Aztec Ship Designs 1925-1928

[The Rock Doctor]

I figured there would be rowers.

Though now I'm wondering how to sim a paddlewheeler.

[TacCovert4]

Fixed.  Mostly  enhanced the minesweeping gear with an additional 10 tons of kit, added 15t of DC/Fire Pumps, with 5t of fire hoses.  And upgraded the hydrophones to the advanced set, which will make this ship easily function as a capable ASW vessel. 

Also, noted the range.  While at the fleet cruise speed of 14kts she can only do 3500nm on her diesels, at a more economical cruise speed for convoys of 10kts she is a true ocean-crossing vessel with 8500nm of range.

MS-28, Aztec Offshore Patrol Vessel laid down 1928

Displacement:
   700 t light; 730 t standard; 788 t normal; 833 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (202.52 ft / 196.85 ft) x 27.23 ft x (9.02 / 9.44 ft)
   (61.73 m / 60.00 m) x 8.30 m  x (2.75 / 2.88 m)

Armament:
      1 - 5.12" / 130 mm 50.0 cal gun - 70.97lbs / 32.19kg shells, 150 per gun
     Quick firing gun in deck mount, 1928 Model
     1 x Single mount on centreline, forward deck centre
      1 - 2.76" / 70.0 mm 50.0 cal gun - 11.09lbs / 5.03kg shells, 200 per gun
     Anti-air gun in deck mount, 1928 Model
     1 x Single mount on centreline, aft deck centre
      8 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 2,000 per gun
     Anti-air guns in deck mounts, 1928 Model
     8 x Single mounts on sides, evenly spread
      Weight of broadside 89 lbs / 40 kg

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

   - Box over magazines:
   1.18" / 30 mm

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

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 6,848 shp / 5,109 Kw = 22.00 kts
   Range 2,000nm at 14.00 kts
   Bunker at max displacement = 103 tons

Complement:
   73 - 96

Cost:
   £0.227 million / $0.906 million

Distribution of weights at normal displacement:
   Armament: 19 tons, 2.4 %
      - Guns: 19 tons, 2.4 %
   Armour: 18 tons, 2.3 %
      - Armament: 4 tons, 0.5 %
      - Armour Deck: 12 tons, 1.5 %
      - Conning Tower: 2 tons, 0.3 %
   Machinery: 213 tons, 27.1 %
   Hull, fittings & equipment: 192 tons, 24.4 %
   Fuel, ammunition & stores: 88 tons, 11.2 %
   Miscellaneous weights: 258 tons, 32.8 %
      - Hull below water: 105 tons
      - On freeboard deck: 100 tons
      - Above deck: 53 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     672 lbs / 305 Kg = 10.0 x 5.1 " / 130 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.11
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 61 %
         - Recoil effect (Restricted arc if above 1.00): 0.17
   Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.570 / 0.576
   Length to Beam Ratio: 7.23 : 1
   'Natural speed' for length: 14.03 kts
   Power going to wave formation at top speed: 70 %
   Trim (Max stability = 0, Max steadiness = 100): 57
   Bow angle (Positive = bow angles forward): 20.00 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 %,  15.58 ft / 4.75 m,  15.58 ft / 4.75 m
      - Forward deck:   30.00 %,  15.58 ft / 4.75 m,  15.58 ft / 4.75 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      11.89 ft / 3.63 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 109.8 %
      - Above water (accommodation/working, high = better): 115.5 %
   Waterplane Area: 3,812 Square feet or 354 Square metres
   Displacement factor (Displacement / loading): 105 %
   Structure weight / hull surface area: 29 lbs/sq ft or 140 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.63
      - Longitudinal: 3.42
      - Overall: 0.75
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room

75t - Diesel Engines
15t - Enhanced Hydrophones
15t - DC and Fire Pumps

25t - Minesweeping Equipment
4t - DC Throwers
18t - Depth Charges
8t - 2 x 1 x 21in HW TT
50t - Space for Mines
5t - Fire Hoses


3t - 1918 FC
25t - LR Radio
25t - NF Devices

Range:  3500nm @ 14kts or 8500nm @ 10kts

[TacCovert4]

Also, I've started fiddling things to make sure that my anticipated DP guns will be able to be refitted to ships I'm building now.  And yes, this ship will be able to take a refit of both the 130mm surface gun and the 70mm AA gun with a pair of twin 80mm DP guns.

I've been planning my DP guns, and generally I'm looking at the following:

115mm/55 - Single, Twin M&H

80mm/55 - Single, Twin Deck.  Also futzing about with the crazy idea of a 2 row 4 gun barbette, basically an AA shell hose.

[The Rock Doctor]

That Soviet quad 57mm was a cool looking piece.

I've been assuming I'll stick with the same calibers when I get there.

[TacCovert4]

I might even refresh the 30mm, go full pom pom with an octuple mount for my capital ships.

[Kaiser Kirk]

I might even refresh the 30mm, go full pom pom with an octuple mount for my capital ships.

I haven't planned DPs yet, I expect I will create a 120mm or 115-110mm version, depending on weights.
Anything will be designed so I can replace the current 120s, and I'll see if I can make a twin/double that can replace the 165s or 130s

I've eyed the idea of the 8x just for fun.
But I'm going roughly 7.5 - 15 - 23 (22.5) - 30 - 37 (37.5) - 45 and then 57...  the 57's out of sequence, but was replacing a 60mm.
The 45 and 57s are a little large for the rapid fire tech of the 1920s/30s and so will move down in size.

I've introduced GAST actions for my 15mm, and plan on it for my 23mm.
The quad version of the 15/23 is 'two twins', but I want a Wirblewind style 30 or 37.
I'm aware the USN chose the 28mm as the sweet spot between hitting power and ROF, and the 30mm - like you- covers that,
but the 37 has slightly more 'reach'....but weighs more.  Which I use may come down to the ship's tolerance for weight,
and which replaces the current 57s easier.

[TacCovert4]

Made a few changes.  Of note, thinned the protection down a little.....I did remove it, but wound up adding it back because it actually helped stability.  Changed the gun from a single 130 to a twin 100 for weight savings.  Looking in future towards potentially an 80mm-100mm DP gun that'll replace the twin surface mount on most ships.  I cut the minelaying ability, I just don't see where mine-laying on an all-purpose OPV really makes sense.  Instead I'll build a dedicated minelaying class, which can be larger and better suited to the job anyway.  Overall she'll still need 2 HY to build, but low tonnage, so I can build up numbers of dedicated escorts, and unlike my old MS-1 class, these have all-aspect escort capabilities..

MS-28, Aztec Offshore Patrol Vessel laid down 1928

Displacement:
   549 t light; 576 t standard; 624 t normal; 663 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (201.39 ft / 196.85 ft) x 24.61 ft x (8.20 / 8.63 ft)
   (61.38 m / 60.00 m) x 7.50 m  x (2.50 / 2.63 m)

Armament:
      2 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 150 per gun
     Quick firing guns in deck mount, 1928 Model
     1 x Single mount on centreline, forward deck centre
      1 - 2.76" / 70.0 mm 50.0 cal gun - 11.09lbs / 5.03kg shells, 200 per gun
     Anti-air gun in deck mount, 1928 Model
     1 x Single mount on centreline, aft deck centre
      8 - 1.18" / 30.0 mm 50.0 cal guns - 0.86lbs / 0.39kg shells, 2,000 per gun
     Anti-air guns in deck mounts, 1928 Model
     8 x Single mounts on sides, evenly spread
      Weight of broadside 83 lbs / 37 kg

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

   - Box over magazines:
   0.79" / 20 mm

   - Conning towers: Forward 0.79" / 20 mm, Aft 0.00" / 0 mm

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 5,730 shp / 4,275 Kw = 22.00 kts
   Range 2,000nm at 14.00 kts
   Bunker at max displacement = 88 tons

Complement:
   62 - 81

Cost:
   £0.187 million / $0.747 million

Distribution of weights at normal displacement:
   Armament: 18 tons, 2.9 %
      - Guns: 18 tons, 2.9 %
   Armour: 12 tons, 1.9 %
      - Armament: 3 tons, 0.5 %
      - Armour Deck: 8 tons, 1.2 %
      - Conning Tower: 1 tons, 0.2 %
   Machinery: 178 tons, 28.6 %
   Hull, fittings & equipment: 153 tons, 24.6 %
   Fuel, ammunition & stores: 75 tons, 12.1 %
   Miscellaneous weights: 187 tons, 30.0 %
      - Hull below water: 68 tons
      - On freeboard deck: 67 tons
      - Above deck: 52 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     479 lbs / 217 Kg = 15.7 x 3.9 " / 100 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.06
   Metacentric height 0.7 ft / 0.2 m
   Roll period: 12.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.21
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.550 / 0.555
   Length to Beam Ratio: 8.00 : 1
   'Natural speed' for length: 14.03 kts
   Power going to wave formation at top speed: 68 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   Bow angle (Positive = bow angles forward): 20.00 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 %,  12.47 ft / 3.80 m,  12.47 ft / 3.80 m
      - Forward deck:   30.00 %,  12.47 ft / 3.80 m,  12.47 ft / 3.80 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      10.33 ft / 3.15 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 113.5 %
      - Above water (accommodation/working, high = better): 105.6 %
   Waterplane Area: 3,380 Square feet or 314 Square metres
   Displacement factor (Displacement / loading): 104 %
   Structure weight / hull surface area: 27 lbs/sq ft or 130 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.65
      - Longitudinal: 2.59
      - Overall: 0.75
   Caution: Hull subject to strain in open-sea
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room

54t - Diesel Engines
15t - Enhanced Hydrophones

35t - Minesweeping Equipment
2t - DC Throwers
18t - Depth Charges
12t - 1x3x21in HW TT


2t - 1918 FC
25t - LR Radio
25t - NF Devices

Range:  3500nm @ 14kts or 8500nm @ 10kts