Japanese Ship Designs 1912+

[Desertfox]

Another purchase the Japanese are considering.

The C-class has one glaring issue, the L:B ratio is 14.8! So like many historically flawed ships, these would have to undergo some sort of fixes. Would the following be enough to mitigate the "moderator-inflicted incidents" problem?

Changes are:
Dumping the gun armor -21t
De-rating the engines (limiting top speed) 31kts -> 30kts + no DD bonus
Dumping the reload torpedoes -24t
Dumping the depth charges -5 t
Limiting flag facilities -1t

Cross sectional: 0.5 -> 0.62
Overall: 0.54 -> 0.67

C-class, Iberia/Japan Destroyer laid down 1908

Displacement:
   1,000 t light; 1,039 t standard; 1,115 t normal; 1,175 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (352.01 ft / 349.00 ft) x 23.56 ft x (10.50 / 10.90 ft)
   (107.29 m / 106.38 m) x 7.18 m  x (3.20 / 3.32 m)

Armament:
      4 - 4.13" / 105 mm 50.0 cal guns - 37.39lbs / 16.96kg shells, 200 per gun
     Quick firing guns in deck mounts, 1908 Model
     4 x Single mounts on centreline, evenly spread
      6 - 0.98" / 25.0 mm 45.0 cal guns - 0.48lbs / 0.22kg shells, 350 per gun
     Machine guns in deck mounts, 1908 Model
     6 x Single mounts on sides, evenly spread
      Weight of broadside 152 lbs / 69 kg

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 19,396 shp / 14,469 Kw = 30.00 kts
   Range 2,700nm at 10.00 kts
   Bunker at max displacement = 136 tons

Complement:
   96 - 125

Cost:
   £0.126 million / $0.506 million

Distribution of weights at normal displacement:
   Armament: 30 tons, 2.7 %
      - Guns: 30 tons, 2.7 %
   Machinery: 594 tons, 53.3 %
   Hull, fittings & equipment: 292 tons, 26.2 %
   Fuel, ammunition & stores: 115 tons, 10.3 %
   Miscellaneous weights: 83 tons, 7.4 %
      - Hull below water: 23 tons
      - Hull above water: 30 tons
      - On freeboard deck: 30 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     250 lbs / 113 Kg = 7.1 x 4.1 " / 105 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.7 ft / 0.2 m
   Roll period: 11.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 76 %
         - Recoil effect (Restricted arc if above 1.00): 0.34
   Seaboat quality  (Average = 1.00): 1.23

Hull form characteristics:
   Hull has raised forecastle,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.452 / 0.459
   Length to Beam Ratio: 14.81 : 1
   'Natural speed' for length: 18.68 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 62
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   26.00 %,  17.06 ft / 5.20 m,  15.91 ft / 4.85 m
      - Forward deck:   30.00 %,  8.86 ft / 2.70 m,  8.86 ft / 2.70 m
      - Aft deck:   24.00 %,  8.86 ft / 2.70 m,  8.86 ft / 2.70 m
      - Quarter deck:   20.00 %,  8.86 ft / 2.70 m,  8.86 ft / 2.70 m
      - Average freeboard:      10.81 ft / 3.30 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 185.0 %
      - Above water (accommodation/working, high = better): 92.3 %
   Waterplane Area: 5,253 Square feet or 488 Square metres
   Displacement factor (Displacement / loading): 53 %
   Structure weight / hull surface area: 27 lbs/sq ft or 134 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.62
      - Longitudinal: 1.24
      - Overall: 0.67
   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

24t - 4x3x450mm Torpedoes
2t - Pumps
25t - LR Wireless
9t - Flag Facilities
23t - Derated Engines

[Desertfox]

Two of the Chikumas, were badly damaged, to repair them would cost almost 5.3 BPs, which is simply too much for obsolete ships. Instead, scrapping and reusing their main armament gets me this for half the cost:

Tone, Japan Colonial Cruiser laid down 1913

Displacement:
   3,900 t light; 4,159 t standard; 4,673 t normal; 5,084 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (403.53 ft / 400.00 ft) x 47.00 ft x (17.40 / 18.55 ft)
   (122.99 m / 121.92 m) x 14.33 m  x (5.30 / 5.65 m)

Armament:
      4 - 8.00" / 203 mm 45.0 cal guns - 258.18lbs / 117.11kg shells, 170 per gun
     Breech loading guns in deck and hoist mounts, 1903 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      10 - 5.00" / 127 mm 45.0 cal guns - 63.03lbs / 28.59kg shells, 170 per gun
     Breech loading guns in deck mounts, 1903 Model
     8 x Single mounts on sides, evenly spread
      12 - 2.00" / 50.8 mm 45.0 cal guns - 4.03lbs / 1.83kg shells, 320 per gun
     Breech loading guns in deck mounts, 1913 Model
     4 x Triple mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 1,711 lbs / 776 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.00" / 51 mm   300.00 ft / 91.44 m   10.00 ft / 3.05 m
   Ends:   Unarmoured
     Main Belt covers 115 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   4.00" / 102 mm   1.00" / 25 mm      4.00" / 102 mm
   2nd:   1.00" / 25 mm         -               -

   - Protected deck - single deck:
   For and Aft decks: 2.00" / 51 mm

   - Conning towers: Forward 4.00" / 102 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 31,964 shp / 23,845 Kw = 27.00 kts
   Range 5,100nm at 14.00 kts
   Bunker at max displacement = 925 tons

Complement:
   282 - 367

Cost:
   £0.482 million / $1.926 million

Distribution of weights at normal displacement:
   Armament: 373 tons, 8.0 %
      - Guns: 373 tons, 8.0 %
   Armour: 689 tons, 14.7 %
      - Belts: 244 tons, 5.2 %
      - Armament: 78 tons, 1.7 %
      - Armour Deck: 343 tons, 7.3 %
      - Conning Tower: 24 tons, 0.5 %
   Machinery: 1,253 tons, 26.8 %
   Hull, fittings & equipment: 1,445 tons, 30.9 %
   Fuel, ammunition & stores: 773 tons, 16.5 %
   Miscellaneous weights: 140 tons, 3.0 %
      - Hull above water: 50 tons
      - On freeboard deck: 45 tons
      - Above deck: 45 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,690 lbs / 1,674 Kg = 14.4 x 8.0 " / 203 mm shells or 0.9 torpedoes
   Stability (Unstable if below 1.00): 1.17
   Metacentric height 2.2 ft / 0.7 m
   Roll period: 13.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.83
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.500 / 0.510
   Length to Beam Ratio: 8.51 : 1
   'Natural speed' for length: 20.00 kts
   Power going to wave formation at top speed: 59 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 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 %,  20.00 ft / 6.10 m,  15.00 ft / 4.57 m
      - Forward deck:   30.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Aft deck:   25.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Quarter deck:   15.00 %,  15.00 ft / 4.57 m,  15.00 ft / 4.57 m
      - Average freeboard:      15.60 ft / 4.75 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 115.1 %
      - Above water (accommodation/working, high = better): 126.9 %
   Waterplane Area: 12,526 Square feet or 1,164 Square metres
   Displacement factor (Displacement / loading): 102 %
   Structure weight / hull surface area: 81 lbs/sq ft or 394 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.83
      - Longitudinal: 1.83
      - Overall: 0.90
   Caution: Hull subject to strain in open-sea
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room

45t - FC & Flagship Facilities
20t - 8 x 18" Torpedo Tubes
25t - LR Wireless
50t - Observation Balloon

[maddox]

Put the guns in twins, and use all 8 of'm in one 6Ktons ship.

[snip]

Keeping the old 127mm BLs seems like a poor plan, as the RoF of said weapons is quite low as recent combat shows. I can see reusing the 203s, but the 127s just need to get scraped with the rest of the ship.

[maddox]

Put the 8" guns in twins, and use all 8 of'm in one 6Ktons ship.

[Desertfox]

I only have four 8in guns available, since only two Chikumas were damaged, the other two suffered no damage. Making twin turrets, defeats the goal of saving money by reusing the guns.

The 5in guns should be QF... but I just realized I have all the PCs listed as 5in BL, while all the SC have 5in QF, when in reality it should be the same gun.

Edit: It would actually help to read the rules first... Repairs are not as expensive as I thought, cheaper to repair them that to build a new ships. Tone will not be built.

[Jefgte]

...Tone will not be built.

Too bad, he would have made an honest cheap colonial cruiser and his speed of 27kts would have allowed him to make reconnaissance in front of a battle line and to support the destroyers of the squadron during a torpedo charge.

[Desertfox]

Not to worry, I just finished 4 Yahagi class destroyer leaders, and the repaired Chikumas are decent colonial cruisers. The Furutakas will be back eventually and they will fulfill those role.

[Desertfox]

A torpedo boat/submarine transport/tender. It can transport and support either 10 x 40t TBs or 4 x 100t submarines. It uses petrol engines for commonality with the ships it supports. 

Jingei class, Japan Torpedo Boat Tender laid down 1913

Displacement:
   2,080 t light; 2,140 t standard; 2,418 t normal; 2,641 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (300.00 ft / 300.00 ft) x 50.00 ft x (9.90 / 10.63 ft)
   (91.44 m / 91.44 m) x 15.24 m  x (3.02 / 3.24 m)

Armament:
      2 - 3.00" / 76.2 mm 45.0 cal guns - 13.62lbs / 6.18kg shells, 250 per gun
     Breech loading guns in deck mounts, 1913 Model
     2 x Single mounts on centreline ends, evenly spread
      12 - 2.00" / 50.8 mm 45.0 cal guns - 4.03lbs / 1.83kg shells, 300 per gun
     Breech loading guns in deck mounts, 1913 Model
     4 x Triple mounts on sides, evenly spread
      Weight of broadside 76 lbs / 34 kg

Machinery:
   Petrol Internal combustion motors,
   Direct drive, 2 shafts, 2,028 ihp / 1,513 Kw = 14.00 kts
   Range 7,700nm at 10.00 kts
   Bunker at max displacement = 501 tons

Complement:
   172 - 224

Cost:
   £0.099 million / $0.394 million

Distribution of weights at normal displacement:
   Armament: 12 tons, 0.5 %
      - Guns: 12 tons, 0.5 %
   Machinery: 96 tons, 4.0 %
   Hull, fittings & equipment: 662 tons, 27.4 %
   Fuel, ammunition & stores: 338 tons, 14.0 %
   Miscellaneous weights: 1,310 tons, 54.2 %
      - Hull below water: 400 tons
      - Hull above water: 80 tons
      - On freeboard deck: 800 tons
      - Above deck: 30 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     7,167 lbs / 3,251 Kg = 530.9 x 3.0 " / 76 mm shells or 3.0 torpedoes
   Stability (Unstable if below 1.00): 1.43
   Metacentric height 3.3 ft / 1.0 m
   Roll period: 11.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.01
   Seaboat quality  (Average = 1.00): 1.50

Hull form characteristics:
   Hull has raised forecastle, raised quarterdeck ,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.570 / 0.580
   Length to Beam Ratio: 6.00 : 1
   'Natural speed' for length: 17.32 kts
   Power going to wave formation at top speed: 36 %
   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:   25.00 %,  15.00 ft / 4.57 m,  14.00 ft / 4.27 m
      - Forward deck:   30.00 %,  7.00 ft / 2.13 m,  7.00 ft / 2.13 m
      - Aft deck:   20.00 %,  7.00 ft / 2.13 m,  7.00 ft / 2.13 m
      - Quarter deck:   25.00 %,  14.00 ft / 4.27 m,  14.00 ft / 4.27 m
      - Average freeboard:      10.60 ft / 3.23 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 37.8 %
      - Above water (accommodation/working, high = better): 82.7 %
   Waterplane Area: 10,667 Square feet or 991 Square metres
   Displacement factor (Displacement / loading): 157 %
   Structure weight / hull surface area: 49 lbs/sq ft or 239 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.10
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Cramped 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

30t - LR wireless + FC
40t - 20 Marines
40t - Camouflage
800t - Cranes and space for 10 x 40t TB or 4 x 100t Submarines
400t - 4,000t of Out-of-port resupply

[snip]

Did we get a firm ruling on if Petrol engines were allowed and if so what sort of modifications they have?

[Desertfox]

Well historical submarines of the time period had ~600hp petrol engines, so I designed it around 4 of them downrated to increase reliability.

[Kaiser Kirk]

Another purchase the Japanese are considering.

The C-class has one glaring issue, the L:B ratio is 14.8! So like many historically flawed ships, these would have to undergo some sort of fixes. Would the following be enough to mitigate the "moderator-inflicted incidents" problem?

Changes are:
Dumping the gun armor -21t
De-rating the engines (limiting top speed) 31kts -> 30kts + no DD bonus
Dumping the reload torpedoes -24t
Dumping the depth charges -5 t
Limiting flag facilities -1t

Cross sectional: 0.5 -> 0.62
Overall: 0.54 -> 0.67

Quite an interesting question.

The solution would be in the consideration of what forces act on the L:B ratio.

The Length : Draft, or Hull Girder is what matters for the tendency of the bow/stern to push "up", or when the ship goes through a wave trough.
So L:B would be more sideway pressures and torsion forces as the ship moves through the waves.
Worse, the further away from the midpoint, the more lever action. So 14:1 is about 36% worse than 12:1.

So...would those measures either strengthen the hull, or lessen the torsion forces?
It's little hard without looking at the original
A) Depth Charges do not exist yet.
B) Derating the engines slightly would only matter if you are attempting to go through waves at top speed. Plus it's a false economy, the Engines are still there and weigh the same, unless you're paying to put in new ones.
C) The reload torpedoes are presumably not kept at the ends of the ship.
D) Flag facilities are high on the ship, but not really at the ends.

E) dumping the gun armor would help, as that would be mass towards the extremes of the ship, and relatively high.  However, the guns are evenly spread, so only the 2 at the ends matter.
Call it 11 tons "saved".

The historical solution was both reducing the forces on the vessel, but also adding internal structure.
But how to figure out what's needed?

Well, the basic hull here is 107.29m * 7.18 * 3.2 with a BC of 0.452 and a freeboard of 2.7 except the forecastle. Which steps up 8 feet, making it hard to fire directly forward.
Sticking a simple 10kt engine in it, Hull, fittings & equipment: 1,029 tons,  of an LD of 1096

If that hull was built to the absolute minimum N7 standard of 12:1, it would be a beam of 8.94, and "Hull, fittings & equipment: 1,346 tons, 96.1 %"

So, to reinforce this hull to the point it's viable in all waters/weathers,  I'm going to say you need to add 317 tons below decks as "structural reinforcement".  11 of that can come from the guns.

I suspect that render this unviable, but it's a ship that never should have been built, so you're trying to fix a colossally flawed ship.

[Kaiser Kirk]

Well historical submarines of the time period had ~600hp petrol engines, so I designed it around 4 of them downrated to increase reliability.

The ruling was that petrol engines are not listed under Engine Techs and so are not used in standard ships, but are specialty items only used in submarines and MTBs and require skilled maintenance folks.

[Desertfox]

The ruling was that petrol engines are not listed under Engine Techs and so are not used in standard ships, but are specialty items only used in submarines and MTBs and require skilled maintenance folks.

Well that's the reason I chose them in the first place, a MTB and sub tender will have plenty of those folks around and the ship's fuel supply can be used for its MTBs as well. Instead of having to carry separate parts and technicians I can use the ones already on board.

B) Derating the engines slightly would only matter if you are attempting to go through waves at top speed. Plus it's a false economy, the Engines are still there and weigh the same, unless you're paying to put in new ones.

I actually kept the total engine weight, de-rating the engines was mainly to limit the top speed and therefore the stresses.

So, to reinforce this hull to the point it's viable in all waters/weathers,  I'm going to say you need to add 317 tons below decks as "structural reinforcement".  11 of that can come from the guns.

So, Im not aiming for the 100% solution but more of an 80% solution. I can't build 1,000t destroyers yet so a flawed ship is better than no ship.  I guess an alternative would be to add bulges, but at that point the ships would go over 1,000t, what would be the ruling in that scenario?

[Kaiser Kirk]

The ruling was that petrol engines are not listed under Engine Techs and so are not used in standard ships, but are specialty items only used in submarines and MTBs and require skilled maintenance folks.

Well that's the reason I chose them in the first place, a MTB and sub tender will have plenty of those folks around and the ship's fuel supply can be used for its MTBs as well. Instead of having to carry separate parts and technicians I can use the ones already on board.

Is it a "Naval Propulsion:" engine?
If Yes - you can use it
If No...then no.

Using petrol engines for naval propulsion at this time fails to comply with our tech rules.
 

So, to reinforce this hull to the point it's viable in all waters/weathers,  I'm going to say you need to add 317 tons below decks as "structural reinforcement".  11 of that can come from the guns.

So, Im not aiming for the 100% solution but more of an 80% solution. I can't build 1,000t destroyers yet so a flawed ship is better than no ship.  I guess an alternative would be to add bulges, but at that point the ships would go over 1,000t, what would be the ruling in that scenario?
[/quote]

Darman was not punished for having illegal legacy designs.
That consideration does not pass on to others.

The basic hull is flawed.
Bulges are typically thin skinned and lightly built. The means and purpose for which they were typically used, and the few cutaway drawings I've seen,  did not include the types of longitudinal structures that would actually strengthen the basic hull. They ride on top of the 'skeleton' of the ship, not adding to it.
So bulges will not of themselves "fix" the ship.

You can use bulges to increase the ship beam so you fit in the needed reinforcement.
However if the ship exceeds 1000 tons, it is no longer under the destroyer architecture.