Pilum Class Destroyers

[snip]

Originally designed as Destroyer Leaders, the Pilum class where the last destroyers designed before The Caicos Afair.  The class was meant to serve as leaders to the 750t and 1000t destroyers of the D, E, F and G classes. Once the conflict had gutted the ranks of those smaller destroyers, the four still building Pilums were redesignated as Destroyers. The planned second quadruplet of ships originally meant for construction in 1915 were posponed after the Battle of Ironclad Bay and canceled in December 1914 before any of the keels had been layed.

Four Ships
--IRS Pilum (Completed December 1914)
--IRS Collidis (Completed December 1914)
--IRS Hastam (Completed December 1914)
--IRS Bipennis (Completed December 1914)

LRD-14B, Imperial Roman Destroyer laid down 1914

Displacement:
   1,500 t light; 1,567 t standard; 1,760 t normal; 1,914 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (354.32 ft / 344.49 ft) x 31.17 ft x (13.94 / 14.75 ft)
   (108.00 m / 105.00 m) x 9.50 m  x (4.25 / 4.50 m)

Armament:
      8 - 3.94" / 100 mm 45.0 cal guns - 30.86lbs / 14.00kg shells, 225 per gun
     Quick firing guns in deck mounts, 1906 Model
     3 x Twin mounts on centreline ends, majority forward
      1 raised mount - superfiring
     1 x Twin mount on centreline, aft deck forward
      1 raised mount aft
      2 - 1.77" / 45.0 mm 50.0 cal guns - 3.31lbs / 1.50kg shells, 250 per gun
     Quick firing guns in deck mounts, 1905 Model
     2 x Single mounts on sides, aft deck forward
      2 raised mounts
      4 - 0.26" / 6.5 mm 110.0 cal guns - 0.01lbs / 0.00kg shells, 5,000 per gun
     Machine guns in deck mounts, 1911 Model
     4 x Single mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 254 lbs / 115 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.39" / 10 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 36,000 shp / 26,856 Kw = 32.26 kts
   Range 3,500nm at 14.00 kts
   Bunker at max displacement = 347 tons

Complement:
   135 - 176

Cost:
   £0.260 million / $1.039 million

Distribution of weights at normal displacement:
   Armament: 38 tons, 2.2 %
      - Guns: 38 tons, 2.2 %
   Armour: 4 tons, 0.2 %
      - Armament: 4 tons, 0.2 %
   Machinery: 993 tons, 56.4 %
   Hull, fittings & equipment: 415 tons, 23.6 %
   Fuel, ammunition & stores: 260 tons, 14.8 %
   Miscellaneous weights: 50 tons, 2.8 %
      - On freeboard deck: 50 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     382 lbs / 173 Kg = 12.5 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.31
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 11.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.32
   Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a round stern
   Block coefficient (normal/deep): 0.411 / 0.423
   Length to Beam Ratio: 11.05 : 1
   'Natural speed' for length: 18.56 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 64
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 2.07 ft / 0.63 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   10.00 %,  21.33 ft / 6.50 m,  19.69 ft / 6.00 m
      - Forward deck:   15.00 %,  19.69 ft / 6.00 m,  19.69 ft / 6.00 m
      - Aft deck:   60.00 %,  11.48 ft / 3.50 m,  11.48 ft / 3.50 m
      - Quarter deck:   15.00 %,  11.48 ft / 3.50 m,  11.48 ft / 3.50 m
      - Average freeboard:      13.60 ft / 4.15 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 189.9 %
      - Above water (accommodation/working, high = better): 123.2 %
   Waterplane Area: 6,655 Square feet or 618 Square metres
   Displacement factor (Displacement / loading): 60 %
   Structure weight / hull surface area: 31 lbs/sq ft or 152 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.78
      - Overall: 0.57
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

--25t Long Range Wireless
--18t 2x3 530mm Torpedo [Centerline mounts, for and aft of the Q-mount 100mm guns]
--4t 1912 FC
--3t Flotilla Command Facilities

[snip]

By the end of 1922H2, all four ships had been updated to 1918 Fire Control.