Parthian Ships 1928 +

Kaiser Kirk · December 20, 2024, 11:19:55 PM

The recoil on that is a bit high.
I can manage a 32knot, 72-gun version with <1.00 recoil. :)

But..that just seems like so few guns...

Kaiser Kirk · December 21, 2024, 03:21:10 PM

ok the recoil is under 1.0.
Not that it matters - not all the guns even bear on one side.

Speed is enough to move around the formation.
L:B should allow a smaller turn radius.

Armor is waaaaaaay to thin for my tastes.
Displacement far to high.

But it's 72-gun cruiser.

Capable of barrage fire with 40 x 130mm DP on each beam.
Torpedo planes, Vertical Bombers, or Dive Bombers coming in high - lots of AA power.

In an anti-surface role, I'm guessing it could seriously disrupt an incoming torpedo boat attack also.

QuoteRat a tat tat, Parthian Anti-aircraft cruiser laid down 1936

Displacement:
   9,750 t light; 12,211 t standard; 13,647 t normal; 14,796 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (524.93 ft / 518.37 ft) x 68.90 ft x (25.92 / 27.54 ft)
   (160.00 m / 158.00 m) x 21.00 m x (7.90 / 8.40 m)

Armament:
16 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
     Dual purpose guns in casemate mounts, 1936 Model
     16 x Single mounts on sides, evenly spread
      16 hull mounts in lower casemates- Limited use in heavy seas
56 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
     Dual purpose guns in deck and hoist mounts, 1936 Model
     48 x Single mounts on sides, evenly spread
      16 raised mounts
      16 hull mounts in casemates- Limited use in heavy seas
     4 x 2-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
72 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 6,000 per gun
     Anti-air guns in deck and hoist mounts, 1936 Model
     18 x 4-gun mounts on centreline ends, evenly spread
      18 double raised mounts
64 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 8,000 per gun
     Machine guns in deck mounts, 1936 Model
     32 x Twin mounts on centreline, evenly spread
      32 double raised mounts
Weight of broadside 6,343 lbs / 2,877 kg

Armour:
- Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   1.97" / 50 mm   400.92 ft / 122.20 m   9.48 ft / 2.89 m
   Ends:   Unarmoured
     Main Belt covers 119 % of normal length

- Hull void:
      0.00" / 0 mm     0.00 ft / 0.00 m   29.53 ft / 9.00 m

- Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.31" / 8 mm      0.31" / 8 mm
   2nd:   0.79" / 20 mm   0.31" / 8 mm      0.31" / 8 mm
   3rd:   0.31" / 8 mm     -           -
   4th:   0.31" / 8 mm     -           -

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

- Conning towers: Forward 1.97" / 50 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 103,598 shp / 77,284 Kw = 32.00 kts
   Range 8,082nm at 16.00 kts
   Bunker at max displacement = 2,584 tons

Complement:
   630 - 820

Cost:
   £6.642 million / $26.567 million

Distribution of weights at normal displacement:
   Armament: 1,591 tons, 11.7 %
     - Guns: 1,591 tons, 11.7 %
   Armour: 1,149 tons, 8.4 %
     - Belts: 307 tons, 2.2 %
     - Armament: 182 tons, 1.3 %
     - Armour Deck: 636 tons, 4.7 %
     - Conning Tower: 24 tons, 0.2 %
   Machinery: 2,907 tons, 21.3 %
   Hull, fittings & equipment: 3,678 tons, 26.9 %
   Fuel, ammunition & stores: 3,898 tons, 28.6 %
   Miscellaneous weights: 426 tons, 3.1 %
     - Hull below water: 41 tons
     - Hull void weights: 100 tons
     - Hull above water: 20 tons
     - On freeboard deck: 5 tons
     - Above deck: 260 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     11,721 lbs / 5,316 Kg = 174.8 x 5.1 " / 130 mm shells or 1.4 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 4.5 ft / 1.4 m
   Roll period: 13.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.96
   Seaboat quality (Average = 1.00): 1.21

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and small transom stern
   Block coefficient (normal/deep): 0.516 / 0.526
   Length to Beam Ratio: 7.52 : 1
   'Natural speed' for length: 24.73 kts
   Power going to wave formation at top speed: 65 %
   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:   20.00 %, 27.56 ft / 8.40 m, 26.25 ft / 8.00 m
     - Forward deck:   32.50 %, 26.25 ft / 8.00 m, 26.25 ft / 8.00 m
     - Aft deck:   32.50 %, 26.25 ft / 8.00 m, 26.25 ft / 8.00 m
     - Quarter deck:   15.00 %, 26.25 ft / 8.00 m, 26.25 ft / 8.00 m
     - Average freeboard:      26.35 ft / 8.03 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 118.0 %
      - Above water (accommodation/working, high = better): 196.3 %
   Waterplane Area: 24,731 Square feet or 2,298 Square metres
   Displacement factor (Displacement / loading): 111 %
   Structure weight / hull surface area: 107 lbs/sq ft or 523 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.78
      - Longitudinal: 3.05
      - 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

Warning: Too many mounts in specific locations - 4th battery

8 gun positions on each side at each level.

Designed to maximize broadside fire against torpedo bombers or dive bombers.
37 & 23 : 2 mounts up.
130 Above Deck
_____130 On Deck
|130 Below Deck : 'frying pan' deck edge mounts. Mount, Below deck.
|130 Lower Deck : Casement
|

8.0m- freeboard
5.5m - battery deck floor
3.00m - main deck floor
0.50m -

Misc Weight
Reserve :

AD
160t- Fire Control 1930
25t- Hulesmeyer
25t- Searchlights (NF)
25t - Air Search Radar
25t- LR Radio
0t- SR Radio

OD
5t - Paravanes

HAW

10t - Additional Ventilation
10t - Additional Fire Suppresion.

HBW
10t- Additional Pumps
31t - Auxiliary Diesel Generator

Kaiser Kirk · December 22, 2024, 11:25:37 AM

one more rendition of the Rat-a-tat-tat.

Much reduced number of guns.
Down to 24 x 130mm DP on broadside, which is still respectable.
But now the ship and mounts have moderately decent armor.

Overall, a more practical version of the concept.
Still far to expensive, but would be death on anything 130mm guns can shred.
Compared to the broadside of an Atlanta or Dido tonnage for tonnage, decent.
I *may* actually build a couple. Somehow I think other BP demands will get in the way.

Freeboard at 7m to ensure clear in all weather.
Slow and steady roll for best long range accuracy.

Tonnage for each radar system (still need to get better idea of actual weight, these are too heavy)
RPC tonnage introduced for better director control.

Armor is now substantial enough to do something,
and make the various mounts proof against anything but direct hits.

Gunnery is far more modest, but still impressive.
24 x 130mm on each beam, 12 x 130mm fore/aft.
Quad 37mm superimposed over.
Twin 23mm above.

Functional armor belt and deck.

Still 8 gun positions on each side at each level. 1 per 12m of citadel length.

Designed to maximize broadside fire against torpedo bombers or dive bombers
23 : 2 mounts up.
37 Above Deck
_____130 On Deck
|130 Below Deck : 'frying pan' deck edge mounts. Mount, Below deck.
|

QuoteRat a tat tat, Parthian Anti-aircraft cruiser laid down 1936

Displacement:
9,000 t light; 10,421 t standard; 11,788 t normal; 12,882 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(524.93 ft / 518.37 ft) x 65.62 ft x (25.59 / 27.28 ft)
(160.00 m / 158.00 m) x 20.00 m x (7.80 / 8.31 m)

Armament:
8 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
Dual purpose guns in deck and hoist mounts, 1936 Model
4 x 2-gun mounts on centreline, evenly spread
2 raised mounts
32 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
Dual purpose guns in deck and hoist mounts, 1936 Model
16 x 2-gun mounts on sides, evenly spread
8 hull mounts in casemates- Limited use in heavy seas
40 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 6,000 per gun
Anti-air guns in deck and hoist mounts, 1936 Model
8 x 4-gun mounts on sides, evenly spread
8 raised mounts
2 x 4-gun mounts on centreline ends, evenly spread
2 double raised mounts
20 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 8,000 per gun
Machine guns in deck mounts, 1936 Model
10 x Twin mounts on centreline, evenly spread
10 double raised mounts
Weight of broadside 3,517 lbs / 1,595 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 336.94 ft / 102.70 m 11.48 ft / 3.50 m
Ends: Unarmoured
Main Belt covers 100 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Hull void:
0.00" / 0 mm 0.00 ft / 0.00 m 29.53 ft / 9.00 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.56" / 65 mm 1.38" / 35 mm 1.38" / 35 mm
2nd: 2.56" / 65 mm 1.38" / 35 mm 1.38" / 35 mm
3rd: 0.79" / 20 mm 0.31" / 8 mm 0.31" / 8 mm
4th: 0.31" / 8 mm - -

- Armoured deck - single deck:
For and Aft decks: 2.17" / 55 mm
Forecastle: 1.38" / 35 mm Quarter deck: 1.97" / 50 mm

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

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 91,857 shp / 68,526 Kw = 32.00 kts
Range 8,482nm at 16.00 kts
Bunker at max displacement = 2,460 tons

Complement:
565 - 735

Cost:
£5.230 million / $20.920 million

Distribution of weights at normal displacement:
Armament: 951 tons, 8.1 %
- Guns: 951 tons, 8.1 %
Armour: 1,672 tons, 14.2 %
- Belts: 481 tons, 4.1 %
- Armament: 281 tons, 2.4 %
- Armour Deck: 877 tons, 7.4 %
- Conning Tower: 33 tons, 0.3 %
Machinery: 2,577 tons, 21.9 %
Hull, fittings & equipment: 3,398 tons, 28.8 %
Fuel, ammunition & stores: 2,788 tons, 23.7 %
Miscellaneous weights: 402 tons, 3.4 %
- Hull below water: 40 tons
- Hull void weights: 45 tons
- Hull above water: 18 tons
- On freeboard deck: 53 tons
- Above deck: 246 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
11,620 lbs / 5,271 Kg = 173.3 x 5.1 " / 130 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 3.3 ft / 1.0 m
Roll period: 15.3 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.79
Seaboat quality (Average = 1.00): 1.20

Hull form characteristics:
Hull has a flush deck,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.474 / 0.486
Length to Beam Ratio: 7.90 : 1
'Natural speed' for length: 24.75 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 59
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 %, 27.56 ft / 8.40 m, 25.43 ft / 7.75 m
- Forward deck: 32.50 %, 25.43 ft / 7.75 m, 22.97 ft / 7.00 m
- Aft deck: 32.50 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
- Quarter deck: 15.00 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
- Average freeboard: 24.03 ft / 7.32 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 104.9 %
- Above water (accommodation/working, high = better): 180.2 %
Waterplane Area: 22,665 Square feet or 2,106 Square metres
Displacement factor (Displacement / loading): 115 %
Structure weight / hull surface area: 100 lbs/sq ft or 490 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.80
- Longitudinal: 2.60
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

|

Misc Weight
Reserve :
45t

AD
96t- Fire Control 1930
25t- Hulesmeyer
25t- Searchlights (NF)
25t - Air Search Radar
25t - Surface Search Radar
25t - FC Radar
25t- LR Radio
0t- SR Radio

OD
5t - Paravanes
48t - RPC for guns

HAW

9t - Additional Ventilation
9t - Additional Fire Suppresion.

HBW
9t- Additional Pumps
31t - Auxiliary Diesel Generator

7.0 - Weather Deck
4.5 - Battery Deck
2.0 - Armor Deck, Top Main Belt
-0.5 -
....-1.5 - Bottom Main Belt
-3.0 -
-6.5 - Engineering

Kaiser Kirk · December 22, 2024, 12:37:56 PM

As this goes from a 'hey how many guns can I cram onto something'
to
'gee, this might be doable'
I become concerned that I could not fit that many gun positions across the hull.

This is knot slow, 2m wider.
I know Atlanta had 2 wing turrets and a centerline on 16m, so this is +6m.
Perhaps I need to go back up to 10,000 tons and gain more beam for this.
I should look to US Cruisers, some had 40mm tubs over the 5" battery.

Of course if it gets too big, it becomes more efficient to field copies of Atlanta ,
which had a 14 gun broadside, but far less protected.

Rat a tat tat, Parthian Anti-aircraft cruiser laid down 1936

Displacement:
   9,000 t light; 10,422 t standard; 11,826 t normal; 12,949 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (524.93 ft / 518.37 ft) x 72.18 ft x (24.05 / 25.64 ft)
   (160.00 m / 158.00 m) x 22.00 m x (7.33 / 7.82 m)

Armament:
8 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
     Dual purpose guns in deck and hoist mounts, 1936 Model
     4 x 2-gun mounts on centreline, evenly spread
      2 raised mounts
32 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
     Dual purpose guns in deck and hoist mounts, 1936 Model
     16 x 2-gun mounts on sides, evenly spread
      8 hull mounts in casemates- Limited use in heavy seas
40 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 6,000 per gun
     Anti-air guns in deck and hoist mounts, 1936 Model
     8 x 4-gun mounts on sides, evenly spread
      8 raised mounts
     2 x 4-gun mounts on centreline ends, evenly spread
      2 double raised mounts
20 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 8,000 per gun
     Machine guns in deck mounts, 1936 Model
     10 x Twin mounts on centreline, evenly spread
      10 double raised mounts
Weight of broadside 3,517 lbs / 1,595 kg

Armour:
- Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.95" / 75 mm   336.94 ft / 102.70 m   11.48 ft / 3.50 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

- Hull void:
      0.00" / 0 mm     0.00 ft / 0.00 m   29.53 ft / 9.00 m

- Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.56" / 65 mm   1.38" / 35 mm      1.38" / 35 mm
   2nd:   2.56" / 65 mm   1.38" / 35 mm      1.38" / 35 mm
   3rd:   0.79" / 20 mm   0.31" / 8 mm      0.31" / 8 mm
   4th:   0.31" / 8 mm     -           -

- Armoured deck - single deck:
   For and Aft decks: 2.17" / 55 mm
   Forecastle: 1.38" / 35 mm Quarter deck: 2.17" / 55 mm

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 80,748 shp / 60,238 Kw = 31.00 kts
   Range 8,678nm at 16.00 kts
   Bunker at max displacement = 2,527 tons

Complement:
   566 - 737

Cost:
   £5.000 million / $19.999 million

Distribution of weights at normal displacement:
   Armament: 951 tons, 8.0 %
     - Guns: 951 tons, 8.0 %
   Armour: 1,773 tons, 15.0 %
     - Belts: 486 tons, 4.1 %
     - Armament: 281 tons, 2.4 %
     - Armour Deck: 962 tons, 8.1 %
     - Conning Tower: 44 tons, 0.4 %
   Machinery: 2,266 tons, 19.2 %
   Hull, fittings & equipment: 3,543 tons, 30.0 %
   Fuel, ammunition & stores: 2,826 tons, 23.9 %
   Miscellaneous weights: 467 tons, 3.9 %
     - Hull below water: 40 tons
     - Hull void weights: 110 tons
     - Hull above water: 18 tons
     - On freeboard deck: 53 tons
     - Above deck: 246 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     14,589 lbs / 6,617 Kg = 217.6 x 5.1 " / 130 mm shells or 1.9 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 4.3 ft / 1.3 m
   Roll period: 14.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.55
   Seaboat quality (Average = 1.00): 1.21

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and small transom stern
   Block coefficient (normal/deep): 0.460 / 0.472
   Length to Beam Ratio: 7.18 : 1
   'Natural speed' for length: 24.90 kts
   Power going to wave formation at top speed: 61 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   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 %, 27.89 ft / 8.50 m, 26.25 ft / 8.00 m
     - Forward deck:   32.50 %, 26.25 ft / 8.00 m, 22.97 ft / 7.00 m
     - Aft deck:   32.50 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
     - Quarter deck:   15.00 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
     - Average freeboard:      24.29 ft / 7.40 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 96.1 %
      - Above water (accommodation/working, high = better): 197.1 %
   Waterplane Area: 24,628 Square feet or 2,288 Square metres
   Displacement factor (Displacement / loading): 121 %
   Structure weight / hull surface area: 104 lbs/sq ft or 509 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.81
      - Longitudinal: 2.36
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Adequate 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

A more practical version of the concept.
Still far to expensive,
but would be death on anything 130mm guns can shred.

Freeboard at 8m to ensure clear in all weather.
Slow and steady roll for best long range accuracy.
RPC introduced for better director control.
Armor is now substantial enough to do something,
and make the various mounts proof against
anything but direct hits.

Gunnery is far more modest, but still impressive.
24 x 130mm on each beam, 12 x 130mm fore/aft.
Quad 37mm superimposed over.
Twin 23mm above.

Functional armor belt and deck.

Still 8 gun positions on each side at each level.

Designed to maximize broadside fire against torpedo bombers or dive bombers.
23 : 2 mounts up.
37 Above Deck
_____130 On Deck
|130 Below Deck : 'frying pan' deck edge mounts. Mount, Below deck.
|
|

Misc Weight
Reserve :
45t

AD
96t- Fire Control 1930
25t- Hulesmeyer
25t- Searchlights (NF)
25t - Air Search Radar
25t - Surface Search Radar
25t - FC Radar
25t- LR Radio
0t- SR Radio

OD
5t - Paravanes
48t - RPC for guns

HAW

9t - Additional Ventilation
9t - Additional Fire Suppresion.

HBW
9t- Additional Pumps
31t - Auxiliary Diesel Generator

7.0 - Weather Deck
4.5 - Battery Deck
2.0 - Armor Deck, Top Main Belt
-0.5 -
....-1.5 - Bottom Main Belt
-3.0 -
-6.5 - Engineering

Jefgte · December 22, 2024, 03:49:55 PM

Quote32 - 5.12" / 130 mm 50.0 cal guns - 85.98lbs / 39.00kg shells, 480 per gun
Dual purpose guns in deck and hoist mounts, 1936 Model
16 x 2-gun mounts on sides, evenly spread
8 hull mounts in casemates- Limited use in heavy seas

I think that 8 x 130 in casemates are not useful & 130DP in casemate not mechanical possible (?).

You have 8 x 2 x130 on the deck each side.

4 x 2250t DD AA would be better than 1 x 9000t.

Kaiser Kirk · December 23, 2024, 05:59:05 PM

Bah humbug lost my reply.

Casements & below deck mounts
Casements are intentionally DP, to allow use versus both surface targets AND torpedo bombers.
They obviously would have the elevation constraints of casements ~22 degrees.

The idea from this comes from a book by a local author.
He served on the USS Maryland. When rebuilt after Pearl Harbor, her 5/54 battery was replaced with 5/38, including the casements.
The casements were provided with information & AA shells so they could engage in barrage fire vs. torpedo bombers. Only happened a couple times, and they only claimed to down 1 plane (with a prox fuse as I recall).

The below deck mount are the RN's 'frying pan' 4.5" mounts mounted flush with the freeboard. So their mounting is actually ' below deck'

Cruiser vs. Destroyers

The core concept here is that to launch, torpedo planes will want to be ahead and ~1000 yards off the bow of the carrier.
If there is a CLAA there, that launch point becomes suicidal.
So they will try to be near there and launch from a less optimal spot.
Likewise, dive bombers and vertical bombers will prefer to come from the bow and fly down the axis of the carrier, which would force them to overflight the CLAA first.
In all cases, the mere presence of the CLAA somewhat disrupts the attack, while the fire effect
would disrupt and damage or destroy the planes.

4 Destroyers would physically need to be separated by hundreds of meters to ensure they have maneuver room,
and would have difficulty coordinating fire on a single attack vector or telling individual ships effects.

Destroyers also should not be as good an AA platform as a cruiser.
Stability and Seakeeping are relative value, and smaller vessels do not perform as well as larger.
Just the baseline freeboard of my cruiser is much higher, even the casement guns are at the same
level as a destroyer's main battery. Sea state and sea spray would have a lesser effect.
As a cruiser, she can use Mount and Hoist, which is not a destroyer fitting, allowing for sustained fire.
Mast height for radar and fire control is lower, leading to lesser ranges.
Space and weight issues tended to make Destroyer Fire Control set ups smaller and simplified.
I believe the same for radar sets and fusesetting apparatus.

Then there's the # of guns bearing on broadside. The least of these ships is 24x130mm.
The Destroyer's I've noticed are 6x guns, so 4 match the 24 guns of the least ship, but not the larger.
Further these are usually ~114/115mm/4.5", so smaller burst radius.

So I do not view 4 destroyers as the equivalent of 1 cruiser in this case.

TacCovert4 · December 24, 2024, 06:29:00 AM

It's going to be very interesting that's for sure. With all those heavy guns, your CLAA will certainly be able to put up serious barrage fire, but will also be subject to (quoting Firefly) "Experience some slight turbulence and then....explode" if it start's taking shots from heavy guns......given it's gotta have a couple of huge magazines for all those DP guns.

For now, the Aztec meta is going to be more in the medium sphere, as HAA is useful but not the plane-killer it'll become once radar directed gunnery and VT fuses become a thing. After years in service, the 40mm Gatling mount is finally serviceable, and since it's a fully enclosed powered mount and hoist, it can accommodate the same FC gear as a 120mm enclosed mount. So for my ships, as we're still on optical-only for FC, the Aircraft spotting scopes can feed bearing and presumptive horizontal velocity and ranging data through the FC system to give the 40mm gatling mounts a (rough) pointer direction on the bearing they should fire along.

The result is that a 40mm Gatling mount's gunner can slew to follow a pointer coming from centralized FC (or use a local periscope) and fire along a likely intercept bearing. The way these mounts work, they have a top-feed that pulls from 200rd belts sent up the hoist and fed by the crew (feed capacity 400rds) that get de-linked into the feed tray, so at maximum rate it can theoretically fire 6 belts in a minute, or at a more practical rate can fire a 40rd burst in 4 seconds, assess for 4 seconds, then fire another burst, switching to maximum rate firing of 100rd bursts in 5 seconds (with increased chances of a malfunction) as an approaching aircraft or formation closes on the ship.

HAA for the sultanate right now is more to break up formations with barrage fire or force a formation onto an angle where the 40mm mounts can pour fire to actually down aircraft. Overall, the Sultanate is focused on 'bursts of fire' rather than 'continuous fire' as it believes aircraft will only be in prime position to be hit for 20-40 seconds of their attack run before they release weapons. Under those conditions, having a central spotter on a formation feeding the best possible data to the guns is seen as more effective than having individual gunners attempting to find/track/prosecute aerial targets themselves. Ultimately this means that each ship is only targeting 1-2 formations of aircraft at a time rather than being a hornet's nest of fire against all aircraft in range.

Kaiser Kirk · December 29, 2024, 05:14:21 PM

'Bursts of Fire' certainly match the expectation I have. The speed of the planes keeps going up, which means the time in the engagement envelop should be short.

That is why I am comfortable with the GAST 23mm concept, I am sure the guns would overheat in longer engagements, so bursts it is. That also is why I'm playing with these concepts where I could mass a great deal of firepower in one spot.

The lethality of AA is only part of the point. It is expected that if the enemy flies into it, it would be lethal, but the enemy will try to avoid that. As such it will damage and disrupt enemy attacks, particularly making formation attacks less workable, and in turn making the overall attack far less effective while also allowing ship maneuvers to be more effective.

Also, in 1936 I will be in HY2 of 1938 Night Fighting research, so the possibility of proximity fuses and radar assist should be conceivable. SoDak shredded the attacks at Santa Cruz, with half the battery of this ship.

Yes, a proper cruiser or capital ship would be a problem for one of these ships. I- not surprisingly, do expect my ammo characteristics to be more German than Brit, but all the <1.0 recoil designs have less than 130% hullspace, allowing vitals under a protective deck- aka underwater, but I have an Armored Deck fitted at top main belt, so enough space for magazines under armor. The later 31knot version have a 55mm protective deck, which is actually proof vs. most cruiser weapons at range.

Still, their job would be to be tied to the carriers, which in current (1930s) Parthian planning are operating as a separate division near the Battleline, which the carriers would run towards if say a big BC showed up in the rear. Now, if caught at night, those 130mm would have a terrific ROF that should soft kill anything in range.

I really should take the time to look at deck plans to determine a plausible beam for these nested weapons side-side, then make a 'final' version.

Kaiser Kirk · January 03, 2025, 11:47:24 PM

Well bummer, I posted 2 more versions of my Davazdah Rohk cruiser, one at 31 knots and one with a 130mm secondary.

31knots because I'd prefer my cruisers to be there rather than the 30, and the 130mm secondary
because I'd prefer the harder hitting guns in an AS role.

I have a bad habit, I just press Post, then close the window.
So if I took to long and it forces a preview....I don't notice and loose the post.
Apparently I will not learn...

hmm, looks like I need to add the Manzikert and Bahktiari classes to the encyclopedia, and I just updated that before Thanksgiving :)

Kaiser Kirk · January 04, 2025, 03:32:37 PM

This is the 2nd attempt at posting these :)
The first example of the Davazdah Rohk is a couple pages ago. Call that the 'A'.

The 'B' trades the 115mm secondary for a 130mm secondary. Harder hitting for Nighttime battles, torpedo assault swarms, and more height/reach for AA work.

The 'C' increases the speed to 31knots.

The Parthians would like to have their new cruisers at 31 knots, both as more competitive with foreign vessels, and a more decisive margin over older slower cruisers. Add in the speed of the Roman heavies, and 31 seems somewhat more attractive - but the cost in protection makes them (aka me) unhappy.

In both cases the tradeoff is less protection.
These cruisers use the USS Baltimore style magazine box, where the deck/belt plates over the magazine
are thicker, and there are interior screens against fore-aft penetrations. This boosts the magazine protection to be quite high, but the listed belt/deck is what protects the machinery.
Hits to machinery are not desirable, but are unlikely to be suddenly catastrophic.

With the development of conical barbettes reducing turret installation tonnage in cruisers, the old Mount&Hoist 80-90kg maximum for handloading, as reflected in the old 180mm firing an 80/85kg shell, was no longer relevant. Likewise, the turret format would allow much heavier shielded multi-gun mountings to rotate at acceptable speeds.

The Parthians have introduced the quickfire 165mm with a 80kg shell with the Bahktiari class.
This 165mm hits as hard as the old 180mm, but with a better ROF. The light gun also allows them to mount many per hull. Parthians LIKE lots of guns.

They have also shoehorned the 215mm with a 175kg shell with the Manzikert class light armored cruiser. This was developed for the Xiyon class, and where long range visibility allows, can hole 'cruisers' at any range.

With the IJN believed to be fielding 8"/203 guns with roughly 117kg shells, the 190mm with 115kg shell was developed to provide an 8" shell weight (as the IJN is thought to use) in a lighter gun. The fact this came out to be nearly identical to the Byzantine bore was cause for some reassessment, but they decided to field it anyhow.

QuoteDavazdah Rohk-B, Parthia Cruiser laid down 1936

Displacement:
10,000 t light; 10,757 t standard; 12,105 t normal; 13,184 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(524.93 ft / 518.37 ft) x 72.18 ft x (21.33 / 22.76 ft)
(160.00 m / 158.00 m) x 22.00 m x (6.50 / 6.94 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 - 5.12" / 130 mm 47.0 cal guns - 85.98lbs / 39.00kg shells, 320 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
16 - 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
12 - 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
6 x Twin mounts on sides, evenly spread
6 double raised mounts
Weight of broadside 4,107 lbs / 1,863 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.33" / 110 mm 336.94 ft / 102.70 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: 6.50" / 165 mm 2.17" / 55 mm 5.12" / 130 mm
2nd: 2.56" / 65 mm 0.98" / 25 mm 1.38" / 35 mm
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Armoured deck - single deck:
For and Aft decks: 2.26" / 58 mm
Forecastle: 1.38" / 35 mm Quarter deck: 1.97" / 50 mm

- Conning towers: Forward 5.12" / 130 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 74,980 shp / 55,935 Kw = 30.00 kts
Range 8,080nm at 16.00 kts
Bunker at max displacement = 2,428 tons

Complement:
576 - 750

Cost:
£5.224 million / $20.895 million

Distribution of weights at normal displacement:
Armament: 1,038 tons, 8.6 %
- Guns: 1,038 tons, 8.6 %
Armour: 2,303 tons, 19.0 %
- Belts: 637 tons, 5.3 %
- Armament: 551 tons, 4.6 %
- Armour Deck: 1,057 tons, 8.7 %
- Conning Tower: 58 tons, 0.5 %
Machinery: 2,104 tons, 17.4 %
Hull, fittings & equipment: 4,080 tons, 33.7 %
Fuel, ammunition & stores: 2,105 tons, 17.4 %
Miscellaneous weights: 475 tons, 3.9 %
- Hull below water: 66 tons
- Hull void weights: 60 tons
- Hull above water: 30 tons
- On freeboard deck: 115 tons
- Above deck: 204 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
16,318 lbs / 7,402 Kg = 78.0 x 7.5 " / 190 mm shells or 2.1 torpedoes
Stability (Unstable if below 1.00): 1.18
Metacentric height 4.2 ft / 1.3 m
Roll period: 14.9 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.65
Seaboat quality (Average = 1.00): 1.02

Hull form characteristics:
Hull has a flush deck,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.531 / 0.542
Length to Beam Ratio: 7.18 : 1
'Natural speed' for length: 24.76 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 49
Bow angle (Positive = bow angles forward): 11.00 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, 22.97 ft / 7.00 m
- Forward deck: 32.50 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
- Aft deck: 32.50 %, 22.97 ft / 7.00 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: 22.46 ft / 6.85 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 86.1 %
- Above water (accommodation/working, high = better): 194.6 %
Waterplane Area: 26,278 Square feet or 2,441 Square metres
Displacement factor (Displacement / loading): 118 %
Structure weight / hull surface area: 119 lbs/sq ft or 583 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.82
- Longitudinal: 2.01
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

Warning: Beam between bulkheads too wide

Davazdah Rohk - Twelve Battles.

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 Magazine Box thickened deck over magazine.
118t 65mm magazine box
939t 35/50/50mm deck
------
1057t needeed

1049t paid

Misc

Reserve
60t

AD
104t - FC 1930
25t - LR radio
0t - SR Radio
25t - Hulesmeyer
25t - Air Search Radar
25t - Searchlight Tower (NF)

OD
5t paravanes
100t 4x floatplanes ( 2 fighter, 2 scout 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
46nm of fuel is Diesel

Decks
+6.30 Weather Deck
+3.70 Battery Deck
+1.20 Armor Deck, main deck
-1.8 bottom main belt
-1.30 1st Platform Deck
-4.80 Engineering
-5.81 Double Bottom
-6.66 Keel

QuoteDavazdah Rohk C, Parthia Cruiser laid down 1936

Displacement:
10,000 t light; 10,703 t standard; 12,026 t normal; 13,084 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(545.40 ft / 538.06 ft) x 72.18 ft x (21.85 / 23.25 ft)
(166.24 m / 164.00 m) x 22.00 m x (6.66 / 7.09 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, 358 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
16 - 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
12 - 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
6 x Twin mounts on sides, evenly spread
6 double raised mounts
Weight of broadside 3,737 lbs / 1,695 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.33" / 110 mm 349.74 ft / 106.60 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 2.17" / 55 mm 4.33" / 110 mm
2nd: 1.18" / 30 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Armoured deck - single deck:
For and Aft decks: 2.23" / 57 mm
Forecastle: 1.38" / 35 mm Quarter deck: 1.97" / 50 mm

- Conning towers: Forward 5.12" / 130 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 81,936 shp / 61,124 Kw = 31.00 kts
Range 8,056nm at 16.00 kts
Bunker at max displacement = 2,381 tons

Complement:
573 - 746

Cost:
£5.235 million / $20.940 million

Distribution of weights at normal displacement:
Armament: 962 tons, 8.0 %
- Guns: 962 tons, 8.0 %
Armour: 2,242 tons, 18.6 %
- Belts: 656 tons, 5.5 %
- Armament: 480 tons, 4.0 %
- Armour Deck: 1,047 tons, 8.7 %
- Conning Tower: 58 tons, 0.5 %
Machinery: 2,299 tons, 19.1 %
Hull, fittings & equipment: 4,078 tons, 33.9 %
Fuel, ammunition & stores: 2,026 tons, 16.8 %
Miscellaneous weights: 418 tons, 3.5 %
- Hull below water: 66 tons
- Hull void weights: 60 tons
- Hull above water: 30 tons
- On freeboard deck: 65 tons
- Above deck: 197 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
15,275 lbs / 6,928 Kg = 73.0 x 7.5 " / 190 mm shells or 2.0 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 4.2 ft / 1.3 m
Roll period: 14.7 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.56
Seaboat quality (Average = 1.00): 1.02

Hull form characteristics:
Hull has a flush deck,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.496 / 0.507
Length to Beam Ratio: 7.45 : 1
'Natural speed' for length: 25.25 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, 22.97 ft / 7.00 m
- Forward deck: 30.00 %, 22.97 ft / 7.00 m, 20.67 ft / 6.30 m
- Aft deck: 35.00 %, 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: 21.68 ft / 6.61 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 89.7 %
- Above water (accommodation/working, high = better): 186.0 %
Waterplane Area: 26,398 Square feet or 2,452 Square metres
Displacement factor (Displacement / loading): 117 %
Structure weight / hull surface area: 117 lbs/sq ft or 573 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.83
- Longitudinal: 1.85
- Overall: 0.90
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

Warning: Beam between bulkheads too wide

Davazdah Rohk - Twelve Battles.

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.
114t 65mm magazine box
945t 35/50/50mm deck
------
1049t needeed

1049t paid

Misc

Reserve
60t

AD
97t - FC 1930
25t - LR radio
0t - SR Radio
25t - Hulesmeyer
25t - Air Search Radar
25t - Searchlight Tower (NF)

OD
5t paravanes
50t 2x floatplanes ( 2 scout 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
46nm of fuel is Diesel

Decks
+6.30 Weather Deck
+3.70 Battery Deck
+1.20 Armor Deck, main deck
-1.8 bottom main belt
-1.30 1st Platform Deck
-4.80 Engineering
-5.81 Double Bottom
-6.66 Keel

The Rock Doctor · January 04, 2025, 05:55:05 PM

Curious to see what you do with the planeguard concept.

Kaiser Kirk · January 04, 2025, 06:39:32 PM

Quote from: The Rock Doctor on January 04, 2025, 05:55:05 PMCurious to see what you do with the planeguard concept.

I got distracted by my Rat-at-tat-tat musings.
Oh the veritable plethora of guns, the glorious hedgehog-like profiles ...with casements !!!

But yes, I'm designing my destroyers in 4 ship units, with the idea of 3 triangulating and 1 attacking.
Or 2 flanking the formation and 2 leap frogging ahead in sprint & drift. Or a diamond formation around the formation. All of which gets disrupted when DDs are needed to shadow carriers.

So it's definitely on the *need* list. First I'm going to need to free up more build capacity. Right now I'm completing a bunch of big ships and trying to replace my ancient protected cruisers. Between scrapping's and completions 1936.5 looks better.

Earlier for the role, I was thinking of the cheap option of Manban class ASW sloops, but they are too slow.
So I'll either build a specialty light cruiser in the 3000 ton range, or dedicated large destroyers - probably variant hulls. My fast minelayers are attractive for that as they have the minedeck area for recovery operations..

Kaiser Kirk · January 04, 2025, 09:35:45 PM

This is a first effort at the type of small cruiser I'm conceptualizing
for Planeguard duties.

It's not much larger than a destroyer, and not much slower.

Needing a vessel for Planeguard duty,
the choice was between a destroyer dedicated to the purpose, or a light cruiser or frigate.
Currently the role is probably taking the efforts of a 1300-2000 ton destroyer. So while it's a needed role, I don't particularly want to build a 6000 ton light cruiser to replace. So we're talking Frigate 3000-5000 tons or one of the 2000-2500 Destroyer designs,

My Destroyer/Fast Minesweepers all have substantially less range at 6000nm than the carrier. Which creates a extra logistics hassle. They also have barely 1.0 seakeeping, and are tight designs with no extra interior room.

Yes, I just built 8 oilers, to supplement the 'handwave' merchant marine oilers, so the logistics is not as imposing, but still not desirable.

The choice was made for a frigate with speed similar to the carriers,
the same range and cruise speed, with some additional fittings for the task at hand.

Firepower is slightly greater than the largest destroyer, but seakeeping is much better.
These ships, tailing behind the carrier, will provide heavy AA screening power.

A long forecastle is cut down aft, and the lowered the Fantail will allow easier recovery of aircrew.

A single amidships aircraft is fitted, which can be launched to spot for downed aircraft.
The amphibian can also fly the recovered pilot back to the host ship.

Two rescue motor launches are added to the ships boats. These high speed launches have additional warming heaters, line launcher and even hoist nets to pluck aircrew from waters cold or hot.

Two long 'excavator' type arms are fitted with both hand & footholds and large seive type baskets, with the idea of being able to dip aircrew out of the water.

Since these ships will be pretty much dedicated to the carrier anti-surface combat and ASW actions are not part of their intended role. The 130mm gun fires a decent shell for anti-surface work, but an argument could be made to fit the 115mm instead.

QuoteAtossa, Parthian Planeguard Frigate laid down 1936

Displacement:
3,000 t light; 3,231 t standard; 4,165 t normal; 4,911 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(462.60 ft / 456.04 ft) x 44.29 ft x (17.06 / 19.08 ft)
(141.00 m / 139.00 m) x 13.50 m x (5.20 / 5.82 m)

Armament:
8 - 5.12" / 130 mm 47.0 cal guns - 85.98lbs / 39.00kg shells, 320 per gun
Dual purpose guns in deck and hoist mounts, 1936 Model
4 x 2-gun mounts on centreline ends, evenly spread
2 raised mounts - superfiring
24 - 1.46" / 37.0 mm 70.0 cal guns - 1.73lbs / 0.79kg shells, 480 per gun
Anti-air guns in deck and hoist mounts, 1936 Model
6 x 2 row quad mounts on side ends, majority forward
6 raised mounts
20 - 0.91" / 23.0 mm 90.0 cal guns - 0.43lbs / 0.20kg shells, 3,000 per gun
Machine guns in deck mounts, 1936 Model
8 x Twin mounts on sides, evenly spread
8 raised mounts
2 x 2 row quad mounts on centreline ends, evenly spread
2 double raised mounts
Weight of broadside 738 lbs / 335 kg

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.38" / 35 mm 0.98" / 25 mm 1.38" / 35 mm
3rd: 0.79" / 20 mm 0.31" / 8 mm 0.31" / 8 mm
4th: 0.31" / 8 mm - -

- Box over magazines:
2.17" / 55 mm

- Conning towers: Forward 1.38" / 35 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 3 shafts, 42,542 shp / 31,736 Kw = 31.00 kts
Range 8,400nm at 18.00 kts
Bunker at max displacement = 1,680 tons

Complement:
258 - 336

Cost:
£1.782 million / $7.126 million

Distribution of weights at normal displacement:
Armament: 197 tons, 4.7 %
- Guns: 197 tons, 4.7 %
Armour: 114 tons, 2.7 %
- Armament: 51 tons, 1.2 %
- Armour Deck: 55 tons, 1.3 %
- Conning Tower: 8 tons, 0.2 %
Machinery: 1,194 tons, 28.7 %
Hull, fittings & equipment: 1,270 tons, 30.5 %
Fuel, ammunition & stores: 1,164 tons, 28.0 %
Miscellaneous weights: 226 tons, 5.4 %
- Hull below water: 3 tons
- Hull void weights: 15 tons
- Hull above water: 23 tons
- On freeboard deck: 90 tons
- Above deck: 95 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3,223 lbs / 1,462 Kg = 48.1 x 5.1 " / 130 mm shells or 0.9 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 1.7 ft / 0.5 m
Roll period: 14.1 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.73
Seaboat quality (Average = 1.00): 1.21

Hull form characteristics:
Hull has rise forward of midbreak,
a ram bow and small transom stern
Block coefficient (normal/deep): 0.423 / 0.446
Length to Beam Ratio: 10.30 : 1
'Natural speed' for length: 23.01 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 15.00 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 %, 23.62 ft / 7.20 m, 21.16 ft / 6.45 m
- Forward deck: 40.00 %, 21.16 ft / 6.45 m, 18.70 ft / 5.70 m
- Aft deck: 25.00 %, 10.50 ft / 3.20 m, 10.50 ft / 3.20 m
- Quarter deck: 15.00 %, 10.50 ft / 3.20 m, 10.50 ft / 3.20 m
- Average freeboard: 16.60 ft / 5.06 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 110.8 %
- Above water (accommodation/working, high = better): 155.4 %
Waterplane Area: 12,908 Square feet or 1,199 Square metres
Displacement factor (Displacement / loading): 124 %
Structure weight / hull surface area: 60 lbs/sq ft or 294 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.69
- Longitudinal: 1.57
- Overall: 0.75
Caution: Hull subject to strain in open-sea
Adequate 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

Warning: Beam between bulkheads too wide

Needing a vessel for Planeguard duty,
the choice was between a destroyer dedicated to the purpose,
or a light cruiser or frigate

The choice was made for a frigate with speed similar to the carriers,
the same range and cruise speed.

Firepower is slightly greater than the largest destroyer, but seakeeping is much better.
These ships, tailing behind the carrier, will provide heavy AA screening power.

A long forecastle is cut down aft, and the lowered the Fantail will allow easier recovery of aircrew.

A single amidships aircraft is fitted, which can be launched to spot for downed aircraft.
The amphibian can also fly the recovered pilot back to the host ship.

Two rescue motor launches are added to the ships boats. These high speed launches have additional warming heaters, line launcher and even hoist nets to pluck aircrew from waters cold or hot.

Two long 'excavator' type arms are fitted with both hand & footholds and large seive type baskets, with the idea of being able to dip aircrew out of the water.

Resv :5

AD
20t FC
25t LR Radio
25t Air Search Rada
25t Fire Control Radar

OD
5t - Paravanes
25+5 - Scout amphibian + Gunpowder Cat
20t - 2 x 10t rescue motor launches (unarmed)
20t - Medical Wards
10t - Port & Starboard rescue cranes (excavator arms with attachments)
10t - Additional searchlights, floodlights, in Red/Blue/White to assist in searches.

HAW
3t - CO2 Compressor AC
20t - VIP quarters

HBW
3t - Improved Pumps

Jefgte · January 05, 2025, 01:37:48 AM

I have the same project for 3000t frigates with T2x133 => evolution of the 1932 Othu class.

A pocket Dido.

The Rock Doctor · January 05, 2025, 08:24:54 AM

I was playing with something very similar myself, last night. But I think I'm sticking with just having a destroyer do the plane guard function.