Aztec Ship Designs 1921-1924

[Desertfox]

I have to agree, offensive minelayers should be somewhat expendable. Defensive ones can be big and slow.

[TacCovert4]

Probably worth looking at.  Maybe strip the aft armament and torpedoes off of an F-class DD, and use the weight savings for mines.

[TacCovert4]

In other news, the Sultanate finds itself with its first multi-national internal waterway, that being the Missouri River.  Thus conversations begin about ways to patrol this waterway and potentially protect it in wartime, as well as use the mobility of the river to support ground forces.  The Missouri is a wide and relatively shallow river, but already has a significant amount of riverboat traffic, even traders headed up into unsettled country to trade with the natives, as well as the lucrative trade from Kansas City, Geronimo to the Mississippi valley. 

Key features for a boat like this would be ability to survive hits from shore-based light guns or machine guns without incident, nice steady boat for general patrolling, customs, and rescue work, and a relatively heavy anti-aircraft battery as it is more likely that such a boat would come under aircraft attack than any other type of attack save shore-based guns.  Speed is not necessary, merely enough to make steady headway upstream in all conditions.  The necessary element is for it to be light and nimble, with a shallow draft, as those are vitally important to avoiding grounding in the Missouri.

Creek, Aztec River Patrol Boat laid down 1922

Displacement:
    114 t light; 126 t standard; 129 t normal; 132 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (82.02 ft / 82.02 ft) x 14.76 ft x (5.74 / 5.84 ft)
    (25.00 m / 25.00 m) x 4.50 m  x (1.75 / 1.78 m)

Armament:
      2 - 3.94" / 100 mm 45.0 cal guns - 30.77lbs / 13.96kg shells, 200 per gun
      Quick firing guns in deck mounts, 1922 Model
      2 x Single mounts on centreline ends, evenly spread
      4 - 1.18" / 30.0 mm 50.0 cal guns - 0.87lbs / 0.40kg shells, 1,000 per gun
      Anti-air guns in deck and hoist mounts, 1922 Model
      2 x Twin mounts on sides, aft deck forward
      4 - 0.47" / 12.0 mm 70.0 cal guns - 0.06lbs / 0.03kg shells, 2,000 per gun
      Machine guns in deck mounts, 1922 Model
      4 x Single mounts on sides, evenly spread
      Weight of broadside 65 lbs / 30 kg

Armour:
   - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    1.57" / 40 mm          -                  -
    2nd:    0.79" / 20 mm          -            0.79" / 20 mm

   - Box over machinery & magazines:
    1.57" / 40 mm

   - Conning towers: Forward 1.57" / 40 mm, Aft 0.00" / 0 mm

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 2 shafts, 568 shp / 424 Kw = 14.00 kts
    Range 1,000nm at 8.00 kts
    Bunker at max displacement = 6 tons

Complement:
    18 - 24

Cost:
    £0.028 million / $0.113 million

Distribution of weights at normal displacement:
    Armament: 13 tons, 9.9 %
       - Guns: 13 tons, 9.9 %
    Armour: 43 tons, 33.1 %
       - Armament: 9 tons, 6.7 %
       - Armour Deck: 33 tons, 25.7 %
       - Conning Tower: 1 tons, 0.7 %
    Machinery: 19 tons, 14.9 %
    Hull, fittings & equipment: 32 tons, 24.6 %
    Fuel, ammunition & stores: 15 tons, 11.5 %
    Miscellaneous weights: 8 tons, 5.9 %
       - On freeboard deck: 6 tons
       - Above deck: 2 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      185 lbs / 84 Kg = 6.1 x 3.9 " / 100 mm shells or 0.3 torpedoes
    Stability (Unstable if below 1.00): 1.12
    Metacentric height 0.3 ft / 0.1 m
    Roll period: 10.5 seconds
    Steadiness    - As gun platform (Average = 50 %): 54 %
            - Recoil effect (Restricted arc if above 1.00): 0.92
    Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
    Hull has a flush deck,
      a normal bow and a cruiser stern
    Block coefficient (normal/deep): 0.650 / 0.652
    Length to Beam Ratio: 5.56 : 1
    'Natural speed' for length: 9.06 kts
    Power going to wave formation at top speed: 73 %
    Trim (Max stability = 0, Max steadiness = 100): 53
    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 %,  8.20 ft / 2.50 m,  7.22 ft / 2.20 m
       - Forward deck:    30.00 %,  7.22 ft / 2.20 m,  6.89 ft / 2.10 m
       - Aft deck:    35.00 %,  6.89 ft / 2.10 m,  6.89 ft / 2.10 m
       - Quarter deck:    15.00 %,  6.89 ft / 2.10 m,  6.89 ft / 2.10 m
       - Average freeboard:        7.08 ft / 2.16 m
    Ship tends to be wet forward

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 80.5 %
        - Above water (accommodation/working, high = better): 68.4 %
    Waterplane Area: 928 Square feet or 86 Square metres
    Displacement factor (Displacement / loading): 104 %
    Structure weight / hull surface area: 21 lbs/sq ft or 105 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.69
        - Longitudinal: 9.78
        - Overall: 0.90
    Caution: Hull subject to strain in open-sea
    Excellent machinery, storage, compartmentation space
    Cramped accommodation and workspace room

2t - 1918 FC

[The Rock Doctor]

Looks handy - you have shipbuilding capability on the river, then?

[TacCovert4]

Potentially.  Looking at a 40m drydock in Kansas City or another one of the bustling port towns.  Part of a way to improve the river shipping industry as multiple nations start to ply the Missouri.  A drydock would let us locally build purpose-designed patrol vessels rather than rail-shipping some 20t MTBs.  And when it's not building the handful of patrol vessels or doing maintenance, it would be a local commercial boon to the region as a place to get commercial shipping built and maintained.

[The Rock Doctor]

I suppose I should look at establishing a lock at Louisville making the Ohio a little more user-friendly.

[TacCovert4]

I did research, and it looks like not only can I use the Missouri to trade with the Norse via the Roman Mississippi, I can also use it to trade with the Norse directly, and even with the Japanese.  The Missouri appears to be passable by ships of 1.8m draft all the way up to Montana during most months of the year.

[The Rock Doctor]

My reading suggests the Ohio's natural limit is around 1.2 m up at Pittsburgh (not that I own Pittsburgh) so I have fewer options, but still options.

[TacCovert4]

Yeah.  Quite shallow.  But then you're looking at a boat to do 2 things.  1)  General Patrol Work.  2)  Ground Support and River Control.  Hence I'm looking at a riverboat with a gun that would be quite out of proportion for actually defending the river, but it's a solidly protected platform for operating an artillery piece far inland. 

I did a variation on the design, stretched it a little in length and beam and made the draft even shallower.  Cut the aft 100mm mount in favor of a 70mm AA gun.  Thought is that at the ranges of a fight against small craft, the 30 and 70mm AA guns and the 12mm MGs would be more than adequate over open sights anyway, the fire control is for anti-aircraft defense and for the 100mm gun if it's in support of ground troops ashore.  Yellowstone, a historical paddle steamer, was 37m x 6m x 1.8m.  So mine should be quite a bit more capable on the river.  Sped it up by one knot, cruise is also twice the other design at a higher cruise speed.....so even more range at a slow cruising speed for long loitering in parts away from home. 

Creek, Aztec Gunboat laid down 1922

Displacement:
   136 t light; 146 t standard; 157 t normal; 166 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (98.43 ft / 98.43 ft) x 16.40 ft x (5.25 / 5.51 ft)
   (30.00 m / 30.00 m) x 5.00 m  x (1.60 / 1.68 m)

Armament:
      1 - 3.94" / 100 mm 50.0 cal gun - 32.30lbs / 14.65kg shells, 200 per gun
     Quick firing gun in deck mount, 1922 Model
     1 x Single mount on centreline, forward deck centre
      4 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     2 x Twin mounts on sides, forward deck aft
      6 - 0.47" / 12.0 mm 70.0 cal guns - 0.07lbs / 0.03kg shells, 2,000 per gun
     Machine guns in deck mounts, 1922 Model
     6 x Single mounts on sides, evenly spread
      1 - 2.76" / 70.0 mm 50.0 cal gun - 11.08lbs / 5.03kg shells, 200 per gun
     Anti-air gun in deck mount, 1922 Model
     1 x Single mount on centreline, aft deck aft
      Weight of broadside 47 lbs / 21 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.59" / 15 mm            -
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm
   3rd:   0.59" / 15 mm         -               -
   4th:   0.79" / 20 mm         -               -

   - Box over machinery & magazines:
   1.26" / 32 mm

   - Conning towers: Forward 1.18" / 30 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 769 shp / 574 Kw = 15.00 kts
   Range 2,000nm at 10.00 kts
   Bunker at max displacement = 20 tons

Complement:
   21 - 28

Cost:
   £0.031 million / $0.126 million

Distribution of weights at normal displacement:
   Armament: 11 tons, 6.8 %
      - Guns: 11 tons, 6.8 %
   Armour: 47 tons, 30.1 %
      - Armament: 13 tons, 8.0 %
      - Armour Deck: 34 tons, 21.6 %
      - Conning Tower: 1 tons, 0.5 %
   Machinery: 26 tons, 16.6 %
   Hull, fittings & equipment: 43 tons, 27.0 %
   Fuel, ammunition & stores: 22 tons, 13.8 %
   Miscellaneous weights: 9 tons, 5.7 %
      - Hull below water: 3 tons
      - On freeboard deck: 4 tons
      - Above deck: 2 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     259 lbs / 118 Kg = 8.5 x 3.9 " / 100 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 0.5 ft / 0.1 m
   Roll period: 10.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 59 %
         - Recoil effect (Restricted arc if above 1.00): 0.45
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.655
   Length to Beam Ratio: 6.00 : 1
   'Natural speed' for length: 9.92 kts
   Power going to wave formation at top speed: 71 %
   Trim (Max stability = 0, Max steadiness = 100): 59
   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 %,  7.55 ft / 2.30 m,  7.22 ft / 2.20 m
      - Forward deck:   30.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Aft deck:   35.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Quarter deck:   15.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Average freeboard:      7.24 ft / 2.21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 78.1 %
      - Above water (accommodation/working, high = better): 81.0 %
   Waterplane Area: 1,237 Square feet or 115 Square metres
   Displacement factor (Displacement / loading): 114 %
   Structure weight / hull surface area: 22 lbs/sq ft or 107 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.73
      - Longitudinal: 5.67
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room

2t - 1918 FC

3t - Temporary spaces for up to 8 troops

4t - 1 x 2t flat-bottomed skiff

[TacCovert4]

A third variation.  Changes are a reduction in range to 1500nm, spaces for 2 Seal Warriors (Marines) permanent berthing, these would do customs inspections as well as man the infantry mortar.  A below waterline arms locker is also included for the Seal Warriors personal weapons and an infantry mortar and some ammunition (figure 50-100 rounds or so) for use as support for ground troops.  Seal Warriors cabin can also be used to temporarily accommodate up to 16 troops for short day trips.  A strengthened and prepared bit of deck with proper mounting plate for a light infantry mortar is also included.

Creek, Aztec Gunboat laid down 1922

Displacement:
   138 t light; 149 t standard; 157 t normal; 164 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (98.43 ft / 98.43 ft) x 16.40 ft x (5.25 / 5.45 ft)
   (30.00 m / 30.00 m) x 5.00 m  x (1.60 / 1.66 m)

Armament:
      1 - 3.94" / 100 mm 50.0 cal gun - 32.30lbs / 14.65kg shells, 200 per gun
     Quick firing gun in deck mount, 1922 Model
     1 x Single mount on centreline, forward deck centre
      4 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     2 x Twin mounts on sides, forward deck aft
      6 - 0.47" / 12.0 mm 70.0 cal guns - 0.07lbs / 0.03kg shells, 2,000 per gun
     Machine guns in deck mounts, 1922 Model
     6 x Single mounts on sides, evenly spread
      1 - 2.76" / 70.0 mm 50.0 cal gun - 11.08lbs / 5.03kg shells, 200 per gun
     Anti-air gun in deck mount, 1922 Model
     1 x Single mount on centreline, aft deck centre
      Weight of broadside 47 lbs / 21 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.59" / 15 mm            -
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm
   3rd:   0.59" / 15 mm         -               -
   4th:   0.79" / 20 mm         -               -

   - Box over machinery & magazines:
   1.26" / 32 mm

   - Conning towers: Forward 1.18" / 30 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 769 shp / 574 Kw = 15.00 kts
   Range 1,500nm at 10.00 kts
   Bunker at max displacement = 16 tons

Complement:
   21 - 28

Cost:
   £0.032 million / $0.127 million

Distribution of weights at normal displacement:
   Armament: 11 tons, 6.8 %
      - Guns: 11 tons, 6.8 %
   Armour: 47 tons, 30.1 %
      - Armament: 13 tons, 8.0 %
      - Armour Deck: 34 tons, 21.6 %
      - Conning Tower: 1 tons, 0.5 %
   Machinery: 26 tons, 16.6 %
   Hull, fittings & equipment: 43 tons, 27.1 %
   Fuel, ammunition & stores: 19 tons, 12.1 %
   Miscellaneous weights: 12 tons, 7.3 %
      - Hull below water: 5 tons
      - On freeboard deck: 5 tons
      - Above deck: 2 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     255 lbs / 116 Kg = 8.3 x 3.9 " / 100 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.19
   Metacentric height 0.5 ft / 0.1 m
   Roll period: 10.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 59 %
         - Recoil effect (Restricted arc if above 1.00): 0.45
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.654
   Length to Beam Ratio: 6.00 : 1
   'Natural speed' for length: 9.92 kts
   Power going to wave formation at top speed: 71 %
   Trim (Max stability = 0, Max steadiness = 100): 59
   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 %,  7.55 ft / 2.30 m,  7.22 ft / 2.20 m
      - Forward deck:   30.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Aft deck:   35.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Quarter deck:   15.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Average freeboard:      7.24 ft / 2.21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 79.4 %
      - Above water (accommodation/working, high = better): 81.0 %
   Waterplane Area: 1,237 Square feet or 115 Square metres
   Displacement factor (Displacement / loading): 112 %
   Structure weight / hull surface area: 22 lbs/sq ft or 107 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.73
      - Longitudinal: 5.68
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room

2t - 1918 FC

4t- Quarters for 2 Marines (mortar crew) or temporary berthing for 16 troops

4t - 1 x 2t flat-bottomed skiff aft centerline

.5t - Strengthened Deck Plate for mounting of infantry mortar

1t - Arms locker for Infantry mortar and ammunition

[TacCovert4]

And finally the last design iterations.  This first one aims for utility, with the ability to carry a notable Seal Warrior detachment permanently, or about two platoons of infantry for a day trip.  A pair of flat bottom skiffs are aboard to provide boat-shore movements.  The 100mm and 70mm guns have been removed in favor of a 130mm gun, which would be notable in a fire support role as it would be as heavy as divisional artillery, with more ammunition and better fire control.  A pair of baseplates have been built in for the onboard Marines to provide mortar support to ground troops as well, and an aft twin 30mm AA mount has been added to supplement the loss of all other aft armament. 

Creek, Aztec Gunboat laid down 1922

Displacement:
   177 t light; 192 t standard; 202 t normal; 210 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (114.83 ft / 114.83 ft) x 18.04 ft x (5.25 / 5.42 ft)
   (35.00 m / 35.00 m) x 5.50 m  x (1.60 / 1.65 m)

Armament:
      1 - 5.12" / 130 mm 45.0 cal gun - 67.61lbs / 30.67kg shells, 200 per gun
     Quick firing gun in deck mount, 1922 Model
     1 x Single mount on centreline, forward deck centre
      6 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     3 x Twin mounts on sides, forward deck aft
      6 - 0.47" / 12.0 mm 70.0 cal guns - 0.07lbs / 0.03kg shells, 2,000 per gun
     Machine guns in deck mounts, 1922 Model
     6 x Single mounts on sides, evenly spread
      Weight of broadside 73 lbs / 33 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.59" / 15 mm            -
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm
   3rd:   0.59" / 15 mm         -               -

   - Box over machinery & magazines:
   1.18" / 30 mm

   - Conning towers: Forward 1.18" / 30 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 816 shp / 609 Kw = 15.00 kts
   Range 1,500nm at 10.00 kts
   Bunker at max displacement = 18 tons

Complement:
   26 - 34

Cost:
   £0.039 million / $0.157 million

Distribution of weights at normal displacement:
   Armament: 14 tons, 7.1 %
      - Guns: 14 tons, 7.1 %
   Armour: 48 tons, 23.7 %
      - Armament: 13 tons, 6.6 %
      - Armour Deck: 34 tons, 16.7 %
      - Conning Tower: 1 tons, 0.4 %
   Machinery: 28 tons, 13.7 %
   Hull, fittings & equipment: 54 tons, 26.9 %
   Fuel, ammunition & stores: 25 tons, 12.2 %
   Miscellaneous weights: 33 tons, 16.3 %
      - Hull below water: 20 tons
      - Hull above water: 2 tons
      - On freeboard deck: 9 tons
      - Above deck: 2 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     319 lbs / 145 Kg = 4.8 x 5.1 " / 130 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.23
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 10.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.46
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.654
   Length to Beam Ratio: 6.36 : 1
   'Natural speed' for length: 10.72 kts
   Power going to wave formation at top speed: 66 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   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 %,  7.55 ft / 2.30 m,  7.22 ft / 2.20 m
      - Forward deck:   30.00 %,  7.22 ft / 2.20 m,  6.96 ft / 2.12 m
      - Aft deck:   35.00 %,  6.96 ft / 2.12 m,  6.56 ft / 2.00 m
      - Quarter deck:   15.00 %,  6.56 ft / 2.00 m,  6.56 ft / 2.00 m
      - Average freeboard:      6.95 ft / 2.12 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 80.4 %
      - Above water (accommodation/working, high = better): 80.4 %
   Waterplane Area: 1,587 Square feet or 147 Square metres
   Displacement factor (Displacement / loading): 114 %
   Structure weight / hull surface area: 25 lbs/sq ft or 120 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.78
      - Longitudinal: 3.35
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room

2t - 1918 FC

20t - Quarters for 10 Marines or 80 temporary PAX

8t - 2 x 2t flat-bottomed skiff

1t - Strengthened Deck Plate for mounting of infantry mortar x 2

2t - Arms locker for Infantry mortars and ammunition

[TacCovert4]

And the last design concept.  Gone are the Marines, extra ships boats, or shorter range support capability like mortars or 70mm guns.  Instead she's got a pair of 130mm guns, basically an entire heavy field battery, with 4 twin 30mm guns for AA and emergency light boat defense or for shooting up the shoreline, and the single 12mm MGs have been traded for twin 12mm MGs to give her ferocious power in closer fights.  This design is truly a gunboat, without any nods given to non-combat duties.


Creek, Aztec Gunboat laid down 1922

Displacement:
   168 t light; 192 t standard; 202 t normal; 210 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (114.83 ft / 114.83 ft) x 18.04 ft x (5.25 / 5.42 ft)
   (35.00 m / 35.00 m) x 5.50 m  x (1.60 / 1.65 m)

Armament:
      2 - 5.12" / 130 mm 45.0 cal guns - 67.61lbs / 30.67kg shells, 200 per gun
     Quick firing guns in deck mounts, 1922 Model
     2 x Single mounts on centreline ends, evenly spread
      8 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     4 x Twin mounts on sides, evenly spread
      12 - 0.47" / 12.0 mm 70.0 cal guns - 0.07lbs / 0.03kg shells, 2,000 per gun
     Machine guns in deck mounts, 1922 Model
     6 x Twin mounts on sides, evenly spread
      Weight of broadside 143 lbs / 65 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.59" / 15 mm            -
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm
   3rd:   0.59" / 15 mm         -               -

   - Box over machinery & magazines:
   1.18" / 30 mm

   - Conning towers: Forward 1.18" / 30 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 816 shp / 609 Kw = 15.00 kts
   Range 1,500nm at 10.00 kts
   Bunker at max displacement = 18 tons

Complement:
   26 - 34

Cost:
   £0.048 million / $0.194 million

Distribution of weights at normal displacement:
   Armament: 27 tons, 13.4 %
      - Guns: 27 tons, 13.4 %
   Armour: 56 tons, 27.6 %
      - Armament: 19 tons, 9.2 %
      - Armour Deck: 36 tons, 18.0 %
      - Conning Tower: 1 tons, 0.4 %
   Machinery: 28 tons, 13.7 %
   Hull, fittings & equipment: 55 tons, 27.2 %
   Fuel, ammunition & stores: 34 tons, 16.6 %
   Miscellaneous weights: 3 tons, 1.5 %
      - Above deck: 3 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     290 lbs / 131 Kg = 4.3 x 5.1 " / 130 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 0.5 ft / 0.2 m
   Roll period: 10.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.94
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.654
   Length to Beam Ratio: 6.36 : 1
   'Natural speed' for length: 10.72 kts
   Power going to wave formation at top speed: 66 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   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 %,  7.55 ft / 2.30 m,  7.22 ft / 2.20 m
      - Forward deck:   30.00 %,  7.22 ft / 2.20 m,  7.22 ft / 2.20 m
      - Aft deck:   35.00 %,  7.22 ft / 2.20 m,  6.56 ft / 2.00 m
      - Quarter deck:   15.00 %,  6.56 ft / 2.00 m,  6.56 ft / 2.00 m
      - Average freeboard:      7.03 ft / 2.14 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 88.3 %
      - Above water (accommodation/working, high = better): 81.9 %
   Waterplane Area: 1,587 Square feet or 147 Square metres
   Displacement factor (Displacement / loading): 106 %
   Structure weight / hull surface area: 28 lbs/sq ft or 136 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.76
      - Longitudinal: 4.07
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Cramped accommodation and workspace room

3t - 1918 FC

[TacCovert4]

After getting advice, I've made a revised conceptual minelayer.  Went with the DD based minelayer, still relatively fast, though slower than some DDs.  Armament is biased Aft as she's not meant to be an offensive DD.  Though she does have a pair of twin torpedo tubes athwart the bridge, as a present threat to any larger ship that might want to really try to get too close.  But the big thing, is the surprising number of mines that can get packed onto her sides from basically the bridge all the way back to the quarterdeck rail.  90 mines!

Bomb, Aztec Minelayer laid down 1922

Displacement:
   1,478 t light; 1,532 t standard; 1,767 t normal; 1,955 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (348.00 ft / 344.49 ft) x 29.53 ft x (11.06 / 11.98 ft)
   (106.07 m / 105.00 m) x 9.00 m  x (3.37 / 3.65 m)

Armament:
      6 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 150 per gun
     Quick firing guns in deck mounts, 1922 Model
     3 x Twin mounts on centreline ends, majority aft
      1 raised mount aft - superfiring
      6 - 1.18" / 30.0 mm 50.0 cal guns - 0.87lbs / 0.40kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     3 x Twin mounts on centreline, aft evenly spread
      1 raised mount
      Weight of broadside 199 lbs / 90 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm         -               -
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm

   - Conning towers: Forward 0.98" / 25 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 34,946 shp / 26,070 Kw = 31.50 kts
   Range 5,500nm at 14.00 kts
   Bunker at max displacement = 423 tons

Complement:
   136 - 177

Cost:
   £0.525 million / $2.098 million

Distribution of weights at normal displacement:
   Armament: 34 tons, 1.9 %
      - Guns: 34 tons, 1.9 %
   Armour: 12 tons, 0.7 %
      - Armament: 9 tons, 0.5 %
      - Conning Tower: 3 tons, 0.2 %
   Machinery: 923 tons, 52.2 %
   Hull, fittings & equipment: 398 tons, 22.5 %
   Fuel, ammunition & stores: 289 tons, 16.4 %
   Miscellaneous weights: 110 tons, 6.2 %
      - On freeboard deck: 106 tons
      - Above deck: 4 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     439 lbs / 199 Kg = 14.4 x 3.9 " / 100 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.15
   Metacentric height 1.0 ft / 0.3 m
   Roll period: 12.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.35
   Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.550 / 0.561
   Length to Beam Ratio: 11.67 : 1
   'Natural speed' for length: 18.56 kts
   Power going to wave formation at top speed: 67 %
   Trim (Max stability = 0, Max steadiness = 100): 66
   Bow angle (Positive = bow angles forward): 10.00 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 %,  19.91 ft / 6.07 m,  16.31 ft / 4.97 m
      - Forward deck:   30.00 %,  16.31 ft / 4.97 m,  12.66 ft / 3.86 m
      - Aft deck:   35.00 %,  12.66 ft / 3.86 m,  12.66 ft / 3.86 m
      - Quarter deck:   15.00 %,  12.66 ft / 3.86 m,  12.66 ft / 3.86 m
      - Average freeboard:      14.23 ft / 4.34 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 175.2 %
      - Above water (accommodation/working, high = better): 134.3 %
   Waterplane Area: 7,099 Square feet or 660 Square metres
   Displacement factor (Displacement / loading): 68 %
   Structure weight / hull surface area: 28 lbs/sq ft or 137 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.49
      - Longitudinal: 1.68
      - Overall: 0.56
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

4t - 1918 FC
16t - 2 x 2 x 21in HW TT Sides Foredeck
90t - 90 x Mines
5t - Additional DC Equipment

[TacCovert4]

A further track for design iteration is looking at the potential Razee designs of the new type with the 240mm gun currently in development.  RL - I had a lot of designs, they're lost with my old computer that died, so I'm starting from scratch again.

Surprise, Aztec Razee laid down 1922

Displacement:
   17,184 t light; 17,991 t standard; 19,562 t normal; 20,819 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (728.82 ft / 721.78 ft) x 78.74 ft x (22.31 / 23.43 ft)
   (222.14 m / 220.00 m) x 24.00 m  x (6.80 / 7.14 m)

Armament:
      9 - 9.45" / 240 mm 50.0 cal guns - 446.53lbs / 202.54kg shells, 140 per gun
     Breech loading guns in turret on barbette mounts, 1922 Model
     3 x 3-gun mounts on centreline ends, majority forward
      1 raised mount - superfiring
      12 - 5.12" / 130 mm 50.0 cal guns - 70.97lbs / 32.19kg shells, 200 per gun
     Quick firing guns in deck and hoist mounts, 1922 Model
     6 x Twin mounts on sides, evenly spread
      3 - 2.76" / 70.0 mm 50.0 cal guns - 11.08lbs / 5.03kg shells, 300 per gun
     Anti-air guns in deck mounts, 1922 Model
     3 x Single mounts on centreline, evenly spread
      3 raised mounts
      8 - 1.18" / 30.0 mm 50.0 cal guns - 0.87lbs / 0.40kg shells, 1,000 per gun
     Anti-air guns in deck and hoist mounts, 1922 Model
     4 x Twin mounts on sides, evenly spread
      Weight of broadside 4,911 lbs / 2,227 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   5.51" / 140 mm   524.93 ft / 160.00 m   13.12 ft / 4.00 m
   Ends:   2.76" / 70 mm   196.85 ft / 60.00 m   13.12 ft / 4.00 m
     Main Belt covers 112 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.38" / 35 mm   524.93 ft / 160.00 m   17.95 ft / 5.47 m
   Beam between torpedo bulkheads 65.62 ft / 20.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   5.51" / 140 mm   4.33" / 110 mm      5.12" / 130 mm
   2nd:   2.76" / 70 mm   1.38" / 35 mm      2.76" / 70 mm
   4th:   0.79" / 20 mm         -         0.79" / 20 mm

   - Protected deck - single deck:
   For and Aft decks: 2.76" / 70 mm
   Forecastle: 1.38" / 35 mm  Quarter deck: 1.38" / 35 mm

   - Conning towers: Forward 4.33" / 110 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 107,731 shp / 80,367 Kw = 31.00 kts
   Range 8,500nm at 14.00 kts
   Bunker at max displacement = 2,828 tons

Complement:
   826 - 1,075

Cost:
   £4.429 million / $17.715 million

Distribution of weights at normal displacement:
   Armament: 1,457 tons, 7.4 %
      - Guns: 1,457 tons, 7.4 %
   Armour: 4,920 tons, 25.2 %
      - Belts: 1,809 tons, 9.2 %
      - Torpedo bulkhead: 480 tons, 2.5 %
      - Armament: 731 tons, 3.7 %
      - Armour Deck: 1,832 tons, 9.4 %
      - Conning Tower: 68 tons, 0.3 %
   Machinery: 3,654 tons, 18.7 %
   Hull, fittings & equipment: 6,942 tons, 35.5 %
   Fuel, ammunition & stores: 2,379 tons, 12.2 %
   Miscellaneous weights: 210 tons, 1.1 %
      - Hull above water: 73 tons
      - On freeboard deck: 24 tons
      - Above deck: 113 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     25,597 lbs / 11,611 Kg = 60.7 x 9.4 " / 240 mm shells or 3.6 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 4.2 ft / 1.3 m
   Roll period: 16.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.54
   Seaboat quality  (Average = 1.00): 1.11

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.540 / 0.547
   Length to Beam Ratio: 9.17 : 1
   'Natural speed' for length: 26.87 kts
   Power going to wave formation at top speed: 51 %
   Trim (Max stability = 0, Max steadiness = 100): 63
   Bow angle (Positive = bow angles forward): 15.00 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 %,  26.25 ft / 8.00 m,  23.79 ft / 7.25 m
      - Forward deck:   30.00 %,  23.79 ft / 7.25 m,  18.70 ft / 5.70 m
      - Aft deck:   35.00 %,  18.70 ft / 5.70 m,  18.70 ft / 5.70 m
      - Quarter deck:   15.00 %,  18.70 ft / 5.70 m,  18.70 ft / 5.70 m
      - Average freeboard:      20.68 ft / 6.30 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 102.7 %
      - Above water (accommodation/working, high = better): 180.1 %
   Waterplane Area: 39,294 Square feet or 3,651 Square metres
   Displacement factor (Displacement / loading): 113 %
   Structure weight / hull surface area: 137 lbs/sq ft or 670 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.00
      - Longitudinal: 0.99
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

146t - 1918 FC
25t - LR Radio
25t - NF Devices
24t - 2 x 3 x 21in HW TT on sides Aft

[The Rock Doctor]

Adjusting the freeboard upward a bit might give you a bit of extra hull strength on the razee to play with.

On the other hand, Bomb's cross-sectional strength is a tad too low.

I hear you on files.  I lost most of the pre-game stuff with my last computer.  At some point, I think I might attach my current .sship files to the encyclopedia entries so they never get lost.