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 The old Simurgh class BBs are simply outdated and so will not be rebuilt again.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

[Kaiser Kirk]

This version has to make slight changes, but fits a 4th 2G 115mm in "X".
Otherwise it's a Sher that weighs more and has 33% more gun armanent.

Given the length compared to the I-class, I could fit a 3rd Torpedo mount in.
Further, I could go with quintiple mounts.
That would up torpedo weight from 32 to 60.

The only way to 'pay' for that is to drop the Hulesmeyer prox detector.
Thats really a place holder for either LR radio, Air Search Radar, Sea Search Radar or Fire Control Radar.

The Hulesmeyer gives a proximity warning and a bearing, and that's it, but when charging around at night, that could be very useful. One could also find out if on expected bearings there are ships following. Once Sea Search radar is mature enough, I will fit that. I need to do more research, but guessing that will be ~10 tons. In which case the 3 radars can be 'paid for' by removing the Hulesmeyer and using some reserve weight.

Anyhow, I guess I could remove that and add torpedoes, it's just shuffling misc weight.
That would give 8x 115DP and 15x 21" 4t Torpedoes as the armaments, which is substantial. 

'Kastar'  Destructive, Parthian Corvette laid down 1935

Displacement:
    2,500 t light; 2,671 t standard; 3,128 t normal; 3,493 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 / 15.96 ft)
    (119.77 m / 118.00 m) x 12.50 m  x (4.50 / 4.86 m)

Armament:
      8 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 320 per gun
      Dual purpose guns in deck mounts, 1932 Model
      4 x 2-gun mounts on centreline ends, evenly spread
        2 raised mounts - superfiring
      8 - 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
      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 463 lbs / 210 kg

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

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 2 shafts, 58,244 shp / 43,450 Kw = 34.68 kts
    Range 4,500nm at 18.00 kts
    Bunker at max displacement = 821 tons

Complement:
    208 - 271

Cost:
    £1.674 million / $6.695 million

Distribution of weights at normal displacement:
    Armament: 86 tons, 2.7 %
      - Guns: 86 tons, 2.7 %
    Armour: 1 tons, 0.0 %
      - Armament: 1 tons, 0.0 %
    Machinery: 1,562 tons, 50.0 %
    Hull, fittings & equipment: 730 tons, 23.3 %
    Fuel, ammunition & stores: 627 tons, 20.1 %
    Miscellaneous weights: 121 tons, 3.9 %
      - Hull below water: 25 tons
      - Hull void weights: 7 tons
      - Hull above water: 3 tons
      - On freeboard deck: 44 tons
      - Above deck: 42 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      934 lbs / 423 Kg = 20.1 x 4.5 " / 115 mm shells or 0.4 torpedoes
    Stability (Unstable if below 1.00): 1.29
    Metacentric height 2.1 ft / 0.6 m
    Roll period: 11.9 seconds
    Steadiness    - As gun platform (Average = 50 %): 70 %
            - Recoil effect (Restricted arc if above 1.00): 0.28
    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 / 0.482
    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:    35.00 %,  19.36 ft / 5.90 m,  17.06 ft / 5.20 m
      - Aft deck:    30.00 %,  17.06 ft / 5.20 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:        18.01 ft / 5.49 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 172.0 %
        - Above water (accommodation/working, high = better): 172.1 %
    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 187 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.50
        - Longitudinal: 2.10
        - 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
7t Reserve

AD
8.6t    FC
8.6tt  Night Vision
0t    SR Radio
25t  Hulesmeyer Station Keeping

OD
2t light Paravanes

32t  2T4 Torpedoes 21"  4t

2t K-Throwersx2
8t DC  : 24x 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

[Kaiser Kirk]

This version follows up on Jefgte's suggestion.

Dropping to 0.9 seakeeping frees up a great deal of weight.
Oddly I have to add a tiny bit of machinery, reaching 34.75knots. Which is fast.

The ship still can make 1.0 seakeeping at 33.16knots, which is good - and only 1.59kts slower,
so still slightly faster than the Sher at 1.0.

For fun, I allocated the extra misc weight in a 3rd Quintuple Torpedo mount,
mounting a total of 15 x 24" torpedoes and 8x 115mm DP.
That's pretty decent.

Overall, it may well be worth dropping to 0.9 seaboat.

'Kastar'  Destructive, Parthian Corvette laid down 1935

Displacement:
   2,500 t light; 2,671 t standard; 3,128 t normal; 3,493 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (392.77 ft / 387.14 ft) x 41.01 ft x (14.76 / 15.96 ft)
   (119.71 m / 118.00 m) x 12.50 m  x (4.50 / 4.86 m)

Armament:
      8 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 320 per gun
     Dual purpose guns in deck mounts, 1932 Model
     4 x 2-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      8 - 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
      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 463 lbs / 210 kg

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 58,741 shp / 43,821 Kw = 34.75 kts
   Range 4,500nm at 18.00 kts
   Bunker at max displacement = 821 tons

Complement:
   208 - 271

Cost:
   £1.676 million / $6.703 million

Distribution of weights at normal displacement:
   Armament: 86 tons, 2.7 %
      - Guns: 86 tons, 2.7 %
   Armour: 1 tons, 0.0 %
      - Armament: 1 tons, 0.0 %
   Machinery: 1,565 tons, 50.0 %
   Hull, fittings & equipment: 689 tons, 22.0 %
   Fuel, ammunition & stores: 627 tons, 20.1 %
   Miscellaneous weights: 159 tons, 5.1 %
      - Hull below water: 25 tons
      - Hull void weights: 2 tons
      - Hull above water: 3 tons
      - On freeboard deck: 87 tons
      - Above deck: 42 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     850 lbs / 385 Kg = 18.3 x 4.5 " / 115 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 1.8 ft / 0.6 m
   Roll period: 12.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0.29
   Seaboat quality  (Average = 1.00): 0.90

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and large transom stern
   Block coefficient (normal/deep): 0.467 / 0.482
   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): 80
   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 %,  21.00 ft / 6.40 m,  18.37 ft / 5.60 m
      - Forward deck:   30.00 %,  18.37 ft / 5.60 m,  16.08 ft / 4.90 m
      - Aft deck:   35.00 %,  16.08 ft / 4.90 m,  16.08 ft / 4.90 m
      - Quarter deck:   15.00 %,  16.08 ft / 4.90 m,  16.08 ft / 4.90 m
      - Average freeboard:      17.09 ft / 5.21 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 172.3 %
      - Above water (accommodation/working, high = better): 162.3 %
   Waterplane Area: 10,675 Square feet or 992 Square metres
   Displacement factor (Displacement / loading): 84 %
   Structure weight / hull surface area: 38 lbs/sq ft or 185 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.76
      - Overall: 0.56
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Kastar means Destructive or Destroyer.

Seakeeping is 1.0 at 33.16knots.


Miscellaneous Weight
2t Reserve

AD
8.6t    FC
8.6tt   Night Vision
0t     SR Radio
25t   Hulesmeyer Station Keeping

OD
2t light Paravanes

75t   3T5 Torpedoes 24"  5t

2t K-Throwersx2
8t DC  : 24x 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

[TacCovert4]

Transom DDs are also the bane of my existence. 

I too have the need to do Pacific storms, as well as those pesky hurricanes that wrecked so many Roman DDs with .75 seakeeping.  My minimum seakeeping is therefore a .8, which is going to make it difficult to set up a balanced ship.

[Kaiser Kirk]

Transom DDs are also the bane of my existence. 

I too have the need to do Pacific storms, as well as those pesky hurricanes that wrecked so many Roman DDs with .75 seakeeping.  My minimum seakeeping is therefore a .8, which is going to make it difficult to set up a balanced ship.

I may work the Kastar in as a destroyer leader. That last posted version has 1.0 seaboat at the same speed as my Sher class, but 159tons in misc weight, so room for LR radio and a squadron coordination room. Overall, I need to play with different misc wt configurations.

1...no one HAS to use transoms...
2...I am very likely to continue building my 2 pre-transom destroyer classes
3...that pesky 50% rule is the real issue, as engines get lighter, it mandates higher and higher speeds.
4... As I recall some of the Romans were under 0.75. Should not have left the Adriatic.
But the USN lost destroyers in storms as well. So even 0.75 and slowing down is not always enough.

[Kaiser Kirk]

As replacements for the 3000 ton Artesmia and Sayyida Classes, I posted the 4500 ton Atossa earlier.
It does not look like 1935.0 will be a good time for that ship, but perhaps 1935.5....
or maybe I do want to upgun. For the low, low cost of 800 tons I can field a 5300 ton
ship called Boran. The 6000 ton Tomyris is only 700 tons more and so tempting....but is also 2x the size of the ships it's trying to replace. 50% is a lot of hull growth in the first place.

Anyhow, the Boran for 800 tons has 50% more main guns.

Boran, Parthian Maritime Patrol Frigate laid down 1935

Displacement:
   5,300 t light; 5,680 t standard; 6,555 t normal; 7,256 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (520.92 ft / 515.09 ft) x 52.49 ft x (15.29 / 16.55 ft)
   (158.78 m / 157.00 m) x 16.00 m  x (4.66 / 5.04 m)

Armament:
      6 - 6.50" / 165 mm 47.0 cal guns - 176.37lbs / 80.00kg shells, 200 per gun
     Quick firing guns in deck and hoist mounts, 1935 Model
     3 x 2-gun mounts on centreline ends, majority forward
      1 raised mount - superfiring
      8 - 3.54" / 90.0 mm 54.0 cal guns - 24.25lbs / 11.00kg shells, 400 per gun
     Dual purpose guns in deck and hoist mounts, 1935 Model
     4 x 2-gun mounts on sides, evenly spread
      16 - 1.46" / 37.0 mm 70.0 cal guns - 1.72lbs / 0.78kg shells, 3,200 per gun
     Anti-air guns in deck mounts, 1935 Model
     4 x 4 row quad mounts on sides, evenly spread
      4 raised mounts
      32 - 0.91" / 23.0 mm 90.0 cal guns - 0.44lbs / 0.20kg shells, 5,000 per gun
     Anti-air guns in deck mounts, 1935 Model
     4 x 2 row quad mounts on side ends, evenly spread
     8 x Twin mounts on sides, evenly spread
      8 double raised mounts
      Weight of broadside 1,294 lbs / 587 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.94" / 100 mm   321.39 ft / 97.96 m   14.27 ft / 4.35 m
   Ends:   Unarmoured
     Main Belt covers 96 % 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:   0.98" / 25 mm   0.98" / 25 mm      0.98" / 25 mm
   2nd:   0.79" / 20 mm         -         0.79" / 20 mm
   3rd:   0.79" / 20 mm         -               -
   4th:   0.79" / 20 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 1.53" / 39 mm
   Forecastle: 0.98" / 25 mm  Quarter deck: 1.38" / 35 mm

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

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 50,827 shp / 37,917 Kw = 30.00 kts
   Range 10,360nm at 14.00 kts
   Bunker at max displacement = 1,576 tons

Complement:
   363 - 473

Cost:
   £2.546 million / $10.184 million

Distribution of weights at normal displacement:
   Armament: 323 tons, 4.9 %
      - Guns: 323 tons, 4.9 %
   Armour: 1,345 tons, 20.5 %
      - Belts: 751 tons, 11.5 %
      - Armament: 52 tons, 0.8 %
      - Armour Deck: 532 tons, 8.1 %
      - Conning Tower: 10 tons, 0.2 %
   Machinery: 1,444 tons, 22.0 %
   Hull, fittings & equipment: 1,970 tons, 30.1 %
   Fuel, ammunition & stores: 1,256 tons, 19.2 %
   Miscellaneous weights: 218 tons, 3.3 %
      - Hull below water: 23 tons
      - Hull void weights: 55 tons
      - Hull above water: 20 tons
      - On freeboard deck: 61 tons
      - Above deck: 59 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     8,025 lbs / 3,640 Kg = 58.6 x 6.5 " / 165 mm shells or 1.4 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 2.6 ft / 0.8 m
   Roll period: 13.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 75 %
         - Recoil effect (Restricted arc if above 1.00): 0.65
   Seaboat quality  (Average = 1.00): 1.50

Hull form characteristics:
   Hull has a flush deck,
     a ram bow and small transom stern
   Block coefficient (normal/deep): 0.555 / 0.567
   Length to Beam Ratio: 9.81 : 1
   'Natural speed' for length: 24.29 kts
   Power going to wave formation at top speed: 57 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 13.00 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 %,  25.26 ft / 7.70 m,  22.80 ft / 6.95 m
      - Forward deck:   31.00 %,  22.80 ft / 6.95 m,  20.34 ft / 6.20 m
      - Aft deck:   34.00 %,  20.34 ft / 6.20 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:      20.89 ft / 6.37 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 91.1 %
      - Above water (accommodation/working, high = better): 209.0 %
   Waterplane Area: 19,428 Square feet or 1,805 Square metres
   Displacement factor (Displacement / loading): 119 %
   Structure weight / hull surface area: 66 lbs/sq ft or 321 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.68
      - Longitudinal: 1.61
      - 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

Designed as a new class of Maritime Patrol Frigate
for solo deep ocean patrols and showing the flag worldwide.

Protection

Armored Belt, armored Deck, and magazine box.
Magazine Box is abuts belt and deck, where plates are
thickened to 135mm and 70mm.

Horizontal Protection @ Waterline
Magazines : 135mm + slope
Machinery : 100mm + slope

Vertical Protection
Magazines : 70mm
Machinery : 35mm

Belt : 2.7 to -1.5m
Outsloped 15 degrees
4.2/cos(15) = 4.3481599 = 4.35


487t  Deck 25/35/35
45t  Magazine Box : 35mm
----
532 needed
532 modeled

Miscellaneous Weight
Reserve
55t

AD
33t - FC 1930
25t - LR Radio
0t - SR Radio
25t - Hulesmeyer
6t - Night Fighting Gear

OD
5t - Paravanes
26t - Power assist main battery
25t - (Ftr) Scout Floatplane on stern
5t -  Catapult


HAW
5t - CO2 compressor AC
5t - Hanger
10t - Brig

HBW
5t - Extra pumps
15t - Ench Hydrophones
3t - DC for Floatplanes to drop

6.20 to 5.20  Weather Deck
    2.7   Battery Deck - Top Main Belt, Armored Deck.
    0.2   Main Deck
    -1.5   Bottom Main Belt
-  2.3m  1st Platform deck 
-  4.15  Engineering
-  4.66  Keel

[Kaiser Kirk]

Just for fun, this is a not-built showing I really really did consider a Parthian battlewagon of 30 knots, but built to stay at range due to weak belt armor.

Hmm, this wasn't the file I thought it was. Misnamed.
And it got the main turret type wrong.
Looks like a tinkering design.
I'll have to look around again. 

[Kaiser Kirk]

Ahh here we go.

The "Mastadon" class was a sort of 'Tillman' battleship exercise.

Very big. Very fast. Very heavily Armed and Armored.

Granted, had I taken 6 years to build it, ~4800/hy, it would have completed in 1932
and would be ....competitive... with the ships afloat.

Would have been interesting to fielded 4 of these.

Mastadon, Parthian Battleship laid down 1926

Displacement:
   57,600 t light; 61,057 t standard; 64,576 t normal; 67,391 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (853.02 ft / 846.46 ft) x 114.83 ft (Bulges 124.67 ft) x (31.50 / 32.78 ft)
   (260.00 m / 258.00 m) x 35.00 m (Bulges 38.00 m)  x (9.60 / 9.99 m)

Armament:
      9 - 17.13" / 435 mm 47.0 cal guns - 3,185.68lbs / 1,445.00kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1926 Model
     3 x 3-gun mounts on centreline ends, majority forward
      1 raised mount - superfiring
      20 - 4.72" / 120 mm 44.0 cal guns - 55.12lbs / 25.00kg shells, 300 per gun
     Dual purpose guns in deck and hoist mounts, 1926 Model
     8 x 2-gun mounts on side ends, evenly spread
      4 raised mounts - superfiring
     2 x 2-gun mounts on centreline ends, evenly spread
      2 double raised mounts
      20 - 2.24" / 57.0 mm 60.0 cal guns - 6.61lbs / 3.00kg shells, 900 per gun
     Breech loading guns in deck and hoist mounts, 1926 Model
     10 x 2-gun mounts on sides, evenly spread
      8 raised mounts
      24 - 0.59" / 15.0 mm 70.0 cal guns - 0.11lbs / 0.05kg shells, 3,000 per gun
     Machine guns in deck mounts, 1926 Model
     12 x Twin mounts on sides, evenly spread
      12 double raised mounts
      Weight of broadside 29,908 lbs / 13,566 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   15.3" / 389 mm   550.20 ft / 167.70 m   17.06 ft / 5.20 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length
     Main Belt inclined -20.00 degrees (positive = in)

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      2.24" / 57 mm   550.20 ft / 167.70 m   30.64 ft / 9.34 m
   Beam between torpedo bulkheads 85.30 ft / 26.00 m

   - Hull Bulges:
      0.35" / 9 mm   564.30 ft / 172.00 m   22.64 ft / 6.90 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   19.7" / 500 mm   7.87" / 200 mm      16.1" / 410 mm
   2nd:   2.17" / 55 mm   1.38" / 35 mm      1.38" / 35 mm
   3rd:   0.51" / 13 mm         -               -
   4th:   0.24" / 6 mm         -               -

   - Armoured deck - multiple decks:
   For and Aft decks: 6.50" / 165 mm
   Forecastle: 0.00" / 0 mm  Quarter deck: 5.31" / 135 mm

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

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 206,413 shp / 153,984 Kw = 30.00 kts
   Range 9,303nm at 14.00 kts
   Bunker at max displacement = 6,335 tons

Complement:
   2,025 - 2,633

Cost:
   £18.465 million / $73.860 million

Distribution of weights at normal displacement:
   Armament: 5,064 tons, 7.8 %
      - Guns: 5,064 tons, 7.8 %
   Armour: 20,826 tons, 32.3 %
      - Belts: 6,200 tons, 9.6 %
      - Torpedo bulkhead: 1,400 tons, 2.2 %
      - Bulges: 167 tons, 0.3 %
      - Armament: 4,645 tons, 7.2 %
      - Armour Deck: 8,278 tons, 12.8 %
      - Conning Tower: 137 tons, 0.2 %
   Machinery: 6,607 tons, 10.2 %
   Hull, fittings & equipment: 23,027 tons, 35.7 %
   Fuel, ammunition & stores: 6,976 tons, 10.8 %
   Miscellaneous weights: 2,075 tons, 3.2 %
      - Hull below water: 1,153 tons
      - Bulge void weights: 150 tons
      - Hull above water: 71 tons
      - On freeboard deck: 70 tons
      - Above deck: 631 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     88,470 lbs / 40,129 Kg = 35.2 x 17.1 " / 435 mm shells or 14.0 torpedoes
   Stability (Unstable if below 1.00): 1.12
   Metacentric height 7.6 ft / 2.3 m
   Roll period: 19.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.69
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has rise forward of midbreak,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.680 / 0.682
   Length to Beam Ratio: 6.79 : 1
   'Natural speed' for length: 29.09 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 69
   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 %,  28.87 ft / 8.80 m,  28.87 ft / 8.80 m
      - Forward deck:   30.00 %,  28.87 ft / 8.80 m,  28.87 ft / 8.80 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:      24.77 ft / 7.55 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 95.0 %
      - Above water (accommodation/working, high = better): 176.0 %
   Waterplane Area: 76,520 Square feet or 7,109 Square metres
   Displacement factor (Displacement / loading): 109 %
   Structure weight / hull surface area: 240 lbs/sq ft or 1,171 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.15
      - Overall: 1.01
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform


Armor Scheme:
Only 1 deck level aft and 2 deck levels forward are unprotected, giving a great reserve of bouyancy.

The 130mm main deck caps the belt armor system and is meant to stop shells at all reasonable ranges. This is backed by a substantial splinter deck.

An exterior 75mm decapping plate also serves to defeat HE shells and bombs.

Underwater, below the exterior belt, is the exterior bulge.

The interior belt is sloped at 20 degrees and is 330mm above the waterline, tapering once 1m below the waterline down to 230mmm.

The TDS rises behind the main belt, sealing to the bottom of the splinter deck. The TDS, with it's 3x 19mm bulkheads is expected to be splinter proof on it's own. The TDS also provides a firm base of structural support for the main belt. The Fact the innermost bulkhealds rises behind the belt gives a flooding limit even if the belt is pushed in.

The splinter deck is a 35mm protective deck meant to stop high order splinters from either the belt or deck from penetrating to the vitals.

Belt Armor Math:

The exterior shell is a 75mm homogeneous decapping plate from -2.6 to +2.6m high.
That is 5.2 x 75 = 390


The interior belt is inclined outwards at 20degrees and tapers
Starting at 330mm above water from +2.6m to -1m below waterline, then
From 1m to -3m it tapers to 230mm.

The Main Belt Math :
1188  =  (2.6 - -1) x 330mm
460 = (-1 to -3) x 230mm
100 = (-1 to -3) x 1/2  x (330-230)
= 1738
cos 20
= 1633.1857
= 1633.19
+390 for the Decapping plate
=2023.2
divided over 5.2m = 389 average thickness





The entire inner belt is outsloped

The Bulge goes to the bottom of the exterior plate.

The TDS rises to 0.2m above WL, sealing to the bottom of the splinter deck.

Decks
5.0  Weather Deck - unarmored
2.6  Battery Deck, 130mm Armor
0.2  Top Protective Splinter Deck, 35mm Armor, Top TDS.
-2.3 Bottom edge Splinter Deck
-2.6  Bottom Main Belt.

-5.8 
-8.8 Engineering
-9.5 Keel, Double Bottom


Misc Wt
150t Resv

546t  FC
25   LR Radio
0     SR Radio
10   Air SR Radio
25   Hulesmeyer
25   Night Fight tower


5t  Paravanes
40t 2x Scout
10t 2x CAT
25t Ext Fire Suppression

25t Ext Fire Suppression
46t Climate Control

218 Torpedo Nets
885 tons Turbo-Electric
50t Enhanced Pumps
 

[Kaiser Kirk]

I think I will lay down at least a lead ship in this class.
Then 'Evaluate' it during trials.

I've long wanted to field 'Coastal Destroyers'.
This is the cheapest I could make it. I can pay for this at 4:1 vs. my Sher class, and 2:1 compared to the Robah class.

The ships are built around the idea of dashing out at 22knots for up to 24 hours, traveling 528nm,
giving a 264nm range, with provision for an hour at top speed. The 1934 barge light tenders would be great for supporting these.

In many ways it is like some of the Italian torpedo boats - the Spica class was about the same length with a trio of 100mm guns and a variety of torpedo mountings - including 2 on centerline. I go with a single quintuple amount.

Squadrons of relatively cheap and fast vessels that could dash out and interdict merchant traffic, or swarm and destroy isolated vessels. Should there be an amphibious invasion nearby, they would join in a fleet attack, thickening the torpedo attack vessels. Alternately, they can serve as coastal patrol or maritime escorts for their areas.

For that, numbers of torpedoes is more important for 'wounding' than killing. The damaged vessels can always be hunted down by fleet units later.


I am not sure if I should be devoting 23tons to ASW ability, and just 15 to Torpedoes,
as there is the thought that if I added a second centerline mount, I could have 10 x 21". Only 3t, so shorter range, but given the desired attack parameters, that is ok.
It may be that after the lead vessel does trials, I will reconstruct it and the class will be torpedo heavy.

Conceptually places like Khasab, Tricomalee, Palembang, Brunei, Stonestown, Sofala and Trinadad would be bases for these squadrons.

Sea Hornet VII, Parthian Coastal Destroyer laid down 1935

Displacement:
    655 t light; 684 t standard; 730 t normal; 767 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
    (245.64 ft / 241.67 ft) x 25.43 ft x (9.02 / 9.34 ft)
    (74.87 m / 73.66 m) x 7.75 m  x (2.75 / 2.85 m)

Armament:
      2 - 4.53" / 115 mm 47.0 cal guns - 55.12lbs / 25.00kg shells, 160 per gun
      Quick firing guns in deck mounts, 1932 Model
      2 x 2-gun mounts on centreline ends, evenly spread
      2 - 1.18" / 30.0 mm 80.0 cal guns - 0.95lbs / 0.43kg shells, 1,600 per gun
      Anti-air guns in deck mount, 1931 Model
      1 x 2-gun mount on sides, aft deck forward
        1 raised mount
      8 - 0.91" / 23.0 mm 90.0 cal guns - 0.43lbs / 0.20kg shells, 1,200 per gun
      Anti-air guns in deck mounts, 1929 Model
      4 x Twin mounts on side ends, evenly spread
        4 raised mounts
      Weight of broadside 116 lbs / 52 kg

Machinery:
    Oil fired boilers, steam turbines,
    Geared drive, 1 shaft, 20,781 shp / 15,503 Kw = 31.80 kts
    Range 590nm at 22.00 kts
    Bunker at max displacement = 84 tons

Complement:
    69 - 91

Cost:
    £0.407 million / $1.627 million

Distribution of weights at normal displacement:
    Armament: 20 tons, 2.8 %
      - Guns: 20 tons, 2.8 %
    Machinery: 365 tons, 50.0 %
    Hull, fittings & equipment: 225 tons, 30.8 %
    Fuel, ammunition & stores: 75 tons, 10.2 %
    Miscellaneous weights: 45 tons, 6.1 %
      - Hull below water: 15 tons
      - Hull above water: 1 tons
      - On freeboard deck: 25 tons
      - Above deck: 4 tons

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      233 lbs / 106 Kg = 5.0 x 4.5 " / 115 mm shells or 0.2 torpedoes
    Stability (Unstable if below 1.00): 1.08
    Metacentric height 0.7 ft / 0.2 m
    Roll period: 12.4 seconds
    Steadiness    - As gun platform (Average = 50 %): 55 %
            - Recoil effect (Restricted arc if above 1.00): 0.32
    Seaboat quality  (Average = 1.00): 0.78

Hull form characteristics:
    Hull has a flush deck,
      a normal bow and large transom stern
    Block coefficient (normal/deep): 0.461 / 0.468
    Length to Beam Ratio: 9.50 : 1
    'Natural speed' for length: 17.90 kts
    Power going to wave formation at top speed: 75 %
    Trim (Max stability = 0, Max steadiness = 100): 70
    Bow angle (Positive = bow angles forward): 13.00 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 %,  17.22 ft / 5.25 m,  14.11 ft / 4.30 m
      - Forward deck:    20.00 %,  14.11 ft / 4.30 m,  12.30 ft / 3.75 m
      - Aft deck:    45.00 %,  12.30 ft / 3.75 m,  12.01 ft / 3.66 m
      - Quarter deck:    15.00 %,  12.01 ft / 3.66 m,  12.01 ft / 3.66 m
      - Average freeboard:        12.98 ft / 3.96 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 172.6 %
        - Above water (accommodation/working, high = better): 141.6 %
    Waterplane Area: 4,110 Square feet or 382 Square metres
    Displacement factor (Displacement / loading): 57 %
    Structure weight / hull surface area: 26 lbs/sq ft or 129 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.50
        - Longitudinal: 3.96
        - Overall: 0.61
    Cramped machinery, storage, compartmentation space
    Excellent accommodation and workspace room
    Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Designed as a Coastal Torpedo Boat.

Vessels of this sort are expected to be easy to sustain in small harbors, river mouths, and among islands.

They will be able to dash out at high speed and return within 24hours.
The vessel can make 22knots for 16 hours, allowing a raid to start predawn and end just after dark, while leaving an hours reserve for combat.

The object is to interdict enemy rear area ships, or - en masse- launch a night time torpedo raid on the enemy fleet.

A pair of the new 115L47s provide 'punch',
augmented by a set of Quad 21" TT

For ASW work, an enhanced hydrophone package is paired with depth charges off the stern

Fuel Management
84 tons * 1.15 = 96.6tons efffective

19tons = 1 hour @ 31.66knots
76tons = 24hours @ 22 knots
1.6ton reserve

Reserve
3 tons

AD :
2t  Fire Control
2t  Night fighting provisions (Binoculars, sm. search lights, running lights, red ready rooms etc)
0t    SR Radio

OD
15t    1 TT5  21" Torps 3t
2t      Paravanes
2t      2x Y DC throwers
6t      18x 280kg  Depth Charges, 2 rails

HAW
0.7t    CO2 Compressor AC

HBW
15t    Enhanced Hydrophone package

Decks : 2.45m
5.40    Forecastle Deck
2.95    Weather Deck
0.50    Strength deck
-1.95  1st Deck, pierced by engines
-2.30  Engineering / fuel in double bottom fore.

[Jefgte]

Old destroyers classes under 750t can be converted for this coastal work because they are too small to work with the fleet on the high seas.
Byzantium does not consider DDs under 1000t as being able to work with the Fleet. They are assigned to coastal work and patrols.
Byzantium has more than 200 of these ships: Torpedo Boats and TGB.