Torpedo boote, Esc Coastal torpedoboats laid down 1920
Displacement:
168 t light; 173 t standard; 193 t normal; 210 t full load
Dimensions: Length overall / water x beam x draught
202,46 ft / 196,85 ft x 18,04 ft x 5,41 ft (normal load)
61,71 m / 60,00 m x 5,50 m x 1,65 m
Armament:
1 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,88kg shells, 1920 Model
Quick firing gun in deck mount
on centreline forward
2 - 0,79" / 20,0 mm guns (1x2 guns), 0,24lbs / 0,11kg shells, 1920 Model
Anti-aircraft guns in deck mount
on centreline aft
Weight of broadside 2 lbs / 1 kg
Shells per gun, main battery: 500
4 - 20,9" / 530 mm above water torpedoes
Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 4.271 shp / 3.186 Kw = 25,50 kts
Range 2.500nm at 12,00 kts
Bunker at max displacement = 37 tons
Complement:
25 - 33
Cost:
£0,047 million / $0,188 million
Distribution of weights at normal displacement:
Armament: 0 tons, 0,2 %
Machinery: 98 tons, 50,8 %
Hull, fittings & equipment: 59 tons, 30,7 %
Fuel, ammunition & stores: 25 tons, 13,1 %
Miscellaneous weights: 10 tons, 5,2 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
67 lbs / 30 Kg = 34,3 x 1,6 " / 40 mm shells or 0,1 torpedoes
Stability (Unstable if below 1.00): 1,40
Metacentric height 0,7 ft / 0,2 m
Roll period: 9,1 seconds
Steadiness - As gun platform (Average = 50 %): 52 %
- Recoil effect (Restricted arc if above 1.00): 0,01
Seaboat quality (Average = 1.00): 1,04
Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0,352
Length to Beam Ratio: 10,91 : 1
'Natural speed' for length: 14,03 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15,42 ft / 4,70 m
- Forecastle (20 %): 8,20 ft / 2,50 m (6,56 ft / 2,00 m aft of break)
- Mid (50 %): 6,56 ft / 2,00 m
- Quarterdeck (15 %): 6,56 ft / 2,00 m
- Stern: 6,56 ft / 2,00 m
- Average freeboard: 7,47 ft / 2,28 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 171,4 %
- Above water (accommodation/working, high = better): 66,5 %
Waterplane Area: 2.156 Square feet or 200 Square metres
Displacement factor (Displacement / loading): 62 %
Structure weight / hull surface area: 15 lbs/sq ft or 73 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,50
- Longitudinal: 1,45
- Overall: 0,56
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Trial speed :30,5 knts
320 nm @25,5 knts
With that much stability reserve (1.40) I'd cut beam to get more strength and better seakeeping. This would then allow you to lower freeboard w/o coasting seakeeping and drop weight while staying over .50 cross-sectional. Maybe even get it down to 150t that way. Remember, these things are so small that any rough sea will swamp them anyway, so the SS Seakeeping number is pointless..I'd just try to keep it above 0.60. Also, you BC is .352, which is below the 0.380 minimum.
Torpedo boote, Esc Coastal torpedoboats laid down 1920
Displacement:
147 t light; 151 t standard; 171 t normal; 186 t full load
Dimensions: Length overall / water x beam x draught
202,46 ft / 196,85 ft x 14,76 ft x 5,41 ft (normal load)
61,71 m / 60,00 m x 4,50 m x 1,65 m
Armament:
1 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,88kg shells, 1920 Model
Quick firing gun in deck mount
on centreline forward
2 - 0,79" / 20,0 mm guns (1x2 guns), 0,24lbs / 0,11kg shells, 1920 Model
Anti-aircraft guns in deck mount
on centreline aft
Weight of broadside 2 lbs / 1 kg
Shells per gun, main battery: 500
4 - 20,9" / 530 mm above water torpedoes
Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 3.913 shp / 2.919 Kw = 25,50 kts
Range 2.500nm at 12,00 kts
Bunker at max displacement = 35 tons
Complement:
23 - 30
Cost:
£0,042 million / $0,166 million
Distribution of weights at normal displacement:
Armament: 0 tons, 0,2 %
Machinery: 87 tons, 50,9 %
Hull, fittings & equipment: 50 tons, 29,3 %
Fuel, ammunition & stores: 24 tons, 13,8 %
Miscellaneous weights: 10 tons, 5,9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
45 lbs / 20 Kg = 23,0 x 1,6 " / 40 mm shells or 0,1 torpedoes
Stability (Unstable if below 1.00): 1,07
Metacentric height 0,3 ft / 0,1 m
Roll period: 10,9 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0,02
Seaboat quality (Average = 1.00): 1,05
Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0,380
Length to Beam Ratio: 13,33 : 1
'Natural speed' for length: 14,03 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15,42 ft / 4,70 m
- Forecastle (20 %): 8,20 ft / 2,50 m (5,74 ft / 1,75 m aft of break)
- Mid (50 %): 5,74 ft / 1,75 m
- Quarterdeck (15 %): 5,74 ft / 1,75 m
- Stern: 5,74 ft / 1,75 m
- Average freeboard: 6,81 ft / 2,08 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 172,5 %
- Above water (accommodation/working, high = better): 5,4 %
Waterplane Area: 1.772 Square feet or 165 Square metres
Displacement factor (Displacement / loading): 60 %
Structure weight / hull surface area: 13 lbs/sq ft or 65 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,50
- Longitudinal: 1,41
- Overall: 0,56
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor
Trial speed :30,5 knts
320 nm @25,5 knts
Quote
Length to Beam Ratio: 13,33 : 1
12:1 is max
Not entirely, 12-1 is the limit ships can be build without inviting moderator induced problems.