Vilnius Union Ships, 1930+: The Good, The Bad, and the Unseaworthy

[The Rock Doctor]

Refit for the river depot ship Zackwycajacy is pretty much just replacing the armament and fire control.

The cost is a very economic $0.02 and 0.011 BP.


Enter ship name, Enter country Enter ship type laid down 1914, refit 1933

Displacement:
   1,191 t light; 1,232 t standard; 1,304 t normal; 1,362 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (299.23 ft / 295.28 ft) x 42.65 ft x (5.58 / 5.79 ft)
   (91.20 m / 90.00 m) x 13.00 m  x (1.70 / 1.76 m)

Armament:
      4 - 1.97" / 50.0 mm 60.0 cal guns - 4.18lbs / 1.89kg shells, 1,500 per gun
     Anti-air guns in deck mounts, 1914 Model
     4 x Single mounts on sides, evenly spread
      4 raised mounts
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 5,000 per gun
     Machine guns in deck mounts, 1914 Model
     2 x Single mounts on centreline, evenly spread
      2 raised mounts
     2 x Single mounts on sides amidships
      2 raised mounts
      Weight of broadside 17 lbs / 8 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.59" / 15 mm         -               -
   2nd:   0.59" / 15 mm         -               -

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 2 shafts, 603 shp / 450 Kw = 10.61 kts
   Range 2,000nm at 10.00 kts
   Bunker at max displacement = 130 tons (100% coal)

Complement:
   108 - 141

Cost:
   £0.059 million / $0.238 million

Distribution of weights at normal displacement:
   Armament: 5 tons, 0.4 %
      - Guns: 5 tons, 0.4 %
   Armour: 5 tons, 0.4 %
      - Armament: 5 tons, 0.4 %
   Machinery: 26 tons, 2.0 %
   Hull, fittings & equipment: 624 tons, 47.9 %
   Fuel, ammunition & stores: 114 tons, 8.7 %
   Miscellaneous weights: 530 tons, 40.6 %
      - Hull below water: 100 tons
      - Hull above water: 100 tons
      - On freeboard deck: 304 tons
      - Above deck: 26 tons

Fittings:
-100 t:  Supply for 1,000 t of small craft (BW)
-100 t:  Crew amenities and facilities (AW)
-250 t:  Accommodation for 125 (FD)
-50 t:  Cranes and cargo handling (FD)
-4 t:  Weight reserve (FD)
-25 t:  L/R wireless (AD)
-1 t:  1930 fire control (AD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     12,436 lbs / 5,641 Kg = 3,260.5 x 2.0 " / 50 mm shells or 4.6 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 2.2 ft / 0.7 m
   Roll period: 12.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.01
   Seaboat quality  (Average = 1.00): 1.54

Hull form characteristics:
   Hull has low forecastle, rise forward of midbreak, low quarterdeck ,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.654
   Length to Beam Ratio: 6.92 : 1
   'Natural speed' for length: 17.18 kts
   Power going to wave formation at top speed: 21 %
   Trim (Max stability = 0, Max steadiness = 100): 46
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 1.00 ft / 0.30 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  16.73 ft / 5.10 m,  12.80 ft / 3.90 m
      - Forward deck:   30.00 %,  20.67 ft / 6.30 m,  20.67 ft / 6.30 m
      - Aft deck:   30.00 %,  12.80 ft / 3.90 m,  12.80 ft / 3.90 m
      - Quarter deck:   20.00 %,  4.92 ft / 1.50 m,  4.92 ft / 1.50 m
      - Average freeboard:      13.90 ft / 4.24 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 26.8 %
      - Above water (accommodation/working, high = better): 284.7 %
   Waterplane Area: 9,648 Square feet or 896 Square metres
   Displacement factor (Displacement / loading): 217 %
   Structure weight / hull surface area: 49 lbs/sq ft or 238 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 1.78
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Excellent 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

[The Rock Doctor]

I took the 1931 A-class torpedo-boat, updated the machinery, and added a hypothetical transom stern.  I recognize it's too soon for the stern, but wanted to see how it affected the rest of the design.

And the answer is, I need almost a full knot more speed to keep the machinery percentage at 50%, which knocks down the seakeeping and also costs much of the A-class's weight reserve.

So on that basis, I'd actually have to say it does not help me here.  I was happy with the A-class' 33.1 knots as it was.


Enter ship name, Enter country Enter ship type laid down 1933

Displacement:
   2,152 t light; 2,280 t standard; 2,603 t normal; 2,862 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (406.35 ft / 393.70 ft) x 37.40 ft x (15.09 / 16.06 ft)
   (123.86 m / 120.00 m) x 11.40 m  x (4.60 / 4.90 m)

Armament:
      4 - 5.12" / 130 mm 45.0 cal guns - 67.61lbs / 30.67kg shells, 400 per gun
     Dual purpose guns in deck and hoist mounts, 1933 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      4 - 1.97" / 50.0 mm 60.0 cal guns - 4.18lbs / 1.89kg shells, 1,500 per gun
     Anti-air guns in deck mounts, 1933 Model
     2 x Twin mounts on sides, forward deck aft
      2 raised mounts
      8 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1933 Model
     4 x Twin mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 288 lbs / 131 kg

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 50,604 shp / 37,750 Kw = 34.27 kts
   Range 5,500nm at 15.00 kts
   Bunker at max displacement = 582 tons

Complement:
   181 - 236

Cost:
   £1.348 million / $5.392 million

Distribution of weights at normal displacement:
   Armament: 83 tons, 3.2 %
      - Guns: 83 tons, 3.2 %
   Armour: 28 tons, 1.1 %
      - Armament: 28 tons, 1.1 %
   Machinery: 1,303 tons, 50.1 %
   Hull, fittings & equipment: 608 tons, 23.4 %
   Fuel, ammunition & stores: 451 tons, 17.3 %
   Miscellaneous weights: 129 tons, 5.0 %
      - Hull below water: 25 tons
      - On freeboard deck: 50 tons
      - Above deck: 54 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     619 lbs / 281 Kg = 9.2 x 5.1 " / 130 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.16
   Metacentric height 1.5 ft / 0.5 m
   Roll period: 12.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.40
   Seaboat quality  (Average = 1.00): 0.93

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and small transom stern
   Block coefficient (normal/deep): 0.410 / 0.423
   Length to Beam Ratio: 10.53 : 1
   'Natural speed' for length: 21.38 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 65
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 3.94 ft / 1.20 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  23.95 ft / 7.30 m,  19.03 ft / 5.80 m
      - Forward deck:   25.00 %,  19.03 ft / 5.80 m,  19.03 ft / 5.80 m
      - Aft deck:   40.00 %,  11.15 ft / 3.40 m,  11.15 ft / 3.40 m
      - Quarter deck:   15.00 %,  11.15 ft / 3.40 m,  11.15 ft / 3.40 m
      - Average freeboard:      15.09 ft / 4.60 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 174.6 %
      - Above water (accommodation/working, high = better): 139.2 %
   Waterplane Area: 9,327 Square feet or 866 Square metres
   Displacement factor (Displacement / loading): 77 %
   Structure weight / hull surface area: 37 lbs/sq ft or 181 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.38
      - Overall: 0.55
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[Jefgte]

...And the answer is, I need almost a full knot more speed to keep the machinery percentage at 50%, which knocks down the seakeeping and also costs much of the A-class's weight reserve.

So on that basis, I'd actually have to say it does not help me here.  I was happy with the A-class' 33.1 knots as it was.

I agree, seakeeping is more important.

[Kaiser Kirk]

The 50% rule has long been a problem with seakeeping.
It's an issue Foxy raised, and he had a valid point, but it makes for workable DDs with not a great ability to exploit.
Never had the time to explore alternatives. 

Replacing DD engines makes the rebuild close to non-viable costwise,
How many knots would you loose stepping down to 0.75 comp hull and becoming a cruiser?

[The Rock Doctor]

The seakeeping is not a huge issue for me - it's a destroyer, 0.93 really ought to be good.  I'm more cranky about the weight cost, really.

[The Rock Doctor]

The 1933 light cruiser improves on the Mulde mainly in terms of bunkerage and the fitting of a Huelsmeyer device, although the secondary battery is now a dedicated AA set-up.


Enter ship name, Enter country Enter ship type laid down 1933

Displacement:
    8,647 t light; 9,083 t standard; 10,094 t normal; 10,903 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (605.26 ft / 590.55 ft) x 58.73 ft x (22.64 / 23.92 ft)
    (184.48 m / 180.00 m) x 17.90 m  x (6.90 / 7.29 m)

Armament:
      8 - 5.91" / 150 mm 50.0 cal guns - 121.25lbs / 55.00kg shells, 250 per gun
      Breech loading guns in turret on barbette mounts, 1933 Model
      4 x 2-gun mounts on centreline ends, evenly spread
        2 raised mounts - superfiring
      8 - 3.94" / 100 mm 45.0 cal guns - 30.78lbs / 13.96kg shells, 400 per gun
      Anti-air guns in deck mounts, 1933 Model
      4 x Twin mounts on side ends, evenly spread
      12 - 1.97" / 50.0 mm 60.0 cal guns - 4.19lbs / 1.90kg shells, 1,500 per gun
      Anti-air guns in deck mounts, 1933 Model
      6 x Twin mounts on sides, evenly spread
      8 - 0.59" / 15.0 mm 90.0 cal guns - 0.11lbs / 0.05kg shells, 5,000 per gun
      Machine guns in deck mounts, 1933 Model
      4 x Twin mounts on sides, evenly spread
        4 raised mounts
      Weight of broadside 1,267 lbs / 575 kg

Armour:
  - Belts:        Width (max)    Length (avg)        Height (avg)
    Main:    3.94" / 100 mm    383.86 ft / 117.00 m    16.37 ft / 4.99 m
    Ends:    Unarmoured
      Main Belt covers 100 % of normal length
      Main Belt inclined 16.00 degrees (positive = in)

  - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    5.91" / 150 mm    1.97" / 50 mm        3.94" / 100 mm
    2nd:    0.79" / 20 mm    0.59" / 15 mm              -
    3rd:    0.59" / 15 mm          -                  -
    4th:    0.59" / 15 mm          -                  -

  - Armoured deck - single deck:
    For and Aft decks: 1.97" / 50 mm
    Forecastle: 1.97" / 50 mm  Quarter deck: 1.97" / 50 mm

  - Conning towers: Forward 3.94" / 100 mm, Aft 0.00" / 0 mm

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 2 shafts, 84,450 shp / 63,000 Kw = 32.14 kts
    Range 8,000nm at 15.00 kts
    Bunker at max displacement = 1,820 tons

Complement:
    503 - 654

Cost:
    £3.568 million / $14.273 million

Distribution of weights at normal displacement:
    Armament: 328 tons, 3.2 %
      - Guns: 328 tons, 3.2 %
    Armour: 2,144 tons, 21.2 %
      - Belts: 1,008 tons, 10.0 %
      - Armament: 284 tons, 2.8 %
      - Armour Deck: 812 tons, 8.0 %
      - Conning Tower: 40 tons, 0.4 %
    Machinery: 2,461 tons, 24.4 %
    Hull, fittings & equipment: 3,422 tons, 33.9 %
    Fuel, ammunition & stores: 1,447 tons, 14.3 %
    Miscellaneous weights: 293 tons, 2.9 %
      - On freeboard deck: 103 tons
      - Above deck: 190 tons

Fittings:
-33 t:  1924 Fire Control (AD)
-25 t:  L/R wireless (AD)
-25 t:  Night-fighting doodads (AD)
-25 t:  Huelsmeyer device (AD)
-50 t:  Command facilities (AD)
-55 t:  2 armed floatplanes and one catapult with hangers aside aft funnel (FD)
-32 t:  2x4 530mm torpedo carriages (no reloads) (FD)
-16 t + 32 t:  Weight reserve (AD/FD)

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      11,955 lbs / 5,423 Kg = 116.1 x 5.9 " / 150 mm shells or 1.7 torpedoes
    Stability (Unstable if below 1.00): 1.07
    Metacentric height 2.6 ft / 0.8 m
    Roll period: 15.3 seconds
    Steadiness    - As gun platform (Average = 50 %): 60 %
            - Recoil effect (Restricted arc if above 1.00): 0.36
    Seaboat quality  (Average = 1.00): 1.08

Hull form characteristics:
    Hull has rise forward of midbreak,
      a normal bow and a cruiser stern
    Block coefficient (normal/deep): 0.450 / 0.460
    Length to Beam Ratio: 10.06 : 1
    'Natural speed' for length: 24.30 kts
    Power going to wave formation at top speed: 55 %
    Trim (Max stability = 0, Max steadiness = 100): 56
    Bow angle (Positive = bow angles forward): 20.00 degrees
    Stern overhang: 4.92 ft / 1.50 m
    Freeboard (% = length of deck as a percentage of waterline length):
                Fore end,    Aft end
      - Forecastle:    20.00 %,  26.90 ft / 8.20 m,  21.65 ft / 6.60 m
      - Forward deck:    30.00 %,  21.65 ft / 6.60 m,  21.65 ft / 6.60 m
      - Aft deck:    35.00 %,  13.78 ft / 4.20 m,  13.78 ft / 4.20 m
      - Quarter deck:    15.00 %,  13.78 ft / 4.20 m,  13.78 ft / 4.20 m
      - Average freeboard:        18.14 ft / 5.53 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 91.0 %
        - Above water (accommodation/working, high = better): 145.9 %
    Waterplane Area: 22,122 Square feet or 2,055 Square metres
    Displacement factor (Displacement / loading): 120 %
    Structure weight / hull surface area: 99 lbs/sq ft or 484 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.96
        - Longitudinal: 1.33
        - Overall: 1.00
    Adequate machinery, storage, compartmentation space
    Excellent accommodation and workspace room


m

[Jefgte]

Classic and efficient.

[The Rock Doctor]

That's me with the mundane 4x2 designs around here.

[Kaiser Kirk]

I rather like the 4x2. I like the 2x3+2x2 better... but this go round I promised my self to do 4-gun.
The advantage of that is my more recent designs are 8-guns, but 'B' and 'X' are now secondary DP mounts,
adding to wing mounts for good all-round secondary arcs.

A 2-gun 150mm even with that armor may fall within the reasonable rotating weight range for a M&H, which would then allow slipping the BC lower, getting the light tonnage under 8000, and so freeing up the 0.9 hull,
which would allow a thicker belt.

I note 55 tons for 2 armed floatplanes, a catapult..and hangers. When I'm specifying hangers I add a little (5t) weight per plane. Otherwise I figure they ride on the catapult exposed in the weather.

[The Rock Doctor]

The planes themselves aren't more than 2 or 3 tonnes apiece, so I'm counting hanger weight as part of the 25 t per aircraft.

[Kaiser Kirk]

It's a guess number anyhow.
In Friedman's cruisers there's a couple areas where it's discussed how much weight fittings removed actually had, likewise for destroyers, but otherwise finding such things out is difficult. I have a feeling we're underestimating 'catapults' but then there's the entire question of ...so what does Springsharp consider "Hull, fittings & equipment: 3,422 tons, 33.9 %", because it's a line item in the report...

[The Rock Doctor]

I think that, other than updating the vintage of fire control, I'm just going to keep ordering the 1931 A-class torpedo-boat as a "new" C-class for 1933/34.  I'm pretty satisfied with the design and don't see a lot of upside to merely tinkering with it just now.

[Kaiser Kirk]

Makes sense.
I tend to run my destroyer designs for years.
Storyline wise, it's more efficient to have classes rather than handfuls of ships.
I very much would like to have maintained building everything in batches of 4.
But the tech levels splintered my build plans.

[The Rock Doctor]

A 1935 CL with a bit more heavy firepower for more independent operations.  There are, after all, some light cruisers that don't spend all their time riding herd on capital ships.

The main battery is reverse-Dido, or Atlanta minus C-turret.  Whichever is easiest to visualize.

Miscellaneous weight would be pretty similar to the 1933 CL posted above - sensors and comms, command, two planes, fire control.


Enter ship name, Enter country Enter ship type laid down 1935

Displacement:
   9,496 t light; 9,984 t standard; 11,033 t normal; 11,873 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (621.79 ft / 606.96 ft) x 60.70 ft x (23.29 / 24.54 ft)
   (189.52 m / 185.00 m) x 18.50 m  x (7.10 / 7.48 m)

Armament:
      10 - 5.91" / 150 mm 50.0 cal guns - 121.25lbs / 55.00kg shells, 250 per gun
     Breech loading guns in turret on barbette mounts, 1935 Model
     4 x 2-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
     1 x 2-gun mount on centreline, aft deck centre
      1 double raised mount aft
      8 - 3.94" / 100 mm 45.0 cal guns - 30.77lbs / 13.96kg shells, 400 per gun
     Anti-air guns in deck mounts, 1935 Model
     4 x Twin mounts on side ends, evenly spread
      12 - 1.97" / 50.0 mm 60.0 cal guns - 4.18lbs / 1.89kg shells, 1,500 per gun
     Anti-air guns in deck mounts, 1935 Model
     6 x Twin mounts on sides, evenly spread
      8 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 5,000 per gun
     Machine guns in deck mounts, 1935 Model
     4 x Twin mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 1,510 lbs / 685 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.94" / 100 mm   394.52 ft / 120.25 m   16.37 ft / 4.99 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length
     Main Belt inclined 16.00 degrees (positive = in)

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   5.91" / 150 mm   1.97" / 50 mm      3.94" / 100 mm
   2nd:   0.79" / 20 mm   0.59" / 15 mm            -
   3rd:   0.59" / 15 mm         -               -
   4th:   0.59" / 15 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 1.97" / 50 mm
   Forecastle: 1.97" / 50 mm  Quarter deck: 1.97" / 50 mm

   - Conning towers: Forward 3.94" / 100 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 87,131 shp / 65,000 Kw = 32.03 kts
   Range 8,000nm at 15.00 kts
   Bunker at max displacement = 1,888 tons

Complement:
   537 - 699

Cost:
   £4.121 million / $16.484 million

Distribution of weights at normal displacement:
   Armament: 397 tons, 3.6 %
      - Guns: 397 tons, 3.6 %
   Armour: 2,317 tons, 21.0 %
      - Belts: 1,040 tons, 9.4 %
      - Armament: 372 tons, 3.4 %
      - Armour Deck: 863 tons, 7.8 %
      - Conning Tower: 42 tons, 0.4 %
   Machinery: 2,475 tons, 22.4 %
   Hull, fittings & equipment: 4,003 tons, 36.3 %
   Fuel, ammunition & stores: 1,537 tons, 13.9 %
   Miscellaneous weights: 304 tons, 2.8 %
      - On freeboard deck: 114 tons
      - Above deck: 190 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     15,151 lbs / 6,872 Kg = 147.1 x 5.9 " / 150 mm shells or 1.9 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 2.8 ft / 0.9 m
   Roll period: 15.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.46
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.450 / 0.460
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 24.64 kts
   Power going to wave formation at top speed: 54 %
   Trim (Max stability = 0, Max steadiness = 100): 42
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 4.92 ft / 1.50 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  27.23 ft / 8.30 m,  22.31 ft / 6.80 m
      - Forward deck:   52.00 %,  22.31 ft / 6.80 m,  22.31 ft / 6.80 m
      - Aft deck:   13.00 %,  14.44 ft / 4.40 m,  14.44 ft / 4.40 m
      - Quarter deck:   15.00 %,  14.44 ft / 4.40 m,  14.44 ft / 4.40 m
      - Average freeboard:      20.50 ft / 6.25 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 85.9 %
      - Above water (accommodation/working, high = better): 172.8 %
   Waterplane Area: 23,499 Square feet or 2,183 Square metres
   Displacement factor (Displacement / loading): 125 %
   Structure weight / hull surface area: 106 lbs/sq ft or 520 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.53
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Good seaboat, rides out heavy weather easily

[The Rock Doctor]

The Union Navy's thinking about a new run of the so-called guntubs, the teeny-weeny shallow-draft boats with a 75mm gun on them.

The first batch, from 1929, was about supplying a bit of fire-support capability for korsarz-based amphibious raids.  This batch would be about supporting riverine operations, working with the small depot ships and other small craft in places where even the usual array of river gunboats can't reach due to draft.

The top speed and cruising speed have been reduced but the bunkerage increased.  A bit of protection is added to the main gun and the control room.  Additionally a third machine gun has been mounted atop the control room for bonus firepower.

The miscellaneous weight is for the diesel engines.



Enter ship name, Enter country Enter ship type laid down 1933

Displacement:
    19 t light; 21 t standard; 22 t normal; 22 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (57.81 ft / 52.49 ft) x 13.12 ft x (2.46 / 2.49 ft)
    (17.62 m / 16.00 m) x 4.00 m  x (0.75 / 0.76 m)

Armament:
      1 - 2.95" / 75.0 mm 45.0 cal gun - 12.98lbs / 5.89kg shells, 150 per gun
      Quick firing gun in deck mount, 1933 Model
      1 x Single mount on centreline, aft deck centre
      1 - 0.59" / 15.0 mm 90.0 cal gun - 0.12lbs / 0.05kg shells, 2,000 per gun
      Machine gun in deck mount, 1933 Model
      1 x Single mount on centreline, forward deck forward
        1 raised mount
      2 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 2,000 per gun
      Machine guns in deck mounts, 1933 Model
      2 x Single mounts on sides amidships
      Weight of broadside 13 lbs / 6 kg

Armour:
  - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    0.59" / 15 mm          -                  -

  - Conning towers: Forward 0.59" / 15 mm, Aft 0.00" / 0 mm

Machinery:
    Diesel Internal combustion motors,
    Geared drive, 2 shafts, 134 shp / 100 Kw = 12.34 kts
    Range 200nm at 10.00 kts
    Bunker at max displacement = 1 tons

Complement:
    4 - 6

Cost:
    £0.010 million / $0.038 million

Distribution of weights at normal displacement:
    Armament: 3 tons, 12.9 %
      - Guns: 3 tons, 12.9 %
    Armour: 1 tons, 6.4 %
      - Armament: 1 tons, 5.9 %
      - Conning Tower: 0 tons, 0.5 %
    Machinery: 4 tons, 17.9 %
    Hull, fittings & equipment: 9 tons, 42.7 %
    Fuel, ammunition & stores: 2 tons, 10.9 %
    Miscellaneous weights: 2 tons, 9.2 %
      - Hull below water: 2 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      35 lbs / 16 Kg = 2.7 x 3.0 " / 75 mm shells or 0.1 torpedoes
    Stability (Unstable if below 1.00): 1.13
    Metacentric height 0.3 ft / 0.1 m
    Roll period: 10.1 seconds
    Steadiness    - As gun platform (Average = 50 %): 70 %
            - Recoil effect (Restricted arc if above 1.00): 0.39
    Seaboat quality  (Average = 1.00): 0.97

Hull form characteristics:
    Hull has a flush deck,
      a normal bow and a cruiser stern
    Block coefficient (normal/deep): 0.450 / 0.452
    Length to Beam Ratio: 4.00 : 1
    'Natural speed' for length: 7.25 kts
    Power going to wave formation at top speed: 74 %
    Trim (Max stability = 0, Max steadiness = 100): 73
    Bow angle (Positive = bow angles forward): 20.00 degrees
    Stern overhang: 1.97 ft / 0.60 m
    Freeboard (% = length of deck as a percentage of waterline length):
                Fore end,    Aft end
      - Forecastle:    20.00 %,  9.19 ft / 2.80 m,  7.22 ft / 2.20 m
      - Forward deck:    20.00 %,  7.22 ft / 2.20 m,  5.25 ft / 1.60 m
      - Aft deck:    45.00 %,  5.25 ft / 1.60 m,  5.25 ft / 1.60 m
      - Quarter deck:    15.00 %,  5.25 ft / 1.60 m,  5.25 ft / 1.60 m
      - Average freeboard:        6.00 ft / 1.83 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 105.9 %
        - Above water (accommodation/working, high = better): 116.2 %
    Waterplane Area: 439 Square feet or 41 Square metres
    Displacement factor (Displacement / loading): 116 %
    Structure weight / hull surface area: 14 lbs/sq ft or 67 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.57
        - Longitudinal: 16.57
        - Overall: 0.80
    Caution: Hull subject to strain in open-sea
    Adequate machinery, storage, compartmentation space
    Adequate accommodation and workspace room
    Ship has slow, easy roll, a good, steady gun platform
    Poor seaboat, wet and uncomfortable, reduced performance in heavy weather