1950 will be cruiser time too for the Royal Navy.
The Acheron class will be what was termed an 'AACL' in the 1940s, but the Acheron carries a full range of anti-aircraft, anti-ship and anti-submarine weapons to revisit the 1920s RN concept of the Escort Cruiser. Designed to form part of a carrier force escort, they carry all the neccessary weapons and sensors for their role, they can unleash a deadly barrage.
The 5.5in guns are those of the Town class cruiser-destroyers but in a new twin mounting. The 3in is a new L/70 AA mount and is backed up by new quad 57mm mounts which is the sextuple 40mm mount but reworked for four 57mm guns. Plenty of fire-control as well. Four will be laid down in 1950 but more will be built during the early 1950s.
Acheron Class, Great Britain Escort Cruiser laid down 1950
Displacement:
8,921 t light; 9,411 t standard; 10,868 t normal; 12,034 t full load
Dimensions: Length overall / water x beam x draught
656.80 ft / 650.00 ft x 56.00 ft x 19.00 ft (normal load)
200.19 m / 198.12 m x 17.07 m x 5.79 m
Armament:
10 - 5.50" / 140 mm guns (5x2 guns), 80.00lbs / 36.29kg shells, 1950 Model
Automatic rapid fire guns in turrets (on barbettes)
on centreline ends, majority forward, 3 raised mounts - superfiring
8 - 3.00" / 76.2 mm guns (4x2 guns), 12.50lbs / 5.67kg shells, 1950 Model
Automatic rapid fire guns in deck mounts with hoists
on side ends, evenly spread
16 - 2.24" / 57.0 mm guns (4x4 guns), 5.65lbs / 2.56kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
8 - 1.57" / 40.0 mm guns (4x2 guns), 1.95lbs / 0.88kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 1,006 lbs / 456 kg
Shells per gun, main battery: 450
8 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.50" / 114 mm 350.00 ft / 106.68 m 13.00 ft / 3.96 m
Ends: Unarmoured
Main Belt covers 83 % of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.50" / 38 mm 1.00" / 25 mm 3.00" / 76 mm
2nd: 1.00" / 25 mm 1.00" / 25 mm 3.00" / 76 mm
3rd: 1.00" / 25 mm 1.00" / 25 mm -
4th: 0.50" / 13 mm 0.50" / 13 mm -
- Armour deck: 3.00" / 76 mm, Conning tower: 2.00" / 51 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 75,000 shp / 55,950 Kw = 31.84 kts
Range 7,000nm at 20.00 kts
Bunker at max displacement = 2,623 tons
Complement:
531 - 691
Cost:
£5.418 million / $21.672 million
Distribution of weights at normal displacement:
Armament: 154 tons, 1.4 %
Armour: 2,602 tons, 23.9 %
- Belts: 865 tons, 8.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 248 tons, 2.3 %
- Armour Deck: 1,468 tons, 13.5 %
- Conning Tower: 21 tons, 0.2 %
Machinery: 1,794 tons, 16.5 %
Hull, fittings & equipment: 3,955 tons, 36.4 %
Fuel, ammunition & stores: 1,947 tons, 17.9 %
Miscellaneous weights: 415 tons, 3.8 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
19,045 lbs / 8,639 Kg = 228.9 x 5.5 " / 140 mm shells or 2.3 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 2.7 ft / 0.8 m
Roll period: 14.4 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.36
Seaboat quality (Average = 1.00): 1.39
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.550
Length to Beam Ratio: 11.61 : 1
'Natural speed' for length: 28.63 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 51
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 32.00 ft / 9.75 m
- Forecastle (20 %): 26.00 ft / 7.92 m
- Mid (43 %): 23.50 ft / 7.16 m (16.00 ft / 4.88 m aft of break)
- Quarterdeck (20 %): 16.00 ft / 4.88 m
- Stern: 18.00 ft / 5.49 m
- Average freeboard: 20.69 ft / 6.31 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71.2 %
- Above water (accommodation/working, high = better): 155.8 %
Waterplane Area: 26,447 Square feet or 2,457 Square metres
Displacement factor (Displacement / loading): 139 %
Structure weight / hull surface area: 91 lbs/sq ft or 445 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.21
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily
Class Names: HMS Acheron, Acasta, Achates, Ardent, Arrow
5.5in automatic mounts simmed with 10 tons per mount
3in automatic mounts simmed with 7 tons per mount
21in torpedo tubes fixed, angled outboard for anti-ship and Mk.20 'Bidder' acoustic-homing anti-submarine torpedoes, 1x reload per tube
2x Squid A/S mortars (30x rounds each)
Electronic Equipment:
One Type 971 aerial search set
One Type 976 height-finding set
One Type 975 target indication set
One Type 276 high-definition surface set
Two MRS7 fire-control systems using Mk.6M directors with twin Type 288 RDF and Simple Electric Deflection Calculator and Flyplane table
Eight MRS8 fire-control systems using CRBF directors with Type 262 RDF
HF/DF Type 292
Passive Intercept Type UA-1
Four RU-series RDF jammers
Radio-Location Jammer Type 298 'Spooky'
VHF Direction Finder Type 295Q
Asdic Type 146M
Asdic Type 147 passive
Asdic Type 941 Passive Torpedo Warning