I/J class , Atlantean Destroyer laid down 1932/36
I class, 16 ships
Names:
Ibex, Ibis, Imaculate, Impact
Impair, Impart, Impose, Impress
Impute, Incise, Incite, Incubus
Iniquity, Insalubrious, Insidious, Insouciant
J class, 16 ships
Names:
Jacinth, Jackel, Jackdaw, Jaguar
Jaunty, Javelin, Jester, Jinx
Joust, Jubilant, Judge, Juggernaut
Junta, Jupiter, Jury, Justice
1 additional ship, the Verde built for Brazil to a modified design.
Displacement:
1,583 t light; 1,667 t standard; 1,906 t normal; 2,096 t full load
Dimensions: Length overall / water x beam x draught
384.37 ft / 375.00 ft x 36.00 ft x 12.20 ft (normal load)
117.16 m / 114.30 m x 10.97 m x 3.72 m
Armament:
6 - 5.10" / 130 mm guns (3x2 guns), 66.33lbs / 30.09kg shells, 1932 Model
Dual purpose guns in deck mounts
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.58" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
6 - 0.79" / 20.0 mm guns (3x2 guns), 0.24lbs / 0.11kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
6 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1932 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 408 lbs / 185 kg
Shells per gun, main battery: 200
10 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 1.00" / 25 mm -
- Conning tower: 1.57" / 40 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 36,776 shp / 27,435 Kw = 33.75 kts
Range 5,400nm at 15.00 kts
Bunker at max displacement = 429 tons
Complement:
143 - 187
Cost:
£1.010 million / $4.039 million
Distribution of weights at normal displacement:
Armament: 51 tons, 2.7 %
Armour: 26 tons, 1.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 21 tons, 1.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 5 tons, 0.3 %
Machinery: 885 tons, 46.4 %
Hull, fittings & equipment: 576 tons, 30.2 %
Fuel, ammunition & stores: 323 tons, 16.9 %
Miscellaneous weights: 45 tons, 2.4 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
652 lbs / 296 Kg = 9.8 x 5.1 " / 130 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.53
Metacentric height 2.2 ft / 0.7 m
Roll period: 10.2 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.23
Seaboat quality (Average = 1.00): 1.17
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.405
Length to Beam Ratio: 10.42 : 1
'Natural speed' for length: 22.31 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 42
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 25.75 ft / 7.85 m
- Forecastle (20 %): 20.50 ft / 6.25 m
- Mid (40 %): 20.50 ft / 6.25 m (12.00 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.00 ft / 3.66 m
- Stern: 12.00 ft / 3.66 m
- Average freeboard: 15.82 ft / 4.82 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 173.6 %
- Above water (accommodation/working, high = better): 82.4 %
Waterplane Area: 8,650 Square feet or 804 Square metres
Displacement factor (Displacement / loading): 72 %
Structure weight / hull surface area: 34 lbs/sq ft or 168 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.97
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
20 tons for 10x21" torpedo's
15 tons for 60 DC's and equipment
9 tons for sonar
3 tons for RDF equipment
3 tons for future growth
The I class use identical guns as the H class but in fully shielded turrets and modified trunnions to improve gun elevation in the AA role, while the J class have modified hoists for improved loading procedure.