Shipbucket

It turned out not to be such a huge problem after all. I reduced the AD to 3 inches, extended the main belt and main AD by 45 feet (by rejigging the hull section percentages) while keeping the upper belt the same...and magically, the new numbers added up to the same overall result. Which makes a pleasant change...
I'd say 20,000t is the maximum displacement for a "small" dreadnought, but really my goal was to design the smallest (and cheapest) ship able to act like a battleship; i.e. not a cruiser killer or a glorified CDS, but something that can face a contemporary battleship without being hopelessly outmatched. With this in mind, my main criteria were:

• 21 kt speed
• Battleship-scale protection, i.e. 12 inch belt etc.
• 6 x 13.5 inch guns

My first attempt, back in 2011 (not 2007...) was 450 feet long, but this really was too cramped so the design has already grown by 50 feet. My main concern with increasing the length any further is that it starts looking like a rather large ship for its armament, but adding an extra turret means hiking the displacement and cost into full-scale battleship territory...which defeats the point of the exercise.

However, I am looking into a modest increase to 525 feet, which would ease the pressure on topside space without pushing the constraints too far.
Given that Britain designed or built battleships for a number of smaller powers, I haven't really worried too much about defining who it was for. I see this ship being ordered by a lower second-tier power who has caught the "battleship bug" but has limited available funds; the intention therefore is to purchase a vessel with sufficient combat power to deter anything but the very latest super dreadnoughts. In essence, it's all about deterence: the nation is challenging a would-be adversary to commit an expensive first-rate ship to deal with a vessel costing 60-75% of the price. For a country not banking on going to war with a stronger adversary, that can be construed as a rational investment.

I have been thinking about a long-term AU project (the flag was designed for a fictional country named Samudra, which yes, was either a British colony or under British protection) but have been struggling to come up with one that has sufficient resources to maintain an extensive shipbuilding programme! Ultimately, there's no point creating a nation that is too poor to afford the sort of ships you enjoy drawing.

IMO anything under 25,000t would work for such a brief seeing as most fully fledged battleships of the period were around 25-27,000t (British Practice that is).

The main issue with only having six rifles is that you lack the ability to accurately spot for the time period as the RN made clear when ordering Renown and Repulse.

Thinking about what you're likely to encounter you might be able to get away with 12" guns too though that might be too much of a downgrade even for export.

525*82*27 would seem to fit the bill size wise...

_________________
AU Projects: | Banbha et al. | New England: The Divided States
Blood and Fire

I'm seeing it as a coast defense ship/convoy escort. For this it seems more than adequate.

Precisely why I didn't want to go with any less! As you say, six is already pushing it. Twelve inch guns, on the other hand, would be retrograde step given that most countries are exploring larger calibres.

My amended design (details below) is 525*88*25.5:



B1 Class, Yasutomi Small Dreadnought laid down 1911

Displacement:
18,272 t light; 19,448 t standard; 20,196 t normal; 20,794 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(525.00 ft / 525.00 ft) x 88.00 ft x (25.50 / 26.12 ft)
(160.02 m / 160.02 m) x 26.82 m x (7.77 / 7.96 m)

Armament:
6 - 13.50" / 343 mm 45.0 cal guns - 1,400.00lbs / 635.03kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1911 Model
3 x 2-gun mounts on centreline ends, majority aft
1 raised mount aft - superfiring
8 - 6.00" / 152 mm 45.0 cal guns - 108.00lbs / 48.99kg shells, 150 per gun
Breech loading guns in casemate mounts, 1911 Model
8 x Single mounts on sides, evenly spread
8 hull mounts in casemates- Limited use in heavy seas
Weight of broadside 9,264 lbs / 4,202 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 357.00 ft / 108.81 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 167.98 ft / 51.20 m 12.00 ft / 3.66 m
Upper: 8.00" / 203 mm 312.00 ft / 95.10 m 9.00 ft / 2.74 m
Main Belt covers 105 % of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 357.00 ft / 108.81 m 24.50 ft / 7.47 m
Beam between torpedo bulkheads 70.00 ft / 21.34 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 12.0" / 305 mm 8.00" / 203 mm 10.0" / 254 mm
2nd: 8.00" / 203 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 3.00" / 76 mm
Forecastle: 1.00" / 25 mm Quarter deck: 1.00" / 25 mm

- Conning towers: Forward 12.00" / 305 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 29,000 shp / 21,634 Kw = 21.07 kts
Range 5,487nm at 10.00 kts
Bunker at max displacement = 1,346 tons

Complement:
846 - 1,101

Cost:
£1.540 million / $6.159 million

Distribution of weights at normal displacement:
Armament: 1,697 tons, 8.4 %
- Guns: 1,697 tons, 8.4 %
Armour: 7,961 tons, 39.4 %
- Belts: 3,552 tons, 17.6 %
- Torpedo bulkhead: 971 tons, 4.8 %
- Armament: 1,560 tons, 7.7 %
- Armour Deck: 1,686 tons, 8.4 %
- Conning Tower: 192 tons, 0.9 %
Machinery: 1,177 tons, 5.8 %
Hull, fittings & equipment: 7,437 tons, 36.8 %
Fuel, ammunition & stores: 1,924 tons, 9.5 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
40,999 lbs / 18,597 Kg = 33.3 x 13.5 " / 343 mm shells or 8.4 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 5.7 ft / 1.7 m
Roll period: 15.5 seconds
Steadiness - As gun platform (Average = 50 %): 85 %
- Recoil effect (Restricted arc if above 1.00): 0.80
Seaboat quality (Average = 1.00): 1.71

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.600 / 0.603
Length to Beam Ratio: 5.97 : 1
'Natural speed' for length: 22.91 kts
Power going to wave formation at top speed: 47 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): -8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 25.50 ft / 7.77 m, 24.00 ft / 7.32 m
- Forward deck: 46.00 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Aft deck: 22.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 12.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 21.40 ft / 6.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 68.3 %
- Above water (accommodation/working, high = better): 162.9 %
Waterplane Area: 33,790 Square feet or 3,139 Square metres
Displacement factor (Displacement / loading): 117 %
Structure weight / hull surface area: 173 lbs/sq ft or 846 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 2.24
- Overall: 1.04
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

While the design works, I do feel the drawing lacks the flavour of the original concept. It just feels too large and rather undergunned.
It could certainly handle those roles. With the benefit of hindsight, it's worth pointing out that a ship like this would have been significant cheaper than a Queen Elizabeth or R Class and yet, suitably modernised, would still have been sufficient to dissuade a Deutschland (or even a Scharnhorst) from engaging a convoy.
If my fictional country could afford a ship of up to 25,000t, then I would propose this:



Tambora, Samudra Fast Dreadnought laid down 1912

Displacement:
23,174 t light; 24,601 t standard; 25,444 t normal; 26,118 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(582.50 ft / 582.50 ft) x 91.00 ft x (28.00 / 28.61 ft)
(177.55 m / 177.55 m) x 27.74 m x (8.53 / 8.72 m)

Armament:
8 - 13.50" / 343 mm 45.0 cal guns - 1,240.67lbs / 562.76kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1912 Model
4 x 2-gun mounts on centreline ends, evenly spread
2 raised mounts - superfiring
10 - 6.00" / 152 mm 45.0 cal guns - 108.93lbs / 49.41kg shells, 150 per gun
Breech loading guns in casemate mounts, 1912 Model
10 x Single mounts on sides, evenly spread
10 hull mounts in casemates- Limited use in heavy seas
Weight of broadside 11,015 lbs / 4,996 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 402.50 ft / 122.68 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 179.98 ft / 54.86 m 12.00 ft / 3.66 m
Upper: 8.00" / 203 mm 357.50 ft / 108.97 m 9.00 ft / 2.74 m
Main Belt covers 106 % of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 402.50 ft / 122.68 m 26.50 ft / 8.08 m
Beam between torpedo bulkheads 70.00 ft / 21.34 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 12.0" / 305 mm 8.00" / 203 mm 10.0" / 254 mm
2nd: 8.00" / 203 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 3.00" / 76 mm
Forecastle: 1.00" / 25 mm Quarter deck: 1.00" / 25 mm

- Conning towers: Forward 12.00" / 305 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 4 shafts, 62,336 shp / 46,502 Kw = 25.00 kts
Range 5,500nm at 10.00 kts
Bunker at max displacement = 1,517 tons

Complement:
1,006 - 1,309

Cost:
£2.136 million / $8.545 million

Distribution of weights at normal displacement:
Armament: 2,252 tons, 8.9 %
- Guns: 2,252 tons, 8.9 %
Armour: 9,534 tons, 37.5 %
- Belts: 3,958 tons, 15.6 %
- Torpedo bulkhead: 1,184 tons, 4.7 %
- Armament: 2,222 tons, 8.7 %
- Armour Deck: 1,946 tons, 7.6 %
- Conning Tower: 224 tons, 0.9 %
Machinery: 2,485 tons, 9.8 %
Hull, fittings & equipment: 8,903 tons, 35.0 %
Fuel, ammunition & stores: 2,270 tons, 8.9 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
38,518 lbs / 17,471 Kg = 31.3 x 13.5 " / 343 mm shells or 6.8 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 5.4 ft / 1.6 m
Roll period: 16.5 seconds
Steadiness - As gun platform (Average = 50 %): 61 %
- Recoil effect (Restricted arc if above 1.00): 0.75
Seaboat quality (Average = 1.00): 1.23

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.600 / 0.603
Length to Beam Ratio: 6.40 : 1
'Natural speed' for length: 24.14 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): -8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 19.31 %, 27.00 ft / 8.23 m, 24.00 ft / 7.32 m
- Forward deck: 50.64 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Aft deck: 18.46 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 11.59 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 21.83 ft / 6.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 88.8 %
- Above water (accommodation/working, high = better): 160.5 %
Waterplane Area: 38,769 Square feet or 3,602 Square metres
Displacement factor (Displacement / loading): 107 %
Structure weight / hull surface area: 181 lbs/sq ft or 883 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.82
- Overall: 1.03
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

There's something to look at from the design process behind Royal Sovereign.

Table 6: Legend of particulars of Design T1

Load displacement: 25,500 tons
Deep displacement: 28750 tons
Length (pp): 580ft
Beam: 88ft
Draught at lwl: 28ft 6 inches
Draught at dwl: 32ft 6 inches
tpi: 91
SHP: 31,000
Speed at load draught: 21.5 knots
Coal at load draught: 900 tons
Coal capacity: 3,000 tons
Oil fuel capacity: 1,500tons

Armament:
Eight 15in 42-cal BL (80rds per gun)
Sixteen 6in 45-cal BL (150rds per gun)
Four 3in HA (200rds per gun)
Four 21in submerged torpedo tubes (20 torpedoes)

Armour:
Belt (Amidships): 13 inch
Belt (Forward and Aft): 6 inch and 4 inch
Upper belt: 6 inch
Bulkheads (forward and aft): 6 inch and 4 inch
Barbettes: 10 to 4 inch
Gun-houses: 11 inch
Conning-tower: 11 inch
Conning-tower tube: 6 and 4 inch
Torpedo-director tower: 6 inch
Torpedo-director tower tube: 4 inch
Vertical protective plating:
Funnel-uptakes: 1.5 inch and 1 inch
Torpedo bulkheads: 1.5 inch and 1 inch
Horizontal protective plating:
Forecastle-deck: 1 inch (over 6in battery)
Upper-deck: 1.25 inch to 1.5 inch (from A to Y barbettes)
Main-deck (flat): 1 inch, 1.5 inch and 2 inch
Main-deck (slope): 2 inch
Lower-deck (forward): 2.5 inch and 1 inch
Lower-deck (aft): 2.5 inch and 4 inch to 3 inch

Weights:
General equipment: 750 tons
Armament: 4,550 tons
Machinery: 2,500 tons
Coal: 900 tons
Armour and protective plating: 8,100 tons
Hull: 8,600 tons
Board margin: 100 tons
Total: 25,500 tons

_________________
AU Projects: | Banbha et al. | New England: The Divided States
Blood and Fire

Those dimensions are scarily similar...

I am a little concerned that the weight the T1 legend gives for 31,000 SHP worth of machinery is pretty much the same as SS' estimate for 62,000 SHP!!! Having said that, T1 has double the weight of armament...

Well, the T1 legend are official admiralty estimates vs SS It's worth noting as well that the projected cost per ship for five vessels was £2,150,000.

_________________
AU Projects: | Banbha et al. | New England: The Divided States
Blood and Fire

Enough said! Do you have the weights for the QE's powerplant, as built? Only extrapolating from those figures, it's reasonable to assume that the weight and space saved in armament could be used for machinery and more extensive (if slightly thinner) armour. The ship might not reach 25kts, but it should be possible to reach a speed above 21.5.

QE is stated as 3,950 tons machinery and engineer's stores for 75,000SHP.

_________________
AU Projects: | Banbha et al. | New England: The Divided States
Blood and Fire

Thanks, Blackbuck...that's a big help.

It would appear that the Tambora is, essentially, a beamier (by 3 ft) T1, with a smaller-calibre armament but more powerful engines...with the weight saved by the former offsetting the latter.