USN WWII Battleships characteristics if true IJN Yamato Class details were known at the onset of war

[Ironmiked]

Question - Had the USN known the true characteristics of the IJN Yamato Class at the onset of war, what, if anything, would have changed with regards to USN battleship design and production? Would have carrier production suffered and the remaining Iowa Class been completed? Would have the Midway Class been canceled in order to build the Montana Class? I'm curious about everyone's thoughts on how things would have changed.

 

[icyplanetnhc (Steve)]

I’ll defer to those more knowledgeable on design history than me, but I would posit that the Montana class design process may have been accelerated, and perhaps the 18”/48 guns would received renewed considerations. It will also depend on when exactly the USN may be aware of those specifications. That being said, the first three Essex-class carriers had their keels laid down before Dec. 7, 1941, and at the time, priority was given to completing ships as quickly as possible, even if they are repeats of older designs. There is also dockyard capacity to consider, and also long lead items like guns, armor plates, etc. In any case, some of the most decisive battles in 1942 and 1943 were fought without the latest Essex and Iowa classes.

 

[that_person]

Doubt it would change much of anything. The USN knew carriers would ultimately decide the war, not battleships.

 

[Dilandu]

Most likely Montana-class would proceed as they are, maybe with improvements in armor protection. Designing hew, heavier guns would require too long. So I think, the first two Montanas would go as pre-planned, the next pair would be redesigned to better stand against 18-inch shells, and the final ship(s) may be redesigned for 18-inch guns. Albeit I doubt that this program would be fully completed.

Also most likely North Carolina and Washington would be rushed to Pacific, instead of staying in Atlantic till mid-1942.

 

[EwenS]

Doubt it would change much of anything. The USN knew carriers would ultimately decide the war, not battleships.

When? If that was the case on the outbreak of war why did the USN choose to only add 2 Essex class to the 11 they had on order at that point? The CVL were Roosevelt's idea and were virtually forced onto the Navy.

FDR certainly favoured carriers in early 1942 but he was in a minority until after the big carrier battles of 1942. After that carrier production ramped up with orders for another 10 Essex class in Aug 1942, and Roosevelt reluctantly approving 2 Midways in Dec 1942.

Work on Kentucky, laid down in March 1942, was only stopped in June 1942 and Illinois was laid down in Dec 1942. Work on battleship design continued until at least 1944 in the USN.

 

[Tzoli]

No, they had no accurate data on the Yamatos, not on the displacement side or the armament side both the USN and the RN even in 1944/45. There were some guesses that they were actually carrying 46cm weapons but these were only guesses

 

[EwenS]

A few points about the Montanas.

Plans to lay them down in 1941 had to be shelved due to industrial bottlenecks. In Dec 1941 it was planned to lay them down between Nov 1942 and March 1943 with build times of 3-4 years at peacetime rates of build. But the design was still being tinkered with in mid-1942. By way of comparison the Iowas took 32-41 months to build, partly peace and partly war. Kentucky when laid down in March 1942 was scheduled for 30 months.

So even if you can lay them down mid-1942 it will be into 1945 before they arrive in the fleet.

In early 1942 FDR felt the war would end around the end of 1945. He was reluctant to agree to build ships that would complete after that. That was a factor in delaying their construction in 1942 when there were higher priorities. Any decision to upgun them to 18", a calibre previously rejected, will mean designing a gun from scratch causing further delays (there was an 18"/47 test gun produced by relining and shortening the barrel length of a 16"/50 but it was nowhere near a production standard weapon). And then the ship would redesigned around that new gun leading to more delays.

The USN knew the Japanese were building new battleships and that they would probably significantly exceed the Treaty limits. The surpsise was by just how much and the 18" guns. But despite the USN having intelligence about this by Feb 1943 it did nothing to change the cancellation of the Montanas in July that year.

So for the Yamatos to affect US battleship policy I think that knowledge about them would have had to have been available around 1940.

Here is an article on what the USN knew and when. Tzoli, note the following tantalising line:-

"By the spring of 1943, CINCPAC (Commander In Chief Pacific) Intelligence listed the ships as being armed with nine 17.7-inch (45 cm) guns (the source of this information is not discussed by Prados)."

Circulating that kind of information in an official document suggests a bit more than a guess given everything else that was being said about them at the time. Hard evidence then became available in Feb 1944 but it seems no one wanted to believe it.

History and Technology - "What did the USN know about Yamato and when?" - NavWeaps

www.navweaps.com

 

[Archibald]

What "onset of war" ? September 3, 1939 or December 7, 1941 ?

In the case of France, long term they planned to a add a third 4*gun turret in the rear, hence 12*380s... hell of a firepower, it would have.

 

[EwenS]

The 45,000 ton 3x4 380mm was never chosen.

After Richelieu & Jean Bart the French had various designs with either 2x4 380mm both forward or one forward and one aft, or 3x3 380mm two forward and one aft with varying secondary and tertiary armaments. Out of that exercise flowed the following:-

Clemenceau with 2x4 380mm forward, 4x3 152mm (2 on the beam and two aft on the centreline) and 6x2 100mm. Laid down at Brest 17 Jan 1939 immediately following the float out of Richelieu.
Gascoyne with 2x4 380mm, one fore and aft, 3x3 152mm (2 forward on the centreline superfiring over A turret and one aft) and 8x2 100mm.

After that the move was to be to the larger Alsace class for which 3 designs were prepared:-
Project Type 1 40,000 tons 3x3 380mm 9x152mm and 8x2 100mm
Project Type 2 42,500 tons 3x3 406mm 9x152mm and 8x2 100mm
Project Type 3 45,000 tons 3x4 380mm 9x152mm and 12x2 100mm

It was the Project Type 1 that was chosen for construction, authorised on 1 April 1940 with construction scheduled to start in 1941. Type 2 was rejected as it would have introduced another gun calibre to the French Navy with risks of delay to the project. Type 3 was rejected as, while it would have outclassed most European construction, was a step too far in terms of the infrastructure available in France to build it.

By the late 1930s the French were encountering the same problems that Britain ran into in WW2, the physical size of the proposed ships relative to building facilities and dry docks. Dunkerque was built at Brest in 2 sections (17m bow and 198m main section) and Richelieu was built in the same building dock in 3 parts (a 43m bow section, 8m stern section and a main 197m section) The various parts were then joined in a dry dock after float out. Clemenceau would have followed the same pattern. Work on a new building facility at Brest had begun pre-war and was scheduled for completion in 1946. The only other facilities capable of building these ships were a slipway at St Nazaire (used for Strasbourg and the liner Normandie) and the Forme Caquot at St Nazaire, first used to build Jean Bart. There were only about 5 naval and a single commercial dry dock in metropolitan France and a dock in Bizerta capable of docking these ships.

 

[Archibald]

The 45,000 ton 3x4 380mm was never chosen.

After Richelieu & Jean Bart the French had various designs with either 2x4 380mm both forward or one forward and one aft, or 3x3 380mm two forward and one aft with varying secondary and tertiary armaments. Out of that exercise flowed the following:-

Clemenceau with 2x4 380mm forward, 4x3 152mm (2 on the beam and two aft on the centreline) and 6x2 100mm. Laid down at Brest 17 Jan 1939 immediately following the float out of Richelieu.
Gascoyne with 2x4 380mm, one fore and aft, 3x3 152mm (2 forward on the centreline superfiring over A turret and one aft) and 8x2 100mm.

After that the move was to be to the larger Alsace class for which 3 designs were prepared:-
Project Type 1 40,000 tons 3x3 380mm 9x152mm and 8x2 100mm
Project Type 2 42,500 tons 3x3 406mm 9x152mm and 8x2 100mm
Project Type 3 45,000 tons 3x4 380mm 9x152mm and 12x2 100mm

It was the Project Type 1 that was chosen for construction, authorised on 1 April 1940 with construction scheduled to start in 1941. Type 2 was rejected as it would have introduced another gun calibre to the French Navy with risks of delay to the project. Type 3 was rejected as, while it would have outclassed most European construction, was a step too far in terms of the infrastructure available in France to build it.

By the late 1930s the French were encountering the same problems that Britain ran into in WW2, the physical size of the proposed ships relative to building facilities and dry docks. Dunkerque was built at Brest in 2 sections (17m bow and 198m main section) and Richelieu was built in the same building dock in 3 parts (a 43m bow section, 8m stern section and a main 197m section) The various parts were then joined in a dry dock after float out. Clemenceau would have followed the same pattern. Work on a new building facility at Brest had begun pre-war and was scheduled for completion in 1946. The only other facilities capable of building these ships were a slipway at St Nazaire (used for Strasbourg and the liner Normandie) and the Forme Caquot at St Nazaire, first used to build Jean Bart. There were only about 5 naval and a single commercial dry dock in metropolitan France and a dock in Bizerta capable of docking these ships.

My readings of Wikipedia (well, it's Wikipedia) told me naval historians are still disagreeing over what project was chosen between 1 and 3.

 

[muttly]

I think that if the U.S had known the true size and specs of yamato when it
was being built an 18in gun would have been included in the design
of our ships.

 

[EwenS]

The 45,000 ton 3x4 380mm was never chosen.

After Richelieu & Jean Bart the French had various designs with either 2x4 380mm both forward or one forward and one aft, or 3x3 380mm two forward and one aft with varying secondary and tertiary armaments. Out of that exercise flowed the following:-

Clemenceau with 2x4 380mm forward, 4x3 152mm (2 on the beam and two aft on the centreline) and 6x2 100mm. Laid down at Brest 17 Jan 1939 immediately following the float out of Richelieu.
Gascoyne with 2x4 380mm, one fore and aft, 3x3 152mm (2 forward on the centreline superfiring over A turret and one aft) and 8x2 100mm.

After that the move was to be to the larger Alsace class for which 3 designs were prepared:-
Project Type 1 40,000 tons 3x3 380mm 9x152mm and 8x2 100mm
Project Type 2 42,500 tons 3x3 406mm 9x152mm and 8x2 100mm
Project Type 3 45,000 tons 3x4 380mm 9x152mm and 12x2 100mm

It was the Project Type 1 that was chosen for construction, authorised on 1 April 1940 with construction scheduled to start in 1941. Type 2 was rejected as it would have introduced another gun calibre to the French Navy with risks of delay to the project. Type 3 was rejected as, while it would have outclassed most European construction, was a step too far in terms of the infrastructure available in France to build it.

By the late 1930s the French were encountering the same problems that Britain ran into in WW2, the physical size of the proposed ships relative to building facilities and dry docks. Dunkerque was built at Brest in 2 sections (17m bow and 198m main section) and Richelieu was built in the same building dock in 3 parts (a 43m bow section, 8m stern section and a main 197m section) The various parts were then joined in a dry dock after float out. Clemenceau would have followed the same pattern. Work on a new building facility at Brest had begun pre-war and was scheduled for completion in 1946. The only other facilities capable of building these ships were a slipway at St Nazaire (used for Strasbourg and the liner Normandie) and the Forme Caquot at St Nazaire, first used to build Jean Bart. There were only about 5 naval and a single commercial dry dock in metropolitan France and a dock in Bizerta capable of docking these ships.

My readings of Wikipedia (well, it's Wikipedia) told me naval historians are still disagreeing over what project was chosen between 1 and 3.

As you will see from the references on the Wiki page the choice is between

1. "British, Soviet, French and Dutch Battleships" by Gazarke and Dulin published way back in 1980 and
2. "French Battleships 1922-1956" by John Jordan and Robert Dumas published in 2009.

The latter, according to its preface, was based on Dumas' own original research published in French during the early 1990s. So there was at least another 10 years of research behind it, and possibly as much as 29. I have both in my library.

Details of the Alsace class in the former are sketchy being covered by a statement that "It seems reasonable to expect" that the armour and secondary armament would be "similar" to Richelieu and / or Gascoyne and the speed would be "at least" 30knots. They then provide an estimated table of particulars, which isn't too different from the latter book in some respects but significantly different in others. The authors go on to state that no design was selected.

Gazarke & Dulin placed their belief in the 3 quad ship on the basis that the French had "never built a triple turret mounting guns of such large calibre" and therefore it would be "logical" to again choose a quad they were already building.

The latter work has much greater detail about the 3 designs including, armament, armour thicknesses and how they related to that of Richelieu, shp for each type (which varied from 170,000shp to 220,000 shp to produce planned speeds of 31-32 knots). It also spends much more time explaining the development of the aviation arrangements proposed for Gasgoyne and later ships (much more than one catapult and one floatplane). It concludes with the statements -

"The choice of the Naval General Staff was relatively straightforward." It then explains the elimination of the 406mm ship and the 45,000 ton ship for the reasons I previously gave. It then goes on:-

".....Type No. 1, on the other hand, was a well balanced design which used existing weaponry and which could be accomodated with relatively minor adjuatments to current infrastructure.

Two battleships of 40,000 tons were duly authorised on 1 April 1940........."

It then goes on to assign yards and building timetables for the first two ships.

So it seems to me that, without having access to original documents, there is sufficient extra detail about the Alsace class in the latter work to supercede what had been published 29 years earlier in the former work.

 

[Archibald]

Ok thanks. In turn, this mean that french battleships beyond Richelieu would be chopped liver against any Yamato...

 

[EwenS]

Not nearly so simple as that. Depends on range for one thing.

Yamato - side armour up to 410mm, deck armour 200-230mm
French 380mm gun could theoretically penetrate 270mm of deck armour at 38,000m and 393mm of side armour at 22,000m

All sorts of factors coming into play. Quality of armour, thicker doesn't always mean better. Dispersal of shells, problem for the French until post war. Quality of shells, problem for the French pre 1943. Who gets in the first hits. Damage control. The golden bullet! Perhaps most importantly the French also have a speed advantage so can choose the range they want to fight at.

But the French ships would find it hard to resist Japanese 18.1" shells unless against their deck armour at 20,000 yards.

If you want to lose some days (or weks months!) go check out the gun data over on the NavWeaps site.

Naval Weapons of the World - NavWeaps

www.navweaps.com

And for one persons take on the "Best Battleship" (be warned there are as many people in the world as opinions about this subject!!!)

Battleship Comparison

The Richelieu doesn't come out of this too badly. Third of 7 as the best all round ship and runner up of 5 in the middleweight category. I must admit to having a soft spot for them.

 

[JFC Fuller]

As a disclaimer, I find French ship designs to be amongst the most interesting and underrated of the pre-WW2 rearmament period. However, when it comes to battleships the French Navy were willing to expend an enormous amount of design effort to extract relatively marginal, and in some cases dubious, improvements from their basic 35k ton treaty design. Gascogne is an example of this, the changes made to her design offer some advantages in terms of secondary armament layout but hardly seem worth the enormous redesign effort. Relocating one of the main armament turrets aft is almost amusing to someone who has read the British analysis of capital ship shell output written in support of the 1944/45 Lion design effort (forward guns fired far more shells than those aft during the war). If the preferred option for the Alsace class really was a 40k ton nine x 15" ship then the class could be seen as the final step in a journey from radicalism to conservatism in capital ship design. An incredible amount of effort to deliver one additional 15" gun - new hull layout, new turret design, etc.

By contrast I can see why earlier historians, without examining files covering the decision making process, would have assumed the twelve x 15" design would have been built. It used the existing turret designs and produced a very well balanced ship within the 45k ton limit at the limits of the existing infrastructure - but still viable. The British appear to have concluded that a twelve x 16" gun ship could not realistically be built within 45k tons without significant sacrifices elsewhere whilst a nine x 16" gun ship didn't really need 45k tons unless one other area (speed or protection) was pushed to extremes. The French quad 15" was a happy accident that enabled an almost perfect twelve gun 45k ton design. I don't find the argument that a 12 x 15" design would have outclassed most European construction particularly compelling either, such a design feels like a very logical counter to the 16" ships that would have been coming out of German yards. Finally, this sort of trend to conservatism isn't obvious in French heavy cruiser design of the period.

 

[Archibald]

What always bothered me is the Bretagne having 340 mm guns and the Dunkerques, 330 mm.

It is a bit a pity the Bretagnes couldn't be upgraded with Dunkerques 330 mm guns - if only to a) get more modern guns and b) remove one caliber.

Even with guns a little smaller. But also lighter maybe, this may have helped the slow Bretagnes speed.

The spares 340 mms could have gone to coastal batteries - well the Germans (the irony) did exactly that, in Toulon (Cap Cepet) and elsewhere.

However, when it comes to battleships the French Navy were willing to expend an enormous amount of design effort to extract relatively marginal, and in some cases dubious, improvements from their basic 35k ton treaty design.

Yup. You British found the "basic shape" - 4*2*380 mm guns - with the Q.E right from 1912 , and did not moved a lot afterwards and until 1948, Vanguard included - except for very specific cases: the Rodney / Nelson and KVGs.
In fact the Q.E basic layout spread to many other navies afterwards.

The French battleline was far more diverse - gun calibers included.
The story of French dreadnoughts is one of immense waste and way too many false starts, stops, start again.

There are weird parallels between the Normandies in WWI and the Richelieus in WWII.
Including Béarn being turned into a carrier, and Jean Bart nearly meeting a similar fate 20 years later.

 

[EwenS]

The Washington Treaty changed everything for all navies. All of a sudden, with a Treaty tonnage limit, everyone had to extract the maximum bang for the buck in terms of the speed/armour/armament mix.

For the RN, twin turrets meant a longer ship and sacrifices elsewhere when compared to a ship with three quads or triples, or the same weight of armour spread more thinly. In that scheme of things Vanguard is the outlier of this generation of RN designs and illustrates the problem when compared to the Lion it was developed from. It was purposely designed to reuse twin turrets from Courageous and Glorious as an extra fast battleship to the planned Lions, not through choice but expediency because no more Lions could be accommodated by industry. The RN had rejected a proposal for a 35k ton modified KGV with 3 twin recycled 15” turrets around 1939. So for the RN an even larger 40k+ ton vessel with only 6x15” represented too light an armament in the speed/armour/armament mix. So Vanguard had to have 4 turrets and thinner armour accepted.

The French tackled the problem in the Richelieu class by opting for two quads (or rather two double twins due to their interior layout) thereby following a trend it started with the Dunkerque. The Germans and Italians took different courses that involved significantly exceeding Treaty limits.

The USN moved to triples when it increased the calibre from 12” to 14” in WW1 then replaced triple 14” with twin 16”. But then went to three triple 16” in the 1930s, planning to simply add another turret in the Montanas.

I don’t see the weird parallels re the carrier conversions. Bearn was maximisation of the use of money spent on an already existing hull in the 1920s. The proposed conversion of Jean Bart was something considered during WW2 by all major navies either as complete conversions or as hybrids. Britain and the US rejected them as the carrier requirements were severely impacted but Japan went ahead an converted the Shinano due to its desperate need for carriers.

Edit:- Re Bearn, in the same timeframe there were conversions of existing hulls to carriers in Eagle, Furious, Courageous and Glorious in the RN, Lexington and Saratoga in the USN and Akagi and Kaga in the IJN. So not an uncommon practice at all.

 

[CV12Hornet]

Moving back to the US Navy, 18" guns are very unlikely. Besides the already-stated problem of the amount of time the necessary redesign would take the US Navy had not been impressed with its tests of the 18"/48. The opinion of BuOrd was that the gun offered only marginal improvements over contemporary 16" weapons, something that would only become more pronounced in comparison to the newer guns with super-heavy shells. Further, the 18"/48 was a 1920s design effort and there was only one gun. The time needed to develop an all-new gun likely would have been prohibitive.

 

[Hood]

Moving back to the US Navy, 18" guns are very unlikely. Besides the already-stated problem of the amount of time the necessary redesign would take the US Navy had not been impressed with its tests of the 18"/48. The opinion of BuOrd was that the gun offered only marginal improvements over contemporary 16" weapons, something that would only become more pronounced in comparison to the newer guns with super-heavy shells.

This is true, increasing calibre had little effect once shell and gun design had improved during the interwar period. 16in was probably the sweet spot and larger guns had too many compromising trade offs (weight, blast etc.).
The Japanese got sidtetracked with emphasising the numbers game, they knew they couldn't outbuild the USN so they went for what they thought were qualitatively superior ships based on big guns and thick armour. Sadly that had its own flaws, the armour was not that good due to Japan's armour plate manufacturing processes and the 18in gun in itself was nothing remarkably superior.
Had Japan settled for a newer 16in gun and built a smaller ship, something like a North Carolina or Iowa in terms of design, they might have found it more affordable. Either way its not likely that an Iowamto would have been any more successful or useful to the IJN than the Yamatos.

 

[Archibald]

an Iowamto

Took me a brief moment of WTH to understand it wasn't a typo (nor a cat having walked on your keyboard).

 

[Colonial-Marine]

Moving back to the US Navy, 18" guns are very unlikely. Besides the already-stated problem of the amount of time the necessary redesign would take the US Navy had not been impressed with its tests of the 18"/48. The opinion of BuOrd was that the gun offered only marginal improvements over contemporary 16" weapons, something that would only become more pronounced in comparison to the newer guns with super-heavy shells. Further, the 18"/48 was a 1920s design effort and there was only one gun. The time needed to develop an all-new gun likely would have been prohibitive.

The 18"/48 Mark 1 was indeed a 1920s design effort but I don't think developing a new "Mark 2" using newer construction techniques would have been prohibitive. Look at how fast the 16"/50 Mark 7 appeared after it was discovered the 16"/50 Mark 2 and Mark 3 wouldn't fit in the turrets designed for the Iowa class due to some earlier miscommunication.

If the true specifications of the Yamato class were known at such an early date I think construction of at Montana class would have proceeded and been given priority over the additional two Iowas that were authorized in the Two Ocean Navy Act. The USN might design a new class which would basically be a Montana with 3x3 18" guns (or 4x2) but chances are the war would be over before any are laid down.

After learning the truth about the Yamato class would the USN react to reports of Japanese "super battleships" with 20" guns that they are building after the Yamatos?

 

[Foo Fighter]

I doubt anything different would have been done with the constraints actually controlling events. Either way you put it, there is no time for anything more exotic. Japan posited the Taranto attack could be successful in a larger form but failed to complete the mission. The USN took the tactics, made them part of general strategy and royally finished and proved the tactic. Naval aircraft were here to stay.

 

[muttly]

Didn't the 18in bring about the 16in 56cal that were to used on the Montana ?

 

[CV12Hornet]

Didn't the 18in bring about the 16in 56cal that were to used on the Montana ?

The Montanas were to use the regular 16"/50 Mk. 7. So no.

 

[muttly]

So the 16''/56 was just for testing?

 

[Colonial-Marine]

So the 16''/56 was just for testing?

Yes, although I think an updated production version of the 16"/56 was briefly considered for the main battery in battleship design studies for what would eventually become the Montana class. I think the problem (besides for excessive barrel wear) is that it's going to be roughly as heavy as the 18" option so you're aren't going to fit the same number as you could 16"/50 caliber guns.

I think the same 16"/56 gun was used for some "immunity zone" calculations during those many pre-Montana studies as well.

 

[royabulgaf]

OK, let's say the USN has hard evidence of the Yamatos as they really were by 1940. Since there seemed to be a tendency among the great powers to to imitate rival navies, ie if Japan builds a ship with X capability, the US hs to build a ship with X+1 capability. Since the USN has no 18" gun in the pipeline, why not go to 20? I see a priority given to the Montanas with 4 double 20" turrets. I leave it to those with greater knowledge of dockyard capacity, lead times, what construction can be halted (remember an Iowa or Essex is better than nothing), and Imshallah a Montana may be conducting sea trials by 1944.

 

[alexi]

OK, let's say the USN has hard evidence of the Yamatos as they really were by 1940. Since there seemed to be a tendency among the great powers to to imitate rival navies, ie if Japan builds a ship with X capability, the US hs to build a ship with X+1 capability. Since the USN has no 18" gun in the pipeline, why not go to 20? I see a priority given to the Montanas with 4 double 20" turrets. I leave it to those with greater knowledge of dockyard capacity, lead times, what construction can be halted (remember an Iowa or Essex is better than nothing), and Imshallah a Montana may be conducting sea trials by 1944.

Doesn't seems too far from "Maximum battleship 1936" studies, i could see they revive such concept with updated hull and improvements.

 

[CV12Hornet]

OK, let's say the USN has hard evidence of the Yamatos as they really were by 1940. Since there seemed to be a tendency among the great powers to to imitate rival navies, ie if Japan builds a ship with X capability, the US hs to build a ship with X+1 capability. Since the USN has no 18" gun in the pipeline, why not go to 20? I see a priority given to the Montanas with 4 double 20" turrets. I leave it to those with greater knowledge of dockyard capacity, lead times, what construction can be halted (remember an Iowa or Essex is better than nothing), and Imshallah a Montana may be conducting sea trials by 1944.

Ain't going to happen. If the US was unsatisfied with 18" guns they're sure as heck not going to leap to 20".

They're certainly not going to be conducting sea trials by 1944; the earliest they can be laid down is 1942 given wholly new shipbuilding facilities needed to be built for the Montanas (and the Midways, for that matter), and that means ships in 1945 at the earliest.

 

[EwenS]

Now things begin to fit together about the planned lay down dates of the Montanas being from Nov 1942 as I noted in an earlier post.

Article here about the expansion of the US Navy yards from 1938. Annoyingly while start dates for the new dry docks are given completion dates are not. There is a comment that the building time of the docks for the Montanas took 17-21 months which means the earliest wouldn’t have been available until mid-1942. I’ll have a more careful read later.

HyperWar: Building the Navy's Bases in World War II [Chapter 8]

Re the Midways, while initial plans were to build these in the Navy Yards, ultimately only the FDR was, at New York NY. Midway and Coral Sea were built in the civilian yard at Newport News which had been specialising in carrier construction since the early 1930s with Ranger.

 

[muttly]

The design board had decided that the then new 2700lb 16in shell was all
that was needed and was only armored against with the Montana. My
question is : was the Yamato shells that much more of a threat than our
16in.

 

[Ironmiked]

I did some additional research. It's been proven that the 161/50 heavy shell could penetrate the IJN Yamato Class turret face. At long range both the16-inch/50-caliber Mark 7 gun and the IJN 46 cm/45 Type 94 naval gun had similar penetration and performance characteristics. Had that been known and, added to that, the superior speed, fire control, damage control and maneuverability of the U.S. battleship designs, I think the USN Navy would have pressed for the production of the higher speed but equally armored Montana Class derivative beginning with BB-65. Design study of the BB65-8 scheme called or a 33-knot battleship with a standard displacement over 66,000 long tons (67,000 t), waterline length of 1,100 feet (340 m), and required 320,000 shaft horsepower (239 MW). Thoughts?

History and Technology - Ballistic Tests on the IJN Shinano's Turret Face Armor - NavWeaps

www.navweaps.com