Giant battleship question

[lord Martiya]

I was reading about the oversized battleships ipotized before and during WWII, like the original A-150 Japanese design (originally ipotized as a 90000 t monster with eight or nine 510mm guns, then shrunked to a less irrealistic 70000 t and six 510mm guns), the American Tillman-proposed Maximum Battleship designs (the Tillman III and both Tillman IV were 80000 t ships) and the German H-42, H-43 and H-44 battleship proposals (from the 98000 t H-42 to the insane 131088 t of the H-44), and I have a question: have those designs ever being actually considered for building or their only influence was in designing smaller battleships like the various Tillman variants?

[paladin]

I think the Japanese and German designs were actually planned to be built. The German design probably more given Hitler's thing for enlarging weapon systems to completely useless size.(i.e. - The Schwerer Gustav cannon(800 mm or 31.5 inch caliber).

[Marcus Aurelius]

I think the Japanese and German designs were actually planned to be built. The German design probably more given Hitler's thing for enlarging weapon systems to completely useless size.(i.e. - The Schwerer Gustav cannon(800 mm or 31.5 inch caliber).

In fact Hitler was quite skeptical about battleships in general; he saw them basically as propaganda weapons and he was much more enthusiastic about submarines. It seems likely that post-war accounts have exaggerated his significance in the battleship design process. Blaming Hitler for everything was the standard excuse made by German officers after the war.

The big battleships were just as much pipe dreams of the German battleship admirals. All major nations of course had their own set of them, but the German ones were perhaps a little more influential than their British or American counterparts, even if the latter weren't exactly in the margin, either. The H-42 battleships were supposed to be built at some point when their design process was started, but they were not yet as crazy as the later ones. The H-43 and H-44 were design studies which nobody actually believed would be built any time soon, if ever, since by that point it was clear that Germany did not have the resources to build new battleships.

The Schwerer Gustav was a specialized fortress busting weapon designed to be used against the Maginot line and other heavy fortresses, which in WW1 had presented significant problems. In addition it was designed before air power was proven to work in that capacity. Only hindsight allows us to say that it was useless, although it eventually turned out to be of limited usefulness.

[Sea Skimmer]

The Tillman designs were made in response to a question from Congress on where the yearly size increases in battleships were eventually going to lead. The idea was to look and see if it would be worth it to just ‘skip ahead’ and build something really big out of hand. The conclusion was you could build such a ship limited only by the Panama canal locks, but just one of them would cost as much as the entirely yearly USN construction budget. So it was never serious.

Everything past H-41 was not serious, and indeed the latter designs are not really worked out in much detail as they all have the exact same secondary armament as Bismarck, rather ludicrous in ships that grew to over 120,000 tons.

The 90,000 metric ton Yamato was serious, but Japan just couldn’t have built it because the hull would draw too much water to even enter Japanese ports. Very extensive dredging would have been required as well as entirely new dry docks (Yamato could use an existing dock at Kure with some enlargement). Of course, serious Japanese planning in the Circle 5 and Circle 6 Fleet replenishment programs was still divorced from reality. Japans obvious inability to fulfill those plans while also fighting in China is a major factor in why they choose war.

Another really big battleship that was very serious was the Russian Project 24. However that ship was going to get built if Stalin didn’t die. He was more then a bit nuts on naval matters and just plain refused to accept that the aircraft carrier had replaced the battleship of king of the seas after WW2. However the Project 82 Battlecruiser was given higher priority, with work commencing on one unit, so Project 24 was never laid down.

[paladin]

I remember reading somewhere that the H-44 was going to mount Schwerer Gustav cannons as her main battery. Would that have been possible?

[atg]

I remember reading somewhere that the H-44 was going to mount Schwerer Gustav cannons as her main battery. Would that have been possible?

Thoeretically with a big enough hull. However said ship would be unable to enter any German ports.

Edit: IIRC it would have required a ship weight of something like ~140,000t. Twice that of the Yamato.

[Thanas]

I remember reading somewhere that the H-44 was going to mount Schwerer Gustav cannons as her main battery.

This is wrong. The H-44 was "only" to be armed with 20" cannons. The Schwerer Gustav is a 31.5 inch cannon.

[Stuart]

I remember reading somewhere that the H-44 was going to mount Schwerer Gustav cannons as her main battery. Would that have been possible?

No, that's primarily internet speculation. Mounting a huge gun like that on a ship would require a massive hull, many times larger than that of H-44 (which was already impossibly large). Such ships are without any real tactical value anyway. The H-44 appears in one very good piece of alternate history fiction called "The Voyage of the Stekhanovite" )it can be found HERE. I think this is the best Nazi uberweapon story I have ever read.

As a ballpark estimate, I think a ship armed with eight Schwerer Gustav would displace close to a million tons. I actually worked it out once and I seem to remember it coming out to around that figure.

[Purple]

Just hypothetically speaking, if such a ship was made and if it actually could float and carry at least 1 round for each gun. Would it not break apart or just sink it self upon firing even one of them, let alone a broadside?

[Stuart]

Just hypothetically speaking, if such a ship was made and if it actually could float and carry at least 1 round for each gun. Would it not break apart or just sink it self upon firing even one of them, let alone a broadside?

That's what drives the displacement up. The hull has to be big enough to absorb the shock. I'm not sure it can do that; 1940s materials technology may simply not be up to it.

[Starglider]

As a ballpark estimate, I think a ship armed with eight Schwerer Gustav would displace close to a million tons. I actually worked it out once and I seem to remember it coming out to around that figure.

Did it look like this?

The hull has to be big enough to absorb the shock. I'm not sure it can do that; 1940s materials technology may simply not be up to it.

How is the shock handled for large railway guns? Does it simply destroy the rails? Does the ground act as part of the shock absorber?

[Marcus Aurelius]

How is the shock handled for large railway guns? Does it simply destroy the rails? Does the ground act as part of the shock absorber?

Railway guns usually have just the one barrel, which is fired more or less in the general direction of the rails (many railway mounts had no traversing capability at all). This provides a pretty good recoil absorber for the horizontal element of the recoil. The Wikipedia article on railway guns is actually a reasonably good summary including an explanation of different recoil mechanisms, and it has in-line citations:

http://en.wikipedia.org/wiki/Railway_gun

[Sea Skimmer]

How is the shock handled for large railway guns? Does it simply destroy the rails? Does the ground act as part of the shock absorber?

Railroad mounts come in a number of types, most of which require some sort of prepared position to fire from because of the recoil issue. Only small caliber railroad guns; or guns using a rolling recoil system can fire from normal railroad track without causing damage.

The most common mounts were sliding mounts, in which a number of additional very heavy duty rails (usually flat topped I-beams) were laid on the firing track. Big screw jacks then pushed a bank of pads onto those rails, lifting most of the railroad guns weight off the regular rails and onto the sliding rails. The gun then fired, slide backwards on the rails, and then you had to lower it back down, push it back forward, then jack it back up to fire. Usually they had to do all that by hand too.

This book has almost everything you’d want to know on the subject through 1922
http://books.google.com/books?id=gQQtAA ... &q&f=false

The Gustav cannon used primarily cradle recoil but it required specially constructed track with a total of ten rails in ordered to support the forces involved. That's dispite the vast spread of the wheels. Even then the tracks did suffer damage, but the Germans had 1,000 people handy to repair it and only fired a few rounds each day. It took much longer to build the firing track the one time the cannon was used, then it did to even assemble the damn thing.

[Night_stalker]

Yeah, but the size of the shells means that any naval vessel would have to dedicate a lot of room for storing them. I saw a pic of one of those, and it was taller than a old T-34 Soviet tank.

[Crossroads Inc.]

Ye GODS Starglider!!!

Is that "thing" even feasible?
Did ther Germans REALLY consider building such a monstrosity?
Or is it just dreamed up by Battleship wankers?

[CaptHawkeye]

I can't imagine a ship like that being anymore than a big,easy target for aircraft. Not like it would matter. You'd probably have to spend 5 years building dry docks and support facilities just for it. By which time the original design would be hopelessly obsolete.

[JBG]

I think the Japanese and German designs were actually planned to be built. The German design probably more given Hitler's thing for enlarging weapon systems to completely useless size.(i.e. - The Schwerer Gustav cannon(800 mm or 31.5 inch caliber).

In fact Hitler was quite skeptical about battleships in general; he saw them basically as propaganda weapons and he was much more enthusiastic about submarines. It seems likely that post-war accounts have exaggerated his significance in the battleship design process. Blaming Hitler for everything was the standard excuse made by German officers after the war.

The big battleships were just as much pipe dreams of the German battleship admirals.

Germany historically usually saw herself as a continental power. The army came first and when air power came along to support the army it did well. The navy as always at the back of the queue. The Z plan was just a fantasy of those few Germans who rated or were involved with the navy and nautical issues. All the bigger stuff had serious flaws. The planned even bigger stuff...

Just hypothetically speaking, if such a ship was made and if it actually could float and carry at least 1 round for each gun. Would it not break apart or just sink it self upon firing even one of them, let alone a broadside?

That's what drives the displacement up. The hull has to be big enough to absorb the shock. I'm not sure it can do that; 1940s materials technology may simply not be up to it.[/quote]

How about Pycrete? Let's wrap up together several wild ideas!

[Sea Skimmer]

I don’t have propellant weight handy for Dora to calculate actual recoil energy, but for just muzzle energy its 7,100kg at 720m/s = 1,866,890,319 joules muzzle energy for 80cm weapon. The 18in gun on Yamato would fire 1,460kg at 780m/s for about 450,603,014 joules of muzzle energy in comparison. So the 80cm weapon is around four times more powerful. It would also need a really massive mounting just to accommodate the shear bulk of the weapon and its ammunition. Mounting singles should be feasible, a twin might not be. You certainly would have lots of space for the turret turntable and ring bearings though.

[Spoonist]

Also wasn't the ammo to the Schwerer Gustav increasingly larger because the barrel expanded with each shot. Then finally the barrel had to be replaced. So imagine what that means for a naval vessel...

[Sir Sirius]

Also wasn't the ammo to the Schwerer Gustav increasingly larger because the barrel expanded with each shot. Then finally the barrel had to be replaced. So imagine what that means for a naval vessel...

No, that was the WW1 Paris gun.

[Spoonist]

Also wasn't the ammo to the Schwerer Gustav increasingly larger because the barrel expanded with each shot. Then finally the barrel had to be replaced. So imagine what that means for a naval vessel...

No, that was the WW1 Paris gun.

Ah, my mistake.

[erik_t]

I don’t have propellant weight handy for Dora to calculate actual recoil energy, but for just muzzle energy its 7,100kg at 720m/s = 1,866,890,319 joules muzzle energy for 80cm weapon. The 18in gun on Yamato would fire 1,460kg at 780m/s for about 450,603,014 joules of muzzle energy in comparison. So the 80cm weapon is around four times more powerful. It would also need a really massive mounting just to accommodate the shear bulk of the weapon and its ammunition. Mounting singles should be feasible, a twin might not be. You certainly would have lots of space for the turret turntable and ring bearings though.

Newton would suggest that what we really care about is the max acceleration of the shell (just a function of working pressure) and the allowed recoil stroke. Obviously if the gun is given fifty feet of nonlinear dashpot to dissipate energy, it matters very little the total recoil energy. I don't have chamber pressure data for Dora/Gustav, but Navweaps quotes a working pressure of between 294MPa and 314MPa for the Japansese 46cm weapon, and 294MPa for the German 53cm/52 Gerät 36. In the absence of other data, I'm willing to assume 300MPa for the 80cm weapon. The recoil force F(t) will be the cross-sectional area of the shell times the pressure at any given time (neglecting the friction of the driving band); with essentially the same max pressure, we can then imagine that the maximum recoil force of the 80cm weapon is (80/46)^2 ~= 3.0 times that of the 46cm weapons of Yamato.

A heavier weapon will in this sense be beneficial as it will "smear" the recoil in time. I have no idea as to the recoil stroke the Germans were willing to accept in a supermonitor application (I think "battleship" is probably a misnomer, Hitler's delusions of anti-ship fire with the weapon notwithstanding).

[CaptainChewbacca]

Well, if we're going to get silly there's always Project Habakkuk for really, really big boats.

[lord Martiya]

OK, the Britons just won first place in my little list of planning silly ships...

[Omeganian]

For Dora; Franz Halder defined it as a useless state of the art.