Parthian vessels 1937 - 1940

Jefgte · March 28, 2025, 07:43:30 PM

QuoteThere is a certain shocked state of denial when you move to File, skim down to the one below "Save data file" and accidentally click "Clear all" on one's just finalized potential carrier....

You must redone immediately or very soon after... Datas are still fresh in the mind.

Kaiser Kirk · March 28, 2025, 08:04:53 PM

I have now.
But it generated a question about the Deck Park tech, so I've put that in the future tech thread for discussion.

Kaiser Kirk · March 29, 2025, 02:50:34 PM

So the question on deck parks I put here : Deck Parks

stems from my work on this ship - the Afson class Flight Deck Carrier.
That was the vessel I had finished my 'final' version of and then clicked "clear all".
Curiously, while I swiftly reconstructed it, the weights were off by ~5tons.

For it I've allocated 20% (10 planes) as an "early" deck park, but I could easily reduce that (15% = 8 planes) and move the 190 tonnage to misc reserve or add some armor. I've classed those 2 planes as 'mail planes' so they don't really matter offensively.

The reason for this class rather than replicating the "Burning Bow" is complex.
The "Burning Bow" has been in service a year, and while designed pre-naval monoplane, is the first to host naval monoplanes.

Meanwhile carrier operations continue to evolve, now involving spotting large groups of planes on the aft of the flight deck for rapid take off. The "lead" plan must have sufficient runway room to liftoff, limiting the area of flight deck usable for spotting.

The improvement in operations coincides with the growth of carrier decks and the aggressive cantilevering of width, allowing landing of planes while some are on deck, providing the possibility of a deck park.

Further, it is among the first vessels to mount a naval RADAR facility. For Carriers, early long range detection of incoming attackers, even if currently unreliable.

These considerations make having a flying off deck to allow emergency launch of fighters regardless of if operations allow the main flight deck to be used as well..not as critical. Further, reclaiming that deck length means the "lead" plane of a spotted group can be placed further forward, increasing the number of planes that can be spotted. These also helps ensure the newer planes will have takeoff and landing room.

This combination of factors has also made the Parthians reconsider relying on their 190m docks for Carriers. They have a limited number of 235m docks, and want to keep at least 1 at Home, Atlantic and Pacific theaters clear for emergency repairs or refits of any class. The newest battleships are taking up two, leaving only 1 for this carrier class.

If needed, more drydocks can be built, but that may wait until the Parthians have developed a better idea of desired parameters, as they concede even longer may be needed. Total displacement of carrier has skyrocketed, which is viewed as concerning as they seem somewhat vulnerable.

QuoteAfson "Incantation" VII, Parthia Fleet Carrier laid down 1937

Displacement:
24,500 t light; 25,493 t standard; 28,336 t normal; 30,610 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(767.43 ft / 754.59 ft) x 82.02 ft x (27.72 / 29.47 ft)
(233.91 m / 230.00 m) x 25.00 m x (8.45 / 8.98 m)

Armament:
24 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 420 per gun
Dual purpose guns in deck and hoist mounts, 1930 Model
8 x 2-gun mounts on centreline ends, evenly spread
4 x 2-gun mounts on sides, forward deck aft
2 raised mounts - superfiring
24 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 3,200 per gun
Anti-air guns in deck and hoist mounts, 1929 Model
6 x 2 row quad mounts on sides, evenly spread
36 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 5,000 per gun
Anti-air guns in deck mounts, 1929 Model
10 x Twin mounts on side ends, majority forward
8 x Twin mounts layout not set
4 double raised mounts
Weight of broadside 1,380 lbs / 626 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 490.49 ft / 149.50 m 16.99 ft / 5.18 m
Ends: 0.98" / 25 mm 264.07 ft / 80.49 m 12.01 ft / 3.66 m
Main Belt covers 100 % of normal length
Main Belt inclined -15.00 degrees (positive = in)

- Torpedo Bulkhead - Additional damage containing bulkheads:
2.24" / 57 mm 490.49 ft / 149.50 m 28.74 ft / 8.76 m
Beam between torpedo bulkheads 59.06 ft / 18.00 m

- 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: 1.38" / 35 mm 1.38" / 35 mm 1.38" / 35 mm
2nd: 0.59" / 15 mm - -
3rd: 0.31" / 8 mm - -

- Armoured deck - single deck:
For and Aft decks: 3.15" / 80 mm
Forecastle: 1.38" / 35 mm Quarter deck: 2.56" / 65 mm

- Conning towers: Forward 3.54" / 90 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 3 shafts, 141,871 shp / 105,836 Kw = 32.00 kts
Range 8,164nm at 18.00 kts
Bunker at max displacement = 5,117 tons

Complement:
1,091 - 1,419

Cost:
£8.377 million / $33.507 million

Distribution of weights at normal displacement:
Armament: 383 tons, 1.4 %
- Guns: 383 tons, 1.4 %
Armour: 5,010 tons, 17.7 %
- Belts: 1,141 tons, 4.0 %
- Torpedo bulkhead: 1,170 tons, 4.1 %
- Armament: 139 tons, 0.5 %
- Armour Deck: 2,488 tons, 8.8 %
- Conning Tower: 71 tons, 0.3 %
Machinery: 3,932 tons, 13.9 %
Hull, fittings & equipment: 8,499 tons, 30.0 %
Fuel, ammunition & stores: 3,836 tons, 13.5 %
Miscellaneous weights: 6,676 tons, 23.6 %
- Hull below water: 2,671 tons
- Hull void weights: 121 tons
- Hull above water: 2,640 tons
- On freeboard deck: 1,000 tons
- Above deck: 244 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
51,920 lbs / 23,550 Kg = 1,118.8 x 4.5 " / 115 mm shells or 6.9 torpedoes
Stability (Unstable if below 1.00): 1.26
Metacentric height 5.6 ft / 1.7 m
Roll period: 14.5 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.14
Seaboat quality (Average = 1.00): 1.67

Hull form characteristics:
Hull has a flush deck,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.578 / 0.587
Length to Beam Ratio: 9.20 : 1
'Natural speed' for length: 29.44 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 42
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 29.53 ft / 9.00 m, 29.53 ft / 9.00 m
- Forward deck: 30.00 %, 29.53 ft / 9.00 m, 29.53 ft / 9.00 m
- Aft deck: 35.00 %, 29.53 ft / 9.00 m, 29.53 ft / 9.00 m
- Quarter deck: 15.00 %, 29.53 ft / 9.00 m, 29.53 ft / 9.00 m
- Average freeboard: 29.53 ft / 9.00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 99.5 %
- Above water (accommodation/working, high = better): 234.3 %
Waterplane Area: 45,454 Square feet or 4,223 Square metres
Displacement factor (Displacement / loading): 136 %
Structure weight / hull surface area: 119 lbs/sq ft or 579 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 1.58
- 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

An flight deck carrier meant to either part of fleet defense or be part of a separate high speed strike element, working with cruisers and armored cruisers.

Incantation - Afson
Magician - Kundag
Sorcerer - Jadug
Magic - Kundagih
Sorcery - Jadugih
Magus - Moymard
Spell - Marig

Air group

Early Deck Park : 10
1 flight Ftr 8
Mail planes 2

Hanger : 52
1 Sqd Ftr 16
1 Sqd Ftr/Div 16
1 Sqd Torp/Rec 16
1 Lance Torp 4

Hanger Calculations :
4223 / 77 = 54.84

54 * 95 = 5130 = (2565 / 2565)

Early Deck Park : Not defined, est 10% of single hanger.
10 * 95 = 950

Control Tower
One tower, on the starboard side is fitted.
The tower is designed to be as smooth as possible
so as not to disrupt air flow.

Guns
As the historical British carriers, two mounts are mounted on each corner of the deck, for a total of 8.

In true Parthian form, they then follow the American practice of two-gun mounts for and aft of the tower. For 4 more.

The 37mm and 23mm alternate down the sides of the deck,
and each side of the tower has 1 twin 23mm on each face at each level.

Armor

The Hanger deck floor is the top of the armor system.
That serves as the main armor deck, with a splinter deck below.
All hatches are in the form of vertical risers flanking the space, with
a substantial lip. The hanger deck is slightly crowned, with drain holes leading through the hanger walls, to allow fluid spills to be hosed to the exterior of the vessel.

The main armor belt covers from the hanger deck down to -1.5m.
The lower portion is backed by both a protective deck and TDS, to
ensure bomb and torpedo stores are protected.

Belt
2 Deck levels (5.0m) high
outsloped 15 degrees
5/cos(15) = 5.17638 = 5.18

TDS rises behind belt, above WL to seal to protective deck at +1m.

Waterline protection :
75mm inclined + 25mm protective deck + 57mm TDS
75 + ((25*1.5)/2)+(57/2) = 122+ incline

armor Decks
Hanger Deck floor is 50mm and caps main armor belt.
A protective deck at 25mm covers from +1 to -1.5m.

Vert pen : 67mm

End Belt Fore : Protective deck 50 flats / 85 slopes
End Belt Stern : Protective Deck 75 flates /110 slopes

Miscellaneous Weight
121t - Reserve

AD
39t - Fire Control 1930
25t - Long Range Radio
0t - SR Radio
10t - SR Radio - Deck Operations
10t - SR Radio - CAG
10t - Radio Jammer
25t - Air Search Radar
25t - Hulesmeyer device
25t - Night Fighting (& landing aids) Gear
50t - Squadron Assembly Room.
25t - Vessel Ventilation, intakes

OD
950t - Ealy deck park - Provisions for 10 aircraft
5t - Paravanes
25t - Vessel Ventilation
20t - 2 x Steam catapults

HAW
2565t - Provisions for 27 Aircraft
25t Additional Fire Extinguishers
25t Hanger Ventilation
25t Vessel Ventilation

HBW
2565t - Provisions for 27 Aircraft
25t Hanger Ventilation
25t Extra Pumps
25t Extra Fire Ext
31t Aux Diesel Generator 1000kw - 164nm of fuel.

Decks
+9 Flight Deck
+3.5 Hanger Deck, upper armor deck, Top main belt
+1.0 Main Armor Deck, Top TDS
-1.5 2nd Platform Deck, bottom main belt
-4.0 1st Platform Deck
-6.6 Engineering
-7.62 Double Bottom
- 8.33 Keel

Jefgte · March 30, 2025, 11:01:10 AM

I always thought your 188m CVs were too short.

Since 1932, Byzantium, having observed the evolution of aviation, has been building in 225m dry docks.
Regarding hangar heights, I considered, with the first CVs,
two 2.44m decks => 4.88m available.

I also note a speed of 32 knots, better for taking off heavier aircraft, and lighter armor for reasonable displacement.

Kaiser Kirk · March 30, 2025, 11:24:30 AM

They are from a WWII perspective, which I think influences most folks.

With monoplanes, you can definitely fly from shorter decks, but it does limit how much strike ability you can generate in one launch, which as the tech is allowing larger and larger launches makes a difference.

But the goals of Parthian aircraft carriers have mainly been to put fighters up to deny the other side reconn/spotting/strike - which is quite doable on those shorter decks. Indeed I called the earlier 160m ones 'Fighter Carriers' and modeled them on HMS Hermes/ USS Commencement Bay. The main problem is now they are slow, but I can restrict them to tailing the battleline and they will ensure fighter cover while letting the larger carriers roam.

The 190m ones should be able to launch small strike groups, but I generally assumed that the low numbers of strike aircraft one could fly off in that time period were not sufficient to do much more than nuisance damage, and attrition would rapidly eliminate the strike groups. But they should be able to sustain the fighter aspect, which will mean there's a platform for the next batch of strike aircraft to fly from.

The last carriers the 'Burning Bow' and 'Barkusc' were designed during the Biplane time, with some strike ability to wound/slow down the enemy forces. This one is looking at being more strike oriented and is after monoplanes are in service, so you're seeing that shift now. The 32knot speed is an acknowledgement that it may steam with my 32knot ACs on a strike.

Kaiser Kirk · April 13, 2025, 12:35:27 AM

Parthian Destroyers are not typically the vessel someone looking at Janes will pick out as the Best !
They have higher cruising speeds combined with higher ranges, so overall a larger proportion devoted to fuel. This requires a larger beam and BC than comparable vessels, resulting in slower speeds.
Then they impose more weight with a demand for adequate seakeeping to transit oceans in all seasons.
This bulkier hull form usually means they are slightly less fragile than their foreign contemporaries,
but usually not enough to matter.

Ironically Chinese copies of License-built Parthian destroyers did very well in the 1st Sino-Japanese war.

The 1932 "Lion" and "Fox" class destroyers have been in production for 5 years by 1938.
14 of each class have been completed, and at least 2 more of each will be built.

That will make 16 of each, allowing Destroyer Squadrons to break down into 4 lances of 4 ships.
With 1 ahead, 1 on each flank, and 1 trailing, the 4 vessels in each lance can take turns with 'sprint and drift' to provide ASW coverage around the squadron.

Of course if a submarine is contacted, the Lance will stay to prosecute the contact until the Marban class sloops close up and take over. Essentially escort destroyers, the Marbans are slow but have lots and lots of Depth Charges.

For 1938 I am considering a 'unified' destroyer, the Caracal.
Same # guns as a Lion, with similar range, but with a displacement halfway between a Fox and a Lion.

The name is reused from an earlier effort which became the Robah or Fox.
I made 8 versions of this, from 1350tons to 1800tons, with various combinations of torpedoes.

For a while I had 4 sets of tubes, and wanted them on centerline, but looking at deck planes of various IJN destroyers convinced me I lacked the length for that. Like wise on a 33ft beam, mounting
side by side Quintuple 24" tubes did not seem to make sense.
Each set of tubes would be something like 5 x 30" = 150"
So 2 sets side by side would be 150 x 2 = 300" or 25ft.
So perhaps 7 feet between them.
Further, the tubes, in order to train, need to rotate...no room for that.

So this version dropped to 2xTT5.

Anyhow, I think it's a pretty solid design.

QuoteSiahgus "Caracal", Parthian Empire Destroyer laid down 1938

Displacement:
1,650 t light; 1,782 t standard; 2,023 t normal; 2,215 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(359.30 ft / 354.33 ft) x 32.81 ft x (12.30 / 13.21 ft)
(109.51 m / 108.00 m) x 10.00 m x (3.75 / 4.03 m)

Armament:
6 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 316 per gun
Dual purpose guns in deck mounts, 1931 Model
3 x 2-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
8 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 2,800 per gun
Anti-air guns in deck mounts, 1930 Model
2 x 2 row quad mounts on sides, forward deck aft
2 raised mounts
12 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 4,400 per gun
Machine guns in deck mounts, 1930 Model
4 x Twin mounts on side ends, evenly spread
2 x Twin mounts on centreline ends, evenly spread
2 double raised mounts
Weight of broadside 350 lbs / 159 kg

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.24" / 6 mm 0.24" / 6 mm -
2nd: 0.24" / 6 mm - -
3rd: 0.24" / 6 mm - -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 1 shaft, 43,502 shp / 32,453 Kw = 32.75 kts
Range 4,410nm at 16.00 kts
Bunker at max displacement = 433 tons

Complement:
150 - 196

Cost:
£1.220 million / $4.881 million

Distribution of weights at normal displacement:
Armament: 65 tons, 3.2 %
- Guns: 65 tons, 3.2 %
Armour: 7 tons, 0.4 %
- Armament: 7 tons, 0.4 %
Machinery: 1,012 tons, 50.1 %
Hull, fittings & equipment: 458 tons, 22.7 %
Fuel, ammunition & stores: 373 tons, 18.4 %
Miscellaneous weights: 106 tons, 5.3 %
- Hull below water: 25 tons
- Hull void weights: 5 tons
- Hull above water: 2 tons
- On freeboard deck: 60 tons
- Above deck: 15 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
514 lbs / 233 Kg = 11.1 x 4.5 " / 115 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.20
Metacentric height 1.3 ft / 0.4 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.41
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): 0.495 / 0.505
Length to Beam Ratio: 10.80 : 1
'Natural speed' for length: 18.82 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 70
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 %, 18.54 ft / 5.65 m, 16.24 ft / 4.95 m
- Forward deck: 45.00 %, 16.24 ft / 4.95 m, 13.62 ft / 4.15 m
- Aft deck: 20.00 %, 13.62 ft / 4.15 m, 13.62 ft / 4.15 m
- Quarter deck: 15.00 %, 13.62 ft / 4.15 m, 13.62 ft / 4.15 m
- Average freeboard: 14.91 ft / 4.55 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 174.9 %
- Above water (accommodation/working, high = better): 136.6 %
Waterplane Area: 7,405 Square feet or 688 Square metres
Displacement factor (Displacement / loading): 76 %
Structure weight / hull surface area: 32 lbs/sq ft or 157 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.78
- Overall: 0.56
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

Warning: Beam between bulkheads too wide

The Siahgus is named for a Caracal, which was long trained as a hunting companion for small animals and birds. This represents the vessels expected role, engaging planes, subs, and smaller surface craft.

Intended to replace the 'Fox' and possibly the 'Lion' classes,
1/3 larger than the Fox, and 80% of the Lion,
it has nearly the same speed and armanent, but 3/4 the range of the Lions.

The TDC is in the column holding up the platform and the torpedoes
are immediately fore and aft of that.
Looking at the IJN Destroyers, 2 sets of tubes is reasonable.

Basic Sonar + Enhanced Hydrophones for an ASW role

The Twin 23mm AA is mounted above the main battery fore/aft , and at the superstructure corners.

The Quad 37 AA is mounted on a lozenge shaped platform over the TDC - allowing those guns 180degree fire, plus a window on the opposite beam.

The AA is fitted with spray shields.

b (s1) 'y' d DC
A(B) [a] TT tdc TT [f] (X) Y
c (s2) 'y' e DC

Range @ Speeds :

Basw Speed is
Trial Speed is 33.23 knts
Bonus of 0.53 kts

430 fuel tons = 4410 @ 16kts
The Parthians want a reserve of 2200nm @ 10knts,
which would allow their vessels to "get to nearest base" virtually anywhere in the world.

2200nm at 10knots : 88t to "get home"

The 10% from gearing is udes to offset fouling/old engines/etc.

430-88 = 342t are available for offensive operations,
more if "base" is close.

342t is good for :

520nm @ 31kts 80% power
906nm @ 26kts
1480nm @ 22kts
2570nm @ 18kts
3470nm @ 16kts +
4800nm @ 14 kts
all + 2200 @ 10knts reserve

Allowing the destroyer to freely operate at higher speeds for
extended periods and safely return to base.

Miscellaneous Weight

Reserve : 5t

AD
6.5t FC 1930
6.5t Night Fighting
0.5 TDC (FC for Torpedoes)
0t Short Range Radio
1t Colored Beacons, flares, rockets for MTB leader role

OD
2t Lt. Paravanes
2t 2x 'Y' Thrower
6t 18x 280kg DC

50t 2TT5 24" 5t torpedo

HAW
1.7t - CO2 compressor AC

HBW
15t - Enhanced Hydophone package
10t - Basic Sonar

Kaiser Kirk · April 13, 2025, 07:36:48 PM

The Parthians cruisers currently fall in three classes - the Bahktiari 16x165mm , the Davazdah Rohk 12 x 190mm, and the Manzikert 8 x 215mm.

Which each class, the first two were built and evaluated, and then an updated variant was standardized on.

This is the updated Davazdah Rohk after the first vessels completed sea trials.
A new feature is the 'Auxiliary' AA FC. This is a second FC set for just the DP/AA tonnage.
While Cruiser Architecture have backups to start with, this is intended to allow the ship to engage incoming aircraft from multiple directions, allowing it to both defend itself and vessels near it.

This is also the among the first vessels to field Sea Search Radar. The Hulesmeyer proximity detector is retained, as it is a comforting asset for nighttime maneuvers to help avoid embarrassing collisions. I expect that in the future I will remove the Hulesmeyer, probably after the next tech level.

Why 3 classes?
Part of this is simple uncertainty on what is needed is part of it. Slower, longer ranged and heavier hitting? Or hammer the foe into scrap with a blizzard of shells? Of course if spotting at range, ROF tends to drop to allow time for the spot, the call, the adjustment, and the next volley. So at long range, might as well have the bigger shells. Meanwhile the new 190mm is meant to be the happy answer between the 165 and 215.

Part of it dates back to 1910 when the Parthians built 4 larger raiders, each a different combination of guns- 165 or 180 - and a different combination of speed - 28 or 30knots.
The Parthians calculated that a ship class able to catch and kill all of the 4 would have to be much larger to have the speed for the 30 knot ships, the guns to penetrate the armor of the 165mm/28knot combo, and armor to withstand the 180mm gunned version.

So having several cruiser types makes it hard for any one design to be clearly superior to all three.

QuoteDavazdah Rohk series II, Parthia Cruiser laid down 1938

Displacement:
10,000 t light; 10,754 t standard; 12,036 t normal; 13,061 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(548.68 ft / 541.34 ft) x 68.90 ft x (22.15 / 23.54 ft)
(167.24 m / 165.00 m) x 21.00 m x (6.75 / 7.18 m)

Armament:
12 - 7.48" / 190 mm 47.0 cal guns - 253.53lbs / 115.00kg shells, 160 per gun
Quick firing guns in turret on barbette mounts, 1935 Model
3 x 4-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
12 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 420 per gun
Dual purpose guns in deck and hoist mounts, 1931 Model
4 x 2-gun mounts on side ends, evenly spread
2 x 2-gun mounts on centreline ends, evenly spread
2 double raised mounts
24 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 3,000 per gun
Breech loading guns in deck and hoist mounts, 1929 Model
4 x 2 row quad mounts on side ends, evenly spread
4 raised mounts
2 x 2 row quad mounts on centreline ends, evenly spread
2 double raised mounts
16 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 5,000 per gun
Breech loading guns in deck mounts, 1929 Model
8 x Twin mounts on sides, evenly spread
8 double raised mounts
Weight of broadside 3,752 lbs / 1,702 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.33" / 110 mm 351.87 ft / 107.25 m 10.20 ft / 3.11 m
Ends: Unarmoured
Main Belt covers 100 % of normal length
Main Belt inclined -15.00 degrees (positive = in)

- 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: 6.30" / 160 mm 2.95" / 75 mm 4.72" / 120 mm
2nd: 1.18" / 30 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.79" / 20 mm 0.31" / 8 mm 0.31" / 8 mm
4th: 0.79" / 20 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 2.27" / 58 mm
Forecastle: 1.38" / 35 mm Quarter deck: 1.97" / 50 mm

- Conning towers: Forward 4.72" / 120 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 81,995 shp / 61,168 Kw = 31.00 kts
Range 7,960nm at 16.00 kts
Bunker at max displacement = 2,307 tons

Complement:
573 - 746

Cost:
£5.572 million / $22.286 million

Distribution of weights at normal displacement:
Armament: 972 tons, 8.1 %
- Guns: 972 tons, 8.1 %
Armour: 2,315 tons, 19.2 %
- Belts: 657 tons, 5.5 %
- Armament: 570 tons, 4.7 %
- Armour Deck: 1,034 tons, 8.6 %
- Conning Tower: 53 tons, 0.4 %
Machinery: 2,245 tons, 18.7 %
Hull, fittings & equipment: 4,002 tons, 33.3 %
Fuel, ammunition & stores: 2,036 tons, 16.9 %
Miscellaneous weights: 466 tons, 3.9 %
- Hull below water: 66 tons
- Hull void weights: 11 tons
- Hull above water: 30 tons
- On freeboard deck: 115 tons
- Above deck: 244 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14,723 lbs / 6,678 Kg = 70.4 x 7.5 " / 190 mm shells or 2.0 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 3.5 ft / 1.1 m
Roll period: 15.4 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.68
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:
Hull has a flush deck,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.510 / 0.521
Length to Beam Ratio: 7.86 : 1
'Natural speed' for length: 25.23 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 16.00 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 %, 25.59 ft / 7.80 m, 23.13 ft / 7.05 m
- Forward deck: 32.50 %, 23.13 ft / 7.05 m, 20.67 ft / 6.30 m
- Aft deck: 32.50 %, 20.67 ft / 6.30 m, 20.67 ft / 6.30 m
- Quarter deck: 15.00 %, 20.67 ft / 6.30 m, 20.67 ft / 6.30 m
- Average freeboard: 21.76 ft / 6.63 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 88.9 %
- Above water (accommodation/working, high = better): 181.7 %
Waterplane Area: 25,683 Square feet or 2,386 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 116 lbs/sq ft or 566 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.83
- Longitudinal: 1.81
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

Warning: Calibre too large for QF, AA or DP gun - Main Battery

Davazdah Rohk - Twelve Battles.
Series II

Armor

Protection

Magazine Box forms thicker Belt/Deck plates

Horizontal @ waterline :
Magazines : 175 + incline
Machinery : 110 + incline

Vertical.
Magazines : 115
Machinery : 50

Belt Armor
110 mm, +65mm abreast magazines
Covers from 1.2m to -1.8m
Outsloped 15 degrees
3.00/cos(15) = 3.1058 = 3.11

Deck armor
50mm citadel + 65mm Magizine Box thickened deck over magazine.
116t 65mm magazine box
917t 35/50/50mm deck
------
1033t needeed

1034t paid

Misc

Reserve
11t

AD
98t - FC 1930
21t - Aux AA FC 1930
25t - LR radio
0t - SR Radio
25t - Hulesmeyer
25t - Air Search Radar
25t - Surface Search Radar
25t - Searchlight Tower (NF)

OD
5t paravanes
100t 4x floatplanes ( 2 scout, 2 Ftr typically)
10t - 2x Catapults

HAW
20t - hanger in stern
10t - CO2 Compressor AC

HBW
10t - Ex Fire Ext
10t - Ex Pumps
15t - Hydrophones
31t - Auxiliary Diesel generator 1000kw
50nm of fuel is Diesel

Decks
+6.30 Weather Deck
+3.75 Battery Deck
+1.20 Armor Deck, main deck
-1.8 bottom main belt
-1.30 1st Platform Deck
-5.00 Engineering
-6.00 Double Bottom
-6.75 Keel

Jefgte · April 14, 2025, 11:26:20 AM

The cruiser is quite similar to the Byzantine C49 Rhiskos class. The fire density is favored to crush the enemy.

Kaiser Kirk · April 15, 2025, 12:02:52 AM

Quote from: Jefgte on April 14, 2025, 11:26:20 AMThe cruiser is quite similar to the Byzantine C49 Rhiskos class. The fire density is favored to crush the enemy.

Our designs are converging a bit.
I had been using 180mm, and limited shell weight to be slightly more workable by hand , but with the shift to 190mm with heavyweight shells to take advantage of a turret's power equipment, the Parthian and Byzantine weapons become very similar.

The 215mm is still able to pierce armor further away
while the 165mm with 80kg round has very good penetration, but is reliant on aerial or radar for spotting longer range fire.

I really don't know which design I'll standardize on.
This one is most likely as it strikes a good median between striking power and volume of fire.

I have a design Tomyris (reuse of that name) with 6x 165, 32knots. But that's likely 1938.5.
and I have considered bringing the Manzikert up to 12,000 tons as a new light armored cruiser.
Both of which which would give more differences in the cruiser range.

If Snip could find the real life time to engage, I'd have some Roman designs to worry about,
and I can use those as a parallel for Japanese designs, as they both prioritize speed.

Kaiser Kirk · April 15, 2025, 11:25:17 PM

Darn it, wrote up a long post about the reason behind my Sentry Cruisers,
and then the refurbishment options for the Maelstrom class.

Someday, I'll get used to the fact I can't just hit post and tab away anymore.
But it's been a while and I'm still loosing posts occasionally. My bad.

Kaiser Kirk · April 16, 2025, 05:09:50 PM

First the long blathering...

I need to refurbish or rebuild the old Maelstrom class of "Sentry Cruiser".
This is a fleet role I believe peculiar to the Parthian navy.
So I figured I'd blather endlessly about how and why they were built.

The Maelstrom and Ranger classes were 12 in number, and
5000 tons light, belted cruisers of 29 knots, 6x165mm QF bearing forward,
Loaded with the 1913 latest in sensor gear – Amidships Searchlight tower and other Night fighting gear, Hulesmeyer proximity device (~10,000m range), even a 'War Tuba' array to listen for distant motors.

A further 3 old scout cruisers were rebuilt as 'Sentry Frigates', while a further 4 'Sentry Frigates' of the Bakr class were built.

That gave them a total of 19 platforms to use as picket & interception duty.
In the same period you see Parthian ships not only continue with both Torpedo bulkheads and Torpedo nets, but actually retrofit new ships of the Tiamat class to have torpedo nets.

Why?
"Sentry" cruisers were the Parthian response to the 1912 Sino-Japanese war.
Meant to be be able to deploy away from the main fleet and detect incoming MTBs/Destroyers at sufficient range to allow vessels to be vectored towards them. The emphasis on forward firing QF guns was meant to allow them shred the incoming waves of torpedo vessels.

The role is a bit obsolete now. Most vessels in the fleet have hulesmeyer, primarily to allow night maneuvers without running into each other. In 1938, Sea Search Radar is finally available to enter fleet service, and will give much better range and directionally. Air Search has been available for several years and will help find aircraft. War Tubas were never a great concept (i.e. waste of space usually) for noisy ships battering through waves, and enhanced Hydrophones deployed by sprint and drift destroyers do a far better job, but most newer ships have them. Even the torpedo net has been slowly discarded, though the 6 Fleet Net Tenders do mean secure anchorages can be established.

Sino-Japanese War
That war featured battles for an island just off the Chinese coast, where
their torpedo boats could launch night attacks in saturation strength.

The IJN was woefully unprepared.
They had rudimentary fire control, they did not have quick firing guns, the ships had no torpedo defenses - too early for torpedo blisters. Torpedo Nets were in use with the Norse, and Parthians...and Chinese, but not most other nations. Ironically the first skirmish saw a Chinese cruiser with nets survive an IJN torpedo attack. The IJN though was caught steaming through a strait by a large number of MTBs and took serious damage.

Foxy innovated well, and through out a defense of well separated waves of destroyers, forcing the fragile MTBs to spend considerable time under fire.

The final battle saw a 3 way convergence by the Chinese, with MTBs sweeping North and South of Jeju island, while the main fleet came from the South East- using the mountaintop radio as a beacon. The couple of IJN pickets to the North missed the Chinese MTBs. The Chinese attack timing was off, with the Southern attack being largely defeated by time the Northern came into range, but had drawn the IJN DDs away and only some made it back in time. The IJN was badly wounded, and so the arrival of the Chinese fleet a couple hours later ended the battle.
The Chinese, seeking support, published their version of the battle as it happened and afterwards.

The Aztec-Roman war also featured torpedo attacks, though the two sides did better than before.

Unseen in all this was that the MTBs were launching from very close in, frequently under 3000m, and still had a low hit rate. The further torpedo formula has distance as a variable, which really should be time to target, but it means the further out you launch the lower the hit rate. This is further complicated by ships having a limited time to turn from broadside where casements can bear to combing the wakes.

Torpedo Nets were successful in limited use in this war, much like they were in the historic Russo-Japanese war, but that hides several inefficiencies.
The original torpedo nets were mounted on wooden poles, and the Royal Navy successfully steamed down the English Channel at 5 knots with them out in the 1890s. Later evolutions of the nets improved their resilience, featured steel poles allowing 12knots and then 15knots, and had steam driven gear to launch them in about a minute, and recover them in under five, making them quickly deployable.

Using the nets then involves limits – your vessel needs to be at their limiting speed or be able to rapidly (via a hard turn) bring speed down to that range. This makes them impractical on ships expected to be at higher speeds. Combing the wake with torpedo nets out rendered them worthless. Going broadside though increased the target area massively and meant the stern with the propellers and rudders could be hit. It is possible to angle the ship so that bow is a couple points off from the torpedo tracks. In that case the stern is protected, the nets are probably more effective on the slant, and you risk a hit on the bow that might glance off. This is what you see in the Battle of Vera Cruz when the slow Mayan line turns and deploys nets.

The downsides remained. They were subject to being shot away and fouling the ships rudders or propellers. Worse, they didn't cover the bow or stern normally, so a portion of the ship were subject to being torpedoed. A hit to the bow is not critical, but interior bulkheads are not stressed for water and speed, the limiting factor seeming to be about 19-20 knots, though frequently you see more about 12-15 after damage, increasing after shoring efforts. A hit to the stern normally would not be as big a deal, as the steering gear is all heavy duty and hard to damage without direct impact, but it's not good, as Bismarck and Prince of Wales demonstrate, hits on the shafts, props or rudders could be catastrophic...

Then advances in torpedo technology reduced the effectiveness of Torpedo Nets.
The introduction of netcutters allowed them to do just that, but you might need multiple shots in the same panel, which is hard unless the firer and target are stationary relative to each other. The Brits actually did testing vs. heavier & torpedoes and found a growing failure rate – about 1/3rd vs. 21".
So the Brits went to blisters and then interior & exterior blisters.

Now, as late as WWII nets were in use by merchants, steaming along at 15knots, stopping aerial torpedoes that hit them- the aerial, and I presume PT, were typically lighter and so couldn't breach. Ironically the nets only worked 2/3rds of the time....which would match with them not covering the bow and stern.

So...against all that background the Parthians continued the torpedo net, refitting them to some recent ships without, and introduced the Sentry concept. This would allow them to detach the Sentry to a distance, to allow it to first detect and then vector ships to intercept incoming attackers. The concentrated forward fire would allow them to rapidly engage and destroy the MTBs and DDs incoming.

Next...the actual refurbishment options.

Kaiser Kirk · April 17, 2025, 12:20:29 AM

Ok the actual refurbishment options.

Not sure if I should go with #3 or #4.
Simply updating the 'Sentry Cruiser' seems the easiest course of action.
But turning them into AA cruisers seems useful as well.

Takes 3.5 months, base cost $1, and in all cases gives the Parthians a chance to quickly get more of the new Sea Search radars- and Air Search- into service.

1. Replace the engine for more speed, or to free up tonnage. Could push them up to 31 knots, which would be 0.76 seakeeping. But new engines alone cost $3.8, and 1.9 BP, just too expensive.

2 & 3 : Refurbishing as a light cruiser. Use as platform to get more Air Search and Sea Search Radars into service. Both versions plate over the extremely wet lower casements and swap the QF 165L45 65kg for the QF 165L47 80kg shells. The version presented keeps the deck-level casements to allow 4-gun forward fire, allowing it to spot while closing.

4 : Refurbishing into an Anti-Aircraft cruiser, replacing A/B X/Y with 2-Gun 130mm DP. Ironically the 130mm was originally chosen as 2G versions could be put in the 165mm turret rings on old ships.

The 130 is still used as the capital ships secondary with the the current 130L47 having a powerful 39kg shell...and with the 1938 tech it can now fire proximity shells in AA role.

Very top speed would only be a little under the max of ACs/C/CVs, but really can't be helped without the expense of replacing the engine.

Quote#3 - Sentry Cruiser

SC-6 Maelstrom R38, Parthian Cruiser laid down 1913

Displacement:
4,974 t light; 5,244 t standard; 5,962 t normal; 6,536 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(424.87 ft / 419.95 ft) x 41.99 ft x (20.51 / 22.10 ft)
(129.50 m / 128.00 m) x 12.80 m x (6.25 / 6.74 m)

Armament:
4 - 6.50" / 165 mm 47.0 cal guns - 176.37lbs / 80.00kg shells, 145 per gun
Quick firing guns in deck and hoist mounts, 1931 Model
4 x Single mounts on centreline ends, evenly spread
2 raised mounts - superfiring
2 - 6.50" / 165 mm 47.0 cal guns - 176.37lbs / 80.00kg shells, 145 per gun
Quick firing guns in casemate mounts, 1931 Model
2 x Single mounts on sides forward
8 - 3.54" / 90.0 mm 54.0 cal guns - 24.25lbs / 11.00kg shells, 360 per gun
Anti-air guns in deck mounts, 1927 Model
4 x 2-gun mounts on side ends, evenly spread
4 raised mounts
16 - 1.18" / 30.0 mm 80.0 cal guns - 0.95lbs / 0.43kg shells, 3,200 per gun
Anti-air guns in deck mounts, 1930 Model
8 x 2-gun mounts on sides, evenly spread
8 double raised mounts
Weight of broadside 1,267 lbs / 575 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.94" / 100 mm 335.96 ft / 102.40 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 123 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.56" / 65 mm 1.38" / 35 mm 3.94" / 100 mm
2nd: 0.98" / 25 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Protected deck - single deck:
For and Aft decks: 1.57" / 40 mm
Forecastle: 0.79" / 20 mm Quarter deck: 1.18" / 30 mm

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

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 3 shafts, 49,527 shp / 36,947 Kw = 29.00 kts
Range 4,438nm at 16.00 kts
Bunker at max displacement = 1,291 tons

Complement:
338 - 440

Cost:
£0.577 million / $2.310 million

Distribution of weights at normal displacement:
Armament: 260 tons, 4.4 %
- Guns: 260 tons, 4.4 %
Armour: 972 tons, 16.3 %
- Belts: 519 tons, 8.7 %
- Armament: 66 tons, 1.1 %
- Armour Deck: 359 tons, 6.0 %
- Conning Tower: 28 tons, 0.5 %
Machinery: 1,941 tons, 32.6 %
Hull, fittings & equipment: 1,630 tons, 27.3 %
Fuel, ammunition & stores: 988 tons, 16.6 %
Miscellaneous weights: 171 tons, 2.9 %
- Hull above water: 5 tons
- On freeboard deck: 40 tons
- Above deck: 126 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
4,122 lbs / 1,870 Kg = 30.1 x 6.5 " / 165 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.14
Metacentric height 1.8 ft / 0.5 m
Roll period: 13.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.93
Seaboat quality (Average = 1.00): 1.21

Hull form characteristics:
Hull has a flush deck,
a ram bow and a cruiser stern
Block coefficient (normal/deep): 0.577 / 0.587
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 20.49 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 41
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: -6.56 ft / -2.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 12.00 %, 20.73 ft / 6.32 m, 19.09 ft / 5.82 m
- Forward deck: 45.00 %, 19.09 ft / 5.82 m, 17.45 ft / 5.32 m
- Aft deck: 35.00 %, 17.45 ft / 5.32 m, 17.45 ft / 5.32 m
- Quarter deck: 8.00 %, 17.45 ft / 5.32 m, 19.09 ft / 5.82 m
- Average freeboard: 18.16 ft / 5.54 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120.2 %
- Above water (accommodation/working, high = better): 127.4 %
Waterplane Area: 12,624 Square feet or 1,173 Square metres
Displacement factor (Displacement / loading): 102 %
Structure weight / hull surface area: 70 lbs/sq ft or 342 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.79
- Longitudinal: 2.64
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

Original Cost : 4.997
Orginal Engine : 1941
Original Bunker : 1291
Original Main Mags : 112t 165, +13t 90mm = 125

The original vessel was meant to have maximum forward firepower, and so like the Omahas had double stacked forward casements, the lower of which were expected to be wet, and were. But as they were for engaging torpedo boats and DDs who were only expected out in decent weather, that was viewed as acceptatable.

Refurbishment :
Refurbish boilers and engines.

- lower casements, plate over.
+ replace 165L45 with 165L47
Replace 90mm and 15mm with 90mm and 30mm
Gun Armor : +61t
new Mags : 124 , ammo lockers for 30mm.
Fuel : Still oil, new cruise speed = same bunkerage.

Costs :
Base : 5 * .2 = $1
Arms : 260t = $0.52, 0.26 BP
Armor + Func Misc : 60+171 = $0.231, 0.231
Hull : N/A
Fuel/Ammo/NF Misc : 1291 +151 = 1442 = $ 0.721
----
$2.472 = $2.48
0.491 BP = 0.5

Misc Wt :

AD
26t - FC 1930
25t - LR Radio
0t - SR Radio
25t - Searchlight Tower (NF)
25t - Air Search Radar
25t - Sea Search Radar

OD
5t - Paravanes
24t - 2TT3 21" 4t
11t- Power Assist 165mm 5%

HAW
5t - CO2 Compressor AC

Decks
+5.32m 4th Deck
+2.88m 3rd Deck
+1.5m top main belt
+0.44m 2nd deck, 40mm protective armor deck crown
-1.5m bottom main belt
-5.44m Engineering Deck, Stores

Quote#4 - AA Cruiser

SC-6 Maelstrom R38, Parthian Cruiser laid down 1913

Displacement:
4,954 t light; 5,244 t standard; 5,962 t normal; 6,536 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(424.87 ft / 419.95 ft) x 41.99 ft x (20.51 / 22.10 ft)
(129.50 m / 128.00 m) x 12.80 m x (6.25 / 6.74 m)

Armament:
8 - 5.12" / 130 mm 47.0 cal guns - 85.98lbs / 39.00kg shells, 268 per gun
Dual purpose guns in deck and hoist mounts, 1930 Model
4 x 2-gun mounts on centreline ends, evenly spread
2 raised mounts - superfiring
16 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 3,200 per gun
Quick firing guns in deck mounts, 1929 Model
4 x 2 row quad mounts on side ends, evenly spread
16 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 5,000 per gun
Anti-air guns in deck mounts, 1931 Model
4 x 2-gun mounts on sides, evenly spread
4 raised mounts
4 x 2-gun mounts on side ends, evenly spread
4 double raised mounts
Weight of broadside 722 lbs / 328 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.94" / 100 mm 335.96 ft / 102.40 m 9.84 ft / 3.00 m
Ends: Unarmoured
Main Belt covers 123 % 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: 2.56" / 65 mm 1.38" / 35 mm 3.94" / 100 mm
2nd: 0.79" / 20 mm 0.31" / 8 mm -
3rd: 0.31" / 8 mm - -

- Protected deck - single deck:
For and Aft decks: 1.57" / 40 mm
Forecastle: 0.79" / 20 mm Quarter deck: 1.18" / 30 mm

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

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 3 shafts, 49,527 shp / 36,947 Kw = 29.00 kts
Range 4,438nm at 16.00 kts
Bunker at max displacement = 1,291 tons

Complement:
338 - 440

Cost:
£0.551 million / $2.203 million

Distribution of weights at normal displacement:
Armament: 182 tons, 3.1 %
- Guns: 182 tons, 3.1 %
Armour: 974 tons, 16.3 %
- Belts: 519 tons, 8.7 %
- Armament: 68 tons, 1.1 %
- Armour Deck: 359 tons, 6.0 %
- Conning Tower: 28 tons, 0.5 %
Machinery: 1,941 tons, 32.6 %
Hull, fittings & equipment: 1,600 tons, 26.8 %
Fuel, ammunition & stores: 1,008 tons, 16.9 %
Miscellaneous weights: 258 tons, 4.3 %
- Hull void weights: 25 tons
- Hull above water: 5 tons
- On freeboard deck: 66 tons
- Above deck: 162 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
4,307 lbs / 1,954 Kg = 64.3 x 5.1 " / 130 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 1.7 ft / 0.5 m
Roll period: 13.4 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.61
Seaboat quality (Average = 1.00): 1.22

Hull form characteristics:
Hull has a flush deck,
a ram bow and a cruiser stern
Block coefficient (normal/deep): 0.577 / 0.587
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 20.49 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 41
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: -6.56 ft / -2.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 12.00 %, 20.73 ft / 6.32 m, 19.09 ft / 5.82 m
- Forward deck: 45.00 %, 19.09 ft / 5.82 m, 17.45 ft / 5.32 m
- Aft deck: 35.00 %, 17.45 ft / 5.32 m, 17.45 ft / 5.32 m
- Quarter deck: 8.00 %, 17.45 ft / 5.32 m, 19.09 ft / 5.82 m
- Average freeboard: 18.16 ft / 5.54 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 117.3 %
- Above water (accommodation/working, high = better): 127.4 %
Waterplane Area: 12,624 Square feet or 1,173 Square metres
Displacement factor (Displacement / loading): 105 %
Structure weight / hull surface area: 67 lbs/sq ft or 327 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.80
- Longitudinal: 2.51
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

Refurbished 1938.
The Maelstrom class was designed in the aftermath of the Sino-Japanese war to detect and intercept incoming torpedo boats or destroyers, so heavy forward firepower was emphasised.

20 years later this is seen as less critical.
Conversion to an AA Cruiser with 2G 130mm is considered and will take advantage of the new proximity fused 130mm round.

Power assist is provided as each 2G mount is 51.5t

Original Cost : $4.997 = $5.00
Original Engines : 1941
Original Bunkerage : 1291
Main Mags : 102 165mm +13 90mm

- Casement 165
+ 165L47 M&H w/PA.
+ new bunkerage (cruise speed) : 1290t
+ 90mm 2G
+ 30mm 2G
New Misc Wt : 258, 233 func

Costs :
Base : 20% * 5 = $1
Armanent : 182 = 0.182 BP, $ 0.364
Armor, Func Mist = 62 +233 = 285 = 0.285 BP, $ 0.285
Hull : N/A
Fuel/Ammo/NF Misc = 1291 +171+25 = 1487 = $0.7435
----
$2.3925, 0.467 BP
3.5 months time, 1.4 in dock.

Misc wt :
10t Reserve

AD
18.5t FC 1930
18.5t Aux FC 1930
25t LR Radio
0t SR Radio
25t Hulesmeyer device
25t Air Search Radar
25t Sea Search Radar
25t Searchlight tower (NF)

OD
5t Paravanes
21t 130mm Power Assist
40t 2TT4 24" 5T

HAW
5t CO2 Compressor AC

Decks
+5.32m 4th Deck
+2.88m 3rd Deck
+1.5m top main belt
+0.44m 2nd deck, 40mm protective armor deck crown
-1.5m bottom main belt
-5.44m Engineering Deck, Stores
-5.82m Double bottom

Jefgte · April 17, 2025, 12:35:42 AM

Byzantium simply added 40 pompoms and 12.7 MGs as anti-aircraft guns on the CLs.
The 133 DPs and 114 DPs replaced the old QFs on the ACs and BBs.
The new frigates are equipped with 133 DPs.

Kaiser Kirk · April 17, 2025, 06:02:09 PM

My new Frigates have a mixture of the 130mm for the ~3000 tonners, and 165mm for the 5000-6000 tonners.
The 165mm with heavyweight shell has the striking power of the old 180mm, so it is deemed acceptable for fighting cruisers if needed, while the 130mm with the 39kg is mainly viewed as an anti-Destroyer weapon, it could seriously hurt a cruiser at short ranges.

These ships were upgraded with improved FC in 1922, and then both fire control and AA guns in the fleet wide refits starting ~1931. I am sure you've noted the 37mm & 23mm - or on some ships the 30mm intended as the Parthian version of the logic behind the USA's 1.1" (28mm).

The 130QF and then 130DP like your 133 appears on my capital ships for a dual role vs. lighter combatants.
The 130mm shell weight, both early and later heavyweight 39kg were always considered as needing Mount & Hoist or turret.

The ability to fire proximity rounds in this shell size is new, but viewed as potentially very useful for barrage fire. As nations in this time period overestimated the effect of normal AA shells, the degree of improvement of proximity fuses is probably not fully appreciated.

So for the DDs, I had 90mm for AA and 120mm QF with the latter having 25kg shells. The newer 115DP also has 25kg shells but the smaller heavier round with more ME fires flatter and faster, so better for AA use.

The 90L54 firing 11kg is considered a capable AA gun, and some earlier ships you saw mixed 165mm and 90mm batteries for Anti-Surface & Anti-Aircraft roles, which is what the 130DP has replaced. Now it is typically fitted as AA on lighter ships with that 165-180mm primary, though the mounting is usually DP because why not?

Kaiser Kirk · May 25, 2025, 08:25:00 PM

As it's looking like I will not have sufficient funds to refurbish the Ranger class in 1938, as I have the spare 0.47 bp for 1 vessel... this is a 1939 refurb. Ironically since the engines are the same, there's no change in cost.

The choice is made to continue the vessel as a 'Sentry' cruiser, which sees the lower casement 165mms plated over and that modest weight savings put elsewhere. Between these and the Maelstroms that gives a decent number of 'sentry' platforms. Top speed of 29knots is slightly small, but fast enough to work around the 26knot battleline.

QuoteSC-14 Ranger R38, Parthian Cruiser laid down 1915

Displacement:
   4,973 t light; 5,249 t standard; 5,962 t normal; 6,532 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (424.87 ft / 419.95 ft) x 41.99 ft x (20.51 / 22.09 ft)
   (129.50 m / 128.00 m) x 12.80 m x (6.25 / 6.73 m)

Armament:
4 - 6.50" / 165 mm 45.0 cal guns - 176.37lbs / 80.00kg shells, 180 per gun
     Quick firing guns in deck and hoist mounts, 1930 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
2 - 6.50" / 165 mm 45.0 cal guns - 176.37lbs / 80.00kg shells, 180 per gun
     Quick firing guns in casemate mounts, 1930 Model
     2 x Single mounts on sides, forward deck aft
8 - 3.54" / 90.0 mm 54.0 cal guns - 24.25lbs / 11.00kg shells, 400 per gun
     Anti-air guns in deck mounts, 1929 Model
     4 x 2-gun mounts on sides, evenly spread
12 - 1.18" / 30.0 mm 80.0 cal guns - 0.95lbs / 0.43kg shells, 1,000 per gun
     Anti-air guns in deck mounts, 1929 Model
     4 x 2-gun mounts on side ends, evenly spread
      4 raised mounts
     2 x 2-gun mounts on centreline ends, evenly spread
      2 double raised mounts
16 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 500 per gun
     Anti-air guns in deck mounts, 1929 Model
     8 x Twin mounts on sides, evenly spread
      8 double raised mounts
Weight of broadside 1,271 lbs / 576 kg

Armour:
- Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   4.33" / 110 mm   335.96 ft / 102.40 m   9.84 ft / 3.00 m
   Ends:   Unarmoured
     Main Belt covers 123 % 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:   2.56" / 65 mm   0.98" / 25 mm      2.56" / 65 mm
   2nd:   0.98" / 25 mm   0.98" / 25 mm      0.98" / 25 mm
   3rd:   0.31" / 8 mm     -           -
   4th:   0.31" / 8 mm     -           -
   5th:   0.31" / 8 mm     -           -

- Protected deck - single deck:
   For and Aft decks: 1.57" / 40 mm
   Forecastle: 0.79" / 20 mm Quarter deck: 1.38" / 35 mm

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

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 49,527 shp / 36,947 Kw = 29.00 kts
   Range 4,790nm at 16.00 kts
   Bunker at max displacement = 1,283 tons

Complement:
   338 - 440

Cost:
   £0.751 million / $3.003 million

Distribution of weights at normal displacement:
   Armament: 246 tons, 4.1 %
     - Guns: 246 tons, 4.1 %
   Armour: 1,018 tons, 17.1 %
     - Belts: 571 tons, 9.6 %
     - Armament: 55 tons, 0.9 %
     - Armour Deck: 361 tons, 6.1 %
     - Conning Tower: 31 tons, 0.5 %
   Machinery: 1,876 tons, 31.5 %
   Hull, fittings & equipment: 1,623 tons, 27.2 %
   Fuel, ammunition & stores: 989 tons, 16.6 %
   Miscellaneous weights: 210 tons, 3.5 %
     - Hull below water: 25 tons
     - Hull void weights: 5 tons
     - Hull above water: 10 tons
     - On freeboard deck: 45 tons
     - Above deck: 125 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     4,379 lbs / 1,986 Kg = 31.9 x 6.5 " / 165 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.15
   Metacentric height 1.8 ft / 0.5 m
   Roll period: 13.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.89
   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): 0.577 / 0.587
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 20.49 kts
   Power going to wave formation at top speed: 63 %
   Trim (Max stability = 0, Max steadiness = 100): 41
   Bow angle (Positive = bow angles forward): 12.00 degrees
   Stern overhang: -6.56 ft / -2.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
     - Forecastle:   12.00 %, 20.73 ft / 6.32 m, 19.09 ft / 5.82 m
     - Forward deck:   45.00 %, 19.09 ft / 5.82 m, 17.45 ft / 5.32 m
     - Aft deck:   35.00 %, 17.45 ft / 5.32 m, 17.45 ft / 5.32 m
     - Quarter deck:   8.00 %, 17.45 ft / 5.32 m, 19.09 ft / 5.82 m
     - Average freeboard:      18.16 ft / 5.54 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 116.8 %
      - Above water (accommodation/working, high = better): 127.4 %
   Waterplane Area: 12,624 Square feet or 1,173 Square metres
   Displacement factor (Displacement / loading): 104 %
   Structure weight / hull surface area: 69 lbs/sq ft or 339 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.79
      - Longitudinal: 2.64
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Good seaboat, rides out heavy weather easily

1938 Refurbishment of 1915 Ranger class with it's 1929 Basic AA Refit.

- lower casement 165
+ 165L45s 80kg, 195rpg max
+ FC
+ radar
-/+ torpedoes
-/+ replace A/C
-/+ change to 16kts

Guns : 47
Armor : 50
Func Misc : 205
Mags : 106
Fuel: 1283
NF Misc : 5

Original : 5bp 5$

Baseline : 5x.2 = $1
A: $0.094 , 0.047bp
B: $0.255, 0.255
C: Null hull modifications
D: 1283+106+5 = 1394/2000 = $0.697
-----
$ : 1+.094 +.255+.697 = $2.046
BP : .047

Misc Wt :
5 - void Construction Reserve

AD
25t- 1930 fire control
25t - Long range radio
0t - Short range radio
25t - Air search radar
25t - Sea Search radar
25t - Searchlight tower amidships (NF)

OD
5t - Paravanes
40t - 4TT2 24" Torpedoes 5t

HAW
5t - C02 compressor A/C
5t - Extra Fire Ext.

HBW
10t - Extra pumps
15t - Enhanced Hydrophones