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Petain class, French Coast Defense Monitor laid down 1925
Displacement:
7,525 t light;
7,957 t standard; 9,190 t normal; 10,176 t full load
Dimensions: Length overall / water x beam x draught
393.70
ft / 393.70 ft x 75.46 ft x 18.04 ft (normal load)
120.00 m / 120.00 m x 23.00 m x 5.50 m
Armament:
4 - 12.01"
/ 305 mm guns (2x2 guns), 952.40lbs / 432.00kg shells, 1925 Model
Breech loading guns in turrets (on barbettes)
on
centreline, evenly spread
8 - 4.72" / 120 mm guns (4x2 guns), 61.73lbs / 28.00kg shells, 1925 Model
Dual purpose guns
in deck mounts with hoists
on side, all amidships
16 - 1.57" / 40.0 mm guns (4x4 guns), 1.95lbs / 0.89kg shells, 1925
Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 4,335 lbs / 1,966 kg
Shells
per gun, main battery: 100
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 13.8" / 350 mm 138.62
ft / 42.25 m 8.53 ft / 2.60 m
Ends: Unarmoured
Main Belt covers 54 % of normal length
- Gun armour: Face (max)
Other gunhouse (avg) Barbette/hoist (max)
Main: 13.8" / 350 mm 7.87" / 200 mm 7.87" / 200 mm
2nd: 1.97" / 50 mm 0.98"
/ 25 mm -
3rd: 0.98" / 25 mm - -
- Armour deck: 4.72" / 120 mm, Conning tower: 13.78" / 350 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 8,795 shp / 6,561 Kw = 17.00 kts
Range 9,000nm at 15.00
kts (Bunkerage = 2,220 tons)
Aviation:
1 Seaplane, 1 Crane
Complement:
469 - 610
Cost:
£2.338
million / $9.354 million
Distribution of weights at normal displacement:
Armament: 489 tons, 5.3 %
Armour:
3,495 tons, 38.0 %
- Belts: 889 tons, 9.7 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 577 tons, 6.3 %
-
Armour Deck: 1,899 tons, 20.7 %
- Conning Tower: 130 tons, 1.4 %
Machinery: 286 tons, 3.1 %
Hull, fittings &
equipment: 3,230 tons, 35.1 %
Fuel, ammunition & stores: 1,665 tons, 18.1 %
Miscellaneous weights: 25 tons, 0.3
%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
15,165 lbs / 6,879 Kg = 17.5 x 12.0 " / 305 mm shells or 3.5 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric
height 4.5 ft / 1.4 m
Roll period: 14.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect
(Restricted arc if above 1.00): 0.24
Seaboat quality (Average = 1.00): 1.00
Hull form characteristics:
Hull
has rise forward of midbreak
Block coefficient: 0.600
Length to Beam Ratio: 5.22 : 1
'Natural speed' for length:
19.84 kts
Power going to wave formation at top speed: 44 %
Trim (Max stability = 0, Max steadiness = 100): 70
Bow
angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location
as a percentage of overall length):
- Stem: 12.14 ft / 3.70 m
- Forecastle (20 %): 12.14 ft / 3.70 m
- Mid (40
%): 12.14 ft / 3.70 m (6.56 ft / 2.00 m aft of break)
- Quarterdeck (15 %): 6.56 ft / 2.00 m
- Stern: 6.56 ft / 2.00
m
- Average freeboard: 8.79 ft / 2.68 m
Ship tends to be wet forward
Ship space, strength and comments:
Space
- Hull below water (magazines/engines, low = better): 51.5 %
- Above water (accommodation/working, high = better): 73.0
%
Waterplane Area: 21,728 Square feet or 2,019 Square metres
Displacement factor (Displacement / loading): 115 %
Structure
weight / hull surface area: 124 lbs/sq ft or 603 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
-
Longitudinal: 1.24
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation
and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform
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