Vilnius Union Ships, 1920+: Electric Drive Boogaloo

[Jefgte]

I don't change machines from old DDs, TGBs & TBs.
They have decent speed to be used as patrol boats or gunboats.
I scrap 24/25 yo and the too slow (21kts).

[Kaiser Kirk]

I've done the same, simply changed their official roles.
With some of the oldest, I did an ASW conversion to quickly get platforms in service.

I still had to watch the % as some weight changes seem to alter the "Normal"
and so result in % machinery changes...which is silly.

[Desertfox]

I think we had a whole conversation over that since I complained about it previously. The wonky stuff that happens with SS3 is most annoying.

[Kaiser Kirk]

I think we had a whole conversation over that since I complained about it previously. The wonky stuff that happens with SS3 is most annoying.

Yep, you had a good point then, and it's still a problem now. 
It's going to be a bigger one as this generation of DDs ages and folks want to go the DE route,
so it should be looked at :)

[The Rock Doctor]

The 1924 korweta class is somewhat longer and heavier than preceding types, and the flush deck gives her a decidedly chonky appearance.

The class replaces two 50mm QF with a second 100mm QF and a 50mm AA mount, both aft.  Operating range is increased.

The higher aft freeboard and longer enclosed superstructure should make the ship more habitable and workable in rough sea conditions.

Korweta, type laid down 1924

Displacement:
   500 t light; 523 t standard; 564 t normal; 596 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (170.79 ft / 164.04 ft) x 24.93 ft x (9.84 / 10.26 ft)
   (52.06 m / 50.00 m) x 7.60 m  x (3.00 / 3.13 m)

Armament:
      2 - 3.94" / 100.0 mm 45.0 cal guns - 30.77lbs / 13.96kg shells, 300 per gun
     Quick firing guns in deck mounts, 1924 Model
     2 x Single mounts on centreline, evenly spread
      1 - 1.97" / 50.0 mm 45.0 cal gun - 3.85lbs / 1.75kg shells, 300 per gun
     Anti-air gun in deck mount, 1924 Model
     1 x Single mount on centreline, aft deck forward
      1 raised mount
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1924 Model
     4 x Single mounts on sides amidships
      4 raised mounts
      Weight of broadside 66 lbs / 30 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm   0.12" / 3 mm            -
   2nd:   0.79" / 20 mm   0.12" / 3 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 4,557 shp / 3,400 Kw = 20.66 kts
   Range 4,000nm at 10.00 kts
   Bunker at max displacement = 73 tons

Complement:
   57 - 75

Cost:
   £0.130 million / $0.518 million

Distribution of weights at normal displacement:
   Armament: 12 tons, 2.2 %
   Armour: 4 tons, 0.6 %
      - Armament: 4 tons, 0.6 %
   Machinery: 150 tons, 26.6 %
   Hull, fittings & equipment: 256 tons, 45.4 %
   Fuel, ammunition & stores: 64 tons, 11.3 %
   Miscellaneous weights: 78 tons, 13.8 %
      - Hull below water: 53 tons
      - On freeboard deck: 23 tons
      - Above deck: 2 tons

Fittings:
-38 t:  T-E drive (BW)
-15 t:  Enhanced hydrophone package (BW)
-15 t:  ASW munitions (FD)
-6 t:  Weight reserve (FD)
-2t:  1918 Fire control (AD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     877 lbs / 398 Kg = 28.7 x 3.9 " / 100 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.16
   Metacentric height 0.8 ft / 0.2 m
   Roll period: 11.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.27
   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): 0.490 / 0.497
   Length to Beam Ratio: 6.58 : 1
   'Natural speed' for length: 12.81 kts
   Power going to wave formation at top speed: 70 %
   Trim (Max stability = 0, Max steadiness = 100): 35
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  19.69 ft / 6.00 m,  15.75 ft / 4.80 m
      - Forward deck:   20.00 %,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Aft deck:   45.00 %,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Quarter deck:   15.00 %,  15.75 ft / 4.80 m,  15.75 ft / 4.80 m
      - Average freeboard:      16.06 ft / 4.90 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 104.3 %
      - Above water (accommodation/working, high = better): 142.1 %
   Waterplane Area: 2,701 Square feet or 251 Square metres
   Displacement factor (Displacement / loading): 136 %
   Structure weight / hull surface area: 34 lbs/sq ft or 164 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.70
      - Longitudinal: 24.72
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[The Rock Doctor]

The three Bug-class protected cruisers are now 16 years old, or at least, the design is.

A simple refit would:

-Replace the 50mm QF and 10mm AA with 4x100mm AA and 15mm MG
-Add a bit of misc. weight for heavier torpedos
-Update the fire control

Cost would be quite low.  Like $0.1 / 0.1 BP or thereabouts.

A simple-ish refurb would also convert the machinery to oil-firing.  This doesn't actually add a heck of a lot of range - 4,000 to 5,300.  The cash cost would increase to over a dollar.

A more elaborate refurb would replace the machinery.  I can bump up to 26.5 knots (from 24.2) without seakeeping going below 1.00, and the newer engine year means I get more range out of a ton of oil.  I can bump it to something like 9,500 nm without factoring in the geared bonus.  Cost jumps to $2.84 and 0.965 BP per unit.

I would not be replacing the main battery; while the mount and hoist is maybe dumb, sizing up to 130mm would require me to escalate up to a reconstruction, with higher overall project costs.

The end product is perhaps adequate to continue screening old armored cruisers for a few years, and then take up secondary patrol or trade defence functions.

Thoughts?

[The Rock Doctor]

A (relatively) fast river transport capable of moving a reinforced platoon/half-company of light infantry around.

Why would you want to do that?  Maybe there's a problem with bandits or river pirates, or the locals are pissed off at the local mine/oil well/missionary/store/plantation and somebody needs to get in there quick to calm things down.

The diesels are an expensive item, weight-wise, but would seem to offer more responsiveness than something with boilers. 

Armament is limited to machine guns, but four 15mm/90cal guns is likely fairly daunting to the expected range of domestic trouble-makers.

I'd need to wait till H2/24 in order to finish the gun mount and cruiser tech (yes - world's smallest cruisers).

Enter ship name, Enter country Enter ship type laid down 1924

Displacement:
   104 t light; 107 t standard; 113 t normal; 117 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (151.73 ft / 147.64 ft) x 20.34 ft x (2.62 / 2.71 ft)
   (46.25 m / 45.00 m) x 6.20 m  x (0.80 / 0.83 m)

Armament:
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 2,000 per gun
     Machine guns in deck mounts, 1924 Model
     2 x 2-gun mounts on centreline ends, evenly spread
      Weight of broadside 0 lbs / 0 kg

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

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 1,006 shp / 750 Kw = 17.96 kts
   Range 270nm at 17.96 kts
   Bunker at max displacement = 11 tons

Complement:
   16 - 22

Cost:
   £0.026 million / $0.105 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.4 %
   Armour: 2 tons, 1.6 %
      - Armament: 2 tons, 1.6 %
   Machinery: 33 tons, 29.4 %
   Hull, fittings & equipment: 44 tons, 39.4 %
   Fuel, ammunition & stores: 9 tons, 7.8 %
   Miscellaneous weights: 24 tons, 21.3 %
      - Hull below water: 10 tons
      - On freeboard deck: 14 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     154 lbs / 70 Kg = 1,490.6 x 0.6 " / 15 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.21
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 10.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 0.72

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.505
   Length to Beam Ratio: 7.26 : 1
   'Natural speed' for length: 12.15 kts
   Power going to wave formation at top speed: 59 %
   Trim (Max stability = 0, Max steadiness = 100): 84
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.98 ft / 0.30 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   25.00 %,  8.53 ft / 2.60 m,  6.89 ft / 2.10 m
      - Forward deck:   25.00 %,  6.89 ft / 2.10 m,  5.25 ft / 1.60 m
      - Aft deck:   35.00 %,  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:      6.03 ft / 1.84 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 107.4 %
      - Above water (accommodation/working, high = better): 133.2 %
   Waterplane Area: 2,001 Square feet or 186 Square metres
   Displacement factor (Displacement / loading): 120 %
   Structure weight / hull surface area: 17 lbs/sq ft or 82 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.71
      - Longitudinal: 1.16
      - Overall: 0.75
   Caution: Hull subject to strain in open-sea
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Range also about 1,300 nm @ 10 knots, not addjusting for diesels.

[Kaiser Kirk]

It's interesting.
I've been fielding a number of colonial troop designs, nothing this small.

I doubt even diesels would be happy running 100% for their entire run.

The only thing I really have to compare it to is my TB-IV design, 60t DD.
Which currently serves the same role in Sumatra, but no troops, just a 45mm deck gun and a couple MGs..and 2 x 16" torps.

I'd have to toy with the hull parameters to see if there's a cheaper tonnage combination,
but I'm guessing your 270 @ 18knts fuel parameter is soaking up a lot of hull strength.

[The Rock Doctor]

It may be overkill, and the diesel weight carries a heavy weight penalty as well.

I did like the idea of building to destroyer rules but success has eluded me so far.

[The Rock Doctor]

Knocking the range down from 270 to 200 nm lets me shave off a grand total of 2 tonnes light displacement.

Total bunkerge is only 11 t to start with, so actually it doesn't look like a significant problem area.

[Desertfox]

Or build it to auxiliary rules and get some serious carrying capacity on board. The Toph Marus cost the same but are a lot more capable, with 10 times the range and 6 times the misc weight.

[The Rock Doctor]

That's true, although the much deeper draft of the Maru is a consideration here.  I'm looking at something that can go most places a river bandit could.

[Kaiser Kirk]

my 'Gnat' class probably fits that description.
The draft is a mere 1.66m
The range is less, but again I question if the role requires charging about madly.

They don't have quite the marines or cargo capacity, but reallocation of the below-deck weights could fix that.

The gunboat version has a 90mm, the subchaser just a 57mm so it can have DCs.

Compared to my 1904 60ton TB-V, they cost more, are much slower (no DD bonus), and have the same weapon tonnage, so what the Aux really gets is that miscellaneous weight allowance, not a better warship. Though since hydrophones are misc weight, as are Minesweeper trawls, they work better on the Gnats than TB-Vs.


Bottom of :
https://www.navalism.org/index.php/topic,7658.135.html

[The Rock Doctor]

Union riverine forces in [Uruguay] are supported by a good-sized depot ship, but their comrades in Africa lack such capabilities.  With talk of deploying small MTBs into the Orimiri Delta as part of anti-bandit operations, perhaps the time has come for a small, shallow draft support vessel.

This particular design incorporates a lot of ideas from the recent batch of riverine seaplane tenders, including the provision of a single aircraft right aft for scouting and recce purposes.  Otherwise, it's basically a floating barracks for the crews of four small torpedo-craft and a platoon or so of naval infantry or police.

The ship is not really intended as a combat unit, but the shallow draft and single 50mm gun does allow her to operate in fairly shallow stretches of the river system in a direct-fire support capacity if that need arises.

Enter ship name, Enter country Enter ship type laid down 1924

Displacement:
   299 t light; 307 t standard; 316 t normal; 324 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (163.48 ft / 157.48 ft) x 26.25 ft x (3.94 / 4.02 ft)
   (49.83 m / 48.00 m) x 8.00 m  x (1.20 / 1.22 m)

Armament:
      4 - 0.59" / 15.0 mm 90.0 cal guns - 0.12lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1924 Model
     4 x Single mounts on centreline ends, evenly spread
      4 raised mounts
      1 - 1.97" / 50.0 mm 45.0 cal gun - 3.85lbs / 1.75kg shells, 250 per gun
     Quick firing gun in deck mount, 1924 Model
     1 x Single mount on centreline, forward deck forward
      1 raised mount
      Weight of broadside 4 lbs / 2 kg

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

Machinery:
   Diesel Internal combustion motors,
   Geared drive, 2 shafts, 402 shp / 300 Kw = 11.86 kts
   Range 1,000nm at 10.00 kts
   Bunker at max displacement = 17 tons

Complement:
   36 - 48

Cost:
   £0.039 million / $0.157 million

Distribution of weights at normal displacement:
   Armament: 1 tons, 0.4 %
   Armour: 8 tons, 2.6 %
      - Armament: 8 tons, 2.6 %
   Machinery: 13 tons, 4.2 %
   Hull, fittings & equipment: 99 tons, 31.4 %
   Fuel, ammunition & stores: 17 tons, 5.5 %
   Miscellaneous weights: 177 tons, 56.0 %
      - Hull below water: 12 tons
      - Hull above water: 15 tons
      - On freeboard deck: 145 tons
      - Above deck: 5 tons

Fittings:
-4 t:  Diesel engines (BW)
-8 t:  Stores for 80 t of small craft (BW)
-10 t:  Small craft workshop (AW)
-5 t:  Brig (AW)
-120 t:  Accommodation for 24 MTB crew and 36 naval infantry/police (FD)
-20 t:  Facilities for one unarmed floatplane (FD)
-5 t:  Weight reserve (FD)
-5 t:  Working space (AD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,916 lbs / 869 Kg = 18,603.6 x 0.6 " / 15 mm shells or 2.3 torpedoes
   Stability (Unstable if below 1.00): 1.32
   Metacentric height 1.1 ft / 0.3 m
   Roll period: 10.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.01
   Seaboat quality  (Average = 1.00): 2.00

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.680 / 0.682
   Length to Beam Ratio: 6.00 : 1
   'Natural speed' for length: 12.55 kts
   Power going to wave formation at top speed: 43 %
   Trim (Max stability = 0, Max steadiness = 100): 35
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.98 ft / 0.30 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   25.00 %,  13.78 ft / 4.20 m,  13.78 ft / 4.20 m
      - Forward deck:   25.00 %,  13.78 ft / 4.20 m,  13.78 ft / 4.20 m
      - Aft deck:   35.00 %,  5.91 ft / 1.80 m,  5.91 ft / 1.80 m
      - Quarter deck:   15.00 %,  5.91 ft / 1.80 m,  5.91 ft / 1.80 m
      - Average freeboard:      9.84 ft / 3.00 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 26.2 %
      - Above water (accommodation/working, high = better): 158.2 %
   Waterplane Area: 3,254 Square feet or 302 Square metres
   Displacement factor (Displacement / loading): 147 %
   Structure weight / hull surface area: 21 lbs/sq ft or 103 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.65
      - Longitudinal: 2.42
      - Overall: 0.75
   Caution: Hull subject to strain in open-sea
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[Kaiser Kirk]

Interesting little ship.

Overall I like it- good multi-role platform.

For my tastes,
I'd really want a larger main gun if I could.
One of the advantages of a cruiser build :)

My vague recollection is for field fortifications,
log breastworks could be effective against even 75mm,
while they weren't against 100mm.
I'm guessing a 75 would penetrate but not seriously disrupt,
while splinters would be absorbed.