Royal Navy Lion Class Battleship series 1938-1945

[TomS]

Seems there was one prototype with floats, but I've been unable to track down a photo. I'm not entirely sure the source is accurate.

"All Albacores were landplanes, though the first prototype was later fitted experimentally with floats to determine its prospects for possible catapult operations. Tests were made by MAEE pilots at Hamble early in 1940 and were not markedly successful." from the Putnam Fairey Aircraft.

Thanks. So my source was only semi-accurate, but there was briefly an Albacore floatplane, which could have been the source for this drawing.

 

[Hood]

Its interesting that a Walrus wasn't depicted. But of course the Swordfish had been operated from battleships as a seaplane so it probably appeared logical to assume that the seaplane Albacore would enter service as a lighter seaplane to replace the Swordfish and Seafox. Of course this never happened. Spec S.24/37 that led to Barracuda had initially specified floats as an alternative from use in sheltered waters but this was soon dropped.
Actually I think seaplane versions of most of the late 1930s types proved a flop in some form or another, probably why the Sea Otter was persevered with despite the production delays.

 

[Arjen]

From War Planes of the Second World War - Volume Six - Floatplanes by William Green, Macdonald 1962.

 

[phil gollin]

.

Someone did obtain a photograph of the Albacore floatplane prototype and copied it to people on a confidential basis ( I THINK it was on the secret projects website ). I have a copy, but will abide by the agreement not to spread it.

.

 

[Tzoli]

As a comparison here is the Vanguard as ordered:

Vanguard 1941 As Designed - Google Drive

drive.google.com

and as finished:

Vanguard 1941 as Completed - Google Drive

drive.google.com

 

[M. A. Rozon]

Oh Wow! Thanks, Tzoli, these are great!

 

[TsrJoe]

Albacore & Fulmar floatplane

 

[lordroel]

Thanks @Tzoli, i have learn something new, always assumed that the Lion class was a single design, should have known that designs evolve over time.

 

[Tzoli]

Maybe Lion was the unluckiest ship never to be built? The class kept delayed one after another and modified the design almost yearly!
It's one hell of a luck the HMS Vanguard was even built!

 

[lordroel]

Maybe Lion was the unluckiest ship never to be built? The class kept delayed one after another and modified the design almost yearly!
It's one hell of a luck the HMS Vanguard was even built!

So which of the designs you posted would Vanguard be the closest with.

 

[Tzoli]

Maybe Lion was the unluckiest ship never to be built? The class kept delayed one after another and modified the design almost yearly!
It's one hell of a luck the HMS Vanguard was even built!

So which of the designs you posted would Vanguard be the closest with.

I don't understand your question.

 

[lordroel]

Maybe Lion was the unluckiest ship never to be built? The class kept delayed one after another and modified the design almost yearly!
It's one hell of a luck the HMS Vanguard was even built!

So which of the designs you posted would Vanguard be the closest with.

I don't understand your question.

In the first post of this thread you posted several Lion designs, which one would be the closest to the Vanguard design that was build.

 

[Tzoli]

None and all starting from the 1938 versions. The hull shape is the same as chosen for the 1938 Lion, Superstructure wise from the 1942 versions and up.

 

[lordroel]

None and all starting from the 1938 versions. The hull shape is the same as chosen for the 1938 Lion, Superstructure wise from the 1942 versions and up.

A so a bit of everything then.

 

[Tzoli]

None and all starting from the 1938 versions. The hull shape is the same as chosen for the 1938 Lion, Superstructure wise from the 1942 versions and up.

A so a bit of everything then.

I'm not sure what you are really asking for.
Vanguard is a different line a ship designed to carry to old 15"cannons not a new 16"

 

[lordroel]

None and all starting from the 1938 versions. The hull shape is the same as chosen for the 1938 Lion, Superstructure wise from the 1942 versions and up.

A so a bit of everything then.

I'm not sure what you are really asking for.
Vanguard is a different line a ship designed to carry to old 15"cannons not a new 16"

A okay i understand now.

 

[Horizonwalker]

Thanks for your thorough information! @Tzoli

One question I do bear in mind over the years is what's the 85,000 tons "Large Lion" in D. K. Brown's Nelson to Vanguard? He did not reveal any detail other that this chart.

 

[Tzoli]

That was mentioned in Friedman but after the 1944 series (for when the DP battery was changed to 4,5" Guns not the 5,25 ones) of designs:

Given these depressing figures, ACNS(W), who was responsible for
British naval weapons, proposed cutting armour back, not taking bombs
into account. He suggested the original 15in/6in magazine protection, but
other spaces reduced to 13in/5in and he would even accept 4in deck
armour.11 Instead of taking 90° inclination (the worst case, shells hitting at
right angles to the ship’s course), he would accept 70° inclination, in which
case magazines would be immune to 16in fire between 17,000 and 28,500
yds. ACNS(W) accepted that bombs could not be kept out, so magazine
deck area should be minimised. That might be difficult given the demand
for more rounds and also for flashless powder.
Director of Naval Operations Research doubted that heavy armour was
the best investment in weight. During the first four years of war British
capital ships suffered only fourteen shell hits (five 15in [Hood], two 11in
[Renown in 1940], one 9.4in, five 8in, one 6in); shellfire accounted for
only 15 per cent of ship-months lost, compared to 80 per cent due to
underwater damage, mainly by torpedo. Practicable deck armour would
not keep out bombs likely to be used in future, nor would it force aircraft
to attack from higher altitudes than those imposed by the ship’s antiaircraft
fire. Low-level sneak raiders were best countered by better radarcontrolled
fire and by fighters operating from accompanying carriers. The
projected armour would amount to about 15,000 tons. For every inch
shaved off, 1500 tons would be saved. The question was, what could DNC
do with that weight? Could he improve underwater protection, for
example?
In the wake of ACNS(W)’s memo, DNC ordered more detailed studies,
including drawings of possible arrangements to see whether the ship could
be built within the desired length. The results were depressing. The ship
would be 950–1000ft long on the waterline, with a 120ft beam and deep
draught of 36 to 36½ft, with a 160,000 SHP steam plant. She would meet
staff requirements, including 6000nm at 20 knots deep and dirty in the
tropics and 120 rounds per gun (73in-long shells and flashless powder).
Her armour would be 15in/13in belt and 6in/4in deck, with 2½in holding
bulkheads underwater to deal with the Uncle Tom threat. Underwater
protection would resist a 1200lb TNT charge. Given a Board Margin of
1200 tons, the ship would displace 67,000–70,000 tons deep.

DNC attributed the enormous growth to better underwater side
protection, higher speed, greater endurance, greater freeboard and a wide
range of detailed additions. This huge ship would still be vulnerable to
air attack and she had no protection (other than better subdivision) against
under-bottom attack, for example by non-contact weapons such as ground
(influence) mines and magnetically-fuzed torpedoes. Both were already in
service. It would be better to pare protection to get a smaller ship which
could be built in numbers. Note that none of the runaway growth could be
attributed to increased deck protection to defeat increasingly powerful
bombs.

And

DNC’s battleship designer felt compelled to tabulate the additions which had led to
a 1000ft x 120ft x 35ft (70,000 ton) ship (1945 Battleship Cover, Folio 29). He began
with Lion, which as designed in 1938 would have displaced 46,835 tons deep. To
bring her up to date would have required 495 tons of new deck armour, 700 tons of
holding bulkhead, 100 tons of additional machinery (generators) and 1650 tons of
additional oil fuel. It was assumed that improvements in machinery design would
make it unnecessary to add weight to increase output from 130,000 SHP to 140,000
SHP. However, there was no investigation to see whether machinery weight could be
reduced. The 1650-ton estimate was based on EHP at 20 knots (17,000, propulsive
coefficient 0.5) and the need to add 300 steaming hours at 0.75lb/SHP/hr, allowing
also for a 60 per cent increase in resistance due to foul bottom with 5 per cent residue
in tanks. No increase in reserve feed water or lubricating oil was allowed. Extra
barbette armour would have added 645 tons. Additional protection would have
amounted to 80 tons in the bulkheads at the ends of the citadel, 950 tons of holding
bulkhead and 275 more tons of protective bulkhead (additional height), plus another
790 tons of armament (including more rounds, flashless powder and the two pentad
torpedo tubes) – a total of 5685 tons. Board margin (2 per cent of standard
displacement) would have amounted to another 912 tons. Reductions in armour would
have amounted to 310 tons in side and 400 tons in deck armour, so the net addition
would have been 5887 tons. Ships do not grow on a ton-for-ton basis; there is a
multiplier effect, so that a ton of armour (say) translated into several more tons of
ship. On the basis of the weight equation the British used, displacement should
increase by 20,900 tons (net factor of about 35). That gave 881ft x 118.6ft x 38.3ft,
67,700 tons deep, not far from the result DNC’s designer found. Dimensions

As you can see this is not clearly the 1.000Ft Lion Brown describes and it was noted by a few authors and people that the data for this design is not accurate in Brown's book.

Mentioned in the last part The 1945 Battleship Cover, Folio 29 I might had it, will check when I get home after work.

But apart from Brown I've never seen a modern (post 1930) British Battleship with 18" armour, hell not even the USN armoured their deisgns that well (I'm not sure about the 20" Maximum BB study of 1935-36 though) and only the A-150 Super Yamato would had carried that thick armour!

 

[Tzoli]

Here are the two pages of the 1945 BB cover, folio 29:

These were used as a basis for the 1945 series of designs: A,B,C,D

 

[SARG12]

As a comparison here is the Vanguard as ordered:

Vanguard 1941 As Designed - Google Drive

drive.google.com

and as finished:

Vanguard 1941 as Completed - Google Drive

drive.google.com

Hello, you can repeat it? Files have already been deleted (((.

Regards

 

[Tzoli]

As a comparison here is the Vanguard as ordered:

Vanguard 1941 As Designed - Google Drive

drive.google.com

and as finished:

Vanguard 1941 as Completed - Google Drive

drive.google.com

Hello, you can repeat it? Files have already been deleted (((.

Regards

Here they are:

easyupload.io

easyupload.io

easyupload.io

They are only avaliable for a limited time as I don't know a long time file hosting service. Megaupload was killed so does Rapidshare....

 

[awhalen61]

As a comparison here is the Vanguard as ordered:

Vanguard 1941 As Designed - Google Drive

drive.google.com

and as finished:

Vanguard 1941 as Completed - Google Drive

drive.google.com

Hello, you can repeat it? Files have already been deleted (((.

Regards

[1947] Vanguard as Completed - Google Drive

drive.google.com

[1941] Vanguard As Designed - Google Drive

drive.google.com

Here are some permalinks once the ones that TZoli posted disappear

 

[Fr05ty]

Am I reading this correctly in that several of the Lion designs had a belt armour only 10" (254mm) thick? Seems rather odd to be planning a large battleship with such a thin armour belt at such a late stage in the war. Reminds me a bit of Fisher's large cruisers...

 

[Dilandu]

Am I reading this correctly in that several of the Lion designs had a belt armour only 10" (254mm) thick? Seems rather odd to be planning a large battleship with such a thin armour belt at such a late stage in the war. Reminds me a bit of Fisher's large cruisers...

If I recall correctly, they assumed that with increasing ranges of naval combat, the hits into the deck became much more probable than any belt hits.

 

[JohnR]

By the same measure, some of the postwar studies considered having a 12" deck.

 

[A Tentative Fleet Plan]

By the same measure, some of the postwar studies considered having a 12" deck.

There wasn't a study with a 12" deck, it was just thought that 12" deck would be the only thing offering full immunity against aircraft bombs, and was quickly ruled out as being unfeasible.

 

[Dilandu]

There wasn't a study with a 12" deck, it was just thought that 12" deck would be the only thing offering full immunity against aircraft bombs, and was quickly ruled out as being unfeasible.

Especially considering that US tests of shaped charge bombs in 1945 demonstrated, that even thick armored roofs of gun turrets (they imitated the hit into the battleship's turret top) would not provide enough protection.

 

[Tzoli]

Not 10" belt but mean 10" so 9" machinery and 11" magazines. This was because at long battle ranges and against air power deck was much more important as protecton.
No there were never a 12" deck armoured Lion.
The most was the 1944 series with 7" deck, most had 4" machinery and 6" magazines deck

 

[A Tentative Fleet Plan]

My understanding of 12" deck (and a case that occurred during the design process of Malta class, where 13" Cemented or 15" Non-Cemented Sides and decks would be required to protect against a 3000lb rocket-propelled bomb) was that the Admiralty would make requests for protection against certain weapons, to which the DNC would rapidly reply "it will require X amount of protection and is unfeasible", leading to the end of the request.

 

[SARG12]

Here they are:
https://easyupload.io/m/ohdj9e
They are only avaliable for a limited time as I don't know a long time file hosting service. Megaupload was killed so does Rapidshare....

Thank you very much!!! Just fantastic research material.

 

[SARG12]

As a comparison here is the Vanguard as ordered:

Vanguard 1941 As Designed - Google Drive

drive.google.com

and as finished:

Vanguard 1941 as Completed - Google Drive

drive.google.com

Hello, you can repeat it? Files have already been deleted (((.

Regards

[1947] Vanguard as Completed - Google Drive

drive.google.com

[1941] Vanguard As Designed - Google Drive

drive.google.com

Here are some permalinks once the ones that TZoli posted disappear

Thank you -))

 

[biber550]

For the time being here are the official original plans of the 1938 Lions as ordered:

Lion 1938 - Google Drive

drive.google.com

I am so sorry, you can repeat it? Files have already been deleted

 

[biber550]

Before the Vengard project, it was proposed to equip the Lion with 15-inch towers. There is information?
Thank you in advance!

 

[Tzoli]

I've never heard of this project neither Friedman states it. The only 15" armed Lion was among the 1945 X projects for a new design 15" cannon in two quad turrets apart from this it was always 14" (early versions) or 16"

However....
After KGV but Before Lion DNC made quick estimates for designs with 3x4 14", 3x3 15" or 3x3 16" but DNC was not happy with the 15" armament

 

[Tzoli]

From Friedman's British BB Book:

On 6 July 1936 ACNS held a conference to examine the consequences of a change to a 15in or 16in main battery. DNC produced some quick design estimates. Ship I was armed with three triple 15in guns and adequately protected over magazines (16½in side, 6½in deck). Despite grossly inadequate protection to machinery (11½in side, 1¼in deck) such a ship if designed for 29 knots would displace 41,000 tons. Even a 23-knot ship thus protected and armed would, it seemed, displace 38,000 tons. Ship II was a slow (23-knot) 35,000-ton ship armed with three triple 15in guns. On this basis she could have the protection of the 1937 battleship (15in/14in side, 6in/5in deck). Ship III was a 35,000-ton ship with three triple or twin 16in turrets. If protected against 16in shell like Ship I, the version with triple turrets could not be built, because no weight would be available for machinery. With twin turrets, she could be protected, but speed would be only 22 knots.

Controller pointed out that if the Japanese did adopt a heavier gun, it was nearly certain that they would also break the 35,000-ton limit. If the British went to 15in guns, turret design would take about fifteen months. The only way to save time would be to adopt the existing 16in turret design of the Nelsons, but that would require a jump of about 10,000 tons. A 24 September 1936 meeting in First Lord’s room decided that, since the decision on a gun for the 1937–8 battleships was urgent, the Foreign Office should be urged to ask the Japanese for a definite answer. The ambassador reported helpfully that people qualified to judge, such as the Soviet ambassador and the American advisor to the Japanese Embassy in Washington, had told him that the Japanese government understood that it would be folly to compete in naval construction with the United States and Britain. He admitted this was not conclusive. To further confuse matters, the Japanese began talking about a new conference with the British and the Americans to reach some understanding. The British consoled themselves that any 35,000-ton Japanese ship armed with 16in guns would be unbalanced, hence could be defeated by the new British battleships and that if they embarked on a totally new type the British could quickly outbuild them. Controller was unwilling, however, to mark time and to bet on these possibilities.

By this time the British had some idea of what a well-balanced 16in gun ship with reasonable protection against 16in fire would look like. In connection with projections of Japanese construction, in September 1936 Controller listed two possibilities, both armed with nine I6in: A slow (24-knot) 40,000-ton ship (750ft x 110ft x 30ft). A fast (28-knot) 44,000-ton ship (820ft x 110ft x 30ft). Controller wrote that given British superiority in shipbuilding, even if the Japanese enjoyed a six-month lead with some new design, the British could catch and overtake them in a ratio of 3 to 2. If the British persisted in laying down three more ships in July 1937 (as they did), they would end up with a division of six fine fast capital ships (with Hood) ‘which in the tactics of battle might play a very important part, especially if the enemy’s battleships are slower’.

The Japanese stalled, telling the British Ambassador that they could not talk until the current tension with China (which soon resulted in all-out war) was resolved. By October Controller had ‘no wish to appear suspicious’, but he thought it obvious that the Japanese were simply giving themselves more time for their new design. On 20 October the British formally asked the Japanese Ambassador to Washington for an assurance that his country would not adopt the 16in gun for new ships. The Ambassador said he believed his government favoured the 14in gun, but would be reluctant to commit itself to any arms limit at that point. In December the Japanese Ambassador to London said that his country’s plans were not yet firm; there was a certain amount of confusion. Director of Plans went further: in January 1937 he suggested telling the Japanese that ‘an effort by the Japanese Ministry of Marine to bring down the whole of the treaty system in order to serve their own selfish ends would cause a very bad impression over here’. Finally on 19 March 1937 the Minister for Foreign Affairs told the British Ambassador to Japan that he would shortly receive a note rejecting the 14in gun limit. It arrived the day before the deadline, 31 March 1937.

Early in June the US government asked all the Washington Treaty powers about their intentions regarding gun calibre; it really meant Japan. The Japanese replied that they would no longer be bound by either the 14in gun limit or the 35,000-ton limit. That made US adoption of the 16in gun certain. This decision was communicated to the British on 13 July. The delay in this announcement was due to considerable public pressure to limit armaments, particularly in the United States. The limit embodied in the London Naval Treaty, which had shaped the King George V class, was dead.

The British had already adopted a programme to replace existing battleships: two ships in the 1936–7 programme, three in 1937–8, two in 1938–9, two in 1939–40 and one in 1940–1.4 It was too late to change the three 1937–8 ships, so they were repeat King George Vs. It seemed reasonable to assume that the Japanese would exceed 35,000 tons, although they offered unofficial (false) assurances that they would not build ‘monster’ ships. On that basis in the summer of 1937 DNC investigated the characteristics of larger ships armed with heavier guns, looking towards the 1938 programme. This was no academic exercise. Bids for 1938 programme ships had to be requested in the spring of 1938, which meant that a firm sketch design was needed late in 1937 – before, as it turned out, the escalator clause had been invoked, hence before the British could know what the new treaty limit would be. Because it was very much in their interest to hold down the size (hence the cost) of any new ship, the British wanted to minimise any jump in allowable displacement – but they did not want the jump to be so small that they were precluded from building a ‘balanced’ 16in-gun ship.

On 21 July Goodall reported several sets of characteristics, for ships armed either with three quadruple 14in guns, three triple 15in or three triple 16in.5 A King George V class hull could accommodate two triple 16in turrets on 35,000 tons. Adding a third would cost 2000 tons (design displacement would increase to 37,500 tons). Reducing displacement by that 2000 tons would cost a knot and a half (27 knots) and the midships catapult would have to be replaced by a turret catapult. Replacing each of the turrets of a King George V with a triple 15in turret would cost 1250 tons (36,750 tons), but in that case the ship would be limited to 27 knots and would have the turret catapult.6 Replacing each turret of a King George V with a triple 16in turret would cost 3000 tons (38,500 tons). To cut back to 35,000 tons the ship would have to have her speed reduced to 25 knots and she would also have to have a turret catapult. In this particular case topside arrangement would be critical, so Goodall did not want to be bound to these conclusions until he had prepared a drawing. All of these designs benefitted from limited space and weight savings due to adopting the higher boiler forcing rate employed in the new 8000-ton cruiser (Fiji class). The situation would have been somewhat improved if, as Controller asked, gun elevation was reduced from 40° to 30°, but the main conclusions were unchanged.

None of this was particularly attractive, so Controller asked whether there would be any point in adopting a Nelson arrangement for the 25-knot ship with triple 16in turrets. Turret design had moved on to require a symmetrical disposition of shells around the trunk, which had not been the case in Nelson. That spread out the turrets and lengthened the citadel beyond what was required in the more conventional King George V arrangement. Its extra weight absorbed any saving from grouping the turrets together. Moreover, ammunition supply to the 5.25in guns would have been poor and it would have been difficult to fit in the required four shaft machinery with separated engine and boiler rooms.

Controller tried another approach. On 35,000 tons, with nine 16in and the 28.5 knots (deep) of a King George V, could magazines and barbettes be fully protected against 16in fire between 14,000 and 28,000 yds. How much would be left to protect the machinery? Alternatively, if belt and deck armour over the machinery were an inch less than over magazines and barbettes, what displacement would be needed? How much would be saved if speed were reduced to 26 or 27 knots? It turned out that such a ship would displace 41,000 tons. The 26-knot version would displace 38,500 tons, the 27-knot version 39,500 tons.

Further studies dated mid-August 1937 gave data for a ship with nine 16in guns and a turret (rather than amidships) catapult. Assuming displacement as King George V (35,500 tons) and the same protection for magazines and barbettes, to provide sufficient machinery to make the same speed (100,000 SHP, 28.5 knots in standard condition), machinery protection would be limited to 7in belt and 2¼in deck. Cutting speed to 27 knots would increase the deck to 3in, while cutting to 26 knots would allow for an 11in belt and a 3¾in deck.

By this time the United States had announced that it was building a pair of 27-knot 35,000-ton ships armed with nine 16in guns, the North Carolinas. How was that being done? At the beginning of September, DTD asked DNC further questions. Could the 41,000-tonner – the fully protected 16in ship – go through the Panama Canal? She would be designed to do that, probably with a 106ft beam. What if the armoured deck were brought down to middle deck level, as in earlier battleships? If magazines were fully protected and the machinery was covered by a 5in (rather than 6in, as over magazines) deck, how much could be provided over the machinery? If magazines were protected against 15in fire, how much would be left for machinery? It turned out that bringing the armoured deck down a deck level did save considerable weight, so that machinery could be protected by an 11in belt in the first case. In the second (protected against 15in fire), machinery spaces would have 13½in side protection.

In mid-September Controller tried another approach: two triple turrets and high speed, about 30 knots. A rough estimate showed the same displacement as King George V (35,500 tons) with the same aircraft arrangements and a 16½in belt and 6in deck, both throughout. If the same guns were mounted in twin turrets, the displacement would be the same, but the belt would be reduced to 15in over magazines and 14in over machinery, with corresponding deck thicknesses of 6in and 5in. However, in the first case protection would cover less of the ship’s length, 48 per cent rather than 55 per cent as in King George V. In the second case that would increase to 54 per cent. These designs were ruled out on the grounds that the minimum number of guns adequate for fire control was eight (four-gun salvoes if possible).

For 1938 the 14in gun was ruled out as too obviously inferior to 16in.7 The Naval Staff considered nine 15in uneconomical in terms of broadside weight, but on the other hand a ship so armed could be shorter than one with either nine 16in or twelve 14in. DNC’s battleship designer Pengelly found that a ship armed with 15in guns might come close to the treaty limit. Armament, barbette armour, etc, would add 450 tons to a King George V, equivalent to 1in on the belt and ½in on the deck over the machinery. Alternatively, the addition might be accepted with the knowledge that the ship would complete heavy ‘but it is considered that the ship should be redesigned with this in view’. Pengelly also pointed out that if it were accepted at the outset that the ship would end up drawing, say, 1ft 3in more than the reported standard, then it would be possible to combine nine 16in with King George V machinery and protection, at the cost of perhaps half a knot; the final standard displacement would be 1500 tons greater (37,000 tons). ‘This … would not be the first occasion that the draught of a Capital Ship on completion exceeded the estimate by more than 1 foot.’

 

[zen]

Just add this is fascinating stuff, and gives a different perspective on drydocks.

 

[biber550]

I've never heard of this project neither Friedman states it. The only 15" armed Lion was among the 1945 X projects for a new design 15" cannon in two quad turrets apart from this it was always 14" (early versions) or 16"

However....
After KGV but Before Lion DNC made quick estimates for designs with 3x4 14", 3x3 15" or 3x3 16" but DNC was not happy with the 15" armament

Such an offer was made in October 1939, but the Director of Naval Construction objected that it was better to have an LC with 9-16dm in 1944 than an LC with 6-15dm six months earlier.

 

[Tzoli]

huh?? What??
What is an LC to you? or dm??

 

[biber550]

huh?? What??
What is an LC to you? or dm??

Sorry
LC- BB, and of course 15", 16"
my native language is not english

 

[Tzoli]

But if I decode correctly what you mention is DNC's proposal to speed up battleship construction by using the already existing 15" turrets of Courageous and Glorious as the RN had a bottleneck for big turret construction.

By January 1939 Director of Plans was promoting an annual programme including three battleships. These ships alone would absorb about 42,000 tons of the total capacity of 56,000 tons; DNC warned that it left too narrow a margin for carriers, cruisers and other ships. DNO proposed expansion as reasonable insurance against probable increased building by Germany, at a probable cost of £5 million. That made the alternative of using the 15in turrets from the two Courageous class attractive – they ended up in HMS Vanguard. DNC was less than impressed, arguing that a 38,000-ton ship (as then envisaged) with eight 15in was a relatively extravagant use of armour, which would take as long to build as a Lion.

By May the three-battleship annual programme was being discussed seriously (the rest of the annual programme was one carrier and four cruisers). It was impossible unless the third battleship used existing 15in gun mountings, meaning the ship which became Vanguard.

These are the closest to your statemant if I understand correctly any other mention of post 1936 construction of battleship with 15" turrets are for Vanguard. The 3x2 15" variant was a study of a KGV whose turrets got replaced by them but that was from 1937-38:

A 6 April 1937 report outlined the way in which the King George V design could be modified to accept the four twin 15in turrets.37 This seems to have been the earliest approach to what became Vanguard. A second study examined simply replacing the three 14in turrets with twin 15in from the two ‘large light cruisers’. No particular problems were expected, but the ship would displace about 1000 tons less. It might be necessary to place magazines above shell rooms, as in the original ‘large light cruisers’. This study was dated 28 September 1938. The idea of using the surplus 15in mountings apparently resurfaced early in 1939; DNC gave his initial estimates in a report to CNS dated 13 February.38 He thought a ship armed with four twin 15in turrets would displace 37,000 tons and cost about £7 million, including only the cost of modernising existing guns and mountings.