Amazon Ad

Saturday, May 04, 2013

My fast Italian six inch gunned cruiser concept

I have a photograph of what I have thought that the more modern fast Italian six inch gunned cruiser would look like. The ships would look a lot like the Attilio Regolo, except longer and lower, with eight six inch guns.

My first attempt in a Springsharp design in years

I have had the concept for a modernized version of the early Italian fast light cruisers. I can tell that I have become extremely rusty using SpringSharp. This is supposed to be a flush-decked version, sort of like the Capitani Romani ships. I thought that 8-6in guns, 8-4in DP, and 8 torpedo tubes might work. I wanted to get 36 knots out of the design. I am not even sure any more how to publish the report. I gave it some armor and machinery, but I am sure that I am doing something inappropriate:

Fast Light Cruiser, Italy Light Cruiser laid down 1941

Displacement:
 9,685 t light; 10,001 t standard; 11,129 t normal; 12,031 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (564.95 ft / 555.00 ft) x 62.00 ft x (22.00 / 23.32 ft)
 (172.20 m / 169.16 m) x 18.90 m  x (6.71 / 7.11 m)

Armament:
      8 - 5.91" / 150 mm 50.0 cal guns - 109.02lbs / 49.45kg shells, 150 per gun
   Breech loading guns in turret on barbette mounts, 1941 Model
   4 x Twin mounts on centreline, evenly spread
  2 raised mounts
      8 - 3.94" / 100.0 mm 45.0 cal guns - 30.77lbs / 13.96kg shells, 150 per gun
   Dual purpose guns in deck and hoist mounts, 1941 Model
   8 x Single mounts on sides, evenly spread
  8 raised mounts
      Weight of broadside 1,118 lbs / 507 kg
      Main Torpedoes
      8 - 20.9" / 530 mm, 68.90 ft / 21.00 m torpedoes - 4.227 t each, 33.817 t total
 In 4 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 2.00" / 51 mm 350.00 ft / 106.68 m 12.00 ft / 3.66 m
 Ends: 1.00" / 25 mm 100.00 ft / 30.48 m 10.00 ft / 3.05 m
   105.00 ft / 32.00 m Unarmoured ends
   Main Belt covers 97 % of normal length
   Main belt does not fully cover magazines and engineering spaces
   Main Belt inclined 2.00 degrees (positive = in)

   - Torpedo Bulkhead - Strengthened structural bulkheads:
  0.75" / 19 mm 360.00 ft / 109.73 m 15.00 ft / 4.57 m
 Beam between torpedo bulkheads 54.00 ft / 16.46 m

   - Hull Bulges:
  0.50" / 13 mm 360.00 ft / 109.73 m 15.00 ft / 4.57 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 3.00" / 76 mm 2.00" / 51 mm  3.00" / 76 mm
 2nd:       -        -   2.00" / 51 mm

   - Armoured deck - multiple decks:
 For and Aft decks: 2.00" / 51 mm
 Forecastle: 1.00" / 25 mm  Quarter deck: 1.00" / 25 mm

   - Conning towers: Forward 2.00" / 51 mm, Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 156,810 shp / 116,980 Kw = 36.00 kts
 Range 3,500nm at 22.00 kts
 Bunker at max displacement = 2,030 tons

Complement:
 541 - 704

Cost:
 £6.396 million / $25.583 million

Distribution of weights at normal displacement:
 Armament: 361 tons, 3.2 %
    - Guns: 294 tons, 2.6 %
    - Weapons: 68 tons, 0.6 %
 Armour: 1,672 tons, 15.0 %
    - Belts: 389 tons, 3.5 %
    - Torpedo bulkhead: 150 tons, 1.3 %
    - Bulges: 100 tons, 0.9 %
    - Armament: 216 tons, 1.9 %
    - Armour Deck: 796 tons, 7.2 %
    - Conning Tower: 21 tons, 0.2 %
 Machinery: 4,144 tons, 37.2 %
 Hull, fittings & equipment: 3,507 tons, 31.5 %
 Fuel, ammunition & stores: 1,444 tons, 13.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   7,239 lbs / 3,284 Kg = 70.3 x 5.9 " / 150 mm shells or 0.4 torpedoes
 Stability (Unstable if below 1.00): 1.02
 Metacentric height 2.5 ft / 0.8 m
 Roll period: 15.3 seconds
 Steadiness - As gun platform (Average = 50 %): 57 %
   - Recoil effect (Restricted arc if above 1.00): 0.40
 Seaboat quality  (Average = 1.00): 0.71

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and a round stern
 Block coefficient (normal/deep): 0.550 / 0.561
 Length to Beam Ratio: 9.57 : 1
 'Natural speed' for length: 23.56 kts
 Power going to wave formation at top speed: 66 %
 Trim (Max stability = 0, Max steadiness = 100): 80
 Bow angle (Positive = bow angles forward): 12.00 degrees
 Stern overhang: 4.00 ft / 1.22 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  28.00 ft / 8.53 m,  23.00 ft / 7.01 m
    - Forward deck: 35.00 %,  23.00 ft / 7.01 m,  19.00 ft / 5.79 m
    - Aft deck: 25.00 %,  19.00 ft / 5.79 m,  17.00 ft / 5.18 m
    - Quarter deck: 15.00 %,  17.00 ft / 5.18 m,  15.00 ft / 4.57 m
    - Average freeboard:  20.50 ft / 6.25 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 149.6 %
  - Above water (accommodation/working, high = better): 140.0 %
 Waterplane Area: 24,014 Square feet or 2,231 Square metres
 Displacement factor (Displacement / loading): 101 %
 Structure weight / hull surface area: 100 lbs/sq ft or 489 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.52
  - Overall: 0.99
 Caution: Hull subject to strain in open-sea
 Cramped machinery, storage, compartmentation space
 Excellent accommodation and workspace room
 Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Amazon Context Links