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Saturday, October 15, 2005

A British very large battlecruiser

I had started to treat this as an American ship, but the secondary armament clearly marks it as British. The armament is 9-21in and 20-5.25in DP guns. I added a light AA armament, and reduced the draft. In 1999, I was willing to have these very deep drafts, but not now. The specification from 1999 simply said:
Displacement=120,000 tons      Cp=0.57   9-21in/45
Length=1180ft                  Cm=0.92  20-5.25in DP
Beam=147ft
Draft=46ft-2in
Speed=35 knots
V/sqrt(L)=35/34.351128=1.0188894
This is the Springsharp report for the modified design (less draft):
GB/CB/1942 Large, Great Britain Battlecruiser laid down 1942

Displacement:
 108,407 t light; 112,992 t standard; 120,000 t normal; 125,606 t full load

Dimensions: Length overall / water x beam x draught
 1,184.59 ft / 1,180.00 ft x 147.00 ft x 38.00 ft (normal load)
 361.06 m / 359.66 m x 44.81 m  x 11.58 m

Armament:
      9 - 21.00" / 533 mm guns (3x3 guns), 4,630.50lbs / 2,100.36kg shells, 1942 Model
   Breech loading guns in turrets (on barbettes)
   on side ends, majority forward, 1 raised mount - superfiring
      20 - 5.25" / 133 mm guns (12 mounts), 72.35lbs / 32.82kg shells, 1942 Model
   Dual purpose guns in turrets (on barbettes)
   on side, all amidships, 8 raised mounts - superfiring
      84 - 1.57" / 40.0 mm guns (21x4 guns), 1.95lbs / 0.89kg shells, 1942 Model
   Anti-aircraft guns in deck mounts 
   on side ends, majority aft
      56 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1942 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 43,299 lbs / 19,640 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 16.0" / 406 mm 780.00 ft / 237.74 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead:
  4.00" / 102 mm 780.00 ft / 237.74 m 37.00 ft / 11.28 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 18.0" / 457 mm 11.0" / 279 mm  16.0" / 406 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm
 3rd: 1.00" / 25 mm       -         -
 4th: 1.00" / 25 mm       -         -

   - Armour deck: 7.00" / 178 mm, Conning tower: 18.00" / 457 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 6 shafts, 473,837 shp / 353,482 Kw = 35.00 kts
 Range 8,500nm at 18.00 kts
 Bunker at max displacement = 12,614 tons
   Caution: Too much power for number of propellor shafts

Complement:
 3,222 - 4,190

Cost:
 £64.105 million / $256.420 million

Distribution of weights at normal displacement:
 Armament: 5,412 tons, 4.5 %
 Armour: 38,720 tons, 32.3 %
    - Belts: 9,047 tons, 7.5 %
    - Torpedo bulkhead: 4,271 tons, 3.6 %
    - Armament: 7,451 tons, 6.2 %
    - Armour Deck: 17,006 tons, 14.2 %
    - Conning Tower: 943 tons, 0.8 %
 Machinery: 12,378 tons, 10.3 %
 Hull, fittings & equipment: 51,897 tons, 43.2 %
 Fuel, ammunition & stores: 11,593 tons, 9.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   182,469 lbs / 82,767 Kg = 39.4 x 21.0 " / 533 mm shells or 33.8 torpedoes
 Stability (Unstable if below 1.00): 1.25
 Metacentric height 13.3 ft / 4.1 m
 Roll period: 16.9 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.42
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.637
 Length to Beam Ratio: 8.03 : 1
 'Natural speed' for length: 34.35 kts
 Power going to wave formation at top speed: 50 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  37.00 ft / 11.28 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (50 %):  27.00 ft / 8.23 m
    - Quarterdeck (15 %): 27.00 ft / 8.23 m
    - Stern:  27.00 ft / 8.23 m
    - Average freeboard: 27.80 ft / 8.47 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 78.4 %
  - Above water (accommodation/working, high = better): 209.6 %
 Waterplane Area: 131,324 Square feet or 12,200 Square metres
 Displacement factor (Displacement / loading): 112 %
 Structure weight / hull surface area: 303 lbs/sq ft or 1,479 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 1.17
  - Longitudinal: 0.95
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
I experimented with the original draft, and the design changes a good bit. Except for the draft being unworkable (minor detail), the ship is much better:
GB/CB/1942 Large, Great Britain Battlecruiser laid down 1942

Displacement:
 103,862 t light; 108,447 t standard; 120,000 t normal; 129,242 t full load

Dimensions: Length overall / water x beam x draught
 1,184.59 ft / 1,180.00 ft x 147.00 ft x 46.17 ft (normal load)
 361.06 m / 359.66 m x 44.81 m  x 14.07 m

Armament:
      9 - 21.00" / 533 mm guns (3x3 guns), 4,630.50lbs / 2,100.36kg shells, 1942 Model
   Breech loading guns in turrets (on barbettes)
   on side ends, majority forward, 1 raised mount - superfiring
      20 - 5.25" / 133 mm guns (12 mounts), 72.35lbs / 32.82kg shells, 1942 Model
   Dual purpose guns in turrets (on barbettes)
   on side, all amidships, 8 raised mounts - superfiring
      84 - 1.57" / 40.0 mm guns (21x4 guns), 1.95lbs / 0.89kg shells, 1942 Model
   Anti-aircraft guns in deck mounts 
   on side ends, majority aft
      56 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1942 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 43,299 lbs / 19,640 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 17.0" / 432 mm 780.00 ft / 237.74 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead:
  4.00" / 102 mm 780.00 ft / 237.74 m 37.00 ft / 11.28 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 17.0" / 432 mm 11.0" / 279 mm  16.0" / 406 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm
 3rd: 1.00" / 25 mm       -         -
 4th: 1.00" / 25 mm       -         -

   - Armour deck: 9.00" / 229 mm, Conning tower: 18.00" / 457 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 6 shafts, 447,890 shp / 334,126 Kw = 35.00 kts
 Range 15,000nm at 18.00 kts
 Bunker at max displacement = 20,795 tons

Complement:
 3,222 - 4,190

Cost:
 £62.489 million / $249.955 million

Distribution of weights at normal displacement:
 Armament: 5,412 tons, 4.5 %
 Armour: 41,860 tons, 34.9 %
    - Belts: 9,556 tons, 8.0 %
    - Torpedo bulkhead: 4,271 tons, 3.6 %
    - Armament: 7,408 tons, 6.2 %
    - Armour Deck: 19,681 tons, 16.4 %
    - Conning Tower: 943 tons, 0.8 %
 Machinery: 11,700 tons, 9.8 %
 Hull, fittings & equipment: 44,890 tons, 37.4 %
 Fuel, ammunition & stores: 16,138 tons, 13.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   174,208 lbs / 79,019 Kg = 37.6 x 21.0 " / 533 mm shells or 31.9 torpedoes
 Stability (Unstable if below 1.00): 1.18
 Metacentric height 12.2 ft / 3.7 m
 Roll period: 17.7 seconds
 Steadiness - As gun platform (Average = 50 %): 61 %
   - Recoil effect (Restricted arc if above 1.00): 0.47
 Seaboat quality  (Average = 1.00): 1.21

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.524
 Length to Beam Ratio: 8.03 : 1
 'Natural speed' for length: 34.35 kts
 Power going to wave formation at top speed: 48 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  37.00 ft / 11.28 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (50 %):  27.00 ft / 8.23 m
    - Quarterdeck (15 %): 27.00 ft / 8.23 m
    - Stern:  27.00 ft / 8.23 m
    - Average freeboard: 27.80 ft / 8.47 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 76.3 %
  - Above water (accommodation/working, high = better): 188.7 %
 Waterplane Area: 118,204 Square feet or 10,982 Square metres
 Displacement factor (Displacement / loading): 111 %
 Structure weight / hull surface area: 274 lbs/sq ft or 1,336 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.04
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

3 comments:

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Roberto Iza Valdes said...
This comment has been removed by a blog administrator.
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