Port Shepstone , laid down 1913, rebuild 1927
Port St. Johns , laid down 1913, rebuild 1927
Port Alfred , laid down 1914, rebuild 1927
Porto Alegre , laid down 1915, rebuild 1928
ex-SAE
Displacement:
4.348 t light; 4.537 t standard (4.500 t officially); 5.162 t normal; 5.662 t full load
Dimensions: Length overall / water x beam x draught
451,51 ft / 442,91 ft x 44,29 ft x 19,03 ft (normal load)
137,62 m / 135,00 m x 13,50 m x 5,80 m
Armament:
8 - 5,91" / 150 mm guns (4x2 guns), 102,98lbs / 46,71kg shells, 1913 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 4,13" / 105 mm guns in single mounts, 35,32lbs / 16,02kg shells, 1926 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,88kg shells, 1913 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
10 - 0,79" / 20,0 mm guns (6 mounts), 0,24lbs / 0,11kg shells, 1913 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 983 lbs / 446 kg
Shells per gun, main battery: 150
6 - 21,0" / 533 mm above water torpedoes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1,97" / 50 mm 420,60 ft / 128,20 m 11,48 ft / 3,50 m
Ends: Unarmoured
Upper: 0,79" / 20 mm 286,09 ft / 87,20 m 8,20 ft / 2,50 m
Main Belt covers 146% of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,38" / 35 mm 0,79" / 20 mm -
2nd: 0,79" / 20 mm - -
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -
- Armour deck: 1,18" / 30 mm, Conning tower: 1,18" / 30 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 64.344 shp / 48.000 Kw = 32,10 kts
Range 7.000nm at 15,00 kts
Bunker at max displacement = 1.125 tons
Complement:
303 - 395
Cost:
£0,589 million / $2,355 million
Distribution of weights at normal displacement:
Armament: 123 tons, 2,4%
Armour: 775 tons, 15,0%
- Belts: 449 tons, 8,7%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 37 tons, 0,7%
- Armour Deck: 282 tons, 5,5%
- Conning Tower: 8 tons, 0,1%
Machinery: 2.031 tons, 39,3%
Hull, fittings & equipment: 1.399 tons, 27,1%
Fuel, ammunition & stores: 814 tons, 15,8%
Miscellaneous weights: 20 tons, 0,4%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2.332 lbs / 1.058 Kg = 22,6 x 5,9 " / 150 mm shells or 0,6 torpedoes
Stability (Unstable if below 1.00): 1,32
Metacentric height 2,4 ft / 0,7 m
Roll period: 11,9 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0,35
Seaboat quality (Average = 1.00): 1,16
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,484
Length to Beam Ratio: 10,00 : 1
'Natural speed' for length: 21,05 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 61
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: 23,62 ft / 7,20 m
- Forecastle (30%): 21,00 ft / 6,40 m
- Mid (55%): 21,00 ft / 6,40 m (13,12 ft / 4,00 m aft of break)
- Quarterdeck (20%): 13,12 ft / 4,00 m
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 17,77 ft / 5,42 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 146,1%
- Above water (accommodation/working, high = better): 109,1%
Waterplane Area: 12.883 Square feet or 1.197 Square metres
Displacement factor (Displacement / loading): 88%
Structure weight / hull surface area: 56 lbs/sq ft or 275 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,68
- Longitudinal: 1,90
- Overall: 0,76
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform