I've made some modifications to the design to address some of the variances from the historical example and to address issues of stability. I feel I've gone about as far on the historical issues as I should. The question is whether I have achieved sufficient stability and yet have a margin of strength.
Your comments are most welcome.
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C-1 Rev B, TBD River-Sea Freighter laid down 1940
Displacement: 4,988 t light; 5,094 t standard; 5,300 t normal; 5,465 t full load
Dimensions: Length overall / water x beam x draught
308.40 ft / 282.15 ft x 44.95 ft x 19.52 ft (normal load)
94.00 m / 86.00 m x 13.70 m x 5.95 m
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: Unarmoured
- Torpedo Bulkhead:
13.4" / 340 mm 196.85 ft / 60.00 m 22.97 ft / 7.00 m
Machinery: Diesel Internal combustion motors, Geared drive, 1 shaft, 1,353 shp / 1,009 Kw = 11.00 kts; Range 6,000nm at 10.00 kts; Bunker at max displacement = 371 tons
Complement: 30 - 40
Cost: £1.078 million / $4.311 million
Distribution of weights at normal displacement:
Armament: 0 tons, 0.0 %
Armour: 2,239 tons, 42.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 2,239 tons, 42.2 %
- Armament: 0 tons, 0.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 36 tons, 0.7 %
Hull, fittings & equipment: 1,712 tons, 32.3 %
Fuel, ammunition & stores: 312 tons, 5.9 %
Miscellaneous weights: 1,000 tons, 18.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship): 2,264 lbs / 1,027 Kg = 21 x 6 " / 152 mm shells or 1.1 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 1.8 ft / 0.6 m
Roll period: 14.0 seconds
Steadiness - As gun platform (Average = 50 %): 90 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 2.00
Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.749
Length to Beam Ratio: 6.28 : 1
'Natural speed' for length: 16.80 kts
Power going to wave formation at top speed: 33 %
Trim (Max stability = 0, Max steadiness = 100): 45
Bow angle (Positive = bow angles forward): 40.00 degrees
Stern overhang: 6.43 ft / 1.96 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.62 ft / 7.20 m
- Forecastle (20 %): 20.34 ft / 6.20 m (13.12 ft / 4.00 m aft of break)
- Mid (50 %): 21.33 ft / 6.50 m
- Quarterdeck (15 %): 13.12 ft / 4.00 m
- Stern: 21.33 ft / 6.50 m
- Average freeboard: 18.11 ft / 5.52 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 43.9 %
- Above water (accommodation/working, high = better): 112.7 %
Waterplane Area: 10,615 Square feet or 986 Square metres
Displacement factor (Displacement / loading): 160 %
Structure weight / hull surface area: 92 lbs/sq ft or 448 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.35
- Longitudinal: 5.92
- Overall: 1.57
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, rides out heavy weather easily
Low-stowed cargo simmed as torpedo bulkhead
High-stowed cargo simmed as miscellaneous weight
Rev A - Total cargo - 1646+800 = 2446 vice Historical Deadweight 3900dwt
Rev B - Added stern overhang to adjust overall length
Rev B - Increased torpedo bulkhead, nodified miscellaneous weight to seek imporved stability - 2239+1000 = 3239 tons vice 3900 dwt
Rev B - Modified block coefficient by increasing displacement to historical 5300 tons
Final crew size and damage values divided by 10 for civilian ships