Gunbooat for overland transport

[AnchorSteam]

TWELVE OF THESE

Thanks to Kirk -

RGB-1, Ethiopian Rail Transport Gunboat laid down 1903

Displacement:
   49 t light; 50 t standard; 52 t normal; 54 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (65.62 ft / 65.62 ft) x 13.12 ft x (3.28 / 3.37 ft)
   (20.00 m / 20.00 m) x 4.00 m  x (1.00 / 1.03 m)

Armament:
      2 - 1.77" / 45.0 mm 45.0 cal guns - 2.80lbs / 1.27kg shells, 250 per gun
     Quick firing guns in deck mounts, 1899 Model
     2 x Single mounts on centreline ends, evenly spread
      2 - 0.30" / 7.5 mm 74.0 cal guns - 0.01lbs / 0.00kg shells, 1,500 per gun
     Breech loading guns in deck mounts, 1899 Model
     2 x Twin mounts on sides amidships
      Weight of broadside 6 lbs / 3 kg

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

   - Conning towers: Forward 0.39" / 10 mm, Aft 0.00" / 0 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 1 shaft, 58 ihp / 43 Kw = 9.00 kts
   Range 1,000nm at 6.00 kts
   Bunker at max displacement = 4 tons (100% coal)

Complement:
   9 - 12

Cost:
   £0.003 million / $0.013 million

Distribution of weights at normal displacement:
   Armament: 1 tons, 2.6 %
      - Guns: 1 tons, 2.6 %
   Armour: 2 tons, 3.7 %
      - Armament: 2 tons, 3.5 %
      - Conning Tower: 0 tons, 0.2 %
   Machinery: 9 tons, 16.4 %
   Hull, fittings & equipment: 14 tons, 25.9 %
   Fuel, ammunition & stores: 4 tons, 7.5 %
   Miscellaneous weights: 23 tons, 43.8 %
      - Hull below water: 5 tons
      - Hull above water: 10 tons
      - On freeboard deck: 8 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     80 lbs / 36 Kg = 28.9 x 1.8 " / 45 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.31
   Metacentric height 0.4 ft / 0.1 m
   Roll period: 8.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 89 %
         - Recoil effect (Restricted arc if above 1.00): 0.11
   Seaboat quality  (Average = 1.00): 1.79

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.653
   Length to Beam Ratio: 5.00 : 1
   'Natural speed' for length: 8.10 kts
   Power going to wave formation at top speed: 56 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 0.00 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 %,  4.92 ft / 1.50 m,  4.92 ft / 1.50 m
      - Forward deck:   30.00 %,  4.92 ft / 1.50 m,  4.92 ft / 1.50 m
      - Aft deck:   35.00 %,  4.92 ft / 1.50 m,  4.92 ft / 1.50 m
      - Quarter deck:   15.00 %,  4.92 ft / 1.50 m,  4.92 ft / 1.50 m
      - Average freeboard:      4.92 ft / 1.50 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 92.3 %
      - Above water (accommodation/working, high = better): 67.7 %
   Waterplane Area: 650 Square feet or 60 Square metres
   Displacement factor (Displacement / loading): 115 %
   Structure weight / hull surface area: 14 lbs/sq ft or 69 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.76
      - Longitudinal: 4.26
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

The Assault Lighter is a small coastal and riverine craft with a minimal keel.
The ship can maintain 6 knots for 7 days, which is the designed operating range.

A 1 ton winch sits on the foredeck, 

18 tons represent room and provision for a Section (16 troops and an officer), 

Misc Weight
1 - Winch
18 - Quarters
1 - Extra Quarters
3 - storage