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