I'm not sure what it says about Springsharp, but I made the Super-Fast Battlecruiser "work"

It isn't pretty, but by increasing the beam and displacement, I was able to design a 40-knot ship to carry 4-17in/45 and 16-4in guns. It "sort of works", if you don't mind unseaworthiness. I keep seeing correctable problems, which I have iterated over (mistakes in filling out the specs).

GB/CB/SuperFast, Great Britain Battlecruiser laid down 1921

Displacement:
	37,862 t light; 39,107 t standard; 40,431 t normal; 41,490 t full load

Dimensions: Length overall / water x beam x draught
	800.58 ft / 800.00 ft x 90.00 ft x 31.00 ft (normal load)
	244.02 m / 243.84 m x 27.43 m  x 9.45 m

Armament:
     4 - 17.00" / 432 mm guns in single mounts, 2,456.50lbs / 1,114.25kg shells, 1921 Model
	  Breech loading guns in turrets (on barbettes)
	  on centreline ends, evenly spread, all raised mounts - superfiring
     16 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1921 Model
	  Quick firing guns in deck mounts
	  on side ends, evenly spread, all raised mounts - superfiring
	Weight of broadside 10,338 lbs / 4,689 kg
	Shells per gun, main battery: 75

Armour:
  - Belts:		Width (max)	Length (avg)		Height (avg)
	Main:	4.00" / 102 mm	425.00 ft / 129.54 m	16.00 ft / 4.88 m
	Ends:	Unarmoured
	  Main Belt covers 82 % of normal length
	  Main belt does not fully cover magazines and engineering spaces

  - Torpedo Bulkhead:
		1.00" / 25 mm	425.00 ft / 129.54 m	27.00 ft / 8.23 m

  - Gun armour:	Face (max)	Other gunhouse (avg)	Barbette/hoist (max)
	Main:	8.00" / 203 mm	5.00" / 127 mm		8.00" / 203 mm
	2nd:	2.00" / 51 mm	      -			      -

  - Armour deck: 1.50" / 38 mm

Machinery:
	Oil fired boilers, steam turbines,
	Geared drive, 8 shafts, 480,197 shp / 358,227 Kw = 40.00 kts
	Range 3,600nm at 15.00 kts
	Bunker at max displacement = 2,383 tons

Complement:
	1,425 - 1,853

Cost:
	£12.029 million / $48.116 million

Distribution of weights at normal displacement:
	Armament: 1,292 tons, 3.2 %
	Armour: 4,902 tons, 12.1 %
	   - Belts: 1,193 tons, 2.9 %
	   - Torpedo bulkhead: 425 tons, 1.1 %
	   - Armament: 1,776 tons, 4.4 %
	   - Armour Deck: 1,508 tons, 3.7 %
	   - Conning Tower: 0 tons, 0.0 %
	Machinery: 16,536 tons, 40.9 %
	Hull, fittings & equipment: 15,132 tons, 37.4 %
	Fuel, ammunition & stores: 2,569 tons, 6.4 %
	Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
	Survivability (Non-critical penetrating hits needed to sink ship):
	  18,394 lbs / 8,343 Kg = 7.5 x 17.0 " / 432 mm shells or 1.9 torpedoes
	Stability (Unstable if below 1.00): 1.14
	Metacentric height 5.5 ft / 1.7 m
	Roll period: 16.2 seconds
	Steadiness	- As gun platform (Average = 50 %): 33 %
			- Recoil effect (Restricted arc if above 1.00): 0.72
	Seaboat quality  (Average = 1.00): 0.39

Hull form characteristics:
	Hull has rise forward of midbreak
	Block coefficient: 0.634
	Length to Beam Ratio: 8.89 : 1
	'Natural speed' for length: 28.28 kts
	Power going to wave formation at top speed: 66 %
	Trim (Max stability = 0, Max steadiness = 100): 57
	Bow angle (Positive = bow angles forward): 1.00 degrees
	Stern overhang: 0.00 ft / 0.00 m
	Freeboard (% = measuring location as a percentage of overall length):
	   - Stem:		33.00 ft / 10.06 m
	   - Forecastle (20 %):	32.00 ft / 9.75 m
	   - Mid (45 %):		32.00 ft / 9.75 m (25.00 ft / 7.62 m aft of break)
	   - Quarterdeck (15 %):	25.00 ft / 7.62 m
	   - Stern:		0.00 ft / 0.00 m
	   - Average freeboard:	26.36 ft / 8.03 m

Ship space, strength and comments:
	Space	- Hull below water (magazines/engines, low = better): 200.0 %
		- Above water (accommodation/working, high = better): 201.2 %
	Waterplane Area: 54,350 Square feet or 5,049 Square metres
	Displacement factor (Displacement / loading): 84 %
	Structure weight / hull surface area: 184 lbs/sq ft or 898 Kg/sq metre
	Hull strength (Relative):
		- Cross-sectional: 0.99
		- Longitudinal: 1.11
		- Overall: 1.00
	Hull space for machinery, storage, compartmentation is extremely poor
	Room for accommodation and workspaces is excellent
	Caution: Lacks seaworthiness - very limited seakeeping ability