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1921, RM Calabria

Ships in class;

Calabria (99), Laid down 1921



Calabria, Italian Escort Cruiser laid down 1921

Displacement:
7,819 t light; 8,342 t standard; 10,156 t normal; 11,567 t full load
Loading submergence 615 tons/feet

Dimensions:
492.13 ft x 58.40 ft x 19.03 ft (normal load)
150.00 m x 17.80 m x 5.80 m

Armament:
6 - 10" / 45 M1906 guns (3 Main turrets x 2 guns, 1 superfiring turret)
Superfiring turret is aft
12 -130mm / 50 M1919 guns in duple mounts
1 - 3" / 60 AA gun
8 - 37mm AA guns
Weight of broadside 3,831 lbs / 1,738 kg
6 - 21" above water torpedoes in 2 triple mounts

Armour:
Belt 5.91" / 150 mm, ends unarmoured
Belts cover 73 % of normal area
Main turrets 5.91" / 150 mm, 2nd gun shields 1.18" / 30 mm
Armour deck 3.15" / 80 mm, Conning tower 2.76" / 70 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 32,000 shp / 23,872 Kw = 24.07 kts
Range 3,400nm at 24.00 kts

Complement:
505 - 657

Cost:
£2.113 million / $8.453 million

Distribution of weights at normal displacement:
Armament: 479 tons, 4.7 %
Armour: 2,451 tons, 24.1 %
Belts: 530 tons, 5.2 %, Armament: 638 tons, 6.3 %, Armour Deck: 1,255 tons, 12.4 %
Conning Tower: 28 tons, 0.3 %, Torpedo bulkhead: 0 tons, 0.0 %
Machinery: 1,102 tons, 10.8 %
Hull, fittings & equipment: 3,688 tons, 36.3 %
Fuel, ammunition & stores: 2,337 tons, 23.0 %
Miscellaneous weights: 100 tons, 1.0 %

Metacentric height 2.4

Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.04
Shellfire needed to sink: 13,768 lbs / 6,245 Kg = 27.5 x 10.0 " / 254 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 2.1
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 70 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.98
Relative quality as seaboat: 1.13

Hull form characteristics:
Block coefficient: 0.650
Sharpness coefficient: 0.40
Hull speed coefficient 'M': 6.95
'Natural speed' for length: 22.18 kts
Power going to wave formation at top speed: 52 %
Trim: 62
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 73.2 %
Relative accommodation and working space: 109.5 %
(Average = 100%)
Displacement factor: 118 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.97
(Structure weight / hull surface area: 115 lbs / square foot or 563 Kg / square metre)
Relative longitudinal hull strength: 1.29
(for 15.75 ft / 4.80 m average freeboard, freeboard adjustment 0.56 ft)
Relative composite hull strength: 1.00

1922, RM Elba

Ships in Class;
Elba
Umbria
Puglia



Elba, Italian Escort Cruiser laid down 1922

Displacement:
7,811 t light; 8,288 t standard; 9,989 t normal; 11,350 t full load

Dimensions: Length overall / water x beam x draught
508.84 ft / 492.13 ft x 65.62 ft (Bulges 72.18 ft) x 16.40 ft (normal load)
155.09 m / 150.00 m x 20.00 m (Bulges 22.00 m) x 5.00 m

Armament:
6 - 10.00" / 254 mm guns (2x3 guns), 500.00lbs / 226.80kg shells, 1922 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
8 - 3.94" / 100 mm guns (4x2 guns), 30.42lbs / 13.80kg shells, 1922 Model
Breech loading guns in deck mounts
on side, all amidships
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.83lbs / 0.83kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 3,258 lbs / 1,478 kg
Shells per gun, main battery: 150
6 - 21.0" / 533 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.91" / 150 mm 262.47 ft / 80.00 m 9.22 ft / 2.81 m
Ends: Unarmoured
Main Belt covers 82 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 5.91" / 150 mm 3.94" / 100 mm 3.94" / 100 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -

- Armour deck: 2.76" / 70 mm, Conning tower: 2.76" / 70 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 32,000 shp / 23,872 Kw = 23.98 kts
Range 20,000nm at 12.00 kts
Bunker at max displacement = 3,061 tons

Complement:
499 - 649

Cost:
£2.093 million / $8.370 million

Distribution of weights at normal displacement:
Armament: 407 tons, 4.1 %
Armour: 2,230 tons, 22.3 %
- Belts: 640 tons, 6.4 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 358 tons, 3.6 %
- Armour Deck: 1,204 tons, 12.1 %
- Conning Tower: 28 tons, 0.3 %
Machinery: 1,085 tons, 10.9 %
Hull, fittings & equipment: 3,889 tons, 38.9 %
Fuel, ammunition & stores: 2,178 tons, 21.8 %
Miscellaneous weights: 200 tons, 2.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
16,915 lbs / 7,673 Kg = 33.8 x 10.0 " / 254 mm shells or 2.7 torpedoes
Stability (Unstable if below 1.00): 1.38
Metacentric height 4.7 ft / 1.4 m
Roll period: 14.0 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.29
Seaboat quality (Average = 1.00): 1.20

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.600
Length to Beam Ratio: 6.82 : 1
'Natural speed' for length: 22.18 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.89 ft / 8.50 m
- Forecastle (30 %): 21.33 ft / 6.50 m
- Mid (40 %): 21.33 ft / 6.50 m (13.12 ft / 4.00 m aft of break)
- Quarterdeck (25 %): 13.12 ft / 4.00 m
- Stern: 13.12 ft / 4.00 m
- Average freeboard: 17.19 ft / 5.24 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 69.6 %
- Above water (accommodation/working, high = better): 117.5 %
Waterplane Area: 23,618 Square feet or 2,194 Square metres
Displacement factor (Displacement / loading): 127 %
Structure weight / hull surface area: 115 lbs/sq ft or 563 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.40
- Overall: 1.01
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Good seaboat, rides out heavy weather easily