Parthian Ships 1928 +

[Jefgte]

Huls over 30 years old should be scrapped.

[Kaiser Kirk]

We really do not have any rules on ship lifetimes or what is added/can be added
via refurbishment.

As we've discussed before there are many historical examples of ships remaining in service even longer than 30 years.

As for myself, I consider ships to need refurbishment at 20 years,
and that extends their functional life for a further 15 years (which I think I adopted from expectations about the Queen Elizabeth Class rebuilds).

However, I have noticed that very old vessels simply lack the guns/armor/hull form/displacement to be as effective as a new build. The old Simurgh class BBs are simply outdated and so will not be rebuilt again. The ancient Sparabara ACs will be replaced by the new Manzikert Cruisers who will be larger, faster, and able to penetrate more armor at range. ETC.


This topic falls into where I would have preferred if we had built in different Archtype costs and lifespans to make a more realistic Sim, but I do acknowledge that I don't mind complexity.

The Royal Navy information I've discussed before had different classes with different
life spans and annual costs.

A Nelson Class DN had an expected life expectancy of 26 years .
A 1000 ton submarine a life expectancy of 14 years. I've read 12 in the USN.
Basically an aging gasket breaking is inconvenient in a dreadnaught, and potentially fatal in a sub.
The sub cost 167% per ton of the DN to build and 445% to maintain per ton.
Carriers ran about 300% more cost/ton for maintenance - mainly for the airgroup.

This additional maintenance cost is more significant than N7 as maintenance was more around 4.1% of build cost for Nelson, not 2.5%, so 166% of N7 costs.

The numbers I arrived at were 27 aircraft had the same relative maintenance cost as a battleship.
Which seems reasonable considering the interwar RAF estimated that a single squadron of bombers could be built/maintained instead of a battleship, that seems about the correct pricepoint - presuming carrier op tempo, landings and salt would take an additional toll.

But I'm off topic. :)

[Kaiser Kirk]

Attempting a transom sterned super destroyer or 'Corvette'.

For Parthia, transiting the Monsoons of the Indian Ocean, the Typhoons of the South Pacific, the long storm battered reaches of the Pacific, the blustery weather of the Cape of Good Hope, crossing the Atlantic....I want my "Corvettes' to have at least 1.0 seakeeping.

It winds up faster than my Sher class destroyer, as the transom gives better SHP:Knot
but because of the 50% machinery requirement, I have to put that savings into ..more machinery.
Which hurts seakeeping, so I need more freeboard, or more length.

Length runs into dock sizing, and makes the SHP:Knot even better, which would mean I'd need to put more in machinery, causing seakeeping issues agian. So I went with freeboard.

The ship winds up with roughly the same armament as the Sher, the biggest difference being the Kastar has the tonnage to mount a Hulesmeyer.

but 500 tons more to gain 1.5 knots does not seem a good trade off.
I see it actually has less range as it's geared for 15knots while the Sher has the same range at 18kts.

Floatation rises from 740 to 1100, which is quite an improvement for a destroyer.

'Kastar'  Destructive, Parthian Destroyer Leader laid down 1935

Displacement:
   2,499 t light; 2,654 t standard; 2,969 t normal; 3,221 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (393.47 ft / 387.14 ft) x 45.93 ft x (12.30 / 13.03 ft)
   (119.93 m / 118.00 m) x 14.00 m  x (3.75 / 3.97 m)

Armament:
      6 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 320 per gun
     Dual purpose guns in deck mounts, 1932 Model
     3 x 2-gun mounts on centreline ends, majority forward
      1 raised mount - superfiring
      12 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 2,000 per gun
     Anti-air guns in deck mounts, 1931 Model
     2 x 2 row quad mounts on sides amidships
      2 raised mounts
     1 x 2 row quad mount on sides, aft deck forward
      1 raised mount
      20 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 3,000 per gun
     Anti-air guns in deck mounts, 1931 Model
     8 x Twin mounts on sides, evenly spread
      8 raised mounts
     2 x Twin mounts on centreline ends, evenly spread
      2 double raised mounts
      Weight of broadside 360 lbs / 163 kg

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 55,530 shp / 41,425 Kw = 34.42 kts
   Range 4,530nm at 15.00 kts
   Bunker at max displacement = 566 tons

Complement:
   200 - 261

Cost:
   £1.596 million / $6.384 million

Distribution of weights at normal displacement:
   Armament: 70 tons, 2.3 %
      - Guns: 70 tons, 2.3 %
   Armour: 5 tons, 0.2 %
      - Armament: 5 tons, 0.2 %
   Machinery: 1,483 tons, 50.0 %
   Hull, fittings & equipment: 820 tons, 27.6 %
   Fuel, ammunition & stores: 470 tons, 15.8 %
   Miscellaneous weights: 121 tons, 4.1 %
      - Hull below water: 25 tons
      - Hull void weights: 9 tons
      - Hull above water: 3 tons
      - On freeboard deck: 45 tons
      - Above deck: 39 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,100 lbs / 499 Kg = 23.7 x 4.5 " / 115 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.29
   Metacentric height 2.5 ft / 0.8 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.16
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and large transom stern
   Block coefficient (normal/deep): 0.475 / 0.486
   Length to Beam Ratio: 8.43 : 1
   'Natural speed' for length: 22.84 kts
   Power going to wave formation at top speed: 70 %
   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 %,  23.62 ft / 7.20 m,  21.33 ft / 6.50 m
      - Forward deck:   35.00 %,  21.33 ft / 6.50 m,  18.70 ft / 5.70 m
      - Aft deck:   30.00 %,  18.70 ft / 5.70 m,  18.70 ft / 5.70 m
      - Quarter deck:   15.00 %,  18.70 ft / 5.70 m,  18.70 ft / 5.70 m
      - Average freeboard:      19.87 ft / 6.06 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 171.0 %
      - Above water (accommodation/working, high = better): 222.6 %
   Waterplane Area: 12,041 Square feet or 1,119 Square metres
   Displacement factor (Displacement / loading): 86 %
   Structure weight / hull surface area: 40 lbs/sq ft or 196 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 2.39
      - Overall: 0.59
   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

Kastar means Destructive or Destroyer.

Miscellaneous Weight

AD
7t    FC
7tt   Night Vision
0t     SR Radio
25t   Hulesmeyer Station Keeping

OD
5t Paravanes

24t   2T4 Torpedoes 21" 3t

4t K-Throwers
12t DC  : 36x 280kg
   

HAW
2.5  CO2 Compressor AC

HBW
15t  Enhanced Hydrophones
10t  Sonar

Decks
5.8    Weather deck
3.3     deck
0.8     main deck
-1.7   1st Platform deck
-3.2    Engineering
-3.75  Keel

[Jefgte]

It winds up faster than my Sher class destroyer, as the transom gives better SHP:Knot
but because of the 50% machinery requirement, I have to put that savings into ..more machinery.
Which hurts seakeeping, so I need more freeboard, or more length.

Length runs into dock sizing, and makes the SHP:Knot even better, which would mean I'd need to put more in machinery, causing seakeeping issues agian. So I went with freeboard.

The ship winds up with roughly the same armament as the Sher, the biggest difference being the Kastar has the tonnage to mount a Hulesmeyer.

but 500 tons more to gain 1.5 knots does not seem a good trade off.

500t for + 1.5kts is expensive.

You can indicate the speed for:
"Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily"

[Kaiser Kirk]

500t for + 1.5kts is expensive.

You can indicate the speed for:
"Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily"

Yes, reducing the freeboard and seakeeping and just making a note is an option.

Since the Sher is 1.0 seaboat rating at 32.85knots (1.57 diff)
I supposed I could match that and see what savings there is, but I doubt I am saving much weight.

I think I'll be better off continuing the Sher design.
 

[Kaiser Kirk]

So this is an improved version of the ship.
I looked at LeFantasque, which had a 12m beam and 4.5m draft,
and while I kept my dock-limited length, I lowered beam to 12.5 and deepened the draft to 4.5m.

Speed crept up to 34.66, and I aggressively trimmed seaboat rating to just 1.0.

Miscellaneous weight grew to 16tons,
I also upped the range from 4500@15 to 4600@18knots.
The torpedoes went from 3t 21" to 4t 21", giving better range/speed.
I kept the full 5t paravane and 4 K-guns & large 12t DC loadout.

Between Guns/Ammo/Armor, that is 171 tons.
There is 136 tons Misc weight.
for 307 tons weight allocated or 12.28%

vs. the Sher with 254t and 12.7%


So overall for +500 tons,
I get +1.81 knots
+53 tons of allocated weight.
If I could match the Sherefficiency, I might squeeze another +10 tons.

But it seems unlikely I will manage that without more length.

So I should probably 'play' with that 307 tons to try different gun arrangements.
An 4th 2-G 115mm is possible, or perhaps 130mm.
Alternately I could explore alternate torpedo layouts.

At 120m, they are 20m longer and 2m wider than the RN "H" Destroyer Leaders,
The basic arrangement is the same as usual A/B TT|TT  X/Y DCs with the amid ship quad 37s being en echelon on a raised platform over the 2 sets of centerline tubes, with the TCD supporting the platform.  Right now "x" is the 3rd Quad 37, but could easily be a gun mount.

I tend to view twin 23mm as not space-intensive, the USN at least seem to have stuck Oerlikons everywhere. I worry more about arcs and space for the bigger 30/37mm .

'Kastar'  Destructive, Parthian Destroyer Leader laid down 1935

Displacement:
    2,500 t light; 2,658 t standard; 3,128 t normal; 3,503 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (392.94 ft / 387.14 ft) x 41.01 ft x (14.76 / 15.99 ft)
    (119.77 m / 118.00 m) x 12.50 m  x (4.50 / 4.88 m)

Armament:
      6 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 320 per gun
      Dual purpose guns in deck mounts, 1932 Model
      3 x 2-gun mounts on centreline ends, majority forward
        1 raised mount - superfiring
      12 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 2,000 per gun
      Anti-air guns in deck mounts, 1931 Model
      2 x 2 row quad mounts on sides amidships
        2 raised mounts
      1 x 2 row quad mount on sides, aft deck forward
        1 raised mount
      20 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 3,000 per gun
      Anti-air guns in deck mounts, 1931 Model
      8 x Twin mounts on sides, evenly spread
        8 raised mounts
      2 x Twin mounts on centreline ends, evenly spread
        2 double raised mounts
      Weight of broadside 360 lbs / 163 kg

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

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 2 shafts, 58,103 shp / 43,345 Kw = 34.66 kts
    Range 4,630nm at 18.00 kts
    Bunker at max displacement = 844 tons

Complement:
    208 - 271

Cost:
    £1.653 million / $6.613 million

Distribution of weights at normal displacement:
    Armament: 70 tons, 2.2 %
      - Guns: 70 tons, 2.2 %
    Armour: 5 tons, 0.2 %
      - Armament: 5 tons, 0.2 %
    Machinery: 1,563 tons, 50.0 %
    Hull, fittings & equipment: 726 tons, 23.2 %
    Fuel, ammunition & stores: 628 tons, 20.1 %
    Miscellaneous weights: 136 tons, 4.3 %
      - Hull below water: 25 tons
      - Hull void weights: 16 tons
      - Hull above water: 3 tons
      - On freeboard deck: 53 tons
      - Above deck: 39 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      950 lbs / 431 Kg = 20.5 x 4.5 " / 115 mm shells or 0.4 torpedoes
    Stability (Unstable if below 1.00): 1.31
    Metacentric height 2.1 ft / 0.6 m
    Roll period: 11.8 seconds
    Steadiness    - As gun platform (Average = 50 %): 70 %
            - Recoil effect (Restricted arc if above 1.00): 0.21
    Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
    Hull has a flush deck,
      a normal bow and large transom stern
    Block coefficient (normal/deep): 0.467 / 0.483
    Length to Beam Ratio: 9.44 : 1
    'Natural speed' for length: 22.65 kts
    Power going to wave formation at top speed: 70 %
    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 %,  21.65 ft / 6.60 m,  19.36 ft / 5.90 m
      - Forward deck:    40.00 %,  19.36 ft / 5.90 m,  16.73 ft / 5.10 m
      - Aft deck:    25.00 %,  16.73 ft / 5.10 m,  16.73 ft / 5.10 m
      - Quarter deck:    15.00 %,  16.73 ft / 5.10 m,  16.73 ft / 5.10 m
      - Average freeboard:        17.97 ft / 5.48 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 170.6 %
        - Above water (accommodation/working, high = better): 171.5 %
    Waterplane Area: 10,675 Square feet or 992 Square metres
    Displacement factor (Displacement / loading): 86 %
    Structure weight / hull surface area: 38 lbs/sq ft or 184 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.50
        - Longitudinal: 2.05
        - Overall: 0.57
    Cramped machinery, storage, compartmentation space
    Excellent accommodation and workspace room
    Ship has slow, easy roll, a good, steady gun platform

Kastar means Destructive or Destroyer.

Miscellaneous Weight

AD
7t    FC
7tt  Night Vision
0t    SR Radio
25t  Hulesmeyer Station Keeping

OD
5t Paravanes

32t  2T4 Torpedoes 21" 4t

4t K-Throwers
12t DC  : 36x 280kg
 

HAW
2.5  CO2 Compressor AC

HBW
15t  Enhanced Hydrophones
10t  Sonar

Decks
5.1    Weather deck
2.7    Battery deck
0.4    main deck
-2.1  1st Platform deck
-3.8    Engineering
-4.5  Keel