Persian Light Cruiser

[ledeper]

Omar Khayyam, Persia Ligth Cruiser laid down 1911 (Engine 1906)

Displacement:
   4.474 t light; 4.626 t standard; 5.165 t normal; 5.597 t full load

Dimensions: Length overall / water x beam x draught
   392,25 ft / 388,78 ft x 49,21 ft x 19,69 ft (normal load)
   119,56 m / 118,50 m x 15,00 m  x 6,00 m

Armament:
      4 - 5,91" / 150 mm guns in single mounts, 102,98lbs / 46,71kg shells, 1911 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 3,94" / 100 mm guns in single mounts, 30,51lbs / 13,84kg shells, 1911 Model
     Quick firing guns in deck mounts
     on side, all amidships
      4 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,89kg shells, 1911 Model
     Quick firing guns in deck mounts
     on side, evenly spread
   Weight of broadside 542 lbs / 246 kg
   Shells per gun, main battery: 150
   4 - 18,0" / 457,2 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   5,91" / 150 mm   291,57 ft / 88,87 m   8,43 ft / 2,57 m
   Ends:   Unarmoured
   Upper:   1,97" / 50 mm   291,57 ft / 88,87 m   8,01 ft / 2,44 m
     Main Belt covers 115 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,98" / 25 mm   0,98" / 25 mm      0,98" / 25 mm

   - Armour deck: 1,97" / 50 mm, Conning tower: 3,94" / 100 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 21.357 shp / 15.933 Kw = 24,00 kts
   Range 3.500nm at 14,00 kts
   Bunker at max displacement = 971 tons

Complement:
   304 - 396

Cost:
   £0,408 million / $1,631 million

Distribution of weights at normal displacement:
   Armament: 68 tons, 1,3 %
   Armour: 1.290 tons, 25,0 %
      - Belts: 789 tons, 15,3 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 20 tons, 0,4 %
      - Armour Deck: 456 tons, 8,8 %
      - Conning Tower: 25 tons, 0,5 %
   Machinery: 1.387 tons, 26,8 %
   Hull, fittings & equipment: 1.579 tons, 30,6 %
   Fuel, ammunition & stores: 691 tons, 13,4 %
   Miscellaneous weights: 150 tons, 2,9 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5.885 lbs / 2.670 Kg = 57,2 x 5,9 " / 150 mm shells or 1,1 torpedoes
   Stability (Unstable if below 1.00): 1,23
   Metacentric height 2,5 ft / 0,8 m
   Roll period: 13,1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0,25
   Seaboat quality  (Average = 1.00): 1,39

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,480
   Length to Beam Ratio: 7,90 : 1
   'Natural speed' for length: 19,72 kts
   Power going to wave formation at top speed: 55 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      19,69 ft / 6,00 m
      - Forecastle (10 %):   15,78 ft / 4,81 m
      - Mid (50 %):      15,78 ft / 4,81 m
      - Quarterdeck (15 %):   15,78 ft / 4,81 m
      - Stern:      15,78 ft / 4,81 m
      - Average freeboard:   15,94 ft / 4,86 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 100,8 %
      - Above water (accommodation/working, high = better): 110,7 %
   Waterplane Area: 12.521 Square feet or 1.163 Square metres
   Displacement factor (Displacement / loading): 109 %
   Structure weight / hull surface area: 75 lbs/sq ft or 367 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,92
      - Longitudinal: 2,11
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Jefgte]

With 25% armor (150mm belt & 50 for the deck)
& just 24kts, this is an escort cruiser or a gunboat.
...
Finaly,...Good ship for escort & coastal protection.
A good Defender.


;)