Post-WW1 Scouting Cruiser designed for a US fleet
Derry, Heavy Cruiser laid down 1917
Displacement:
8,350 t light; 8,672 t standard; 10,434 t normal; 11,844 t full load
Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(620.50 ft / 609.00 ft) x 65.00 ft x (16.30 / 18.06 ft)
(189.13 m / 185.62 m) x 19.81 m x (4.97 / 5.50 m)
Armament:
5 - 7.00" / 178 mm 45.0 cal guns - 164.99lbs / 74.84kg shells, 220 per gun
Breech loading guns in deck mounts, 1900 Model
4 x Single mounts on centreline ends, evenly spread
2 raised mounts - superfiring
1 x Single mount on centreline, aft deck centre
1 double raised mount aft
4 - 3.00" / 76.2 mm 50.0 cal guns - 13.01lbs / 5.90kg shells, 450 per gun
Anti-air guns in deck mounts, 1915 Model
4 x Single mounts on sides, forward deck aft
Weight of broadside 877 lbs / 398 kg
Main Torpedoes
8 - 21.0" / 533 mm, 22.56 ft / 6.88 m torpedoes - 1.442 t each, 11.538 t total
In 2 sets of deck mounted side rotating tubes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.50" / 89 mm 400.00 ft / 121.92 m 10.00 ft / 3.05 m
Ends: 1.00" / 25 mm 70.00 ft / 21.34 m 10.00 ft / 3.05 m
139.00 ft / 42.37 m Unarmoured ends
Main Belt covers 101 % of normal length
- Armoured deck - single deck:
Fore and Aft decks: 1.50" / 38 mm
Forecastle: 0.25" / 6 mm Quarter deck: 0.50" / 13 mm
- Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 79,286 shp / 59,147 Kw = 31.00 kts
Range 12,500nm at 14.00 kts
Bunker at max displacement = 3,172 tons
Complement:
516 - 671
Cost:
£1.351 million / $5.404 million
Distribution of weights at normal displacement:
Armament: 162 tons, 1.6 %
- Guns: 139 tons, 1.3 %
- Weapons: 23 tons, 0.2 %
Armour: 1,321 tons, 12.7 %
- Belts: 604 tons, 5.8 %
- Armour Deck: 676 tons, 6.5 %
- Conning Tower: 41 tons, 0.4 %
Machinery: 2,906 tons, 27.9 %
Hull, fittings & equipment: 3,830 tons, 36.7 %
Fuel, ammunition & stores: 2,085 tons, 20.0 %
Miscellaneous weights: 130 tons, 1.2 %
- Hull below water: 40 tons
- Hull above water: 20 tons
- On freeboard deck: 30 tons
- Above deck: 40 tons
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
16,961 lbs / 7,693 Kg = 98.9 x 7.0 " / 178 mm shells or 1.7 torpedoes
Stability (Unstable if below 1.00): 1.32
Metacentric height 4.3 ft / 1.3 m
Roll period: 13.1 seconds
Steadiness - As gun platform (Average = 50 %): 80 %
- Recoil effect (Restricted arc if above 1.00): 0.12
Seaboat quality (Average = 1.00): 1.37
Hull form characteristics:
Hull has a flush deck,
a straight bulbous bow and a cruiser stern
Block coefficient (normal/deep): 0.566 / 0.580
Length to Beam Ratio: 9.37 : 1
'Natural speed' for length: 24.68 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 4.00 ft / 1.22 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 28.00 ft / 8.53 m, 25.00 ft / 7.62 m
- Forward deck: 40.00 %, 25.00 ft / 7.62 m, 22.00 ft / 6.71 m
- Aft deck: 25.00 %, 22.00 ft / 6.71 m, 20.00 ft / 6.10 m
- Quarter deck: 15.00 %, 20.00 ft / 6.10 m, 21.00 ft / 6.40 m
- Average freeboard: 22.97 ft / 7.00 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 96.2 %
- Above water (accommodation/working, high = better): 228.7 %
Waterplane Area: 28,044 Square feet or 2,605 Square metres
Displacement factor (Displacement / loading): 136 %
Structure weight / hull surface area: 90 lbs/sq ft or 442 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.41
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily