Parthian vessels 1916 onwards

[Kaiser Kirk]

New thread !

1916.5 ASW Refits

The Parthians have been slow on the submarine uptake, as the early vessels are so limited they have little use for them. So far they have merely built some experimental examples to explore how they can be deployed. 

Having now finished the 1910 version, and aware that other nations are working on the next generation, the capabilities seem to be moving in a direction which makes the submarine a potential problem.
At this point, submarines are not considered a critical problem for the fleet, but a potential annoyance. That annoyance could blossum to a full fledged problem if left unadressed and untrained for.

The time to start considering that problem is early, and having deduced that foreign navies were using hydrophones for ASW, the Parthians have belatedly developed some kit of their own, which they now wish to deploy.

The biggest problem is the realization that an effective force would require at least 3 vessels to triangulate, but 3 'search' vessels and 1 'attack' vessel sharing plots via radio would be best combo. This means groups of 4 vessels would be necessary to prosecute a submarine contact.

Their newest designs were optimized for surface combat, to engage and destroy enemy torpedo craft as far from the fleet as possible, or launch their own torpedo attacks.  These designs have little development room left, and no spare listening rooms. Further, there is no desire to take these valuable vessels off their primary role to deal with what is still a minor threat.

So the Parthians look to their older destroyers for trial efforts. The 1904 and 1906 classes are partial coal burners, and half way through their lifespan, they are unlikely to be sent on assault missions, so dedicating them to battleline defense seems reasonable.

These can be sent in groups of 4 ahead of the fleet's line of travel and conduct "sprint and drift" operations to help ensure clear passage.

The sixteen 1904 Destroyers are still felt capable vessels, but are unlikely to be assigned to torpedo attack. They can easily be broken into groups of 4.

The first step is removing gear :
-2t : The old windtowers can be removed
-4t : The torpedo outfit can be reduced to just the two "cheek firing" forward 18".
-3t : The construction reserve can be used up.
-4.7t : Remove the rear 90mm gun to clear the deck. (ammo is kept the same)

Then the new ASW elements can be fitted.
1T – New CO2 compresser ACs fitted for habitability. 
5T- The Basic ASW package with the boom mikes, spares and operators.
1T- ASW Kite
6t – Depth Charge rails.

All fall under "Basic Refit" , so the cost is : 13t per 1904 DD.
13 x 16 = 208

COST = $0.021, 0.021

However, as these ships are 12 years old, the Parthians choose to do a "Refurbishment"
For a cost of $.1 each.  BP cost is the same, $ cost is doubled.
Total : $0.1 + ($0.021*2) = $0.142, 0.021BP each
$2.272, 0.336BP for class

ed; bah, forgot the SS

Spear R1916, Parthia Destroyer laid down 1904

Displacement:
   499 t light; 519 t standard; 601 t normal; 666 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (231.63 ft / 228.35 ft) x 22.15 ft x (9.51 / 10.23 ft)
   (70.60 m / 69.60 m) x 6.75 m  x (2.90 / 3.12 m)

Armament:
      1 - 3.54" / 90.0 mm 45.0 cal gun - 22.05lbs / 10.00kg shells, 360 per gun
     Quick firing gun in deck mount, 1899 Model
     1 x Single mount on centreline, forward deck centre
      2 - 3.54" / 90.0 mm 45.0 cal guns - 22.05lbs / 10.00kg shells, 180 per gun
     Quick firing guns in casemate mounts, 1899 Model
     2 x Single mounts on sides, forward deck aft
      Weight of broadside 66 lbs / 30 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.24" / 6 mm         -               -
   2nd:   0.24" / 6 mm         -               -

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

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 9,866 shp / 7,360 Kw = 26.30 kts
   Range 2,650nm at 10.00 kts
   Bunker at max displacement = 146 tons (93% coal)
     Caution: Delicate, lightweight machinery

Complement:
   59 - 78

Cost:
   £0.068 million / $0.272 million

Distribution of weights at normal displacement:
   Armament: 12 tons, 2.0 %
      - Guns: 12 tons, 2.0 %
   Armour: 3 tons, 0.5 %
      - Armament: 1 tons, 0.2 %
      - Conning Tower: 2 tons, 0.3 %
   Machinery: 338 tons, 56.3 %
   Hull, fittings & equipment: 126 tons, 21.0 %
   Fuel, ammunition & stores: 102 tons, 17.0 %
   Miscellaneous weights: 19 tons, 3.2 %
      - Hull below water: 5 tons
      - Hull above water: 7 tons
      - On freeboard deck: 5 tons
      - Above deck: 2 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     140 lbs / 63 Kg = 6.3 x 3.5 " / 90 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.57
   Metacentric height 1.1 ft / 0.3 m
   Roll period: 8.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.13
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.437 / 0.451
   Length to Beam Ratio: 10.31 : 1
   'Natural speed' for length: 15.11 kts
   Power going to wave formation at top speed: 66 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): -15.00 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 %,  11.81 ft / 3.60 m,  11.15 ft / 3.40 m
      - Forward deck:   30.00 %,  11.15 ft / 3.40 m,  8.53 ft / 2.60 m
      - Aft deck:   35.00 %,  8.53 ft / 2.60 m,  8.53 ft / 2.60 m
      - Quarter deck:   15.00 %,  8.53 ft / 2.60 m,  9.35 ft / 2.85 m
      - Average freeboard:      9.56 ft / 2.91 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 189.9 %
      - Above water (accommodation/working, high = better): 94.2 %
   Waterplane Area: 3,192 Square feet or 297 Square metres
   Displacement factor (Displacement / loading): 30 %
   Structure weight / hull surface area: 20 lbs/sq ft or 100 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.73
      - Overall: 0.56
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room

This  Class of Destroyers are an effort to exploit the turbine technology for further speed. The first true Destroyers rather than enlarged ocean going torpedo boats, they are Larger, faster, and better armed. They sacrifice about 1/4knt of performance for slightly better seakeeping, allowing them to operate in the Persian Ocean.

Trial Speed is : 26.3kts + 2.75 : 29.05kts

These little ships rely on boilers burning coal boilers oil sprayed coal, there is sufficient fuel for a 10 day journey, with a 10% reserve. Of the 8 boilers, 2 are 100% coal, and 6 are oil-sprayed coal. They can manage 18.71 knts on the coal fired boilers alone.

The guns are arranged with A and Y, but with  two casements in the superstructure (like the Omaha CLs)  clearance forward, giving 3 guns bearing forward, and 3 on either beam. The guns are equipped with 6mm spray shields.

Miscellaneous weight is as follows :
8t - 4x 18" mm torpedoes. Two torpedoes fire forward from the "cheeks" like an E-boat, and two on a turntable in the rear.
2t - Extra ventilation
2t - 1905 fire control
7t - Void, construction reserve



Speed with the single 100% coal fire boiler is 18.65knts, allowing virtually all peacetime activity to be done using existing coaling facilities around the Persian ocean.

Trial Speed: 25.6+ 2.75 : 29kts

1907 refit : 2t
2t + 1905 fire control
-2t  construction reserve

1916 Refurbishment
1T – New CO2 compresser ACs fitted for habitability. 
5T- The Basic ASW package with the boom mikes, spares and operators.
1T- ASW Kite
6t – Depth Charge rails.

[Kaiser Kirk]

For the 1906 series there are only 8 destroyers, but that will suffice for 2 search groups.
For them the deletions are
-10t Short Range Radio (automatic with refurbishment)
-4 Windcatcher ventilation
-6 construction reserve
- Aft 90mm gun (ammo kept same)

New :
1t : CO2 compressor AC
15t  : enhanced Hydrophone package
1t : ASW Kite
5t : Depth charges
---
22t

Refurbishment : .75 *.2 = $0.15/vessel +.044
$0.194 + 0.022 BP / vessel
$1.552 + 0.176 BP Class

Atlatl, Parthian Fleet Destroyer laid down 1906

Displacement:
   749 t light; 785 t standard; 883 t normal; 960 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (308.19 ft / 304.46 ft) x 31.17 ft x (8.04 / 8.53 ft)
   (93.94 m / 92.80 m) x 9.50 m  x (2.45 / 2.60 m)

Armament:
      3 - 3.54" / 90.0 mm 45.0 cal guns - 22.05lbs / 10.00kg shells, 333 per gun
     Quick firing guns in deck mounts, 1904 Model
     3 x Single mounts on centreline ends, majority forward
      1 raised mount - superfiring
      4 - 2.36" / 60.0 mm 50.0 cal guns - 7.05lbs / 3.20kg shells, 400 per gun
     Quick firing guns in deck mounts, 1904 Model
     4 x Single mounts on side ends, evenly spread
      Weight of broadside 94 lbs / 43 kg

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 11,950 shp / 8,915 Kw = 27.00 kts
   Range 3,600nm at 10.00 kts
   Bunker at max displacement = 175 tons (20% coal)

Complement:
   80 - 105

Cost:
   £0.097 million / $0.387 million

Distribution of weights at normal displacement:
   Armament: 19 tons, 2.1 %
      - Guns: 19 tons, 2.1 %
   Machinery: 468 tons, 53.0 %
   Hull, fittings & equipment: 222 tons, 25.2 %
   Fuel, ammunition & stores: 133 tons, 15.1 %
   Miscellaneous weights: 40 tons, 4.6 %
      - Hull below water: 15 tons
      - Hull above water: 6 tons
      - On freeboard deck: 16 tons
      - Above deck: 3 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     274 lbs / 124 Kg = 12.3 x 3.5 " / 90 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.53
   Metacentric height 1.8 ft / 0.5 m
   Roll period: 9.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.10
   Seaboat quality  (Average = 1.00): 1.23

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.405 / 0.415
   Length to Beam Ratio: 9.77 : 1
   'Natural speed' for length: 17.45 kts
   Power going to wave formation at top speed: 59 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 15.00 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 %,  13.91 ft / 4.24 m,  13.91 ft / 4.24 m
      - Forward deck:   30.00 %,  13.91 ft / 4.24 m,  10.63 ft / 3.24 m
      - Aft deck:   35.00 %,  10.63 ft / 3.24 m,  10.63 ft / 3.24 m
      - Quarter deck:   15.00 %,  10.63 ft / 3.24 m,  10.63 ft / 3.24 m
      - Average freeboard:      11.78 ft / 3.59 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 180.6 %
      - Above water (accommodation/working, high = better): 150.3 %
   Waterplane Area: 5,543 Square feet or 515 Square metres
   Displacement factor (Displacement / loading): 53 %
   Structure weight / hull surface area: 24 lbs/sq ft or 119 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.11
      - Overall: 0.54
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Trial Speed 28.5kts

Misc. Weight.
16t - 8 x 21" TT , 1 sets torpedo
4t - increased ventilation
2t - 1905 Fire control refit
10t- Short ranged radio
6t - construction reserve remaining.

1907 Basic Refit :2t
2t - +1905 Fire control
-2t construction reserve

1916 Refurbishment
1t : CO2 compressor AC
15t  : enhanced Hydrophone package
1t : ASW Kite
5t : Depth charges

[Kaiser Kirk]

Last but not least, a new "Patrol Sloop".

The other piece of the puzzle seems to be numbers, and simply being able to patrol near ports to ensure enemy raiders do not sneak into harbors to torpedo warships or lay mines. These vessels would need to be in place prior to any wars and will help deter potential foes from seeking this asymmetric solution.

The current series of minewarefare vessels are an example of vessels meant to answer that need. Parthian harbors have dedicated minesweeping component run by naval professionals.  With the ASW component being added, a new vessel needs to be considered.

Sentry PS-1, Parthian Senty Class Sloop laid down 1918

Displacement:
   600 t light; 616 t standard; 660 t normal; 696 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (239.52 ft / 236.22 ft) x 29.53 ft x (6.56 / 6.83 ft)
   (73.00 m / 72.00 m) x 9.00 m  x (2.00 / 2.08 m)

Armament:
      1 - 3.54" / 90.0 mm 45.0 cal gun - 22.05lbs / 10.00kg shells, 200 per gun
     Quick firing gun in deck mount, 1899 Model
     1 x Single mount on centreline forward
      3 - 1.77" / 45.0 mm 45.0 cal guns - 2.80lbs / 1.27kg shells, 100 per gun
     Quick firing guns in deck mounts, 1899 Model
     1 x Single mount on centreline, aft deck centre
     2 x Single mounts on sides, forward deck aft
      Weight of broadside 30 lbs / 14 kg

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

Machinery:
   Coal and oil fired boilers, complex reciprocating steam engines,
   Electric motors, 2 shafts, 2,373 ihp / 1,770 Kw = 18.00 kts
   Range 2,600nm at 10.00 kts
   Bunker at max displacement = 79 tons (23% coal)

Complement:
   64 - 84

Cost:
   £0.085 million / $0.341 million

Distribution of weights at normal displacement:
   Armament: 6 tons, 0.9 %
      - Guns: 6 tons, 0.9 %
   Armour: 1 tons, 0.2 %
      - Armament: 1 tons, 0.2 %
   Machinery: 143 tons, 21.7 %
   Hull, fittings & equipment: 255 tons, 38.7 %
   Fuel, ammunition & stores: 60 tons, 9.1 %
   Miscellaneous weights: 195 tons, 29.5 %
      - Hull below water: 60 tons
      - Hull void weights: 4 tons
      - Hull above water: 48 tons
      - On freeboard deck: 32 tons
      - Above deck: 51 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,238 lbs / 561 Kg = 55.6 x 3.5 " / 90 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 11.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.04
   Seaboat quality  (Average = 1.00): 1.55

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.505 / 0.511
   Length to Beam Ratio: 8.00 : 1
   'Natural speed' for length: 15.37 kts
   Power going to wave formation at top speed: 50 %
   Trim (Max stability = 0, Max steadiness = 100): 45
   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 %,  12.30 ft / 3.75 m,  10.66 ft / 3.25 m
      - Forward deck:   30.00 %,  10.66 ft / 3.25 m,  9.84 ft / 3.00 m
      - Aft deck:   35.00 %,  9.84 ft / 3.00 m,  9.84 ft / 3.00 m
      - Quarter deck:   15.00 %,  9.84 ft / 3.00 m,  10.66 ft / 3.25 m
      - Average freeboard:      10.32 ft / 3.15 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 91.1 %
      - Above water (accommodation/working, high = better): 139.4 %
   Waterplane Area: 4,669 Square feet or 434 Square metres
   Displacement factor (Displacement / loading): 133 %
   Structure weight / hull surface area: 36 lbs/sq ft or 178 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 1.81
      - Overall: 1.00
   Adequate 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

A adjunct to the  CPC-1 Mackeral class of coastal patrol cutters,
combining some of it's roles with those of the 40-strong MSE-13 class of minesweepers.

Designed primarily as an affordable subchaser/minesweeper/sentry ship.

Range is sufficient to transit between territories,
while coal burning provision allows for local coal/wood to be used if bunker oil runs short.

A kite balloon, echoing the Japanese, is fitted for reconnaisance purposes, and for sub-spotting.

Minesweeping gear, such as paravanes, booms, trawls, is stored.

The main gun is a 90mm QF, the common light naval gun. The HV rounds will not penetrate water worth a darn, but will provide ranging information on misses. One hit with a SAP is expected to penetrate a submarine hull easily.

45mm QF are also mounted to give 360 degree capability.

Simple rangefinders and plotting tables are fitted. The plotting tables will be used in both FC and plotting attack runs.

A 'full' hydrophone package is fitted.

As is typical in Parthian service, provision for coal/wood firing is made so that the vessel can operate from commercial coal stocks.

A turbo-electric plant is fitted, along with batteries. This is hoped to allow the ship to manuever quietly. Turbo-electric has been used for the MSW class for years, the ability to use full reverse/forward on either screw assisting in manueverability, thought useful in minefields.

The ship has a small hold, as it is anticipated it may be used to ferry cargos along territorial coasts, where it's high manueverability and shallow draft may proove useful.

Mercantile
600t x 0.02 = 12

-4.4 guns
-.5  Firecontrol
=7 tons for ASW weapons.

1t ASW Kite
6t 30x 195kg DCs
= 7 tons ASW weapons

Miscellaneous Weights :
AD :
25t LR radio
0.5t FC
25t Kite Balloon

OD :
1t : ASW Kites
6t : 30x 195kg DC.
25t Minesweeping gear

HAW:
45t Miscellaneous Cargo
3t  CO2 compressor AC

Hull below water:
15t "Enhanced Hydrophone Package".
35t  Turbo-electric generators
10t  Batteries

[Kaiser Kirk]

While posting my HY1 1917 turn, I realized I hadn't refurbished the two Recalde class purchased from Iberia.
Since the unrefitted vessels have breechloading 140mm with no fire control,

I figured I should explore the cost of refurbishment.
The Parthian's floating dock can be towed to Ria de Janerio to accommodate the refeubishment.

We'll start with the costs, then what the refurbished vessel would look like.

The final cost is $0.50 , 0.17 BP each, or $1 and 0.34 for both.

So I'll leave this up a couple days for comments, then likely revise my turn as that's very easy to fit into the budget.  It's close to my surplus amount as is.


1917 Refurbished Armanent
A/1/2 are on deck, "X" is superimposed to allow clear arcs over mine rails.
1/2 are mounted Fore deck aft, above the 1.2m break in deck height, allowing fire aft over the torpedo tubes.

1917 Refurbished Misc Weight
AD---0.7t  Fire Control
AD---25t   Long Range Wireless
AD--- 5t   Flotilla Leader Facilities
OD---18t  2T3 530mm Torpedoes, aft deck forward.
OD---36t  stern mine rails and 40 mines

1917  refurbishment
Base cost : $0.2212
removed armanent
- 140mm BL guns & armor :-83t, 28mag
- 57mm QF guns : -4.7t, 1.9mag
- torpedoes : -32t
- mmines&minelaying : -38t
----
-187.6t

added armanent :
55t    : + 130mm QF gun 
9.6t   : +90mm AA
29.9t : + mags
-----
94.5t
Refurb Cost : 0.0945 BP, $0.189

Armor & Functional Misc Wt
20t    :   Gun shields
0.7t   :   Fire Control AD
18t    :   2T3 21" torpedoes, Aft deck foreward
36t    :   mine rails & 36 mines
-----
74.7t
Refurb Cost : 0.0747 BP, $0.0747

Non-functional Weight
25t   :  Parthian Long Range Radio
5t     :  Flotilla Leaders command center
----
30t

Refurb cost : 0 BP , $0.015

------
Refurbishment costs

         0 BP,  $0.015
0.0747 BP , $0.0747
0.0945 BP,  $0.189
                    $0.2212

Sub total Cost per vessel :
0.1692 BP : Rounds to 0.17 BP
0.4999 $   : Rounds to 0.50 $

The vessel :

Recalde, Iberian Cruiser-Gunboat laid down 1905

Displacement:
   1,106 t light; 1,164 t standard; 1,392 t normal; 1,575 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (257.68 ft / 255.91 ft) x 33.46 ft x (11.15 / 12.31 ft)
   (78.54 m / 78.00 m) x 10.20 m  x (3.40 / 3.75 m)

Armament:
      4 - 5.12" / 130 mm 50.0 cal guns - 70.55lbs / 32.00kg shells, 155 per gun
     Quick firing guns in deck mounts, 1913 Model
     2 x Single mounts on centreline ends, evenly spread
      1 raised mount aft - superfiring
     2 x Single mounts on sides, forward deck aft
      2 - 3.54" / 90.0 mm 50.0 cal guns - 24.25lbs / 11.00kg shells, 220 per gun
     Quick firing guns in deck mounts, 1912 Model
     2 x Single mounts on sides, forward deck aft
      2 double raised mounts
      Weight of broadside 331 lbs / 150 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.98" / 25 mm   255.91 ft / 78.00 m   6.56 ft / 2.00 m
     Main Belt covers 154 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.97" / 50 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 0.98" / 25 mm
   Forecastle: 0.98" / 25 mm  Quarter deck: 0.98" / 25 mm

   - Conning towers: Forward 2.95" / 75 mm, Aft 0.00" / 0 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 4,290 shp / 3,200 Kw = 18.80 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 411 tons (90% coal)

Complement:
   113 - 148

Cost:
   £0.106 million / $0.423 million

Distribution of weights at normal displacement:
   Armament: 64 tons, 4.6 %
      - Guns: 64 tons, 4.6 %
   Armour: 191 tons, 13.7 %
      - Belts: 61 tons, 4.4 %
      - Armament: 20 tons, 1.5 %
      - Armour Deck: 102 tons, 7.3 %
      - Conning Tower: 8 tons, 0.6 %
   Machinery: 354 tons, 25.4 %
   Hull, fittings & equipment: 411 tons, 29.6 %
   Fuel, ammunition & stores: 286 tons, 20.6 %
   Miscellaneous weights: 85 tons, 6.1 %
      - On freeboard deck: 54 tons
      - Above deck: 31 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,748 lbs / 793 Kg = 26.1 x 5.1 " / 130 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.37
   Metacentric height 1.7 ft / 0.5 m
   Roll period: 10.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 65 %
         - Recoil effect (Restricted arc if above 1.00): 0.24
   Seaboat quality  (Average = 1.00): 1.30

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.510 / 0.523
   Length to Beam Ratio: 7.65 : 1
   'Natural speed' for length: 16.00 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 5.00 degrees
   Stern overhang: 0.66 ft / 0.20 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  12.80 ft / 3.90 m,  12.14 ft / 3.70 m
      - Forward deck:   30.00 %,  12.14 ft / 3.70 m,  11.15 ft / 3.40 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:      9.58 ft / 2.92 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 95.8 %
      - Above water (accommodation/working, high = better): 86.6 %
   Waterplane Area: 5,545 Square feet or 515 Square metres
   Displacement factor (Displacement / loading): 121 %
   Structure weight / hull surface area: 52 lbs/sq ft or 253 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.00
      - Longitudinal: 1.79
      - Overall: 1.06
   Adequate machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Good seaboat, rides out heavy weather easily

[Kaiser Kirk]

So, with the proliferation of destroyer designs, I figured I'd post one.
I've been trying different destroyers as well, and may wind up with 2-3 designs.

There seems to be a different need for an oceanic destroyer that has range and seakeeping,
versus a fleet destroyer for more traditional roles.

Then the idea of fights in the Gulf of Aden, or Straits of Madagascar, or Indonesia, or Caribbean
- all smash and dash, pick your weather, hide in riverine deltas... a coastal type.


This one is one of the Oceanic Destroyers.
Like most Parthian ships, tough for it's type but slower than what these young empires are fielding.
But dagnab it, it's hard to keep up with little whippersnappers.

Palang (Leopard), Parthian Corvette laid down 1920

Displacement:
   1,494 t light; 1,563 t standard; 1,852 t normal; 2,082 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (391.97 ft / 387.14 ft) x 36.09 ft x (10.66 / 11.58 ft)
   (119.47 m / 118.00 m) x 11.00 m  x (3.25 / 3.53 m)

Armament:
      4 - 4.72" / 120 mm 43.0 cal guns - 55.12lbs / 25.00kg shells, 200 per gun
     Quick firing guns in deck mounts, 1920 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      2 - 3.54" / 90.0 mm 50.0 cal guns - 24.25lbs / 11.00kg shells, 300 per gun
     Anti-air guns in deck mounts, 1920 Model
     2 x Single mounts on sides, aft deck centre
      2 raised mounts
      Weight of broadside 269 lbs / 122 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.24" / 6 mm         -               -
   2nd:   0.24" / 6 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 30,674 shp / 22,883 Kw = 31.15 kts  Trial Speed: 31.78
   Range 4,750nm at 16.00 kts
   Bunker at max displacement = 519 tons

Complement:
   140 - 183

Cost:
   £0.459 million / $1.834 million

Distribution of weights at normal displacement:
   Armament: 44 tons, 2.4 %
      - Guns: 44 tons, 2.4 %
   Armour: 3 tons, 0.2 %
      - Armament: 3 tons, 0.2 %
   Machinery: 927 tons, 50.1 %
   Hull, fittings & equipment: 447 tons, 24.1 %
   Fuel, ammunition & stores: 358 tons, 19.3 %
   Miscellaneous weights: 73 tons, 3.9 %
      - Hull below water: 15 tons
      - Hull void weights: 25 tons
      - On freeboard deck: 28 tons
      - Above deck: 5 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     596 lbs / 270 Kg = 11.3 x 4.7 " / 120 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.49
   Metacentric height 2.1 ft / 0.7 m
   Roll period: 10.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.21
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.435 / 0.450
   Length to Beam Ratio: 10.73 : 1
   'Natural speed' for length: 19.68 kts
   Power going to wave formation at top speed: 61 %
   Trim (Max stability = 0, Max steadiness = 100): 59
   Bow angle (Positive = bow angles forward): 15.00 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 %,  18.04 ft / 5.50 m,  15.58 ft / 4.75 m
      - Forward deck:   25.00 %,  15.58 ft / 4.75 m,  13.12 ft / 4.00 m
      - Aft deck:   40.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Average freeboard:      14.12 ft / 4.30 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 169.8 %
      - Above water (accommodation/working, high = better): 162.9 %
   Waterplane Area: 8,807 Square feet or 818 Square metres
   Displacement factor (Displacement / loading): 79 %
   Structure weight / hull surface area: 31 lbs/sq ft or 150 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.07
      - Overall: 0.54
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

This has a ~4400nm range to
get to an  base and back, or skip past one,
but also a high cruising speed so that the vessel can move about the battleline.

At the fleet speed of 14knots, that gives them a range of 6500nm.

At maximum speed they can only reach 750nm, which takes 24hours. This would allow them to make a near full speed dash out into a contested area and return to base.

At a more reasonable speed of 20 knots, which fits their hull length, they can manage 2700nm, allowing them to quickly transit between Parthian bases, giving more strategic flexibility.


Additionally, they want them to be able to prosecute contacts, and so are provided with Depth Charges.


Weaponry is meant to be
                        1                           DC
A (B)          ==    ==          (C) D
                          2                         DC

The 1 & 2 90mm AA mounts are mounted en-echelon
on a tower between the torpedo tubes. The
Tower serves as a primitive TDC as well.

The design forfits some gun power for overall seakeeping and range.

Miscellaneous Weight :
25t - reserve
15t - Advanced Hydrophone sets
10t - Depth Charges
18t - 2TT3 21" Torpedoes
5t  - FC

[The Rock Doctor]

It's a well-rounded can, I like it.

[Kaiser Kirk]

So the above Palang destroyer is a candidate for the follow on to the Seahawk class, mainly for Pacific use, where the range and seakeeping will help.
I'm thinking of calling those 'Corvettes'.

I'm toying with 1000-1200 ton 'Fleet destroyers' for the remainder. Enough to fit in ASW suites and normal seakeeping and range.
Then there's the various explorations of 24hr speed run destroyers for coastal work.

I'm also looking at small cruisers.

After the Sino-Japanese war, that need for night time detection pickets and then extra secondaries led to the Maelstrom and Ranger classes.
But they are decent sized vessels, that it would be nice to unshackle from the fleet.

What I need is a vessel fast enough to move around the fleet. 
If bigger/faster cruisers show up, they can retreat to the guns of the Capital ships. So they don't have to outrun everything.
With the new Stormbringers at 26kts, and the old ACs at 27kts, 27-28 seems about right.

These can extend the warning range of the fleet day or night.
Then if there is the sound of lots of high speed propellors, they need to move that direction and form a skirmish line.
Hopefully about 16-18km from the fleet, but I will take what I can get.
Starshell would then cover from ~12km from them, and then between them and the fleet.

Then they need the guns to actually chew up the DDs/MTBs,
and the armor to not take fatal hits from their guns.
They will be small and fast enough that dodging torpedoes is realistic.

So I've been thinking about things like an Atlanta Class cruiser.

In the end I have a range from `2500 tons to 3750 to 6000.
I have them in 165mm single mounts and 130mm twin - about the same wt.

So here's a small, slow cruiser, meant to escort the battleline and chew up MTBs/DDs. 

Bakr,  Parthian Empire Frigate laid down 1919

Displacement:
   4,498 t light; 4,809 t standard; 5,607 t normal; 6,246 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (461.31 ft / 456.04 ft) x 45.93 ft x (18.70 / 20.30 ft)
   (140.61 m / 139.00 m) x 14.00 m  x (5.70 / 6.19 m)

Armament:
      16 - 5.12" / 130 mm 50.0 cal guns - 77.16lbs / 35.00kg shells, 250 per gun
     Quick firing guns in deck and hoist mounts, 1919 Model
     4 x 2-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
     4 x 2-gun mounts on side ends, evenly spread
      4 - 3.54" / 90.0 mm 50.0 cal guns - 24.25lbs / 11.00kg shells, 500 per gun
     Anti-air guns in deck and hoist mounts, 1919 Model
     4 x Single mounts on side ends, evenly spread
      4 raised mounts
      Weight of broadside 1,332 lbs / 604 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   1.97" / 50 mm   314.67 ft / 95.91 m   9.84 ft / 3.00 m
   Ends:   0.98" / 25 mm   141.34 ft / 43.08 m   9.84 ft / 3.00 m
     Main Belt covers 106 % of normal length

   - Hull void:
      0.00" / 0 mm     0.00 ft / 0.00 m   0.00 ft / 0.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.97" / 50 mm   1.18" / 30 mm      1.97" / 50 mm
   2nd:   0.24" / 6 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 1.38" / 35 mm

   - Conning towers: Forward 1.97" / 50 mm, Aft 1.97" / 50 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 38,375 shp / 28,628 Kw = 28.00 kts
   Range 6,600nm at 16.00 kts
   Bunker at max displacement = 1,437 tons

Complement:
   323 - 421

Cost:
   £1.044 million / $4.176 million

Distribution of weights at normal displacement:
   Armament: 369 tons, 6.6 %
      - Guns: 369 tons, 6.6 %
   Armour: 716 tons, 12.8 %
      - Belts: 298 tons, 5.3 %
      - Armament: 87 tons, 1.6 %
      - Armour Deck: 304 tons, 5.4 %
      - Conning Towers: 27 tons, 0.5 %
   Machinery: 1,363 tons, 24.3 %
   Hull, fittings & equipment: 1,602 tons, 28.6 %
   Fuel, ammunition & stores: 1,109 tons, 19.8 %
   Miscellaneous weights: 449 tons, 8.0 %
      - Hull below water: 87 tons
      - Hull void weights: 45 tons
      - Hull above water: 79 tons
      - On freeboard deck: 150 tons
      - Above deck: 88 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     4,961 lbs / 2,250 Kg = 74.0 x 5.1 " / 130 mm shells or 1.0 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 1.9 ft / 0.6 m
   Roll period: 14.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.77
   Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.501 / 0.514
   Length to Beam Ratio: 9.93 : 1
   'Natural speed' for length: 21.36 kts
   Power going to wave formation at top speed: 56 %
   Trim (Max stability = 0, Max steadiness = 100): 47
   Bow angle (Positive = bow angles forward): 15.00 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,  17.22 ft / 5.25 m
      - Forward deck:   30.00 %,  17.22 ft / 5.25 m,  14.76 ft / 4.50 m
      - Aft deck:   39.00 %,  14.76 ft / 4.50 m,  14.76 ft / 4.50 m
      - Quarter deck:   11.00 %,  14.76 ft / 4.50 m,  14.76 ft / 4.50 m
      - Average freeboard:      15.82 ft / 4.82 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 105.4 %
      - Above water (accommodation/working, high = better): 126.0 %
   Waterplane Area: 13,969 Square feet or 1,298 Square metres
   Displacement factor (Displacement / loading): 109 %
   Structure weight / hull surface area: 75 lbs/sq ft or 369 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.85
      - Longitudinal: 1.42
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room

The Parthians are concerned that naval combat is looking
like rock>paper>scissors>rock.

The descriptions from the Sino-Japanese war of 'skirmish' lines seems to be an effective means of dealing with light fast raider forces. There seems to be further emerging threats such as aerial or undersea, both of which can likely be best handled if detected further out.

All of this suggests having a specialized 'escort' ship, which simply needs sufficient speed to manuever around fleet elements.
While the Parthian battleline is 20knots, the newest heavy ships are 26 knots, and the older ACs are 27knots. So a speed of roughly 27-28 knots is needed to ensure widest utlitily.

As they would conceptually be advanced to ~18000m towards any onrushing MTB/DD night attack, they need to be fitted with sufficient fire control to divide fire and rapidly destroy attackers on both sides of the vessel.

Seakeeping is not critical, as those light attackers would do poorly in heavier seastates.

Due to poor development of ASW techniques, they are fitted with depth charges and hydrophones, and equipped for battery use 'on station' while hunting. In reality they are far to big and expensive to be good choices in this role. The hydrophones will help pick up distant propellors though.

Misc Wt
45t - Wt Reserve

40t - Dual Fire Control
25t - LR radio
23t - 30m cage mast (battleship level sight lines)

25t - Hulesmeyer
25t - War Tubas
25t - Night Fighting
25t - Kite Balloon
50t - additional accomodations

22t - 2x T3 21" torpedoes on fantail
7t - depth charge rack on fan tail.

25t - Imp Fire suppression
5t - A/C
50t - additional accomodations

15t - Hydrophones
50t - Reserve space
22t - Imp Pumps


Decks :
4.5m: Weather deck
2.0m : Battery Deck, Top Main Belt, Armor deck
-0.5m : Main Deck
           -1.0m : Bottom main belt
-4.5 : Engineering
-5.0 : Double bottom (liquid filled)

[The Rock Doctor]

We really need to have the abilities of thing like war tubas and hulesmeyer devices quantified in the rules set. 

[Kaiser Kirk]

I was really expecting more along the lines of 'it's to slow and weakly armored' or 'bad idea for X'  or 'hey that might work' or 'damn that's alot of guns'.
A cry for more rules was not expected.

[Desertfox]

I just find the different ways people are dealing with the Sino-Japanese War lessons interesting. Romans with insane secondaries, Parthians with dedicated cruisers, Japanese with hunter-killer destroyer groups.

But looking at the cruiser above, its a golden BB waiting to happen with so much ammo all over the place. Light forces are likely to have cruisers backing them up as well.

[TacCovert4]

It's got a lot of guns.  But honestly too many.  While sure, it can take on maybe 3 DDs simultaneously.....it's not going to be very effective fighting against other cruisers that can just punch holes in it.  50mm belt isn't enough to repel 150mm or 180mm shells, and 180mm is bog standard for a full up cruiser these days.

Overall,  I've also looked into the type.  But I don't think its viable in its tonnage range until the 1920 cruiser tech is complete.   Being able to build it down to .75 comp might make it useful.  Otherwise,  I'd suggest that a Trio of destroyers would be more effective. 

[The Rock Doctor]

I was really expecting more along the lines of 'it's to slow and weakly armored' or 'bad idea for X'  or 'hey that might work' or 'damn that's alot of guns'.
A cry for more rules was not expected.

Maybe it works, maybe not.  It seems very crowded for the size of the hull.

My initial concern remains constraining the capabilities of equipment that has no real history of actual, practical use.  I have no idea whether I should be setting aside for a war tuba because I basically understand it to be fictional at this point.

[Jefgte]

Bakr,  Parthian Empire Frigate laid down 1919

IMO,
8T2x130...too much
4T2 is correct
28kts is the minimum
------------------------------
Byzantium prefers super destroyers to protect BBs and CVs with more classic armament like:
4T2x120 or 4T2x140
or may be 3T2x152 + 4T2x102AA

[Kaiser Kirk]

Lunchtime :)

Let's see

A) Golden BB / To thin armor :  Again, the idea was that these would stay near the fleet, and if big cruisers wanted to fight, they'd scurry back.
So their main foe would be destroyers/MTBs. 
The standard load for a destroyer gun is HE - the foes are unarmored, the guns are small so AP won't penetrate much armor anyhow, and AP has a smaller burster and does less damage.
So normally DDs would not be carrying AP, only HE. For that, 40-50mm will stop all the rounds. The Deck armor will stop all the splinters up to ~200mm shells. So a golden BB is unlikely.

Footnote : USN 6"/53 on the Omahas were expected to penetrate 102mm at 6,300yards, and 51mm at 13,800yards. 

B) 3 DDs instead of Cruiser : That was where I started. Adding the various miscellaneous weights desired, the range desired, and then still fitting under the destroyer rules was not working.
So I produced a 2500ton unarmored cruiser with destroyer armaments. Then I started adding guns and armor. Then I hit 6000t, and decided to trim it down.

C) I don't really want to go down to 8x 130.   This is like Atlanta, with fewer centerline mounts, but an extra pair of flanking mounts aft.
I can however, swap T2 130s for T1 165s at 1:1. So I can field 16x 130mm or 8x 165mm.

D) Crowded hull size  - The SS says :
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room

So, theoretically there's plenty of room.

D) Hulesmeyer / War Tuba. 
I'm not sure what "rule" is needed. Both existed. I don't know if the War Tuba ever was used on ships, and I certainly don't think they look like 25t..but ok.
Hulesmeyer at this time is basically a proximity alert that there's something metal between 0 and 10,000m "that a way".
War Tuba could probably pick up the roar of MTB engines at a considerable distance,
but so can hydrophones when used.


Version 2.
Now - with more armor !...and this is the 165mm version.
... I shaved 1/2 knot, lost the end belts, trimmed the freeboard, and that allowed me to shrink the belt height to +1.5 to -1.0m.
I don't like loosing the 1/2 knot, but I did define the target range as 27-28. So it's still in the design goal.


Bakr, Parthian Empire Escort Cruiser laid down 1919

Displacement:
   4,497 t light; 4,796 t standard; 5,605 t normal; 6,252 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (460.96 ft / 456.04 ft) x 47.01 ft x (18.86 / 20.47 ft)
   (140.50 m / 139.00 m) x 14.33 m  x (5.75 / 6.24 m)

Armament:
      8 - 6.50" / 165 mm 43.0 cal guns - 143.30lbs / 65.00kg shells, 250 per gun
     Quick firing guns in deck and hoist mounts, 1919 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
     4 x Single mounts on side ends, evenly spread
      4 - 3.54" / 90.0 mm 50.0 cal guns - 24.25lbs / 11.00kg shells, 500 per gun
     Anti-air guns in deck and hoist mounts, 1919 Model
     4 x Single mounts on side ends, evenly spread
      4 raised mounts
      Weight of broadside 1,243 lbs / 564 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.94" / 100 mm   296.42 ft / 90.35 m   8.20 ft / 2.50 m
   Ends:   0.98" / 25 mm   159.58 ft / 48.64 m   8.20 ft / 2.50 m
     Main Belt covers 100 % of normal length

   - Hull void:
      0.00" / 0 mm     0.00 ft / 0.00 m   0.00 ft / 0.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   3.94" / 100 mm   1.18" / 30 mm      3.54" / 90 mm
   2nd:   0.24" / 6 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 1.38" / 35 mm
   Forecastle: 0.98" / 25 mm  Quarter deck: 0.98" / 25 mm

   - Conning towers: Forward 3.94" / 100 mm, Aft 1.97" / 50 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 3 shafts, 35,534 shp / 26,509 Kw = 27.50 kts
   Range 6,700nm at 16.00 kts
   Bunker at max displacement = 1,456 tons

Complement:
   323 - 421

Cost:
   £0.962 million / $3.847 million

Distribution of weights at normal displacement:
   Armament: 300 tons, 5.3 %
      - Guns: 300 tons, 5.3 %
   Armour: 928 tons, 16.6 %
      - Belts: 440 tons, 7.8 %
      - Armament: 105 tons, 1.9 %
      - Armour Deck: 343 tons, 6.1 %
      - Conning Towers: 40 tons, 0.7 %
   Machinery: 1,262 tons, 22.5 %
   Hull, fittings & equipment: 1,595 tons, 28.5 %
   Fuel, ammunition & stores: 1,107 tons, 19.8 %
   Miscellaneous weights: 413 tons, 7.4 %
      - Hull below water: 70 tons
      - Hull void weights: 45 tons
      - Hull above water: 60 tons
      - On freeboard deck: 130 tons
      - Above deck: 108 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5,616 lbs / 2,548 Kg = 41.0 x 6.5 " / 165 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.12
   Metacentric height 2.0 ft / 0.6 m
   Roll period: 14.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.62
   Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.485 / 0.499
   Length to Beam Ratio: 9.70 : 1
   'Natural speed' for length: 21.36 kts
   Power going to wave formation at top speed: 55 %
   Trim (Max stability = 0, Max steadiness = 100): 49
   Bow angle (Positive = bow angles forward): 15.00 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 %,  18.37 ft / 5.60 m,  16.08 ft / 4.90 m
      - Forward deck:   30.00 %,  16.08 ft / 4.90 m,  13.45 ft / 4.10 m
      - Aft deck:   35.00 %,  13.45 ft / 4.10 m,  13.45 ft / 4.10 m
      - Quarter deck:   15.00 %,  13.45 ft / 4.10 m,  13.45 ft / 4.10 m
      - Average freeboard:      14.55 ft / 4.44 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 95.4 %
      - Above water (accommodation/working, high = better): 116.8 %
   Waterplane Area: 14,093 Square feet or 1,309 Square metres
   Displacement factor (Displacement / loading): 115 %
   Structure weight / hull surface area: 76 lbs/sq ft or 369 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.87
      - Longitudinal: 1.27
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room

The Parthians are concerned that naval combat is looking
like rock>paper>scissors>rock.

The descriptions from the Sino-Japanese war of 'skirmish' lines seems to be an effective means of dealing with light fast raider forces. There seems to be further emerging threats such as aerial or undersea, both of which can likely be best handled if detected further out.

All of this suggests having a specialized 'escort' ship, which simply needs sufficient speed to manuever around fleet elements.
While the Parthian battleline is 20knots, the newest heavy ships are 26 knots, and the older ACs are 27knots. So a speed of roughly 27-28 knots is needed to ensure widest utlitily.

As they would conceptually be advanced to ~18000m towards any onrushing MTB/DD night attack, they need to be fitted with sufficient fire control to divide fire and rapidly destroy attackers on both sides of the vessel.

Seakeeping is not critical, as those light attackers would do poorly in heavier seastates.

Due to poor development of ASW techniques, they are fitted with depth charges and hydrophones, and equipped for battery use 'on station' while hunting. In reality they are far to big and expensive to be good choices in this role. The hydrophones will help pick up distant propellors though.

Misc Wt
45t - Wt Reserve

60t - Dual Fire Control
25t - LR radio
23t - 30m cage mast (battleship level sight lines)

25t - Hulesmeyer
25t - War Tubas
25t - Night Fighting
25t - Kite Balloon
30t - additional accomodations

22t - 2x T3 21" torpedoes on fantail
8t - depth charge rack on fan tail.

25t - Imp Fire suppression
5t - A/C
30t - additional accomodations

15t - Hydrophones
30t - Reserve space
25t - Imp Pumps


Decks :
4.1m: Weather deck
1.5m : Battery Deck, Top Main Belt, Crown protective deck deck
-1.0m : Main Deck,  Bottom main belt, lower edge protective deck
-4.5 : Engineering
-5.0 : Double bottom (liquid filled)

[Desertfox]

A) Golden BB / To thin armor :  Again, the idea was that these would stay near the fleet, and if big cruisers wanted to fight, they'd scurry back.
So their main foe would be destroyers/MTBs.
The standard load for a destroyer gun is HE - the foes are unarmored, the guns are small so AP won't penetrate much armor anyhow, and AP has a smaller burster and does less damage.
So normally DDs would not be carrying AP, only HE. For that, 40-50mm will stop all the rounds. The Deck armor will stop all the splinters up to ~200mm shells. So a golden BB is unlikely.

Footnote : USN 6"/53 on the Omahas were expected to penetrate 102mm at 6,300yards, and 51mm at 13,800yards. 

It wasn't just about the thin armor, but more the tons of ammo needed to feed all those guns. Golden BB has a lot higher chance to hit a critical spot. Note that at least for Japanese destroyer squadrons, they have one or two light cruisers present as leaders, specifically to provide cover fire against ships like these. Also the Fubukis are designed to take a bit more of a cruiser role and would have AP for the HV 5" guns.