Republic of New England

[Darman]

A bomb ketch. 
Enter ship name, Enter country Enter ship type laid down 1850

Displacement:
   154 t light; 170 t standard; 175 t normal; 179 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (75.00 ft / 75.00 ft) x 20.00 ft x (6.00 / 6.11 ft)
   (22.86 m / 22.86 m) x 6.10 m  x (1.83 / 1.86 m)

Armament:
      1 - 12.00" / 305 mm 15.0 cal gun - 484.02lbs / 219.55kg shells, 50 per gun
     Muzzle loading gun in deck mount, 1850 Model
     1 x Single mount on centreline, forward deck centre
      Weight of broadside 484 lbs / 220 kg

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 1 shaft, 104 shp / 78 Kw = 8.00 kts
   Range 50nm at 8.00 kts
   Bunker at max displacement = 8 tons (100% coal)

Complement:
   23 - 31

Cost:
   £0.020 million / $0.081 million

Distribution of weights at normal displacement:
   Armament: 18 tons, 10.6 %
      - Guns: 18 tons, 10.6 %
   Machinery: 52 tons, 30.0 %
   Hull, fittings & equipment: 83 tons, 47.2 %
   Fuel, ammunition & stores: 21 tons, 12.3 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     29 lbs / 13 Kg = 0.1 x 12.0 " / 305 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.66
   Metacentric height 1.0 ft / 0.3 m
   Roll period: 8.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 1.85
   Seaboat quality  (Average = 1.00): 2.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.681 / 0.682
   Length to Beam Ratio: 3.75 : 1
   'Natural speed' for length: 8.66 kts
   Power going to wave formation at top speed: 53 %
   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 %,  6.00 ft / 1.83 m,  6.00 ft / 1.83 m
      - Forward deck:   30.00 %,  6.00 ft / 1.83 m,  6.00 ft / 1.83 m
      - Aft deck:   35.00 %,  6.00 ft / 1.83 m,  6.00 ft / 1.83 m
      - Quarter deck:   15.00 %,  6.00 ft / 1.83 m,  6.00 ft / 1.83 m
      - Average freeboard:      6.00 ft / 1.83 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 140.8 %
      - Above water (accommodation/working, high = better): 58.2 %
   Waterplane Area: 1,170 Square feet or 109 Square metres
   Displacement factor (Displacement / loading): 98 %
   Structure weight / hull surface area: 54 lbs/sq ft or 261 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.46
      - Longitudinal: 5.42
      - Overall: 0.58
   Caution: Hull subject to strain in open-sea
   Cramped 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

Warning: Beam between bulkheads too wide

[Sachmle]

I'll guess that no matter what the Shipbuilding rules end up being, having a cross-sectional strength under 0.50 won't be allowed for any ship, let alone one doing 8kts. Also, you forgot to set your internal beam.

[Darman]

I knew the cross-sectional looked wrong and couldn't remember why. 
Also, how do you set internal beam?  I don't recall seeing a setting for it. 

[Logi]

First- you are using SS3b3, correct?

If so you go to the Armor tab. In the Belts&Bulkhead section - Under the Torpedo Bulkhead - Type option, there's a fill-in with the label: Beam between bulkheads.

That's what you need to fix - typically setting to ~10' feet narrower than the waterline beam. Else you get the warning: Beam between bulkheads too wide

[Carthaginian]

Doesn't have to be 10' narrower... doesn't have to be a foot narrower.

The most important part is that you select 'Strengthened Bulkheads' instead of 'Additional Bulkheads.'
The 'Additional Bulkheads' option requires there to be several feet of blank space between the outer bulkheads and inner ones. The 'Strengthened Bulkheads' option does not... you just have to change the figure in the box, even to the same number.

[Logi]

I didn't even notice that - probably because I never design using strengthened bulkheads. :)