Trade Protection Cruiser "Ras Dejen"
Laid down 1928 in Italy
Ras Dejen, laid down 1928
Displacement:
5,699 t light; 5,922 t standard; 7,101 t normal; 8,045 t full load
Dimensions: Length overall / water x beam x draught
504.36 ft / 492.13 ft x 55.77 ft x 19.69 ft (normal load)
153.73 m / 150.00 m x 17.00 m x 6.00 m
Armament:
5 - 5.98" / 152 mm guns in single mounts, 110.23lbs / 50.00kg shells, 1928 Model
Breech loading guns in deck mounts with hoists
on centreline, evenly spread, 2 raised mounts
4 - 3.94" / 100 mm guns (2x2 guns), 30.42lbs / 13.80kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, all forward
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.83lbs / 0.83kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 687 lbs / 312 kg
Shells per gun, main battery: 200
6 - 21.0" / 533 mm above water torpedoes
Aircraft:
Up to a maximum of 6. Macchi M.18 and Fiat ICR.20
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.76" / 70 mm 364.17 ft / 111.00 m 8.20 ft / 2.50 m
Ends: Unarmoured
Main Belt covers 114 % of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.98" / 25 mm -
2nd: 0.79" / 20 mm - -
- Armour deck: 0.98" / 25 mm, Conning tower: 2.76" / 70 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 71,600 shp / 53,414 Kw = 31.75 kts
Range 18,610nm at 12.00 kts
Bunker at max displacement = 2,123 tons
Complement:
386 - 502
Cost:
£2.222 million / $8.887 million
Distribution of weights at normal displacement:
Armament: 84 tons, 1.2 %
Armour: 716 tons, 10.1 %
- Belts: 338 tons, 4.8 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 34 tons, 0.5 %
- Armour Deck: 321 tons, 4.5 %
- Conning Tower: 22 tons, 0.3 %
Machinery: 2,229 tons, 31.4 %
Hull, fittings & equipment: 2,520 tons, 35.5 %
Fuel, ammunition & stores: 1,402 tons, 19.7 %
Miscellaneous weights: 150 tons, 2.1 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,860 lbs / 3,111 Kg = 64.0 x 6.0 " / 152 mm shells or 1.1 torpedoes
Stability (Unstable if below 1.00): 1.20
Metacentric height 2.9 ft / 0.9 m
Roll period: 13.7 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.23
Seaboat quality (Average = 1.00): 1.02
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.460
Length to Beam Ratio: 8.82 : 1
'Natural speed' for length: 22.18 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 70
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.61 ft / 7.50 m
- Forecastle (20 %): 21.33 ft / 6.50 m
- Mid (60 %): 21.33 ft / 6.50 m (13.12 ft / 4.00 m aft of break)
- Quarterdeck (15 %): 13.12 ft / 4.00 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 18.43 ft / 5.62 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 113.8 %
- Above water (accommodation/working, high = better): 134.5 %
Waterplane Area: 17,654 Square feet or 1,640 Square metres
Displacement factor (Displacement / loading): 118 %
Structure weight / hull surface area: 87 lbs/sq ft or 425 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.74
- Overall: 1.00
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform