The main problem is with the really ambitious operational depth requirement and applying that to SS. That is a minimum hull strength requirement of 4.92.
Something here although I do not like it. With what I have figured out, I prefer a d:b of over 0.8, preferably between 0.85 and 1.00 although SS does not really allow that when using the unrealistic location of miscellaneous weights for the ballast.
Two sims. The first is the one how it is supposed to be simmed according to the springstyle notes with 310 tons for ballast (roughly 1/6) and 50 tons for the various other things (although 50 tons is probably not enough). For the second sim, I subtracted the 310 tons ballast from the normal displacement by altering the depth of the sub in order to get the hull to a surfaced state. With this sim I calculated how much hp is required for a surface speed of 17.5 knots (=3556 hp) and how much bunker is required for a 7,500 nm range at 10 knots (= 198 tons). Once that is done, I use that power and bunkerage weight to determine the speed and range of the first sim which means that the 16.97 knots speed and 6,550nm at 10 kts range translates to a surface speed and range of 17.5 knots and 7,500 nm at 10 knots. So that is pretty much the absolute minimum of this particular design when it comes to speed and range.
Sink, Argie Submarine laid down 1947
Displacement:
1,698 t light; 1,735 t standard; 1,845 t normal; 1,933 t full load
Dimensions: Length overall / water x beam x draught
230.00 ft / 230.00 ft x 30.00 ft x 20.00 ft (normal load)
70.10 m / 70.10 m x 9.14 m x 6.10 m
Armament:
2 - 0.79" / 20.0 mm guns (1x2 guns), 0.24lbs / 0.11kg shells, 1947 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
Weight of broadside 0 lbs / 0 kg
Shells per gun, main battery: 1,500
6 - 21.0" / 533.4 mm submerged torpedo tubes
Machinery:
Diesel Internal combustion generators plus batteries,
Electric motors, 2 shafts, 3,556 shp / 2,653 Kw = 16.97 kts
Range 6,550nm at 10.00 kts
Bunker at max displacement = 198 tons
Complement:
140 - 183
Cost:
£0.522 million / $2.088 million
Distribution of weights at normal displacement:
Armament: 0 tons, 0.0%
Machinery: 88 tons, 4.8%
Hull, fittings & equipment: 1,250 tons, 67.7%
Fuel, ammunition & stores: 147 tons, 8.0%
Miscellaneous weights: 360 tons, 19.5%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,603 lbs / 727 Kg = 6,566.9 x 0.8 " / 20 mm shells or 1.0 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 1.0 ft / 0.3 m
Roll period: 12.8 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.468
Length to Beam Ratio: 7.67 : 1
'Natural speed' for length: 15.17 kts
Power going to wave formation at top speed: 49 %
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 (% = measuring location as a percentage of overall length):
- Stem: 0.00 ft / 0.00 m
- Forecastle (20%): 0.00 ft / 0.00 m
- Mid (50%): 0.00 ft / 0.00 m
- Quarterdeck (15%): 0.00 ft / 0.00 m
- Stern: 0.00 ft / 0.00 m
- Average freeboard: 0.00 ft / 0.00 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 60.1%
- Above water (accommodation/working, high = better): 0.0%
Waterplane Area: 4,468 Square feet or 415 Square metres
Displacement factor (Displacement / loading): 344%
Structure weight / hull surface area: 180 lbs/sq ft or 881 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 4.34
- Longitudinal: 4.35
- Overall: 4.34
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability
Sink, Argie Submarine laid down 1947
Displacement:
1,401 t light; 1,433 t standard; 1,543 t normal; 1,631 t full load
Dimensions: Length overall / water x beam x draught
230.00 ft / 230.00 ft x 30.00 ft x 16.72 ft (normal load)
70.10 m / 70.10 m x 9.14 m x 5.10 m
Armament:
2 - 0.79" / 20.0 mm guns (1x2 guns), 0.24lbs / 0.11kg shells, 1947 Model
Anti-aircraft guns in deck mount
on centreline amidships, all raised guns - superfiring
Weight of broadside 0 lbs / 0 kg
Shells per gun, main battery: 1,500
6 - 21.0" / 533.4 mm submerged torpedo tubes
Machinery:
Diesel Internal combustion generators plus batteries,
Electric motors, 2 shafts, 3,556 shp / 2,653 Kw = 17.50 kts
Range 7,500nm at 10.00 kts
Bunker at max displacement = 198 tons
Complement:
122 - 159
Cost:
£0.447 million / $1.786 million
Distribution of weights at normal displacement:
Armament: 0 tons, 0.0%
Machinery: 88 tons, 5.7%
Hull, fittings & equipment: 954 tons, 61.8%
Fuel, ammunition & stores: 141 tons, 9.2%
Miscellaneous weights: 360 tons, 23.3%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,131 lbs / 513 Kg = 4,631.7 x 0.8 " / 20 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 1.0 ft / 0.3 m
Roll period: 12.8 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.468
Length to Beam Ratio: 7.67 : 1
'Natural speed' for length: 15.17 kts
Power going to wave formation at top speed: 51 %
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 (% = measuring location as a percentage of overall length):
- Stem: 0.00 ft / 0.00 m
- Forecastle (20%): 0.00 ft / 0.00 m
- Mid (50%): 0.00 ft / 0.00 m
- Quarterdeck (15%): 0.00 ft / 0.00 m
- Stern: 0.00 ft / 0.00 m
- Average freeboard: 0.00 ft / 0.00 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71.2%
- Above water (accommodation/working, high = better): 0.0%
Waterplane Area: 4,468 Square feet or 415 Square metres
Displacement factor (Displacement / loading): 288%
Structure weight / hull surface area: 150 lbs/sq ft or 733 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3.93
- Longitudinal: 2.78
- Overall: 3.03
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability