Torpedo boats

[ledeper]

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

[Sachmle]

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.

[ledeper]

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

[Kaiser Kirk]

   
   Length to Beam Ratio: 13,33 : 1

12:1 is max

[maddox]

Not entirely, 12-1 is the limit ships can be build without inviting moderator induced problems.