhit sustained by the BISMARCK in this event. NIKEDAMIUS mentioned that according to W. Garzke, the hit resulted in tearing damage to the TB´s welding seams, resulting in minor progressive flooding beyond it.
I challange Garzke and his interpretation. It is wrong from two points: At first, when he wrote this, there was no wreckage analysis aviable, which could support his speculation and survicors testimony point to different behavior of the TB (which again later was confirmed by wreckage analysis conducted with video documentation of the torpedo bulkhead). Secondly, BISMARCK´s torpedo bulkhead was not welded. According to the BAUBESCHREIBUNG SCHLACHTSCHIFF F the torpedobulkhead of BISMARCK (and TIRPITZ for that matter) was rivetted and not welded, because it was feared that seams of welds may fail under
stress. The HINDENBURG class was scheduled to have welded torpedobulkheads, not the BISMARCK class. W. Garzke made a mistake.
Garzke and Dunn also made a mistake in considering the effects of the final torpedoattack to be substantial in the sinking. This was in part driven by an attempt to proove that the measures of the german crew to scuttle the ship had little to do with the sinking and only hastened the event. Subsequent research on the other hand indicated that the ship had enough buoyoncy reserve to stay afloat for at least two days when the torpedoing was carried out by RODNEY and DORSETSHIRE, assuming progressive cumulative flooding takes place. The TBD was not defeated by torpedoes according to Göde´s and other accounts. Flooding happened, which is in congruence with the flooding of larger outboard hull sections (void cells outside the holding bulkhead), which indeed would happen if a TT strikes the TDS.
CAMERON is no naval architect, but so is GARZKE. Both have an historical and technical interest in the matter and from what I can tell You, both, Garzke and B.Jurens have his opinion in high regard. They don´t reject it because he is no naval design expert, his documentation on the wreckage is the best done so far.

I am convinced You don´t fully understand the values of high metacentric height for the margin of stability.
The BISMARCK class didn´t favoured a high GM for gunnery issues, this is counterproductive (the KGV and LITTORIO class both had a deliberate low metacentric height for a pleasant gunnery platform). They
favoured a high GM because it makes onesided wateringress less effective on the developing list to this side.
See Campbells statement on metacentric height in german ww1 designs (deliberately done in order to have more options once flooding occurred) or some articles publicly aviable on the navweaps site.

Another point of discussion refers to the YAMATO´s TDS. As I said,
ANY main bulkhead beeing of dissimilar material is a cause of errors and failures. In YAMATO´s case this is the joint between the upper and lower main belt. Beside of the problem of having an even and longitodinal joint through basically the whole citadell of the ship, the material is dissimilar. The main torpedobulkhead is made of face hardened armour grade material. This armour is not designed to flex, it will give away after the brittle face is destroyed and has a very rigid structure. The lower belt is made from homogenious armour grade material and designed to flex under the blast effect of a torpedohit. Both materials do not act in the same way when exposed to blast effects, allowing the joint to create a zone of fracture and gaps under blast stress. This design charackteristicum is identic in modern US BB´s other than the NORTH CAROLINA class and the planned but unbuildt MONTANA class. The SD class was constrained by the limits of the WNT, the IOWA class (with an identic system), however, was not.
Under the same conditions, with a blast involving the joint zone of both armour types, the joint will fail unless the blast is small enough to be contained by the lower homogenious part of the belt without beeing flexed.

I will also use this opportunity to explain the torpedo hits sustained on MUSASHI.
 
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The relevant document is
US technical mission to Japan
No. S-06-2
Reports of damage to japanese warships, artcile 2 (42p.)
YAMATO(BB), MUSASHI(BB),
SHINANO (CV), TAIHO (CV).
Issued january 6th, 1946.

The report contains conclusive evaluation of other reports, inclusing USSBS Interrogation reports No. 32, 35,47, 133 and 149.
I quote from p. 17:
3. When this investigation was started, there was little data aviable. That which was aviable was fantastic and completely out of proportion with the charackteristics of the ship, the events which caused YAMATO´s loss, and those involved in the loss of SHINANO. For example the Chief of Staff to the OTC in command reported in USSBS interrogation report No. 149 that she had been hit with 18 torpedoes and 40
bombs -deriving this information, he said, from survivors. Again, the action report briefed in Article, this report, lists 21 torpedohits. Yet MUSASHI did not sink until about four hours after the end of the last and most vicious attack made against her. It appeared that the well known trait of magnifying disaster had had full rein, with no questions asked by any office of the Naval Ministry.

4. Fortunately, the Executive Officer and the Chief Engeneer were made aviable for interrogation. Both had personal notebooks filed with many details of MUSASHI´s loss. Both had interviewed many survivors. Both officers also reported 21 torpedohits, but it turned out that the Executive Officer had assisted in preperation of the action report referred to in (3). Nonetheless, both officers appeared unusually intellegent and well-informed. oncerning ten of the hits, they were able to furnish comparatively large amount of detailed information. On the other eleven they could give absolutely no details, despite the facts that the Executive Officer had received almost all damage controll reports and kept notes of the rports, and that the Engineering Officer was in the machinery spaces almost the entire period of action.



A narrative about the standarts and draft of MUSASHI as well as the details of the action and damage involvd follows. On p. 20f. it goes on with the final attack of the last and most vicious wave:

23. Fatal damage was done by torpedoes. Both Captains reported ten hits. Two of these were reported as duds, striking at frame 140 port. While identifying a dud torpedohit in the midst of a heavy air attack offers ground for speculation, the matter was not pressed beyond determining that they had been reported presumably by eyewitnesses. No flooding inboard of the holding bulkhead was reported, in any event.

24. Of the remaining eight torpedoes, four were quite well identified by flooding reported by the Chief Engineer and Executive Officer. The first was at frame 75 port, in way of turret No.1 magazines. The magazines on the two lower levels were flooded. This hit was reported by the Executive Officer to have hit in the same area as a hit in the fourth attack (which was not assessed as a hit because no flooding was known by either officer). The second certain hit was near frame 125 port, flooding No.8 firerooms immediately, No. 12 fireroom was flooded more slowly. The third certain hit was near frame 145 port, flooding the port outboard engineroom quite rapidly, altough personal escaped. Again, the Executive Officer believed this hit to be in the way of a previous hit from the second attack (which was not assessed as a hit because no inboard signs of damage were recalled by the Chief Engeneerer). The fourth certain hit was near frame 105 starboard, in way of AA magazines immediately forward of the machinery spaces. Magazines of two lower levels were reported to have flooded.

25. Neither officer could recall any specific damage or flooding from the other four torpedohits from this attack, altough the Executive Officer had the location entered in his notebook. This lack of information is understandable, perhaps, altough it is pointed out that about four hours elapsed between the end of the attack and MUSASHI´s sinking. Nonetheless, they are assesed as possible hits in the following location:
About frame 40 port
About frame 60 port
About frame 80 starboard
About frame 165 port

26. At the end of this attack, MUSASHI had a noticable list to starboard, estimated by both officers as about 10 to 12 deg. The trim forward was serious with the waterline at the stem in the vicinity of the flying (U.S. Forecastle) deck. Three certain torpedohits were on the portside and one on the starboard side. The reported list thus is reasonably consistent with the number of hits assesed as certain. It is difficult to assess the possible hits, in terms of either trim or list, inasmuch as the certain hits are consistent with conditions and the possible hits, had they occurred, could reasonably be expected to have produced a much heavier list (three possible were well forward). Actual trim by the bow increased only one deck height. It is considered doubtful that they occurred.

A narrative of the counterefforts undertaken to righten up the ship follows, evnetually, these efforts prooved to be fruitless due to progressive flooding forward. It should be noted that the TDS coverage was way to low to protect these areas properly and counterflooding measures were very limited once the first measure was initiated.

B. Discussion

32. Aircraft torpedoes with warheads containing 600 lbs Torpex were employed against MUSASHI. The depth settings employed are largely unknown but a few were set quite shallow. It is doubtful if any were more shallow than the submarine torpedo, which struck YAMATO in December 1943 (from section I it will be recalled that the depth of this hit, located by the puddle area on the armour, was about four feet). Therefore, all hits other than duds should have caused some inboard flooding.

33. Table

34. Thus there were five starboard and five port certain hits, possibly augmented by one or more of the four purported hits received in the last attack, altough these possible hits are considered improbable. The equal distribution, port and starboard, and the interval between attacks undoubtly were responsible for MUSASHI´s lingering death throes.

There were also nine certain hits on YAMATO mentioned in the report. To state that MUSASHI was the ship with most damage received by underwaterdamage ever is therefore grossly incorrect, when no more than a total of 6,000 lbs TORPEX was involved in the sinking of the ship (evenly placed starboard and port).
Considering the example of SCHARNHORST returns an equal number of torpedohits sustained by the ship, but these were generally DD or CL based weapons and correspondingly had in between 750 and 805 lbs TORPEX each instead of 600lbs. It should also be noted that the YAMATO class is roughly twice the size of SCHARNHORST.


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addendum to the mods:
maybe it is possible to extract the posts with non ARK ROYAL vs BM relevance into an independent thread?
 
Hi,

I believe there was some influence as some calculations i've seen for DB delivered protectiles included both speed and height as a requirement to effect a set estimated penetration. Cambell's work on WW2 weapons includes these figures (300kt dive....release at at least 6500ft etc) Level bombers can only utilize height to influence potential penetration effect. I agree that in the SW case they'd probably have to release higher than a Val, Stuka or Dauntless to compensate for this.

I'm skeptical on the level of proficiency in regards full DB'ing on ships maneuvering at sea. All the examples i've seen have been against non-moving targets which, no offense to the FAA, but would not require as much proficiency as attacking a moving target. Given the light weight of the bombs used I have a hard time seeing the SW pilots spending any appreciable time practicing DB tactics, at least not till later in the war with the Barracuda arriving.

I would suspect that the preferred weapon of the Swordfish would always be the torpedo, as long as any remain in the magazine, and/or the target is accessible via a torpedo attack. "Stationary" targets were often laying behind anti-torpedo nets or in restricted waters where a torpedo attack was not physically possible, and then a DB attack would come to the fore.
 
Actually, the Graf Spee had substantial damage and her captain probably made the correct decision to scuttle. Her system for fitering fuel and lubricants was wrecked as well as the system for obtaining fresh water. She had been hit by perhaps more than 30 shells and holed below the water line. A battle between Graf Spee and the two British CLs, seriously impaired and the CA, Cumberland, would have been truly between the "crippled and the arthritic" but the Graf Spee would almost certainly have not made it home with other Allied units speeding to the scene.

The electronic equipment in WW2 ships was subject to disablement by relatively light damage. The Salt Lake City, CA25, at the Komondorskis, lost much of her electronic capabilities from the concussion of her own ten gun eight inchers, firing the equivalent of eighty salvoes.

That was the point I was making, Graf Spee had not received a hit which penetrated the armour protecting her vitals like magazine and engines but that was enough to cripple her as a fighting ship.

There were many reasons for the decision to scuttle her, her position was impossible. The ships which he knew were outside Montivideo (apart from the propaganda about Renown and Ark Royal) merely had to shadow until a battle fleet cornered Graf Spee. One thing that affected Langsdorf was the condition of his crew who were very young, they were shaken by the encounter and that was with 6 and 8 inch shells. Langsdorf had conducted a fantastic campaign sinking many merchant ships with no real loss of life but he wasnt a nazi fanatic and not the type to impose a suicide mission on his crew.

Several of his prisoners attended Langsdorfs funeral who had won their greatest respect, he was a man from a different era.
 
Hi Nik,

I gotta disagree at here somewhat since your example narrows the types of damage that can be suffered - to reverse your thesis, the belt is still valuable if it stops the enemy shellfire. The ca. 15% longer/larger belt/citadel of the Bismarck - compared to Treaty designs represented a protected box of some 36 meters in length and the same 30-36 meters in width worth of protected buoyancy, or an equivalent of 6500 tons of seawater that is NOT within the ship, quite an amount and explains why Bismarck was so damn hard to sink - she had massive reserves in her. I would not call that irrelevant.

As this was an extra volume - compared to Treaty and post-Treaty BBs - which was completely safe from flooding from a large number of enemy guns at just about any range, and it could still keep out major caliber shells at long range. If that belt wouldn't have been there, the ship would have been considerably more vulnerable to flooding from any guns hitting her (pardon, him!) there - and that includes the literally thousends of secondary fired on her during her last battle.


.

The KGV class had extensions to the belt forward and aft of the main belt, and the deck armour was also extended forward and aft of the main belt, so her protected length was greater then the length of the citadel.

Obviously Bismarck's belt did not make it "completely safe from flooding from a large number of enemy guns at just about any range" since 2 of the 3 14in hits by Prince of Wales caused heavy flooding on Bismarck and left her "...listing 9 degrees to port and her bow lost 2 metres of freeboard...". Bismarck's inefficient use of armour left her main belt armour being too shallow and a 14in shell dived under it to cause damage to Bismarck's machinery spaces and cause a 9 degree list.

When Bismarck was sunk the RN battleships were pounding her a close range, in a heavy sea and it was difficult for the shells to strike below the waterline and sink her.
 
When the last of Bismarcks guns fell silent, why didn't the British battle group cease fire and send in the destroyers and or light cruisers to finish her with torpedoes?
 
When the last of Bismarcks guns fell silent, why didn't the British battle group cease fire and send in the destroyers and or light cruisers to finish her with torpedoes?

pinsong

that is pretty much what happened, there has always been a discussion as to whether she was sunk or scuttled

from wiki

Bismarck continued to fly her ensign. With no sign of surrender, despite the unequal struggle, the British were loath to leave Bismarck. Their fuel and shell supplies were low, a demonstration of how difficult it was for a battleship to sink a similar unit, even in an unbalanced engagement; however, when it became obvious that their enemy could not reach port, Rodney, King George V and the destroyers were sent home. Norfolk had no torpedoes left, so Dorsetshire launched three 21-inch (533 mm) torpedoes at comparatively short range, which may have hit Bismarck. The battleship's upper works were almost completely destroyed but her engines were still functioning, although Johannes "Hans" Zimmermann, a boiler room stoker who survived, confirms that salt water had entered the boiler feed lines causing the engineers to reduce speed to seven knots, fearing an explosion,[51] and the hull appeared to be relatively sound; therefore, rather than risk her being captured, survivors have said the order to scuttle and then abandon ship was given. Many of the crew went into the water, but few sailors from the lower engine spaces survived. As Captain Lindemann was presumed killed with all officers after the bridge was hit by a 16-inch (410 mm) shell, it is unclear whether he could have given the order to scuttle.
 

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