IJN, Post-1900

[Logi]

Right now it's at the SHP limit for turbine engines, I could get to 24 kn by using mixed propulsion but that would require roughly an increase in displacement of 1,400t (7,400t total).

Even with the tonnage increase something has to give - seakeeping and/or armor has to be reduced to maintain 1.09 stability and recoil.

[Tanthalas]

6 - 5.98" / 152 mm 45.0 cal guns - 108.07lbs / 49.02kg shells, 200 per gun
     Breech loading guns in deck and hoist mounts, 1904 Model
     6 x Twin mounts on sides, evenly spread

Fairly sure that was supposed to be single mounts(since there are only 6 guns), switching to single mounts might save you a bit of BC for something else.

[Logi]

Good catch, I've thickened the faces of the 20cm turrets by 25mm (155mm -> 180mm) and the forecastle/quarterdeck decks by 5mm (25mm->30mm). I thickened the deck because I'm still not fully sold on the idea that 25mm is enough deck ends protection despite historical designs with such features. I had to give up 5t of above-deck reserve weight in exchange.

Tenryuu, Japanese Light Cruiser laid down 1904 (Engine 1905)

Displacement:
   6,000 t light; 6,305 t standard; 7,077 t normal; 7,695 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (501.97 ft / 501.97 ft) x 51.21 ft x (18.04 / 19.27 ft)
   (153.00 m / 153.00 m) x 15.61 m  x (5.50 / 5.87 m)

Armament:
      6 - 7.99" / 203 mm 50.0 cal guns - 275.58lbs / 125.00kg shells, 100 per gun
     Breech loading guns in turret on barbette mounts, 1904 Model
     3 x Twin mounts on centreline ends, majority forward
      1 raised mount - superfiring
      6 - 5.98" / 152 mm 45.0 cal guns - 108.07lbs / 49.02kg shells, 200 per gun
     Breech loading guns in deck and hoist mounts, 1904 Model
     6 x Single mounts on sides, evenly spread
      Weight of broadside 2,302 lbs / 1,044 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3.15" / 80 mm   501.97 ft / 153.00 m   9.84 ft / 3.00 m
     Main Belt covers 154 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   7.09" / 180 mm   1.50" / 38 mm      3.94" / 100 mm
   2nd:   1.97" / 50 mm   0.98" / 25 mm      0.98" / 25 mm

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

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

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 20,124 shp / 15,012 Kw = 23.00 kts
   Range 6,000nm at 10.00 kts
   Bunker at max displacement = 1,389 tons (90% coal)

Complement:
   385 - 501

Cost:
   £0.673 million / $2.691 million

Distribution of weights at normal displacement:
   Armament: 576 tons, 8.1 %
      - Guns: 576 tons, 8.1 %
   Armour: 1,366 tons, 19.3 %
      - Belts: 576 tons, 8.1 %
      - Armament: 264 tons, 3.7 %
      - Armour Deck: 495 tons, 7.0 %
      - Conning Tower: 31 tons, 0.4 %
   Machinery: 1,660 tons, 23.5 %
   Hull, fittings & equipment: 2,332 tons, 33.0 %
   Fuel, ammunition & stores: 1,077 tons, 15.2 %
   Miscellaneous weights: 65 tons, 0.9 %
      - Hull above water: 50 tons
      - On freeboard deck: 15 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     6,177 lbs / 2,802 Kg = 24.2 x 8.0 " / 203 mm shells or 1.1 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 2.2 ft / 0.7 m
   Roll period: 14.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.85
   Seaboat quality  (Average = 1.00): 1.22

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.534 / 0.544
   Length to Beam Ratio: 9.80 : 1
   'Natural speed' for length: 22.40 kts
   Power going to wave formation at top speed: 44 %
   Trim (Max stability = 0, Max steadiness = 100): 57
   Bow angle (Positive = bow angles forward): 0.00 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 %,  16.08 ft / 4.90 m,  16.08 ft / 4.90 m
      - Forward deck:   30.00 %,  16.08 ft / 4.90 m,  16.08 ft / 4.90 m
      - Aft deck:   35.00 %,  9.84 ft / 3.00 m,  9.84 ft / 3.00 m
      - Quarter deck:   15.00 %,  9.84 ft / 3.00 m,  9.84 ft / 3.00 m
      - Average freeboard:      12.96 ft / 3.95 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 106.6 %
      - Above water (accommodation/working, high = better): 111.2 %
   Waterplane Area: 17,674 Square feet or 1,642 Square metres
   Displacement factor (Displacement / loading): 102 %
   Structure weight / hull surface area: 99 lbs/sq ft or 482 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.00
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Hull Above Water: 50 t
- 25t, Long-Range Wireless
- 25t, Reserve Weight

On Deck: 15 t
- 12t, 4 x 45cm single side TTs with two reloads each
- 3t, Reserve Weight

[Logi]

I've changed the Kaba design a bit. The ship was lengthened and widened (80m->86m + 6.75m->7.5m). One of the 120mm guns was removed for another 457mm torpedo tube.

Umikaze, Japanese Fleet Destroyer laid down 1904 (Engine 1905)

Displacement:
   500 t light; 519 t standard; 606 t normal; 676 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (282.15 ft / 282.15 ft) x 24.61 ft x (7.25 / 7.81 ft)
   (86.00 m / 86.00 m) x 7.50 m  x (2.21 / 2.38 m)

Armament:
      3 - 4.72" / 120 mm 45.0 cal guns - 53.18lbs / 24.12kg shells, 80 per gun
     Quick firing guns in deck mounts, 1904 Model
     3 x Single mounts on centreline ends, majority aft
      1 raised mount aft - superfiring
      Weight of broadside 160 lbs / 72 kg

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 8,121 shp / 6,058 Kw = 25.89 kts
   Range 3,000nm at 10.00 kts
   Bunker at max displacement = 157 tons (90% coal)

Trial Speed: 28.50 kts

Complement:
   60 - 79

Cost:
   £0.069 million / $0.277 million

Distribution of weights at normal displacement:
   Armament: 28 tons, 4.6 %
      - Guns: 28 tons, 4.6 %
   Machinery: 315 tons, 52.0 %
   Hull, fittings & equipment: 139 tons, 22.9 %
   Fuel, ammunition & stores: 106 tons, 17.5 %
   Miscellaneous weights: 18 tons, 3.0 %
      - On freeboard deck: 18 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     157 lbs / 71 Kg = 3.0 x 4.7 " / 120 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.40
   Metacentric height 1.1 ft / 0.3 m
   Roll period: 9.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.35
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.421 / 0.436
   Length to Beam Ratio: 11.47 : 1
   'Natural speed' for length: 16.80 kts
   Power going to wave formation at top speed: 57 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 0.00 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 %,  14.60 ft / 4.45 m,  14.60 ft / 4.45 m
      - Forward deck:   30.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      9.48 ft / 2.89 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 179.4 %
      - Above water (accommodation/working, high = better): 112.8 %
   Waterplane Area: 4,332 Square feet or 402 Square metres
   Displacement factor (Displacement / loading): 42 %
   Structure weight / hull surface area: 21 lbs/sq ft or 102 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 0.91
      - Overall: 0.53
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Misc Weight: 18t
   10t - Short-Range Wireless
     8t - 4 x 1 45m TT rotating centerline with one reload each

Also the 3d model for it...

[Logi]

The IJN currently lacks ships designed to defeat light ships such as scout cruisers, destroyers, and torpedo boats so the following design is to rectify that.

Chikuma, Japanese Light Cruiser laid down 1904 (Engine 1905)

Displacement:
   4,000 t light; 4,173 t standard; 4,598 t normal; 4,938 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (557.74 ft / 557.74 ft) x 51.18 ft x (13.78 / 14.45 ft)
   (170.00 m / 170.00 m) x 15.60 m  x (4.20 / 4.41 m)

Armament:
      9 - 5.98" / 152 mm 45.0 cal guns - 108.07lbs / 49.02kg shells, 150 per gun
     Quick firing guns in deck and hoist mounts, 1904 Model
     9 x Single mounts on centreline, evenly spread
      4 raised mounts
      Weight of broadside 973 lbs / 441 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm   0.39" / 10 mm      0.98" / 25 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 20,000 shp / 14,920 Kw = 25.07 kts
   Range 4,000nm at 10.00 kts
   Bunker at max displacement = 764 tons (90% coal)

Complement:
   278 - 362

Cost:
   £0.463 million / $1.852 million

Distribution of weights at normal displacement:
   Armament: 258 tons, 5.6 %
      - Guns: 258 tons, 5.6 %
   Armour: 34 tons, 0.7 %
      - Armament: 34 tons, 0.7 %
   Machinery: 1,650 tons, 35.9 %
   Hull, fittings & equipment: 2,015 tons, 43.8 %
   Fuel, ammunition & stores: 598 tons, 13.0 %
   Miscellaneous weights: 43 tons, 0.9 %
      - On freeboard deck: 43 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,408 lbs / 1,546 Kg = 31.8 x 6.0 " / 152 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.23
   Metacentric height 2.7 ft / 0.8 m
   Roll period: 13.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.43
   Seaboat quality  (Average = 1.00): 1.51

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.409 / 0.419
   Length to Beam Ratio: 10.90 : 1
   'Natural speed' for length: 23.62 kts
   Power going to wave formation at top speed: 39 %
   Trim (Max stability = 0, Max steadiness = 100): 47
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   30.00 %,  26.41 ft / 8.05 m,  26.41 ft / 8.05 m
      - Forward deck:   30.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Aft deck:   25.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Quarter deck:   15.00 %,  13.12 ft / 4.00 m,  13.12 ft / 4.00 m
      - Average freeboard:      17.11 ft / 5.22 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 134.7 %
      - Above water (accommodation/working, high = better): 158.9 %
   Waterplane Area: 17,668 Square feet or 1,641 Square metres
   Displacement factor (Displacement / loading): 108 %
   Structure weight / hull surface area: 79 lbs/sq ft or 385 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.09
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Misc Weight: 43t
25t - Long-Range Wireless
10t - Short-Range Wireless
8t - 4x46cm side rotating TTs with 1 reload each

The ship looks something like this:


Increasing light displacement to 5,200 t (+1200 t) and shifting to mixed propulsion will yield a speed of around 25.81 kn (+0.81 kn). However such a ship would start to feel very large for a ship without any armor.

[eltf177]

Chikuma, Japanese Light Cruiser laid down 1904 (Engine 1905)

Armament:
      9 - 5.98" / 152 mm 45.0 cal guns - 108.07lbs / 49.02kg shells, 150 per gun
     Quick firing guns in deck and hoist mounts, 1904 Model
     9 x Single mounts on centreline, evenly spread
      4 raised mounts
      Weight of broadside 973 lbs / 441 kg

Out of curiosity what is the layout?

[snip]

The gun that is directly aft of the midbreak looks really cramped. I wonder if the removal of that gun would make servicing the other 8 much easier.

[Logi]

On the historical Minekaze, the raised platforms holding the 12cm/45 guns are 5.3m across. Specifically, there is 1.65m of space behind the gun breech on the platform.

On the Tenryuu the 14cm/50 fully-enclosed guns have 1.3m to 2.6m of space behind them. (Yes there is a turret which has something 1.3m behind it and it was never reported as a problem.)
The following Kuma-class has a catapult 1.8m behind the fully-enclosed 14cm/50 gun. It also has two back to back 14cm/50 turrets separated by double the distance (3.6m)



On this design, there is 2.1m of space behind the breech of the 15cm/415 gun. The space the gun sits in is 10.1m long.
The 15cm/45 gun is only 1.44m longer than the 12cm/45 gun on the Minekaze. It is 0.16m shorter than the 14cm/50 gun on the Tenryuu and Kuma.
As such there is a tremendous amount more space for the gun than in historical designs.

Remember, this ship is 170m long... that's longer than the historical Omaha-class & Atlanta-class and slightly shorter than Agano-class. Add to the fact that superstructures are much less built-up in this era and there are no catapults/torpedoes taking up centerline space.... the design could still fit on 160m.

[snip]

I have no doubt that it all fits, it just looks very cramped.

[Logi]

My previous post just detailed exactly how it isn't cramped and is in fact more spacious than many historical ships.

[snip]

Looks, as in that is how the drawing makes me feel.

[Logi]

I've moved the gun in question a bit away from the midbreak as well as integrated the break into the ship's lines better. Also I've adjusted all the guns so only the first two mounts (AB) cannot rotate 360 degrees, the rest can do a full rotation. I've moved from the placeholder model for the 15cm/45 mount to the actual fully-enclosed mount. The model has been colored so it looks more presentable. Oh and the smokestack superstructure has been combined into one long house.

[Logi]

A destroyer without torpedoes. I had been considering an all-gun destroyer since torpedo range is so short and take up so much deck space  and weight.
The layout is one gun on the raised forceastle, 2 between the smokestacks, and 3 aft with 1 raised on the rear platform.

If built, it'll probably be a short experimental run of maybe 4-8 ships total.

Sakura, Japanese Fleet Destroyer laid down 1904 (Engine 1905)

Displacement:
   500 t light; 527 t standard; 606 t normal; 669 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (262.47 ft / 262.47 ft) x 23.95 ft x (7.55 / 8.10 ft)
   (80.00 m / 80.00 m) x 7.30 m  x (2.30 / 2.47 m)

Armament:
      6 - 4.72" / 120 mm 45.0 cal guns - 44.97lbs / 20.40kg shells, 100 per gun
     Quick firing guns in deck mounts, 1904 Model
     6 x Single mounts on centreline, evenly spread
      1 raised mount
      Weight of broadside 270 lbs / 122 kg

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 10,000 shp / 7,460 Kw = 26.86 kts
   Range 2,750nm at 10.00 kts
   Bunker at max displacement = 142 tons (90% coal)
     Caution: Delicate, lightweight machinery

Trial Speed: 29.50 kts

Complement:
   60 - 79

Cost:
   £0.077 million / $0.309 million

Distribution of weights at normal displacement:
   Armament: 56 tons, 9.2 %
      - Guns: 56 tons, 9.2 %
   Machinery: 318 tons, 52.4 %
   Hull, fittings & equipment: 126 tons, 20.9 %
   Fuel, ammunition & stores: 106 tons, 17.5 %
   Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     128 lbs / 58 Kg = 2.4 x 4.7 " / 120 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 10.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.62
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.447 / 0.460
   Length to Beam Ratio: 10.96 : 1
   'Natural speed' for length: 16.20 kts
   Power going to wave formation at top speed: 63 %
   Trim (Max stability = 0, Max steadiness = 100): 70
   Bow angle (Positive = bow angles forward): 0.00 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 %,  15.09 ft / 4.60 m,  15.09 ft / 4.60 m
      - Forward deck:   30.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Aft deck:   35.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      9.58 ft / 2.92 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 192.5 %
      - Above water (accommodation/working, high = better): 104.2 %
   Waterplane Area: 4,000 Square feet or 372 Square metres
   Displacement factor (Displacement / loading): 34 %
   Structure weight / hull surface area: 23 lbs/sq ft or 111 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.19
      - Overall: 0.54
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

[Jefgte]

Add 4t for torpedoes & remove 1x 120
then, you have the most powerful DD in the world.

Jef  ;)

[Walter]

The layout is one gun on the raised forceastle, 2 between the smokestacks, and 3 aft with 1 raised on the rear platform.

The thing is that the gun on the raised forceastle forecastle is actually not on the forecastle as it is at the 2.5m height of the rest of the ship and not at the 4.6m height of the forecastle. The best way to correctly sim that is to use the mid break instead of the forecastle break. Just make sure that if you do that to set all remaining guns as being located aft of the mid break.