Island-Class Colonial Seaplane Tender

[TacCovert4]

Island-Class, Aztec Colonial Seaplane Tender laid down 1929

Displacement:
   12,543 t light; 12,894 t standard; 14,049 t normal; 14,973 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (489.04 ft / 485.56 ft) x 65.62 ft x (19.69 / 20.86 ft)
   (149.06 m / 148.00 m) x 20.00 m  x (6.00 / 6.36 m)

Armament:
      4 - 5.12" / 130 mm 50.0 cal guns - 70.97lbs / 32.19kg shells, 300 per gun
     Quick firing guns in deck and hoist mounts, 1929 Model
     2 x Twin mounts on centreline, forward evenly spread
      1 raised mount
      8 - 2.76" / 70.0 mm 50.0 cal guns - 11.08lbs / 5.03kg shells, 300 per gun
     Anti-air guns in deck mounts, 1929 Model
     8 x Single mounts on sides, evenly spread
      16 - 1.18" / 30.0 mm 50.0 cal guns - 0.87lbs / 0.40kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1929 Model
     8 x Twin mounts on side ends, evenly spread
      Weight of broadside 386 lbs / 175 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Ends:   Unarmoured

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      0.24" / 6 mm   393.70 ft / 120.00 m   19.69 ft / 6.00 m
   Beam between torpedo bulkheads 59.06 ft / 18.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.79" / 20 mm      0.79" / 20 mm
   3rd:         -            -         0.79" / 20 mm

   - Box over magazines:
   0.79" / 20 mm

   - Conning towers: Forward 0.79" / 20 mm, Aft 0.00" / 0 mm

Machinery:
   Diesel Internal combustion motors,  plus diesel motors,
   Geared drive, 2 shafts, 41,773 shp / 31,163 Kw = 24.00 kts
   Range 8,000nm at 14.00 kts
   Bunker at max displacement = 2,079 tons

Complement:
   644 - 838

Cost:
   £2.624 million / $10.497 million

Distribution of weights at normal displacement:
   Armament: 94 tons, 0.7 %
      - Guns: 94 tons, 0.7 %
   Armour: 107 tons, 0.8 %
      - Torpedo bulkhead: 68 tons, 0.5 %
      - Armament: 12 tons, 0.1 %
      - Armour Deck: 17 tons, 0.1 %
      - Conning Tower: 10 tons, 0.1 %
   Machinery: 1,283 tons, 9.1 %
   Hull, fittings & equipment: 3,601 tons, 25.6 %
   Fuel, ammunition & stores: 1,506 tons, 10.7 %
   Miscellaneous weights: 7,459 tons, 53.1 %
      - Hull below water: 3,688 tons
      - Hull above water: 3,500 tons
      - On freeboard deck: 200 tons
      - Above deck: 71 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     21,963 lbs / 9,962 Kg = 327.6 x 5.1 " / 130 mm shells or 2.5 torpedoes
   Stability (Unstable if below 1.00): 1.44
   Metacentric height 5.0 ft / 1.5 m
   Roll period: 12.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.07
   Seaboat quality  (Average = 1.00): 1.66

Hull form characteristics:
   Hull has rise aft of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.784 / 0.789
   Length to Beam Ratio: 7.40 : 1
   'Natural speed' for length: 22.04 kts
   Power going to wave formation at top speed: 57 %
   Trim (Max stability = 0, Max steadiness = 100): 36
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  19.69 ft / 6.00 m,  16.40 ft / 5.00 m
      - Forward deck:   30.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Aft deck:   35.00 %,  29.53 ft / 9.00 m,  29.53 ft / 9.00 m
      - Quarter deck:   15.00 %,  29.53 ft / 9.00 m,  29.53 ft / 9.00 m
      - Average freeboard:      23.23 ft / 7.08 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 98.2 %
      - Above water (accommodation/working, high = better): 191.6 %
   Waterplane Area: 27,594 Square feet or 2,564 Square metres
   Displacement factor (Displacement / loading): 134 %
   Structure weight / hull surface area: 88 lbs/sq ft or 430 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 1.83
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

11t - 1918 FC
25t - LR Wireless
10t - Additional SR Wireless
25t - NF Devices

50t - 2 x Cranes
50t - Refueling Hoses
50t - Firefighting Hoses
70t - 2 x Catapult & Armed Floatplane

50t - Firefighting Pumps
50t - Refueling Pumps
200t - Workshops

6400t - Air Point And Supports

388t - Diesel Engines
100t - Damage Control Pumps

Range is 16,100nm @ 14kt Cruising Speed w/Geared Diesels