Why did Italy perform so poorly in WW2?

[Captain Seafort]

The fleet air arm sank or crippled four Italian battleships, one of which never returned to service

They didn't sink any, although the Veneto was a bit lucky to get away from Matapan.

the Italians got three all of which returned to service.

Which was the third you're thinking of? The only battleships I'm aware of that are attributable to the Italians are the QE and Valiant at Alex.

British actions were also a lot more repeatable then the Italians one off commando raid that accounted for two of the scores.

One off? They conducted numerous operations accounting for at least two heavy cruisers, two battleships and sundry destroyers and merchantmen.

I have no idea how you could conclude this makes the Italians 'better'.

Because with the exception of the Cavour, all the Taranto casualties were operational within a year. QE and Valiant were out until mid-1943. I don't see how you can call putting ships out of action for a year and a half over less than a year anything but "better".

Especially when the Italians completely failed to exploit the advantages they gained, while the British did heavily. The point of sea power isn't to sink the enemy fleet, its to exploit control of the sea.

I wasn't talking about the strategic impact of their operations - I said that they were better at crippling battleships.

[DarkArk]

They had some of their Battleships temporarily put out of action at Taranto, but they didn't "lose" it. And even with the loses, the RM was still the 4th Biggest navy on the planet and could have played merry hell with the RN in the Med.

Taranto accounted for half of the Italian's battleships at the time. It took them six months to repair two of their battleships and they never finished repairing the third. Hence massively reducing their capability to fight the British during the period. Agreed that my language might have overstated exactly how bad it was for the Italians.

They didn't sink any, although the Veneto was a bit lucky to get away from Matapan.

I believe Sea Skimmer was referring to Conte di Cavour which was so badly damaged at Taranto that it was never returned to service.

[Captain Seafort]

I believe Sea Skimmer was referring to Conte di Cavour which was so badly damaged at Taranto that it was never returned to service.

I know - she was crippled but repairable, albeit never repaired.

[Sea Skimmer]

They didn't sink any, although the Veneto was a bit lucky to get away from Matapan.

Unless you think the following counts as 'floating' Conte di Cavour sank at Taranto



In fact, Andrea Doria and Littorio both certainly would have sank too, but the Italians were able to run them both aground. as it was Littorio still settled with part of her main deck underwater. It is a bit hair splitting to count them as being merely damaged, when say USS California is normally counted as sunk by Japan.

Which was the third you're thinking of? The only battleships I'm aware of that are attributable to the Italians are the QE and Valiant at Alex.

HMS Nelson was heavily damaged and reduced to 14 knots by an Italian aerial torpedo in 1941, in large part because her huge bow torpedo room flooded.

One off? They conducted numerous operations accounting for at least two heavy cruisers, two battleships and sundry destroyers and merchantmen.

The first EMB mission worked and sank HMS York yes, though she could have been raised had the Germans not taken the island. All follow up attempts were slaughtered or failed to even be executed. LIkewise the first human torpedo attack on a fortified harbor worked and got two British battleships, but all followup attempts failed. The repeated attacks at Gibraltar only ever succeeded in attacking ships in the wide open roadstead and not the fortified part of the harbor that held major warships. WW2 is full of examples of novel weapons working great once, and then having radically diminished effect the second time ect... such as airborne attacks. Italy fell right into that hole. Now meanwhile British air power just keep sinking ship after ship after ship until Italy had almost no merchant fleet left and a much diminished navy that was incapable and unwilling to seek battle even at the most critical times, such as the attempt to intercept the Pedestal Convoy that turned back after a British Wellington torpedoed just one of the half dozen cruisers in it.

What's this second heavy cruiser anyway?

Because with the exception of the Cavour, all the Taranto casualties were operational within a year. QE and Valiant were out until mid-1943. I don't see how you can call putting ships out of action for a year and a half over less than a year anything but "better".

Valiant was back in May 1942, and both ships were refloated in a few days and could move. Queen Elizabeth took so long to repair because she actually wasn't being worked on for most of the time, she was sent to hang around South Africa for a while, and then onto the US later. It just wasn't a priority.

I wasn't talking about the strategic impact of their operations - I said that they were better at crippling battleships.

Well considering if we took an honest approach, and recognized that three Italian battleships were effectively sunk by the level of damage inflicted, against a single RN ship.. yeah you could say the Italians crippled more, but the British sank more. In any case, ignoring strategic impacts is dumb, Italy diverted a lot of resources and talent into its special weapons programs and attempts to carry out missions. The fact that so many then failed, and so much planning was based on them working was a major problem.

[Captain Seafort]

In fact, Andrea Doria and Littorio both certainly would have sank too, but the Italians were able to run them both aground. as it was Littorio still settled with part of her main deck underwater. It is a bit hair splitting to count them as being merely damaged, when say USS California is normally counted as sunk by Japan.

By that standard QE and Valiant were both sunk too, given that they were resting on the bottom. I wouldn't count any ship that can be returned to action as quickly as the Italian losses at Taranto, ours at Alex or yours at Pearl as "sunk".

HMS Nelson was heavily damaged and reduced to 14 knots by an Italian aerial torpedo in 1941, in large part because her huge bow torpedo room flooded.

Right ho.

What's this second heavy cruiser anyway?

Bolzano. Rechecking, it should have been three cruisers, since Gorizia was sunk a few days later.

Queen Elizabeth took so long to repair because she actually wasn't being worked on for most of the time, she was sent to hang around South Africa for a while, and then onto the US later. It just wasn't a priority.

[/quote]

The same reason Cavour was never recommissioned.

[Sea Skimmer]

By that standard QE and Valiant were both sunk too, given that they were resting on the bottom. I wouldn't count any ship that can be returned to action as quickly as the Italian losses at Taranto, ours at Alex or yours at Pearl as "sunk".

Valiant was not on the bottom. Not floating and not in a dry dock is a pretty even definition of sunk. You may find a few examples in the war of ships which touched the bottom from flooding that would not have sunk them in the open sea, but it sure isn’t typical.

Bolzano. Rechecking, it should have been three cruisers, since Gorizia was sunk a few days later.

Counting ships that did not even have crews, were already damaged, and attacked in combination with British forces after Italy switched sides means you’re really missing the point. Italy had already lost the damn war.

The same reason Cavour was never recommissioned.

She was worked on pretty much continuously, but the damage compounded by taking almost a year to raise just took a damn lot of effort to fix. As the US found at Pearl harbor it could take months just to clean the oil out of a ship sunk that deeply before you could start repair work.

[lord Martiya]

Why are the French the punchline of all the war jokes?

Because the French had the bad luck of having the Germans able to advance to Paris since the beginning but the Brits couldn't invade mainland Italy until 1943: it gave time to the Italians for occasional acts of valor and the impression the Frenchmen were more surrender-prone.

[CaptHawkeye]

Which i've always thought was massively unfair to the French. If your country had lost an entire generation, most of its industrial capacity, and the grand majority of its finances in the last Great War, one would be pretty "prone" to surrender. I mean it's not like winning paid off all that much last time.

Cue "Why did France perform so poorly in WW2?" thread.

[Lord Revan]

I dunno about where you live around here Italian army (and not the french) is considered the biggest joke of WWII

Which i've always thought was massively unfair to the French. If your country had lost an entire generation, most of its industrial capacity, and the grand majority of its finances in the last Great War, one would be pretty "prone" to surrender. I mean it's not like winning paid off all that much last time.

tbh the biggest problem France had from what I've read was not much the amount of material as the fact it was somewhat out of date (as were their tactics and strategies)

[Elfdart]

The hilarity of everything was they lost Italian Abyssinia a few years later when the British just took the whole country back and their was exactly nothing the Italians could do about it. I've never seen an example of a military so comically set to defeat itself at nearly every turn. Why are the French the punchline of all the war jokes?

Most French-bashing is the result of Charles de Gaulle's post-war politics, as well as the habit among American right-wingers of aping the attitudes of British right-wingers.

It's not like the British Army did any better against the Germans in 1940, and the US Army was a joke until late 1942. The French simply had the misfortune of being on the wrong side of the Atlantic.

[Blayne]

If the war had happened a little bit earlier when the tank disparity in numbers and equipment better favoured the French, or had the Germans use the Schiffilen Plan 2.0 This Time We're Serious (c); the French army while still likely pushed back to near or about Paris would have not had large sections of its military surrounded and stayed intact, allowing for a stalemate. As they could buy time for more of the BEF to be shipped across and allow for the Soviets to mobilize to distract the Germans some through Poland.

[lord Martiya]

That had the potential to be interesting: the Soviets were a wild card (formally allied with Nazi Germany but with huge ideological differences), and Italy still had the potential to stay neutral or even join the Allies (they had already did it the previous war), and the well-trained and locally recruited Alpini for combat on the mounts at the Italy-Germany border.

[Blayne]

The Soviet's signed the non aggression pact after Munich; had the allies went to war over Czechoslovakia the Russians were actually allied to France to defend it. They didn't border them though which was the problem, Poland at the time wasn't likely to play ball and likely would have allied to Germany to keep Stalin away.

[Jade Falcon]

The main thing I've heard against the French was that a lot of their high command was still stuck in WW1 tactics which against the German Blitzkrieg stood no chance. To be fair there were a lot of British commanders stuck in the same mindset.

The use of tanks for instance. De Gaulle was meant to have a lot more ideas regarding the use of tanks properly, but only being a Colonel at the time didn't have much influence. One other prime example was the French Field Marshal who refused to even have a Field telephone in his Chateau headquarters.

Back to the original topic, when it came to Italian equipment surely it wasn't all bad. The SM79 Sparviero torpedo bomber seemed to be a reasonable aircraft and the Sahariana scout car and the Autoblinda AB41 armoured car also seemed to be decent.

[Blayne]

The bigger from with Italy is that even though their equipment was groovy for the very onset of the war, they're industry lacked the ability to constantly adapt and deploy in large numbers newer, heavier equipment.

Reading the Italian conduct during the war, it seems the Italians had a lot of decent minor victories to their name; they were always considered extremely courageous, manning their artillery to the death and various engagements the Italians were noted for being particularly stubborn fighters. Also Rommel's counter attacks relied on large number of Italian soldiers under his command.

[Sea Skimmer]

The Italians had some good equipment, they also had a fair bit of stuff which started to be good and then had some horrendous flaws thrown in like the Littorio class battleships torpedo and bizarre armor protection. Then then they had lots of bad stuff, like every machine gun for the infantry (somehow the tank and aircraft ones were great) and every tank they produced before 1943. artillery was a real mixed bag, like many powers a lot of it was leftover from WW1, which isn't that bad if you modernize the weapons, but many were put into action without modernization and still had things like wooden wheels.

With aircraft they had some good designs, but far too many different ones, and even good planes like the SM79 had drawbacks. Mainly that it had three engines, which means its a lot more expensive to produce then a twin engine bomber, perhaps a strong factor in why so few were built in spite of being the most heavily produced Italian bomber. Only 1,300 from 1936-1943, which means only about one plane every other day. This is a rather serious problem if you are loosing the things in combat. Italy was forced to keep making triomotor bombers until the end because it was unable to keep pace with improving aeroengines that would allow better designs with two. That of course also crippled its fighter force and frankly maybe it made keeping so many CR.42 biplanes a good idea? Better a super agile biplane then a slow monoplane I would think.

A lot of the good weapons were also just hamstrung by insufficient ammunition or spare parts (not an Italian only problem even the US had huge shortages, but the weaker you are the more it hurts). Lack of enough and heavy enough bombs seriously held back the effectiveness of the Italian air force in particular when it was called upon to conduct strategic operations against shipping and major military bases, as opposed to tactical support against swarms of Ethiopian tribesmen with near zero air defense. I was reading a table war damage to British ships recently, and one noteworthy bit was, I may be fudging a bit but it doesn't change anything, a cruiser hit by four 100lb bombs all from the same Italian bomber. Damage, not very much, if they'd been 500lb or 1000lb class bombs the cruiser likely would have sunk. This was not an isolated case.

Reading the Italian conduct during the war, it seems the Italians had a lot of decent minor victories to their name; they were always considered extremely courageous, manning their artillery to the death and various engagements the Italians were noted for being particularly stubborn fighters. Also Rommel's counter attacks relied on large number of Italian soldiers under his command.

Yeah Italian success is proportional to the size of the Italian force used, the more the worse. I can't help but think that besides cultural and training issues, this was also a result of Italy forming too many 'elite' units out of too small a pool of recruits, leaving the regular forces short of good men and officers who are needed to stiffen the average and below average types. Rommel did depend on Italians heavily, but basically to fill space and absorb the shock of enemy attacks. They still tended to fall apart in combat. At El Alamein he had to interspace German and Italian companies in the front line because Italian battalions on the defensive would just get destroyed. Italian engineers were invaluable for clearing the vast minefields of the desert war. He would have been totally defeated at Gazala without them for one high profile example. They cleared the first lane into the Cauldron.

[CaptHawkeye]

The Italians actually had a better AA/AT gun than the Germans did, the Cannone 90/53. Though it was somewhat heavier, i've heard it said it was more comparable to the 10.5cm gun. Compared to that gun though it was lighter and could be placed on a mobile mount. As usual though, the Italians could only afford to build a measly 500-600 of em.

Skimmer i've looked on Google and other places but i'm unable to find a good source on the Pugliese Armor system (visuals would be great too). All I really know about it is that it was unique but way too difficult to repair and didn't work as well on paper as it did on practice. Though no one's torpedo defense did.

[Mr Bean]

Going off of memory here but the Cannone 90/53 was comparable not better than the Flak 18 the infamous 88 as because of lower velocity their penetration was comparable but the 88 was just better designed from a handling prospective meaning it was better over all as lots of everyday tasks could simply be done much faster, everything from laying the gun to switching targets to reloading went smoother on the 88 due to it's design or some claim simply better drilled crews.

No when we are talking about Italian quality we must bring up it's small arms, specifically their pistols and SMG's. But then Beretta was still hand making both of those right up until the end of the war but it was why the Beretta Model 38 SMG and the Beretta M 1934 and M 1935 all of which were widely popular with every army that could get their hands on them. The pistols because of the durability, elegance and easy maintenance. The model 38 because of how utterly dependable it was, it's accuracy despite being an SMG and it's easy handling.

But then a comment was once made and it's killing me who said it that "For the men and material we can produce three of our (mp40) sub machine-guns for every one of their 38/42s, the old 38s we could make five for every one of theirs"

[Sea Skimmer]

The 90/53 had zero depression, which becomes a problem in the anti tank role as it means you have a hard time finding suitable firing positions. This is less of an issue in the desert then in Europe, but the desert is still not flat and defending the heights is ever more important because of how great of observation they give. Heavier weight is an issue when its several tons as is the case here, the Flak 18 was fairly light for its firepower in the first place though so this isn’t exactly a reason to call the Italian gun bad. A big advantage of the Flak 18 though was it could safely fire from its wheels without deploying for action, and was quick to deploy, and equally important quick to limber up and withdrawal. It was always designed to serve as a duel purpose weapon, few other anti aircraft guns were.

The US 90mm M1 and British 3.7in never had much luck in the anti tank role in spite of also being superior ballistically and in ROF to the German weapon because they were also much heavier and slow to deploy, and the M1 lacked any depression (M3 variant added it late war). I’ve heard before that the 3.7in only had depression to make cleaning the barrel easier, and could not be fired below 0 degrees but I don’t know if that is true or not. The Soviet 85mm M1939 had depression and was pretty damn light, but it was also a less powerful smaller weapon, which is why they managed to cram it into a T-34 tank so easily later.


http://img36.imageshack.us/img36/4048/l ... enetio.gif
Here is a diagram of Littorio class armor and side protection over machinery. Armor over magazines was somewhat different and heavier, TDS is more or less the same. Numbers are thickness of plates in millimeters, generally stuff under 10mm is not armor but just structural steel. Notice how the main belt is actually a composite of plates, intended to decap incoming rounds (this may really have worked, may have made this the best belt armor EVER) and the bizarre decision to make the decks thinner outboard, even though only a puny 24mm bulkhead is preventing a bomb or shell that goes through that thinner deck from reaching the vitals.

As for the Pugliese System, the idea was instead of vertical or flat but sloped bulkheads as everyone else on the entire planet used, the center of the system would be a circular drum void inside a liquid loaded compartment. The logic was as a cylinder is much stronger then a vertical bulkhead, more energy would be absorbed crushing it. Then when it collapsed massive turbulence would be unleashed, and fluid displaced, further weakening the torpedo blast. Behind this liquid loaded space was a sloping and then rounded off armored bulkhead to catch fragments and further deflect blast.

I have marked the armored bulkhead in red, and the void space in blue to be clear. The numerous smaller holes in the diagram around the void are preformations in the traverse rib bulkheads that hold the drum void in place so to keep the water or fuel loading even. Some of these supporting rib bulkheads would have actually been solid to divide the side protection into different fuel tanks.

anyway, the problems are several fold. First, hard to build, hard to repair because of so many curves plates, and such bad access working around the damn drum. Even today this would be a pain in the ass to deal with even given computer controlled presses to make the plates and welding to join them. The ship however was mostly riveted.

The main flaw though of the Pugliese System though is it just didn’t work right. As you can see, a torpedo that hits too low or too high will miss the center of the drum, reducing the effectiveness of said drum as a barrier, blast can directly be transmitted to the inner armored bulkhead. That might not be so bad.

What was really bad was, the joint of that inner armored bulkhead with the bottom of the hull was flawed, really flawed. That’s why this diagram bothers having a blowup of it. Basically it would tear completely free of the hull bottom, and the entire torpedo defense system would be displaced onboard a couple feet or so. Result is massive damage, total failure of the holding bulkhead and an extremely difficult repair job to cut it all apart, then rebuild it.

Another problem was, this system has extensive liquid loading, but only the drum is a void, and a void which is not meant to be flooded. Italian solution was to put counterflooding tanks above the torpedo defense system, everyone else used voids within the system below the waterline. So counter flooding was slow as water had t be pumped in by the fire mains, rather then rushing in from the ocean after you opened the proper valve. That means a loss of power would also prevent counterflooding, though this never caused a loss of ship.

The Pugliese System was successful at the most basic requirement of a torpedo defense system, which is to keep blast and fragmentation out of the vital spaces. This is important because torpedo blast entering magazines tends to turn into the ship exploding. Preventing this was the earliest reason for having a TDS at all; a number of dreadnoughts in WW1 for example only had patches of armor over each main battery magazine. Keeping blast and fragments out of the engine rooms is also highly desirable, even if they flood they’ll at least be much easier to fix. Replacing turbines and boilers is very time consuming, and turbines may take years to manufacture if you truly need total replacement (almost unheard of, damn things are huge, don’t get smashed easy)

So while the system was not a complete failure by any means, it was expensive and time consuming, and led to a number of Italian battleships taking very serious damage and heavy flooding from relatively small British aerial torpedo warhead. In general you can’t really stop a torpedo from causing ~1,000 tons of flooding or so, but Italian ships were taking several times that.

[CaptHawkeye]

It's sort of funny how that diagram points out wood paneling was part of the belt armor protection. I would assume its effect on an incoming shell is negligible though. It's just pointed out so one isn't misled into thinking the plates are metal the whole way though. Voidspace not withstanding.

What's the possible example you mention of this system's performance? I would be surprised if the Italians actually found a way to make a better belt than the Germans or even the Japanese.

[Sea Skimmer]

Wooden or concrete backing was common on belt armor around the world. The manufacturing tolerance on heavy armor plates could be as much as 5-10mm of thickness, and to get a snug fit against the ships hull you had to use some kind of spacer. So the Italians used wood in-between the 15mm shell plating of the hull and the 280mm main belt plates. The USN used poured concrete, other people varied. Its not supposed to have any protective value, unlike the wooden backing on mid 19th century ironclads in which the wrought iron armor could be backed by several times its own thickness of wood. This massive wood was intended to absorb fragmentation, since wrong iron could shatter, and it was thought the wood would 'brace' the iron against an impact. That part didn't actually work. This faded away with the first steel armors, and wooden backing was trimmed down to just become a means of assembly. Lighter vessels like cruisers in WW2 wouldn't normally have this kind of backing because the plates were not face hardened and could be rolled to relatively precise thicknesses.


The point of a decapping plate is to knock the AP cap off the shell. If this happens any realistic explosive filled shell is going to shatter. You can’t make the shell body hard enough to pierce face hardened armor or it will be shattered out of hand, so you put a hardened cap on top. Face hardened armor is only face hardened for the same reason, it if was hard all the way through it would easily shatter itself, but the armor is a solid plate, not hollow so it has an advantage.

On paper a decapping plate of suitable thickness backed by an 280mm thick face hardend plate should be immune to any shell ever made at any range. In reality, it’s not clear the narrow gap between plates is enough space for the AP cap to fall off in, at least a half caliber gap is needed and this in turn depends on the angle of shell impact. But in all probability the Italian system would have worked against the 15-16in guns it would have faced.

German naval designers in WW2 were complete idiots for various reasons; it isn’t that hard to beat them at anything. Japan had generally poor armor technology, and Yamato wasn’t trying to be too clever. It would have been very unlikely that Japan would have taken a gamble on a decapping system on such an important part of its entire national strategy. Many variables are involved.

US fast battleships with internal armor belts had some level of decapping built into the design, they had lightly armored shell plating well away from the belt that would decap reasonable sized battleship shells in some circumstances. Its not clear how much this was intentional vs incidental to providing the waterline with light armor against light weapons. I haven’t been on the navweapons forums for a while to know if any new evidence has turned up since Nathan Okun wrote/studied a lot on this stuff in the late 90s and early 2000s.

The British didn’t use decapping plates, but they did have a different trick in mind, which was that on the KGV class battleships the magazine (powder magazines only, not the shell rooms) had an internal box of 2in armor around them. The logic was a shell piercing the shell would almost certainly explode before it reached the actual powder magazine and the armor would then stop the blast and fragmentation from causing an explosion. The shells themselves are not nearly so vulnerable, as the less sensitive explosives are already inside thick tough steel already.

Paper designs exist for Soviet warships with what appear to be decapping belt systems, but the Sovetsky Soyuz class would not have used one.

None of this decapping stuff matters much today because almost all armor piercing kinetic weapons are homogenous masses of solid steel, tungsten or uranium without any kind of AP cap. Meanwhile face hardened armor itself is mainly only used for very lightly armored vehicles to improve resistance against composite (example tungsten core in a steel projectile) rifle and machine gun ammo. But the logic of shattering the incoming projectile as a means of defeating it is now stronger then ever and all kinds of armor systems and materials exist to accomplish it. The spaced armor on some WW2 tanks was effective at decapping projectiles, such as the side skirts on Panzer IV tanks would decap Soviet anti tank rifle rounds. I dont know if that was intentional or not.

[The Duchess of Zeon]

The interesting point about what Skimmer wrote is that if you wanted to seriously armour a warship against modern weapons you'd need to incorporate a lot more volumetrically intensive protection as opposed to tonnage-intensive armour protection. It would actually be possible to defend against even heavy cruise missiles, with sufficient volume. The reason people don't do this is that the incidental damage from a top-diving cruise missile on the ship's electrical systems in the superstructure would likely render it a mission kill anyway, and it would drive up the size of even the smallest warship enormously; and it would still leave the problem of fires aboard, because the ship is still damaged, just intentionally damaged in a way that would notionally preserve all fighting capability.

A related thing is that we could build V-hulls like sailing yachts have as an Under-the-Keel torpedo protection, in the same way we have V-bodies on anti-IED modern fighting vehicles for A-stan and stuff. However, this would in a 20,000 tonne guided missile cruiser require some really impressive drydocking preparations and give her the draught of an aircraft carrier, or more. It would also be relatively easy to modify torpedoes to explode along the side again, which while nowhere near as damaging as a UTK, would pose a variety of serious problems as the lower parts of the V-hull would flood entirely through since they're not thick enough to be provided with TDS, and are essentially part of it. Now this might still be worthwhile, spaced armour and a V-hull against UTK hits, if you're building say a 35,000 tonne particle cannon armed anti-ballistic missile nuclear cruiser and want it to cost more money than a Nimitz, but for the most part it does not make sense when active defence and stealth may yield better results, especially the former; we're presently working on counter-torpedoes for launch from RAM launchers for instance.

[Sea Skimmer]

The interesting point about what Skimmer wrote is that if you wanted to seriously armour a warship against modern weapons you'd need to incorporate a lot more volumetrically intensive protection as opposed to tonnage-intensive armour protection. It would actually be possible to defend against even heavy cruise missiles, with sufficient volume.

The USN indeed considered doing just that during the design studies that led into the Nimitz class aircraft carriers. Big voids filled with multilayer baffles could breakup the shaped charge jets of big commie missiles to protect the magazines. Problem is magazine capacity would drop from over 2,000 tons to under 800 tons for the same overall volume of ship which was unacceptable.

A related thing is that we could build V-hulls like sailing yachts have as an Under-the-Keel torpedo protection, in the same way we have V-bodies on anti-IED modern fighting vehicles for A-stan and stuff. However, this would in a 20,000 tonne guided missile cruiser require some really impressive drydocking preparations and give her the draught of an aircraft carrier, or more.

Me and Eric were musing on that idea while we were brainstorming the Objective Global Warship. The problem is, water pressure tamps blast to a massive degree, air really doesn't, and since blast underwater wants to vent to the surface, making a V-hull on a ship would actually mean you are increasing the amount of blast trapped under the hull compared to a hit on a vertical side. Meanwhile if the torpedo goes off under the keel, the V-hull has the effect of making the overall ship draft much deeper which will greatly increase the tamping effect. Also shaped charges on torpedoes would be an easy countermeasure. Nothing for example would stop you from building a torpedo with a row of shaped charges aimed upward and a multi fusing system so that they don't function when the torpedo is fired in an ASW role.

Equally importantly, modern torpedoes can always just blow off your stern and leave you a sitting duck, not much you can do about that except become OGW sized and have a dozen auxiliary propulsion pods under the bow, or unleash the 1940s British brilliance of shafted bow propellers. Hard kill countermeasures are going to work out better for the money and weight involved, even if the hard kill system is as simple as blowing depth charges over the side from K guns.

Also worth remembering that a lot of insurgent IEDs are made out of ANFO which has a fairly low blast intensity, its ability to shatter steel as opposed to peeling it open is limited, and so blast deflection is very highly effective. The blast wants to lift the entire vehicle into the air more then it wants to take it apart. Some MRAPs have survived stupid large blasts, like 600lb bombs going off a few feet away, more or less torpedo sized, but this just wouldn't work the same way if the bomb had been made out of RDX or HMX.

The reality is since WW2, the concept of the lone warship being a self contained unit simple does not work anymore, warships must operate in groups to fight and survive in high threat situations. You obtain protection through dispersion of assets, and this has only become much more effective now that cooperative engagement capabilities exist. At least in the US Navy, the RN cut out joining in on Type 45 to SAVE MONEY. This way even a damaged ship may be able to contribute to a battle, firing weapons for other ships to control ect...

[The Duchess of Zeon]

It's true that a V-hull would have a lot of problems in application. One more interesting idea I've seen would be a geodetic cylindrical frame in the hull replacing the keel and going from the bottom of the hull to the waterline with the rest of the ship then built on and outside of it. There'd be plenty of problems with that too, though. Mostly the solution is to not build ships which are unexpendable unless like carriers the whole point of the rest of the fleet is based around protecting them.

[Sea Skimmer]

Giant air bags wrapped around the hull might work, also in various NATO trials for minesweeping hovercraft on cushion were found to suffer very little from exploding bottom mines, so hoverships might do rather well against torpedoes, aided by high speed reducing the ability of a torpedo to ever hit them under the keel in the first place. You'll just need a few handy NASA helium cooled direct drive turbine reactors with crushing collision protection to power the thing economically. Shallow draft does wonders for torpedo protection, one of the big British WW1 monitors once took three torpedoes without sinking, which would certainly not happen to any other type of 6,000 ton class warship let alone in WW1.

Thinking about it, one thing we should give Italy serious credit for is aerial torpedoes, they had some of the best in the war, and in 1940 likely the best, which were being exported to the allies in large numbers right up until the outbreak of the war, and later the Germans. Lots of Italian planes could carry torpedoes from the onset of war, nearly all the modern trimotor bombers in fact. So this is rather unlike most national air forces which claimed they could sink ships, but put no real effort into doing so. Effectiveness in combat never really seemed to pan out that well though. Considering the poor state of British anti aircraft defenses one can only imagine this was a training issue and lack of resolve on the part of the crews while flying relatively large aircraft. Still they did damage a good number of allied ships, including HMS Rodney and as I recall several cruisers.