We haven't seen it yet, but the export battleship trade might not be quite so dead in the longer-term future of the story.
Dread Nought but the Fury of the Seas
- Thread starter sts-200
- Start date
The Impossible Ship
The Impossible Ship
In the autumn of 1924, the Admiralty became aware that the Americans were working on a new class of fast capital ship. Unofficial sources said that the US ships would make use of the ‘light battleship’ definition, and that designs with eight or nine guns of 14” calibre were under study.
By the New Year, more than a half-dozen outline British designs had been prepared, and the matter was moving in the direction of which should taken forward for construction.
-o-
Charles Coles, the Deputy Director of Naval Construction Sat at the head of the table. The meeting was about the Royal Navy's next class of capital ship, a light battlecruiser. It was up to him and the others to navigate their way through the minefield of possible options and produce a recommendation at the end.
A few days earlier, the Engineer-in-Chief had confirmed that in a battleship-type environment, it would be possible to deliver 120,000shp from machinery that weighed no more than 2,800 tons. Coles knew there were early indications that figure could be improved on by using superheated steam, but this was not the moment to complicate matters.
‘I favour B3’, said Sir Malcolm Strang as he flicked through a series of blueprints.
‘I think many of us do’, observed Coles, ‘but it would be heavy weather taking it through the Admiralty.’
There were a few faint smiles; nautical phrases were so embedded in the language that it was impossible to avoid them altogether.
The sketch in front of Strang showed design ‘1924-B/3’; a handsome three-funnelled ship which would carry eight 15” guns in twin turrets. It had highly forced, fast running machinery based on that of the E-class cruisers, although it would be reinforced to cope with the shock of firing the heavy guns. In other ways it was relatively conventional; the hull form was modelled after Hood, with an external belt inclined with the hull, a built-in bulge and a break in foc’sle aft of Q-turret.
Coles knew that it had numerous problems, but that they could all be summed up in one way; the design was too conventional. Nevertheless, that was the reason it was popular, as it used safe, well-understood ideas that could be built without great expenditure on new, unproven concepts.
1924-B/3
Superficially a Hood on 23,000 tons, but with an 8" belt she stood no chance in 1925.
‘You know the problem’, continued Coles, ‘protection is only adequate against 14” fire over magazines, with 12” elsewhere. The Admirals will say she’s another Queen Mary waiting to happen – she’s too lightly protected.’
‘That they will’, said Captain Arbuthnot, the Service’s official representative at the meeting. Following post-war trials, it was now widely accepted that the explosion of the battlecruiser Queen Mary at Stavanger had been triggered by a German shell penetrating her belt and exploding in or near the magazine.
‘I’m sure we can squeeze a little more armour in, particularly with what we’ve learned from C2’, suggested Strang, whom Coles had noted particularly favoured B3, perhaps because it was powerful and yet the most traditionally battlecruiser-like of the various designs before them. Strang had served on cruisers and then on Renown during the war, and although he had since left the Service to find a new home in the DNC’s office, he was a plodding old-fashioned sailor at heart. It was a pity he was here at all.
Coles glanced up at the portrait at the other end of the room, at the firm, but nonetheless slightly cheeky face of Admiral Fisher. The old Admiral wouldn’t have put up with Strang for more than about a minute, but Coles had neither Fisher’s level of influence nor his mercurial personality. Diplomacy was the order of the day. Strang was a well-connected Baronet, who hunted with the First Sea Lord. He might be rather stupid, but he was a potentially useful ally.
Today was a day for persuasion, and he turned towards Strang.
‘How would you deal with the armour problem?’, he asked.
‘I don’t see it as a problem,’ replied Strang, ‘we can thicken the belt amidships to provide protection against 14” fire.’
‘Yes…’, mused Coles, while thinking no, ‘but what happens when they have to face ships with 16” guns?’
‘They don’t’, replied Strang confidently, ‘they’re to counter cruisers and other light battleships.’
‘Couldn’t we reduce length by using triple turrets?’, asked Reginald Tyrrell, the newest member of the group, a youngish man who had only joined two weeks earlier. Coles could see he had a bright future, but he was still a bit wet behind the ears at present.
There were murmurs of agreement and several people moved to speak, but Coles got in first.
‘No Mr Tyrrell’, he said firmly, ‘We looked at that with B4, and it was worse; the hull was over stressed by the weight of the turrets, and could be armoured against nothing more than 12” fire, if I recall… it would also be a brand-new turret, with all the Treasury problems that would entail.’
Cost was a significant factor, but Coles also knew that hull stresses were the reason for the A-B-Q-Y arrangement of B3, rather than a more modern A-B-X-Y. It was just too old-fashioned a design, he thought once again.
As this thought passed, there were a few nods from around the room, and Coles resumed.
‘I remain unconvinced by B3. Now, Mr Tyrrell has just mentioned B4, and although that design did not meet our requirements, in my view we should develop it further, using more modern ideas about the layout of armour.’
The Navy’s newest ‘Nelson’ class battleships used armour that was mounted inside the hull, rather than outside as in Hood or the B-series. The scheme had its detractors, who argued that it would make damage more difficult to repair, and that the thin skin of the hull could be riddled by light fire. However, Coles and most of the DNC’s office knew that it was the one of few realistic ways to reduce weight while preserving protection. Internal armour could be sloped sharply inwards towards the bottom of the ship, so that descending shells would strike it at a steep angle, thereby increasing its resistive power.
Young Tyrrell looked encouraged, but it was Strang who spoke first.
‘Rather than start again, what about improving B3? If we took the lessons from C2 and applied them to B3, we could have it all.’
Coles had to resist the temptation to sigh; it was clearly going to be a long day.
‘C2’ was another unsatisfactory attempt to shoehorn nine 15” guns into a workable design, by relying on thick sloped edges to the main deck instead of a traditional armour belt. It saved weight, but it wasn’t very good at protecting the waterline, and would tend to throw shell fragments up into the body of the ship. However, the C-series had an advantage that Coles knew had promise; they used a deep flush-decked hull to reduce stresses and keep weight down.
He and nearly half of his design staff had just finished with the London-class cruisers, which used just such a hull, built using longitudinal framing, which saved a little more weight by cutting down the number of heavy transverse frames inside the hull.
The private yards were still complaining about this ‘new method’, even though it was actually more than 15 years old. Still, he thought, the Londons would have blazed the trail by the time these ships were built.
‘C2 has its merits’, he said, lying cheerfully, ‘but I know we can do better. All the designs in front of us today are adequate to deal with ten or twelve-thousand-ton cruisers, but none of them are good enough to risk in a fleet action.’
There were mumbles of surprise, and agreement from around the room.
‘As Sir Malcolm says, a combination of B3 and C2 would be a start, but I believe we need to incorporate an internal belt, and be far more ruthless about what is and what is not armoured. We are not building a battleship, but we are using battleship tonnage, so this new ship must be safe to engage anything it may encounter, even if it does not do so for long, or does so with the assistance of heavier forces.’
Handing out a plain manilla folder, he continued, ‘Gentlemen, I have here a proposal from Vickers regarding a new hoist layout for gun turrets, which they claim would save considerable weight and improve flash-protection. Bearing this in mind, and given the history of turrets being put out of action, even when they are not wrecked, I believe we must ask ourselves whether using thousands of tons of turret armour is an essential part of a light warship…’
In the autumn of 1924, the Admiralty became aware that the Americans were working on a new class of fast capital ship. Unofficial sources said that the US ships would make use of the ‘light battleship’ definition, and that designs with eight or nine guns of 14” calibre were under study.
By the New Year, more than a half-dozen outline British designs had been prepared, and the matter was moving in the direction of which should taken forward for construction.
-o-
Charles Coles, the Deputy Director of Naval Construction Sat at the head of the table. The meeting was about the Royal Navy's next class of capital ship, a light battlecruiser. It was up to him and the others to navigate their way through the minefield of possible options and produce a recommendation at the end.
A few days earlier, the Engineer-in-Chief had confirmed that in a battleship-type environment, it would be possible to deliver 120,000shp from machinery that weighed no more than 2,800 tons. Coles knew there were early indications that figure could be improved on by using superheated steam, but this was not the moment to complicate matters.
‘I favour B3’, said Sir Malcolm Strang as he flicked through a series of blueprints.
‘I think many of us do’, observed Coles, ‘but it would be heavy weather taking it through the Admiralty.’
There were a few faint smiles; nautical phrases were so embedded in the language that it was impossible to avoid them altogether.
The sketch in front of Strang showed design ‘1924-B/3’; a handsome three-funnelled ship which would carry eight 15” guns in twin turrets. It had highly forced, fast running machinery based on that of the E-class cruisers, although it would be reinforced to cope with the shock of firing the heavy guns. In other ways it was relatively conventional; the hull form was modelled after Hood, with an external belt inclined with the hull, a built-in bulge and a break in foc’sle aft of Q-turret.
Coles knew that it had numerous problems, but that they could all be summed up in one way; the design was too conventional. Nevertheless, that was the reason it was popular, as it used safe, well-understood ideas that could be built without great expenditure on new, unproven concepts.
1924-B/3
Superficially a Hood on 23,000 tons, but with an 8" belt she stood no chance in 1925.
‘You know the problem’, continued Coles, ‘protection is only adequate against 14” fire over magazines, with 12” elsewhere. The Admirals will say she’s another Queen Mary waiting to happen – she’s too lightly protected.’
‘That they will’, said Captain Arbuthnot, the Service’s official representative at the meeting. Following post-war trials, it was now widely accepted that the explosion of the battlecruiser Queen Mary at Stavanger had been triggered by a German shell penetrating her belt and exploding in or near the magazine.
‘I’m sure we can squeeze a little more armour in, particularly with what we’ve learned from C2’, suggested Strang, whom Coles had noted particularly favoured B3, perhaps because it was powerful and yet the most traditionally battlecruiser-like of the various designs before them. Strang had served on cruisers and then on Renown during the war, and although he had since left the Service to find a new home in the DNC’s office, he was a plodding old-fashioned sailor at heart. It was a pity he was here at all.
Coles glanced up at the portrait at the other end of the room, at the firm, but nonetheless slightly cheeky face of Admiral Fisher. The old Admiral wouldn’t have put up with Strang for more than about a minute, but Coles had neither Fisher’s level of influence nor his mercurial personality. Diplomacy was the order of the day. Strang was a well-connected Baronet, who hunted with the First Sea Lord. He might be rather stupid, but he was a potentially useful ally.
Today was a day for persuasion, and he turned towards Strang.
‘How would you deal with the armour problem?’, he asked.
‘I don’t see it as a problem,’ replied Strang, ‘we can thicken the belt amidships to provide protection against 14” fire.’
‘Yes…’, mused Coles, while thinking no, ‘but what happens when they have to face ships with 16” guns?’
‘They don’t’, replied Strang confidently, ‘they’re to counter cruisers and other light battleships.’
‘Couldn’t we reduce length by using triple turrets?’, asked Reginald Tyrrell, the newest member of the group, a youngish man who had only joined two weeks earlier. Coles could see he had a bright future, but he was still a bit wet behind the ears at present.
There were murmurs of agreement and several people moved to speak, but Coles got in first.
‘No Mr Tyrrell’, he said firmly, ‘We looked at that with B4, and it was worse; the hull was over stressed by the weight of the turrets, and could be armoured against nothing more than 12” fire, if I recall… it would also be a brand-new turret, with all the Treasury problems that would entail.’
Cost was a significant factor, but Coles also knew that hull stresses were the reason for the A-B-Q-Y arrangement of B3, rather than a more modern A-B-X-Y. It was just too old-fashioned a design, he thought once again.
As this thought passed, there were a few nods from around the room, and Coles resumed.
‘I remain unconvinced by B3. Now, Mr Tyrrell has just mentioned B4, and although that design did not meet our requirements, in my view we should develop it further, using more modern ideas about the layout of armour.’
The Navy’s newest ‘Nelson’ class battleships used armour that was mounted inside the hull, rather than outside as in Hood or the B-series. The scheme had its detractors, who argued that it would make damage more difficult to repair, and that the thin skin of the hull could be riddled by light fire. However, Coles and most of the DNC’s office knew that it was the one of few realistic ways to reduce weight while preserving protection. Internal armour could be sloped sharply inwards towards the bottom of the ship, so that descending shells would strike it at a steep angle, thereby increasing its resistive power.
Young Tyrrell looked encouraged, but it was Strang who spoke first.
‘Rather than start again, what about improving B3? If we took the lessons from C2 and applied them to B3, we could have it all.’
Coles had to resist the temptation to sigh; it was clearly going to be a long day.
‘C2’ was another unsatisfactory attempt to shoehorn nine 15” guns into a workable design, by relying on thick sloped edges to the main deck instead of a traditional armour belt. It saved weight, but it wasn’t very good at protecting the waterline, and would tend to throw shell fragments up into the body of the ship. However, the C-series had an advantage that Coles knew had promise; they used a deep flush-decked hull to reduce stresses and keep weight down.
He and nearly half of his design staff had just finished with the London-class cruisers, which used just such a hull, built using longitudinal framing, which saved a little more weight by cutting down the number of heavy transverse frames inside the hull.
The private yards were still complaining about this ‘new method’, even though it was actually more than 15 years old. Still, he thought, the Londons would have blazed the trail by the time these ships were built.
‘C2 has its merits’, he said, lying cheerfully, ‘but I know we can do better. All the designs in front of us today are adequate to deal with ten or twelve-thousand-ton cruisers, but none of them are good enough to risk in a fleet action.’
There were mumbles of surprise, and agreement from around the room.
‘As Sir Malcolm says, a combination of B3 and C2 would be a start, but I believe we need to incorporate an internal belt, and be far more ruthless about what is and what is not armoured. We are not building a battleship, but we are using battleship tonnage, so this new ship must be safe to engage anything it may encounter, even if it does not do so for long, or does so with the assistance of heavier forces.’
Handing out a plain manilla folder, he continued, ‘Gentlemen, I have here a proposal from Vickers regarding a new hoist layout for gun turrets, which they claim would save considerable weight and improve flash-protection. Bearing this in mind, and given the history of turrets being put out of action, even when they are not wrecked, I believe we must ask ourselves whether using thousands of tons of turret armour is an essential part of a light warship…’
A man named C.Coles with an off-the-wall idea about turrets. This worked SO well last time...
Hrmmmmmm....I'd still eliminate the Q turret and try go for three triples if possible. You can shorten the citadel, you eliminate a barbette and a bit of a weak point amidships with that big hole there. I'm curious to hear what they have in mind for the turrets. Darn good update, they're getting there but not quite there yet.
Seems to be a Battlecruiser type design so commerce protection/raiding and heavy scouting. Thing is because it needs to use Battleship tonnage then they also want it to be able to stand up to a true capital ship to some degree. I get the impression it either needs to be able to withstand enough to enable it to run away or help with tipping the numbers in a fleet engagement by engaging already engaged ships or finishing off damaged ones.
Seems a big ask but that's just my interpretation of the post.
Oooh-ooh. That's a good-looking ship, but trying to shoehorn an Admiral into 23,000 tons is really pushing it.
The Americans managed 4x2 14", 9" belt, 2.5" decks and 31kt on roughly 24,500 tons (after tweaking) - and the Columbias are very much not intended to fight opposing capital ships. I suspect to get anywhere near acceptable protection with 8x15", they're going to have to grit their teeth and accept a 3- or even 2-turret design - or get creative.
I thought it was interesting that the Americans we building a new class of 14" battlecruisers just as the British and Japanese were scrapping theirs - and here the RN is, discussing an updated Lion just a couple of years after discarding the old one. That will be the lure of the "light battleship" exemption, plus the squeeze on fleet sizes and the number of super-CAs popping up around the world - but I'm not sure it's the best idea.
In TTL's 1920s, there are effectively 4 roles for a big-gun capital ship:
The first is the basic line-of-battle ship, which fights in the line of battle, against the opposing line of battle, and doesn't need the speed to do more than keep her place in the line.
The second is the "fast wing of the battleline", which has the necessary speed margin to force engagements, chase down fleeing enemies and maneuver for tactical advantage during a battle, but is still expected to slug it out with battleships.
The third is the "heavy scout", which supports the cruiser screen and hence needs cruiser speed. It's there to kill cruisers, not to fight battleships. In a fleet battle it will be hanging round the edges, waiting for a chance to finish off damaged or isolated enemies.
The fourth is the "detached raider/hunter", which is sent out into disputed sea to hunt down enemy cruisers (or commerce). Speed is essential, armour is only necessary against heavy-cruiser fire and its response to sighting "real" battleships is to head for the nearest horizon.
The problem is, as the RN found out in WW1, if your ship packs battleship-calibre armament, it will be pressed into the second role in service, no matter how hard the designer insists that it was built for roles 3 & 4. You don't spend all that money bringing a 15" broadside to the fight and then not use it. Which is why the RN is now discussing armouring their "light battlecruiser" against 14" fire. Which can't be legitimately done within Treaty limits.
If all they want is something to kill CAs, then dropping the main armament to 12" or even 10" solves most of their weight problems and probably makes a more effective cruiser-killer. If they want it to face 14" (let alone 16") fire they should accept they're building a fast battleship and 30+ knot speed is to much to ask for. RIght now, they seem to be heading between stools - too weak to fight battleships, too slow to catch cruisers & too expensive to leave home. Which is probably why they're discussing ... radical ... approaches to the weight issue.
(BTW, the last post is missing a threadmark)
My answer would be a treaty limited O3 fast battleship with 15" guns (possibly 2 x triples or even 3 x pairs or even 2 quads?) rated for 28 knots and rely on the Counties for the commerce protection/raiding and heavy scouting.
I appreciate that a full sized fast BB uses more of the tonnage etc but with more ships available.....
Then again if they are replacing the older Slow 13.5" BBs with those then you still end up with a more useful ship!
I have found in one of this in my library, a curious, if not prophetic, thing for the thread, maybe some of you already knew about, but anyway. By the way, @sts-200 this is you're design of inspiration for the LBB?
An excerpt quoted from´Italian Battleships of WWII´
And Design 1928 Battlecruiser from Tzoli for more defined specifics:
"In 1928-29 a design study was made of a 23.000 ton battleship*, three of which could be build within the 70.000 tons allowed to Italy during the building holiday of the Washington Treaty. The proposed ships were to be armed with six 15-inch cannons protected by armor with a maximum thickness of 330mm** and have a speed of 28 to 29 knots. A second design study was for two units of 35.000 tons, the maximum allowed under the treaty. These ships were to be armed with six 16-inch (¡?¡?¡?¡)*** with maximum armor protection of 350mm*** and speed of 29 to 30 knots.
Construction of either of these designs did not proceed due to political and economical reasons. In 1930 the London Naval Conference was held. A number of proposals put forward failed, including one by Britain to reduce the standard displacement of new construction battleships below 35.000 tons, and the allowable calibre of guns below 16 inches. With the demise of this proposal the Italian 23.000 ton design study was abandoned. The 35.000 ton study was developed further.
It would be the French who laid down a new unit first among the Mediterranean powers, the Dunkerque, on Dec.24,1932. This was in response to the much publicized German pocket battleships. Despite its stated purpose it elicited an Italian response."
All in all, the text makes me understand that an Italian Renown was the prefer option inside the Regia but then developments and economics intervened, and actually I was surprise to learn that the Italians were agreed, or so the wording of the paragraph makes me think, with the British proposals, which have some sense cause that would work in the designs favour without looking weak out of necessity.
*: evidently too nimble for a battleship
**: at first sight, the wording of sentence make me thought that was for the turrets which would have justified somewhat the ´battleship´ status.
***: then I saw this and what implied for the prior, and start to laugh.
The picture comes from Here because I couldn't upload it from the book directly. And the example rescued from the Never-were thread in the same site.
Pretty and indeed a paper tiger, or using the scale, a Third or Fourth line LBC. If only there wasn't that fisheresque eagerness for guns bigger than the advisible...
I personnally think that the 13,5" is more than enough of a match (a forced upper limit actually) and if certain weights could be reduce and internal arrangement fixed, maybe an internal 10" belt is possible, but is merely speculative on my part and springsharp don´t have the internal belt option yet, that´s for the next update I think, so cannot verified with certainty. I agree with Merrick and Cryhavoc101, either reduce numbers or get creative or they´ll have to reduce calibre to a "unreasonable" (for the RN) level out of necessity.
and quite an accurate assertion, in my opinion, as is according to my scale system.
An excerpt quoted from´Italian Battleships of WWII´
And Design 1928 Battlecruiser from Tzoli for more defined specifics:
"In 1928-29 a design study was made of a 23.000 ton battleship*, three of which could be build within the 70.000 tons allowed to Italy during the building holiday of the Washington Treaty. The proposed ships were to be armed with six 15-inch cannons protected by armor with a maximum thickness of 330mm** and have a speed of 28 to 29 knots. A second design study was for two units of 35.000 tons, the maximum allowed under the treaty. These ships were to be armed with six 16-inch (¡?¡?¡?¡)*** with maximum armor protection of 350mm*** and speed of 29 to 30 knots.
Construction of either of these designs did not proceed due to political and economical reasons. In 1930 the London Naval Conference was held. A number of proposals put forward failed, including one by Britain to reduce the standard displacement of new construction battleships below 35.000 tons, and the allowable calibre of guns below 16 inches. With the demise of this proposal the Italian 23.000 ton design study was abandoned. The 35.000 ton study was developed further.
It would be the French who laid down a new unit first among the Mediterranean powers, the Dunkerque, on Dec.24,1932. This was in response to the much publicized German pocket battleships. Despite its stated purpose it elicited an Italian response."
All in all, the text makes me understand that an Italian Renown was the prefer option inside the Regia but then developments and economics intervened, and actually I was surprise to learn that the Italians were agreed, or so the wording of the paragraph makes me think, with the British proposals, which have some sense cause that would work in the designs favour without looking weak out of necessity.
*: evidently too nimble for a battleship
**: at first sight, the wording of sentence make me thought that was for the turrets which would have justified somewhat the ´battleship´ status.
***: then I saw this and what implied for the prior, and start to laugh.
The picture comes from Here because I couldn't upload it from the book directly. And the example rescued from the Never-were thread in the same site.
1924-B/3
Superficially a Hood on 23,000 tons, but with an 8" belt she stood no chance in 1925.
Pretty and indeed a paper tiger, or using the scale, a Third or Fourth line LBC. If only there wasn't that fisheresque eagerness for guns bigger than the advisible...
I personnally think that the 13,5" is more than enough of a match (a forced upper limit actually) and if certain weights could be reduce and internal arrangement fixed, maybe an internal 10" belt is possible, but is merely speculative on my part and springsharp don´t have the internal belt option yet, that´s for the next update I think, so cannot verified with certainty. I agree with Merrick and Cryhavoc101, either reduce numbers or get creative or they´ll have to reduce calibre to a "unreasonable" (for the RN) level out of necessity.
and quite an accurate assertion, in my opinion, as is according to my scale system.
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Love this, another example:
TTL Regia Marina currently:
type | FIRST LINE | SECOND LINE | THIRD LINE | FOURTH LINE |
| fast battleship | Caracciolo | |||
| battleship | Cavour class, Duilio class, Dante | |||
| battlecruiser | Vesuvius class | |||
| LBB/LBC | Vesuvius class | Vesuvius class |
Compare to, say, USN:
| type | FIRST LINE | SECOND LINE | THIRD LINE | FOURTH LINE |
| fast battleship | ||||
| battleship | All the Standards and prior 14 inchers, plus the SoDak´s | |||
| battlecruiser | Lexington class | Columbia class, Lexington class | ||
| LBB/LBC | Columbia class |
Which means that the Lex´s could take on Caracciolo or even the Columbia´s if needed, while the Standards can take them all.
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If the Brits use the 3,000 ton exception for aircraft, they could write off the AA, bulges, and maybe build the ships with lighter deck armor then swap it out for the original plan, which they would legally be able to do if they want to push the limits. That might get them a decent strip of the ship protected agains 14" shells.
The problem with such an idea is getting the treasury to pay for such an extensive and thus expensive refit on a brand new ship especially when the older capital ships actually need refits to keep going
Deleted member 94680
Doesn’t have to be a refit as such. Just have the work carried out “towards the end” of the build, whilst the ship is still in the dockyards.
From memory OTL trials at this time involved a mine layer and sucked the mines back towards the ship.
HMS Adventure, they rebuilt her because yeah the stern didn't work. Several of the OTL BB/BC designs in the 20's had transom sterns as well.
Regarding the calibre of this new ship.
I can understand the rational for wanting the heaviest guns possible but it really is a big push to get them into a ship of this required displacement.
If the calibre drops you can get more wiggle room for a better balanced ship. At some point someone will point out that a 12" gun, whilst not able to match a 15" or 16" in raw power is still able to severely damage most capital ships. Yes it wont win a fight against any Battle line ship but it can mission kill them by damaging vital equipment and has the advantage of placing limits on the Germans.
At some point someone will have to lay it out that you cant have a ship that does it all on the displacement available, their will have to be sacrifices. Designing a ship to a purpose, even if it is a secondary purpose is more likely to produce a useful and adaptable design than trying to design an adaptable ship to strict limits.
I can understand the rational for wanting the heaviest guns possible but it really is a big push to get them into a ship of this required displacement.
If the calibre drops you can get more wiggle room for a better balanced ship. At some point someone will point out that a 12" gun, whilst not able to match a 15" or 16" in raw power is still able to severely damage most capital ships. Yes it wont win a fight against any Battle line ship but it can mission kill them by damaging vital equipment and has the advantage of placing limits on the Germans.
At some point someone will have to lay it out that you cant have a ship that does it all on the displacement available, their will have to be sacrifices. Designing a ship to a purpose, even if it is a secondary purpose is more likely to produce a useful and adaptable design than trying to design an adaptable ship to strict limits.
I just had a thought, correct me if I'm wrong. IIRC, the Germans can't put any new guns on their capital ships. The smallest British caliber at the moment is 13.5" or 34.3cm. German calibers at the moment are 12"/30.5cm and 13.8"/35cm, which is larger than the British 34.3cm gun, making it illegal. As long as the Germans aren't allowed to mount a new gun on their ships for the duration of the treaty, that means they are effectively limited to 12".
My understanding is the Germans are limited to no new capital ships until 1928 then they can build brand new as long as they don't exceed the British smallest calibre. I could be wrong though.