SDN World 3 Ship Design Thread

[Ma Deuce]

Example of variable barbette thickness. The USN did this too, but as far as I can tell it only thinned the barbettes pointing aft. Other navies varied.

I know it was common practice to reduce the thickness of the barbette below deck (Springsharp's value is apparently the below-deck thickness), but did anyone bother varying the barbette along it's radius before the treaties had everyone looking for creative ways to save weight?

Question: How does Spring Sharp handle Armored Decks ? What does Single and multiple decks mean here? Multiple as in, one decap deck and then the single chunk beneath?

It could also include a splinter deck below the main thickness; even in ships not designed against aerial bombs, a thin deck to catch spall that comes off the bottom of the main deck when hit hard or partially penetrated is a common feature. Such a deck need not be very thick; even one inch would probably be excessive for most designs; the Iowa for instance had a 5/8ths inch (16mm) splinter deck

[Sea Skimmer]

I know it was common practice to reduce the thickness of the barbette below deck (Springsharp's value is apparently the below-deck thickness), but did anyone bother varying the barbette along it's radius before the treaties had everyone looking for creative ways to save weight?

Yeah they did, but usually only on the rear of barbettes, when facing another barbette which added as a screen against a hit with a favorable (for penetration) angle. So that let you shave off a couple inches with no real loss of protection. The closer spaced the barbettes the more acceptable this was. In some cases the mass of the superstructure, which could collectively add up to quite a few inches of material even if it wasn’t armor, was also taken into consideration with thinning the rear of barbettes facing the middle of the ship. Of course it’s also worth considering that almost all pre treaty ships other then those of the US Navy had hoards of incremental armoring around the turrets, and so barbette thickness would change at every deck level.

On almost all (might in fact be all) treaty ships, the barbette stopped completely upon reaching the main armor deck. If any vertical armor continued below this, it was only a splinter shield with much less structural purpose then a barbette. Thickness would be 1.5-3in max, usually closer to the former. Older ships had fairly heavy barbettes going deep into the hull because they had no proper armor decks, nor very much thick side armor.

It could also include a splinter deck below the main thickness; even in ships not designed against aerial bombs, a thin deck to catch spall that comes off the bottom of the main deck when hit hard or partially penetrated is a common feature. Such a deck need not be very thick; even one inch would probably be excessive for most designs; the Iowa for instance had a 5/8ths inch (16mm) splinter deck

You can basically group splinter decks into two categories. Some ships like Iowa or Yamato had only a very thin splinter deck which is perhaps more accurately called a rivet catching deck. These could be as thin as 9mm, and they were attached directly to the bottom of the girders supporting the main armor deck. The gap would only be a matter of a foot or two. So mainly they just caught rivets and bits of spall. Really heavy spalling, or the fragmentation from a shell which burst while holing the deck armor wasn’t going to be much impeded in its travel. In Iowa’s case this was accepted because they had that 1.5in upper deck to reduce the severity of hits on the main deck (the weight was a direct tradeoff in the design process). Yamato accepted it because the deck was just thick as hell already.

The other category are proper heavy splinter decks, not unlike the way all deck armor was on warships prior to the USS Nevada and designs collectively known as ‘post Jutland’. These splinter decks are located a full deck level lower then the main armor deck, and are usually at least 30mm thick and sometimes as much as 50mm thick. 40mm was a very typical value. These decks can stop nearly any piece of spalling, and if a shell was to pierce the main armor deck and burst below it, the heavy splinter deck will actually be able to stop the very heavy (as in 40lb chunks or more) high velocity fragments produced by the burst of an APC shell. So this provided a lot more protection in the event of perforation of the main armor deck… but it means the deck under the main armor isn’t fully protected. It also took up a fair bit more weight, but this weight was lower in the ship had a less negative impact. On the other hand, some battleship designs had no additional deck in-between the main armor deck and the machinery space, so design choices were limited.

You can certainly find exception to this division of design philosophy into two categories, like ships with a very thin deck a full deck height lower; or ships with a heavy splinter deck attached to the girders below the main deck, but this generally the way things worked. Even with an all or nothing design philosophy this is a tradeoff that can be made, between trying to prevent damage, with fewer, thicker layers of armor higher in the ship, accepting more damage from penetrations, or localizing it in with more layers exploiting the full height of the ship at the cost of only fully protection the lowest areas. No real life consensus ever existed on this subject, the British, Americans, French and Japanese all of whom had generally similar ideas on post Jutland battleship design (all or nothing armoring, emphasis on long range shellfire and bomb protection) all came up with much different combinations of deck protection. The important is just, have a crap load of deck armor.

Now for visual examples in case reading my ramblings is annoying or unclear.

Thin rivet shield on Iowa 16mm thick, plus 37mm bomb deck and 121mm main deck (50lb STS backing not represented). Note that the 13mm thickness of the 3rd deck is not armor, its just the normal steel of the decking. This is an engine room cross section.


The heavy deck height separated splinter deck on Richelieu, 40mm thick with a 50mm thick slope covering behind the belt. She also has a 24mm thick bomb deck (barely enough to work). Note that this is the armor over machinery; the magazines had a 170mm thick main deck.

[CmdrWilkens]

Well, I went back and did some serious retooling, while... bulging the ship so much I think it might be butt ugly, and here's the result...

Justinian, Byzantine Empire Battleship laid down 1926

40 - 1.57" / 40.0 mm 56.0 cal guns - 2.12lbs / 0.96kg shells, 2,000 per gun
Anti-air guns in deck mounts, 1926 Model
10 x Twin mounts on side ends, majority aft
4 raised mounts - superfiring
16 - 0.50" / 12.7 mm 12.0 cal guns - 0.04lbs / 0.02kg shells, 4,000 per gun
Anti-air guns in deck mounts, 1926 Model
16 x 4-gun mounts on centreline, aft deck forward

I think your mount selection is off for these two.

[Steve]

Is it just me or is it disturbing that this thread has been more active than the actual story thread?

[CmdrWilkens]

Is it just me or is it disturbing that this thread has been more active than the actual story thread?

I don't think it should be...its harder to write IC posts because you have to worry about tone, style, point of view and a host of other story elements. In turn this makes it easier to convey information via OOC type posts. If you consider the amount of in game information contained within the OOC threads there is a ton of stuff that had folks the time to make them in character would probably double the story thread length.

[Fingolfin_Noldor]

So I have been pondering rather hard on this: With some of our ship designs with fantastically wide bulges. Will there be an issue that a shell lands on the bulge and inflict substantial damage to the ship? Or does Spring Sharp assume the bulge is filled with material or is compartmentalised or what?

[Lascaris]

And... armored cruisers

The 1913 program ships laid down in 1914

AC 1913, Cisplatina Armored Cruiser laid down 1914

Displacement:
9.755 t light; 10.197 t standard; 10.906 t normal; 11.474 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(544,55 ft / 525,00 ft) x 70,00 ft x (23,50 / 24,35 ft)
(165,98 m / 160,02 m) x 21,34 m x (7,16 / 7,42 m)

Armament:
8 - 9,20" / 234 mm 47,0 cal guns - 404,99lbs / 183,70kg shells, 90 per gun
Breech loading guns in turret on barbette mounts, 1914 Model
2 x 4-gun mounts on centreline ends, evenly spread
12 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Quick firing guns in deck and hoist mounts, 1914 Model
12 x Single mounts on sides, evenly spread
12 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 150 per gun
Anti-air guns in deck mounts, 1914 Model
12 x Single mounts on sides, evenly spread
Weight of broadside 3.985 lbs / 1.807 kg
Main Torpedoes
12 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,649 t each, 19,782 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8,00" / 203 mm 341,25 ft / 104,01 m 10,04 ft / 3,06 m
Ends: Unarmoured
Main Belt covers 100% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 8,00" / 203 mm 4,00" / 102 mm 7,00" / 178 mm
2nd: 3,00" / 76 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 2,00" / 51 mm

- Conning towers: Forward 7,00" / 178 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 59.211 shp / 44.172 Kw = 28,50 kts
Range 9.000nm at 10,00 kts
Bunker at max displacement = 1.277 tons

Complement:
533 - 693

Cost:
£1,324 million / $5,297 million

Distribution of weights at normal displacement:
Armament: 1.147 tons, 10,5%
- Guns: 1.122 tons, 10,3%
- Weapons: 25 tons, 0,2%
Armour: 2.488 tons, 22,8%
- Belts: 1.151 tons, 10,6%
- Armament: 556 tons, 5,1%
- Armour Deck: 706 tons, 6,5%
- Conning Tower: 74 tons, 0,7%
Machinery: 2.281 tons, 20,9%
Hull, fittings & equipment: 3.838 tons, 35,2%
Fuel, ammunition & stores: 1.152 tons, 10,6%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
12.016 lbs / 5.450 Kg = 30,9 x 9,2 " / 234 mm shells or 1,4 torpedoes
Stability (Unstable if below 1.00): 1,22
Metacentric height 4,2 ft / 1,3 m
Roll period: 14,3 seconds
Steadiness - As gun platform (Average = 50 %): 52 %
- Recoil effect (Restricted arc if above 1.00): 0,44
Seaboat quality (Average = 1.00): 1,04

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,442 / 0,449
Length to Beam Ratio: 7,50 : 1
'Natural speed' for length: 22,91 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 30,00 degrees
Stern overhang: 5,00 ft / 1,52 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 25,20 ft / 7,68 m, 16,04 ft / 4,89 m
- Forward deck: 30,00%, 16,04 ft / 4,89 m, 16,04 ft / 4,89 m
- Aft deck: 35,00%, 16,04 ft / 4,89 m, 16,04 ft / 4,89 m
- Quarter deck: 15,00%, 16,04 ft / 4,89 m, 16,04 ft / 4,89 m
- Average freeboard: 16,77 ft / 5,11 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 99,3%
- Above water (accommodation/working, high = better): 130,3%
Waterplane Area: 23.291 Square feet or 2.164 Square metres
Displacement factor (Displacement / loading): 102%
Structure weight / hull surface area: 129 lbs/sq ft or 631 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,94
- Longitudinal: 1,75
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1917 program ships laid 1918

AC 1913, Cisplatina Armored Cruiser laid down 1918

Displacement:
10.798 t light; 11.269 t standard; 12.351 t normal; 13.216 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(585,10 ft / 565,00 ft) x 70,00 ft x (23,50 / 24,69 ft)
(178,34 m / 172,21 m) x 21,34 m x (7,16 / 7,52 m)

Armament:
8 - 9,20" / 234 mm 47,0 cal guns - 404,99lbs / 183,70kg shells, 90 per gun
Breech loading guns in turret on barbette mounts, 1918 Model
2 x 4-gun mounts on centreline ends, evenly spread
12 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Breech loading guns in deck and hoist mount, 1918 Model
1 x Single mount on sides amidships
12 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 150 per gun
Anti-air guns in deck mounts, 1918 Model
12 x Single mounts on sides, evenly spread
Weight of broadside 3.985 lbs / 1.807 kg
Main Torpedoes
12 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,665 t each, 19,974 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8,00" / 203 mm 368,50 ft / 112,32 m 10,04 ft / 3,06 m
Ends: Unarmoured
Main Belt covers 100% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 8,00" / 203 mm 4,00" / 102 mm 7,00" / 178 mm
2nd: 3,00" / 76 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 2,00" / 51 mm

- Conning towers: Forward 6,00" / 152 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 76.448 shp / 57.030 Kw = 30,00 kts
Range 15.000nm at 10,00 kts
Bunker at max displacement = 1.948 tons

Complement:
585 - 761

Cost:
£2,288 million / $9,150 million

Distribution of weights at normal displacement:
Armament: 1.147 tons, 9,3%
- Guns: 1.122 tons, 9,1%
- Weapons: 25 tons, 0,2%
Armour: 2.565 tons, 20,8%
- Belts: 1.238 tons, 10,0%
- Armament: 482 tons, 3,9%
- Armour Deck: 775 tons, 6,3%
- Conning Tower: 69 tons, 0,6%
Machinery: 2.758 tons, 22,3%
Hull, fittings & equipment: 4.328 tons, 35,0%
Fuel, ammunition & stores: 1.553 tons, 12,6%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
13.541 lbs / 6.142 Kg = 34,8 x 9,2 " / 234 mm shells or 1,4 torpedoes
Stability (Unstable if below 1.00): 1,25
Metacentric height 4,4 ft / 1,3 m
Roll period: 14,1 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0,42
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): 0,465 / 0,474
Length to Beam Ratio: 8,07 : 1
'Natural speed' for length: 23,77 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 30,00 degrees
Stern overhang: 5,00 ft / 1,52 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 26,15 ft / 7,97 m, 16,64 ft / 5,07 m
- Forward deck: 30,00%, 16,64 ft / 5,07 m, 16,64 ft / 5,07 m
- Aft deck: 35,00%, 16,64 ft / 5,07 m, 16,64 ft / 5,07 m
- Quarter deck: 15,00%, 16,64 ft / 5,07 m, 16,64 ft / 5,07 m
- Average freeboard: 17,40 ft / 5,30 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 100,2%
- Above water (accommodation/working, high = better): 135,4%
Waterplane Area: 25.549 Square feet or 2.374 Square metres
Displacement factor (Displacement / loading): 106%
Structure weight / hull surface area: 130 lbs/sq ft or 634 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,95
- Longitudinal: 1,57
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1922 program ships laid down 1923

AC 1922, Cisplatina Armored Cruiser laid down 1923

Displacement:
17.213 t light; 18.014 t standard; 19.772 t normal; 21.178 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(681,32 ft / 660,00 ft) x 75,00 ft x (30,00 / 31,48 ft)
(207,67 m / 201,17 m) x 22,86 m x (9,14 / 9,60 m)

Armament:
8 - 12,00" / 305 mm 47,0 cal guns - 898,76lbs / 407,67kg shells, 86 per gun
Breech loading guns in turret on barbette mounts, 1923 Model
2 x 4-gun mounts on centreline ends, evenly spread
1 raised mount - superfiring
12 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1923 Model
12 x Single mounts on sides, evenly spread
12 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 150 per gun
Anti-air guns in deck mounts, 1923 Model
12 x Single mounts on sides, evenly spread
Weight of broadside 7.935 lbs / 3.599 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 8,00" / 203 mm 400,00 ft / 121,92 m 10,39 ft / 3,17 m
Ends: Unarmoured
Main Belt covers 93% of normal length

- Torpedo Bulkhead - Strengthened structural bulkheads:
1,50" / 38 mm 400,00 ft / 121,92 m 25,26 ft / 7,70 m
Beam between torpedo bulkheads 75,00 ft / 22,86 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 8,00" / 203 mm 4,00" / 102 mm 7,00" / 178 mm
2nd: 3,00" / 76 mm - -
3rd: 0,50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 3,60" / 91 mm

- Conning towers: Forward 6,00" / 152 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 106.162 shp / 79.197 Kw = 32,00 kts
Range 19.000nm at 10,00 kts
Bunker at max displacement = 3.163 tons

Complement:
833 - 1.083

Cost:
£5,420 million / $21,682 million

Distribution of weights at normal displacement:
Armament: 1.821 tons, 9,2%
- Guns: 1.821 tons, 9,2%
Armour: 4.779 tons, 24,2%
- Belts: 1.400 tons, 7,1%
- Torpedo bulkhead: 561 tons, 2,8%
- Armament: 906 tons, 4,6%
- Armour Deck: 1.817 tons, 9,2%
- Conning Tower: 95 tons, 0,5%
Machinery: 3.548 tons, 17,9%
Hull, fittings & equipment: 7.066 tons, 35,7%
Fuel, ammunition & stores: 2.558 tons, 12,9%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
20.978 lbs / 9.515 Kg = 24,3 x 12,0 " / 305 mm shells or 2,9 torpedoes
Stability (Unstable if below 1.00): 1,05
Metacentric height 3,6 ft / 1,1 m
Roll period: 16,6 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0,93
Seaboat quality (Average = 1.00): 1,01

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0,466 / 0,476
Length to Beam Ratio: 8,80 : 1
'Natural speed' for length: 29,75 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 30,00 degrees
Stern overhang: 5,00 ft / 1,52 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20,00%, 28,26 ft / 8,61 m, 23,12 ft / 7,05 m
- Forward deck: 30,00%, 23,12 ft / 7,05 m, 17,98 ft / 5,48 m
- Aft deck: 35,00%, 17,98 ft / 5,48 m, 17,98 ft / 5,48 m
- Quarter deck: 15,00%, 17,98 ft / 5,48 m, 17,98 ft / 5,48 m
- Average freeboard: 20,19 ft / 6,15 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 92,9%
- Above water (accommodation/working, high = better): 145,7%
Waterplane Area: 33.253 Square feet or 3.089 Square metres
Displacement factor (Displacement / loading): 103%
Structure weight / hull surface area: 164 lbs/sq ft or 801 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,94
- Longitudinal: 1,73
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

[Lascaris]

And Light cruisers

The 1914 ships, effectively improved Chicuma class ships

Chikuma, Japan cruiser laid down 1914

Displacement:
5.302 t light; 5.500 t standard; 6.050 t normal; 6.490 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(490,00 ft / 490,00 ft) x 50,00 ft x (16,75 / 17,68 ft)
(149,35 m / 149,35 m) x 15,24 m x (5,11 / 5,39 m)

Armament:
8 - 6,00" / 152 mm 45,0 cal guns - 108,93lbs / 49,41kg shells, 150 per gun
Breech loading guns in deck and hoist mounts, 1914 Model
8 x Single mounts on centreline ends, evenly spread
4 - 3,00" / 76,2 mm 45,0 cal guns - 13,62lbs / 6,18kg shells, 150 per gun
Anti-air guns in deck mounts, 1914 Model
4 x Single mounts on sides, evenly spread
Weight of broadside 926 lbs / 420 kg
Main Torpedoes
12 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,649 t each, 19,782 t total
In 3 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,50" / 89 mm 386,00 ft / 117,65 m 8,49 ft / 2,59 m
Ends: Unarmoured
Main Belt covers 121% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2,00" / 51 mm - -

- Armoured deck - multiple decks:
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,
Geared drive, 2 shafts, 52.120 shp / 38.881 Kw = 30,00 kts
Range 10.000nm at 10,00 kts
Bunker at max displacement = 990 tons

Complement:
342 - 445

Cost:
£0,702 million / $2,809 million

Distribution of weights at normal displacement:
Armament: 265 tons, 4,4%
- Guns: 240 tons, 4,0%
- Weapons: 25 tons, 0,4%
Armour: 1.033 tons, 17,1%
- Belts: 456 tons, 7,5%
- Armament: 45 tons, 0,7%
- Armour Deck: 503 tons, 8,3%
- Conning Tower: 29 tons, 0,5%
Machinery: 2.008 tons, 33,2%
Hull, fittings & equipment: 1.996 tons, 33,0%
Fuel, ammunition & stores: 748 tons, 12,4%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5.092 lbs / 2.310 Kg = 47,2 x 6,0 " / 152 mm shells or 0,7 torpedoes
Stability (Unstable if below 1.00): 1,23
Metacentric height 2,6 ft / 0,8 m
Roll period: 13,1 seconds
Steadiness - As gun platform (Average = 50 %): 59 %
- Recoil effect (Restricted arc if above 1.00): 0,34
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): 0,516 / 0,524
Length to Beam Ratio: 9,80 : 1
'Natural speed' for length: 22,14 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 59
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%, 24,35 ft / 7,42 m, 15,50 ft / 4,72 m
- Forward deck: 30,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Aft deck: 35,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Quarter deck: 15,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Average freeboard: 16,21 ft / 4,94 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120,8%
- Above water (accommodation/working, high = better): 138,2%
Waterplane Area: 16.565 Square feet or 1.539 Square metres
Displacement factor (Displacement / loading): 103%
Structure weight / hull surface area: 81 lbs/sq ft or 395 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,98
- Longitudinal: 1,28
- Overall: 1,01
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1917 ships, practically repeats of the 1914 class

Chikuma, Japan cruiser laid down 1917

Displacement:
5.086 t light; 5.278 t standard; 5.757 t normal; 6.140 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(490,00 ft / 490,00 ft) x 50,00 ft x (16,75 / 17,58 ft)
(149,35 m / 149,35 m) x 15,24 m x (5,11 / 5,36 m)

Armament:
8 - 6,00" / 152 mm 45,0 cal guns - 108,93lbs / 49,41kg shells, 150 per gun
Breech loading guns in deck and hoist mounts, 1917 Model
8 x Single mounts on centreline ends, evenly spread
4 - 3,00" / 76,2 mm 45,0 cal guns - 13,62lbs / 6,18kg shells, 150 per gun
Anti-air guns in deck mounts, 1917 Model
4 x Single mounts on sides, evenly spread
Weight of broadside 926 lbs / 420 kg
Main Torpedoes
12 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,661 t each, 19,926 t total
In 3 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,50" / 89 mm 386,00 ft / 117,65 m 8,49 ft / 2,59 m
Ends: Unarmoured
Main Belt covers 121% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2,00" / 51 mm - -

- Armoured deck - multiple decks:
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,
Geared drive, 2 shafts, 49.913 shp / 37.235 Kw = 30,00 kts
Range 10.000nm at 10,00 kts
Bunker at max displacement = 862 tons

Complement:
329 - 429

Cost:
£0,944 million / $3,776 million

Distribution of weights at normal displacement:
Armament: 265 tons, 4,6%
- Guns: 240 tons, 4,2%
- Weapons: 25 tons, 0,4%
Armour: 1.020 tons, 17,7%
- Belts: 456 tons, 7,9%
- Armament: 45 tons, 0,8%
- Armour Deck: 492 tons, 8,5%
- Conning Tower: 28 tons, 0,5%
Machinery: 1.830 tons, 31,8%
Hull, fittings & equipment: 1.971 tons, 34,2%
Fuel, ammunition & stores: 671 tons, 11,7%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5.194 lbs / 2.356 Kg = 48,1 x 6,0 " / 152 mm shells or 0,8 torpedoes
Stability (Unstable if below 1.00): 1,21
Metacentric height 2,5 ft / 0,8 m
Roll period: 13,3 seconds
Steadiness - As gun platform (Average = 50 %): 61 %
- Recoil effect (Restricted arc if above 1.00): 0,36
Seaboat quality (Average = 1.00): 1,04

Hull form characteristics:
Hull has a flush deck,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0,491 / 0,499
Length to Beam Ratio: 9,80 : 1
'Natural speed' for length: 22,14 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 59
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%, 24,35 ft / 7,42 m, 15,50 ft / 4,72 m
- Forward deck: 30,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Aft deck: 35,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Quarter deck: 15,00%, 15,50 ft / 4,72 m, 15,50 ft / 4,72 m
- Average freeboard: 16,21 ft / 4,94 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 117,0%
- Above water (accommodation/working, high = better): 140,4%
Waterplane Area: 16.191 Square feet or 1.504 Square metres
Displacement factor (Displacement / loading): 105%
Structure weight / hull surface area: 81 lbs/sq ft or 398 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,98
- Longitudinal: 1,33
- Overall: 1,01
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1919 ships. This are Japanese Kuma/Nagara type ships differing in the main battery from the Japanese originals. Practically just very large destroyers...

Enter ship name, Enter country Enter ship type laid down 1919

Displacement:
4.998 t light; 5.191 t standard; 5.604 t normal; 5.933 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(529,13 ft / 520,00 ft) x 46,50 ft x (15,75 / 16,44 ft)
(161,28 m / 158,50 m) x 14,17 m x (4,80 / 5,01 m)

Armament:
8 - 6,00" / 152 mm 50,0 cal guns - 114,33lbs / 51,86kg shells, 150 per gun
Breech loading guns in deck and hoist mounts, 1919 Model
4 x Twin mounts on centreline ends, evenly spread
8 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 500 per gun
Anti-air guns in deck mounts, 1919 Model
8 x Single mounts on sides, evenly spread
Weight of broadside 932 lbs / 423 kg
Main Torpedoes
8 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,669 t each, 13,348 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,00" / 76 mm 312,00 ft / 95,10 m 8,18 ft / 2,49 m
Ends: Unarmoured
Main Belt covers 92% of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3,00" / 76 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 1,50" / 38 mm

- Conning towers: Forward 1,50" / 38 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 82.722 shp / 61.711 Kw = 35,00 kts
Range 9.000nm at 10,00 kts
Bunker at max displacement = 742 tons

Complement:
323 - 420

Cost:
£1,492 million / $5,967 million

Distribution of weights at normal displacement:
Armament: 239 tons, 4,3%
- Guns: 222 tons, 4,0%
- Weapons: 17 tons, 0,3%
Armour: 724 tons, 12,9%
- Belts: 315 tons, 5,6%
- Armament: 35 tons, 0,6%
- Armour Deck: 364 tons, 6,5%
- Conning Tower: 10 tons, 0,2%
Machinery: 2.938 tons, 52,4%
Hull, fittings & equipment: 1.098 tons, 19,6%
Fuel, ammunition & stores: 605 tons, 10,8%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.174 lbs / 533 Kg = 10,9 x 6,0 " / 152 mm shells or 0,3 torpedoes
Stability (Unstable if below 1.00): 1,43
Metacentric height 2,9 ft / 0,9 m
Roll period: 11,4 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0,37
Seaboat quality (Average = 1.00): 1,05

Hull form characteristics:
Hull has raised forecastle,
a normal bow and small transom stern
Block coefficient (normal/deep): 0,515 / 0,522
Length to Beam Ratio: 11,18 : 1
'Natural speed' for length: 24,33 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 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%, 25,08 ft / 7,64 m, 25,08 ft / 7,64 m
- Forward deck: 30,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Aft deck: 30,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Quarter deck: 15,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Average freeboard: 18,24 ft / 5,56 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 185,1%
- Above water (accommodation/working, high = better): 154,0%
Waterplane Area: 16.728 Square feet or 1.554 Square metres
Displacement factor (Displacement / loading): 74%
Structure weight / hull surface area: 41 lbs/sq ft or 201 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,48
- Longitudinal: 0,85
- Overall: 0,51
Caution: Hull subject to strain in open-sea
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1921 ships, follow ups to the 1919

Enter ship name, Enter country Enter ship type laid down 1921

Displacement:
4.937 t light; 5.132 t standard; 5.695 t normal; 6.146 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(529,13 ft / 520,00 ft) x 48,50 ft x (16,00 / 16,92 ft)
(161,28 m / 158,50 m) x 14,78 m x (4,88 / 5,16 m)

Armament:
8 - 6,00" / 152 mm 50,0 cal guns - 114,33lbs / 51,86kg shells, 150 per gun
Breech loading guns in deck and hoist mounts, 1921 Model
4 x Twin mounts on centreline ends, evenly spread
8 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 500 per gun
Anti-air guns in deck mounts, 1921 Model
8 x Single mounts on sides, evenly spread
Weight of broadside 932 lbs / 423 kg
Main Torpedoes
8 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,677 t each, 13,412 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3,00" / 76 mm 286,00 ft / 87,17 m 8,36 ft / 2,55 m
Ends: Unarmoured
Main Belt covers 85% of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3,00" / 76 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 1,50" / 38 mm

- Conning towers: Forward 1,50" / 38 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 82.911 shp / 61.852 Kw = 35,00 kts
Range 13.000nm at 10,00 kts
Bunker at max displacement = 1.015 tons

Complement:
327 - 426

Cost:
£1,705 million / $6,822 million

Distribution of weights at normal displacement:
Armament: 239 tons, 4,2%
- Guns: 222 tons, 3,9%
- Weapons: 17 tons, 0,3%
Armour: 717 tons, 12,6%
- Belts: 300 tons, 5,3%
- Armament: 35 tons, 0,6%
- Armour Deck: 372 tons, 6,5%
- Conning Tower: 10 tons, 0,2%
Machinery: 2.855 tons, 50,1%
Hull, fittings & equipment: 1.126 tons, 19,8%
Fuel, ammunition & stores: 759 tons, 13,3%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.331 lbs / 604 Kg = 12,3 x 6,0 " / 152 mm shells or 0,4 torpedoes
Stability (Unstable if below 1.00): 1,48
Metacentric height 3,3 ft / 1,0 m
Roll period: 11,2 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0,31
Seaboat quality (Average = 1.00): 1,03

Hull form characteristics:
Hull has raised forecastle,
a normal bow and small transom stern
Block coefficient (normal/deep): 0,494 / 0,504
Length to Beam Ratio: 10,72 : 1
'Natural speed' for length: 24,40 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 49
Bow angle (Positive = bow angles forward): 20,00 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%, 25,08 ft / 7,64 m, 25,08 ft / 7,64 m
- Forward deck: 30,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Aft deck: 30,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Quarter deck: 15,00%, 15,96 ft / 4,86 m, 15,96 ft / 4,86 m
- Average freeboard: 18,24 ft / 5,56 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 177,5%
- Above water (accommodation/working, high = better): 155,7%
Waterplane Area: 17.111 Square feet or 1.590 Square metres
Displacement factor (Displacement / loading): 77%
Structure weight / hull surface area: 42 lbs/sq ft or 207 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,48
- Longitudinal: 0,83
- Overall: 0,51
Caution: Hull subject to strain in open-sea
Cramped machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1923 ships, the first genuine large light cruisers

Enter ship name, Enter country Enter ship type laid down 1923

Displacement:
8.648 t light; 9.008 t standard; 9.918 t normal; 10.645 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(629,97 ft / 620,00 ft) x 62,00 ft x (21,00 / 22,03 ft)
(192,01 m / 188,98 m) x 18,90 m x (6,40 / 6,72 m)

Armament:
12 - 6,00" / 152 mm 50,0 cal guns - 114,33lbs / 51,86kg shells, 150 per gun
Breech loading guns in deck and hoist mounts, 1923 Model
4 x 3-gun mounts on centreline ends, evenly spread
2 raised mounts - superfiring
8 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1923 Model
8 x Single mounts on sides, evenly spread
12 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 500 per gun
Anti-air guns in deck mount, 1923 Model
1 x Single mount on sides amidships
Weight of broadside 1.877 lbs / 851 kg
Main Torpedoes
12 - 21,0" / 533 mm, 26,25 ft / 8,00 m torpedoes - 1,685 t each, 20,214 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4,00" / 102 mm 440,00 ft / 134,11 m 9,45 ft / 2,88 m
Ends: Unarmoured
Main Belt covers 109% of normal length

- Torpedo Bulkhead - Strengthened structural bulkheads:
1,00" / 25 mm 440,00 ft / 134,11 m 17,22 ft / 5,25 m
Beam between torpedo bulkheads 62,00 ft / 18,90 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 5,00" / 127 mm 2,00" / 51 mm 5,00" / 127 mm
2nd: 2,00" / 51 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 2,00" / 51 mm

- Conning towers: Forward 1,50" / 38 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 83.373 shp / 62.196 Kw = 33,00 kts
Range 15.000nm at 10,00 kts
Bunker at max displacement = 1.637 tons

Complement:
496 - 645

Cost:
£2,559 million / $10,236 million

Distribution of weights at normal displacement:
Armament: 562 tons, 5,7%
- Guns: 536 tons, 5,4%
- Weapons: 25 tons, 0,3%
Armour: 1.833 tons, 18,5%
- Belts: 671 tons, 6,8%
- Torpedo bulkhead: 280 tons, 2,8%
- Armament: 153 tons, 1,5%
- Armour Deck: 714 tons, 7,2%
- Conning Tower: 15 tons, 0,2%
Machinery: 2.787 tons, 28,1%
Hull, fittings & equipment: 3.467 tons, 35,0%
Fuel, ammunition & stores: 1.269 tons, 12,8%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
10.443 lbs / 4.737 Kg = 96,7 x 6,0 " / 152 mm shells or 1,3 torpedoes
Stability (Unstable if below 1.00): 1,25
Metacentric height 3,6 ft / 1,1 m
Roll period: 13,6 seconds
Steadiness - As gun platform (Average = 50 %): 56 %
- Recoil effect (Restricted arc if above 1.00): 0,39
Seaboat quality (Average = 1.00): 1,12

Hull form characteristics:
Hull has a flush deck,
a normal bow and small transom stern
Block coefficient (normal/deep): 0,430 / 0,440
Length to Beam Ratio: 10,00 : 1
'Natural speed' for length: 26,85 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 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%, 27,39 ft / 8,35 m, 17,43 ft / 5,31 m
- Forward deck: 30,00%, 17,43 ft / 5,31 m, 17,43 ft / 5,31 m
- Aft deck: 30,00%, 17,43 ft / 5,31 m, 17,43 ft / 5,31 m
- Quarter deck: 15,00%, 17,43 ft / 5,31 m, 17,43 ft / 5,31 m
- Average freeboard: 18,43 ft / 5,62 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 108,8%
- Above water (accommodation/working, high = better): 161,6%
Waterplane Area: 24.694 Square feet or 2.294 Square metres
Displacement factor (Displacement / loading): 108%
Structure weight / hull surface area: 106 lbs/sq ft or 515 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,97
- Longitudinal: 1,27
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

The 1925 ships. Yes these are classified as light cruisers. If they were heavy cruisers they'd have 9.2 or 12in pieces.

Enter ship name, Enter country Enter ship type laid down 1925

Displacement:
10.516 t light; 11.023 t standard; 12.154 t normal; 13.058 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(629,97 ft / 620,00 ft) x 62,00 ft x (22,00 / 23,19 ft)
(192,01 m / 188,98 m) x 18,90 m x (6,71 / 7,07 m)

Armament:
12 - 8,00" / 203 mm 50,0 cal guns - 271,01lbs / 122,93kg shells, 120 per gun
Breech loading guns in deck and hoist mounts, 1925 Model
3 x 4-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
8 - 5,00" / 127 mm 40,0 cal guns - 59,90lbs / 27,17kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1925 Model
8 x Single mounts on sides, evenly spread
12 - 1,57" / 40,0 mm 62,0 cal guns - 2,16lbs / 0,98kg shells, 500 per gun
Anti-air guns in deck mount, 1925 Model
1 x Single mount on sides amidships
Weight of broadside 3.757 lbs / 1.704 kg
Main Torpedoes
12 - 24,0" / 610 mm, 30,00 ft / 9,14 m torpedoes - 2,457 t each, 29,490 t total
In 4 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4,00" / 102 mm 440,00 ft / 134,11 m 11,45 ft / 3,49 m
Ends: Unarmoured
Main Belt covers 109% of normal length

- Torpedo Bulkhead - Strengthened structural bulkheads:
1,50" / 38 mm 440,00 ft / 134,11 m 19,50 ft / 5,94 m
Beam between torpedo bulkheads 62,00 ft / 18,90 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 5,00" / 127 mm 2,00" / 51 mm 5,00" / 127 mm
2nd: 2,00" / 51 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 2,60" / 66 mm

- Conning towers: Forward 1,50" / 38 mm, Aft 0,00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 91.989 shp / 68.624 Kw = 33,00 kts
Range 8.000nm at 14,00 kts
Bunker at max displacement = 2.035 tons

Complement:
578 - 752

Cost:
£3,822 million / $15,289 million

Distribution of weights at normal displacement:
Armament: 1.111 tons, 9,1%
- Guns: 1.074 tons, 8,8%
- Weapons: 37 tons, 0,3%
Armour: 2.495 tons, 20,5%
- Belts: 818 tons, 6,7%
- Torpedo bulkhead: 476 tons, 3,9%
- Armament: 176 tons, 1,5%
- Armour Deck: 1.007 tons, 8,3%
- Conning Tower: 17 tons, 0,1%
Machinery: 2.987 tons, 24,6%
Hull, fittings & equipment: 3.924 tons, 32,3%
Fuel, ammunition & stores: 1.637 tons, 13,5%
Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
12.061 lbs / 5.471 Kg = 47,1 x 8,0 " / 203 mm shells or 1,0 torpedoes
Stability (Unstable if below 1.00): 1,16
Metacentric height 3,2 ft / 1,0 m
Roll period: 14,5 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,77
Seaboat quality (Average = 1.00): 1,01

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0,503 / 0,513
Length to Beam Ratio: 10,00 : 1
'Natural speed' for length: 28,41 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 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%, 27,39 ft / 8,35 m, 22,41 ft / 6,83 m
- Forward deck: 30,00%, 22,41 ft / 6,83 m, 17,43 ft / 5,31 m
- Aft deck: 30,00%, 17,43 ft / 5,31 m, 17,43 ft / 5,31 m
- Quarter deck: 15,00%, 17,43 ft / 5,31 m, 17,43 ft / 5,31 m
- Average freeboard: 19,92 ft / 6,07 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 108,3%
- Above water (accommodation/working, high = better): 159,9%
Waterplane Area: 26.709 Square feet or 2.481 Square metres
Displacement factor (Displacement / loading): 100%
Structure weight / hull surface area: 120 lbs/sq ft or 584 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,96
- Longitudinal: 1,41
- Overall: 1,00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

[Ma Deuce]

So I have been pondering rather hard on this: With some of our ship designs with fantastically wide bulges. Will there be an issue that a shell lands on the bulge and inflict substantial damage to the ship? Or does Spring Sharp assume the bulge is filled with material or is compartmentalised or what?

I would assume the bulges are compartmentalized, because that was in fact the case with every single real life application of bulging on warships I can think of; generally the bulges would have to be compartmentalized to maintain structural integrity anyway. As long as you have good underwater protection, (i.e torpedo bulkheads or armor on the exterior of the bulge itself) a single hole in a bulge should not seriously threaten the ship so long as the damage is contained outside the habitable spaces. Provided the bulges are not completely filled with a void material or other deadweight (i.e fuel) wide bulges will allow for very effective application of counterflooding in the event of damage, since the need to flood habitable spaces will be reduced (since void spaces obviously don't need to be evacuated before flooding, nor do they contain vital systems that the flooding will disable, adding to the effects of damage already taken).

I should reiterate that there are downsides to using bulges to add more weight to a vessel of a given displacement, in that your ship will not be able to take on as much water before sinking, given that the volume of the above-water portion of the hull will be less than an unbulged ship of the same displacement. You can see this reflected in Springsharp's survivability calculations (as unrealistic as the torpedo and shell hit figures are, the basic number from which they're derived is still useful for comparing the survivability of designs to each other).

[Thanas]

Hmmm. I prefer 6 inch quickfiring guns in my light cruisers because they have the job of hunting down or defending the fleet against destroyers. I am not sure if 8" is the best caliber for that.

Aside from that, I think your ships are a bit underarmored, but we had that discussion too many times now.

[Lascaris]

Hmmm. I prefer 6 inch quickfiring guns in my light cruisers because they have the job of hunting down or defending the fleet against destroyers. I am not sure if 8" is the best caliber for that.

Aside from that, I think your ships are a bit underarmored, but we had that discussion too many times now.

I'll just point that real life heavy cruisers had less.

The 5000 tonners sure. These are very large DDs with very large torpedoes

[Thanas]

I'll just point that real life heavy cruisers had less.

Yeah, this is beating a dead horse.

The 5000 tonners sure. These are very large DDs with very large torpedoes

My 1924 DD could probably win against one of those. That said, I find it curious why you would not use a 10000 ton hull for a large light cruiser, for example I find my 10000ton light cruiser to be an excellent example of a ship equipped with quickfiring guns.

Then again, you having some sort of semi-heavy cruiser fits well within your design philosophy and might make sense for a nation that does not have so much resources to pour into the Navy.

[Thanas]

Ghetto edit: Lascaris, you might want to try and get your large light cruiser to 10kt, as otherwise it will cost you much more to built them.

[Ma Deuce]

Hmmm. I prefer 6 inch quickfiring guns in my light cruisers because they have the job of hunting down or defending the fleet against destroyers. I am not sure if 8" is the best caliber for that.

I'm sure I pointed this out prior, but an 8" gunned cruiser would in fact be called a light cruiser in the '20s, since the term heavy cruiser did not exist until the London naval treaty of 1930, which differentiated cruisers with 6" and 8" main batteries rather than simply imposing an upper limit as the Washington treaty had. You'll notice that major navies laid down few to no cruisers with guns smaller than 8" between the point those types first appeared in their fleets, and the London naval treaty, which produced incentive to once again build larger 6" gunned "light" cruisers. Of course this goes for Lascaris as well, given his 9.2-12" armed "heavy cruisers".

For the record, my largest cruisers in service (discounting battlecruisers) displace 10,000 tons and are armed with 7.9 inch guns. They're designated "light cruisers" as a ship of that description historically would be called in the '20s. Of course, I'm also building smaller, faster scout cruisers alongside those, which are presently armed with six 5.5 inch deck guns (I'll be moving to 6.3 inches shortly, along with powered hoists & rammers in enclosed turrets)

[Thanas]

Not disputing any of that. But for defending against destroyers a fast ship armed with numerous 6" quickfiring guns seems to me to be the better choice. Also, according to my doctrine their job is not to go up against other light cruisers, I have heavy or battlecruisers for that. Hence, quickfiring 6" guns.


I am also using the terminology because the German Navy did differentiate between light (kleine) and heavy (Große) Kreuzer even back then. Of course, you might argue that small and big does not equal light and heavy cruisers, but this is close enough for my taste.

[Lascaris]

Ghetto edit: Lascaris, you might want to try and get your large light cruiser to 10kt, as otherwise it will cost you much more to built them.

I know. The 1925 design is after all inspired by the Myoko class heavy cruisers (if not using the same hull I can't recall). Now I could just go copy Myoko and claim it was really 10,000t Wikipedia says so after all. Conways says it was 11,000 though hence...

Besides the ships start construction in Q1 1925. I'm not going to change their tonnage now.

[Lascaris]

I'll just point that real life heavy cruisers had less.

Yeah, this is beating a dead horse.

The 5000 tonners sure. These are very large DDs with very large torpedoes

My 1924 DD could probably win against one of those. That said, I find it curious why you would not use a 10000 ton hull for a large light cruiser, for example I find my 10000ton light cruiser to be an excellent example of a ship equipped with quickfiring guns.

Then again, you having some sort of semi-heavy cruiser fits well within your design philosophy and might make sense for a nation that does not have so much resources to pour into the Navy.

The 5,000 tonners have to be taken into the contect of the time they get built namely the 1910s and early years of the 1920s. Compared to their contemporaries they are nasty pieces of work very much like their Japanese counterparts on which they were based.

Whether your 1924 DDs can take them on... they have 8 6in guns, make 35 knots and are armored. So unless your DDs are much better than the Fubuki clones Cisplatina and Chilitina are making which I find... implausible I'll still still with the light cruisers.

Post that my 1923 design is probably the only example of a true treaty light cruiser with Cisplatina, it's comparable to the Town class cruisers after all...

[Ma Deuce]

Not disputing any of that. But for defending against destroyers a fast ship armed with numerous 6" quickfiring guns seems to me to be the better choice. Also, according to my doctrine their job is not to go up against other light cruisers, I have heavy or battlecruisers for that. Hence, quickfiring 6" guns.

I recognize the value of smaller quick-firing guns for destroyer-killing, hence why it's one of the roles of my so-called scout cruisers, along with scouting (naturally) and flotilla leading. My "Light Cruisers" are more intended for general cruiser work, including engaging other cruisers. Although I didn't have a huge number of SCs at the time, my 8" gunned light cruiser class was built with the knowledge that when they joined the fleet, there would already be a large number of older 5.5" gunned light cruisers already in service that are still quite effective against DDs, and by the time they retired, there would be enough new scout cruisers for anti-destroyer screening. My logic is that if you're going to build a cruiser for destroyer killing (that's not meant to take on other cruisers), it's better to have a smaller faster ship that can still decisively outgun your typical destroyer, than less-numerous big cruisers with a large number of QF guns each: Destroyers are plentiful, and one ship can only engage so many targets at once. It just so happened my scout cruisers did that job well enough that I figured it was better to simply build more of them then creating a specialized type.

I am also using the terminology because the German Navy did differentiate between light (kleine) and heavy (Große) Kreuzer even back then. Of course, you might argue that small and big does not equal light and heavy cruisers, but this is close enough for my taste.

I thought that "Große Kreuzer" was the Kaiserliche Marine's designation for what everyone else called a battlecruiser? In a similar vein, I also seem recall them designating their battleships as "Linienschiff". However as an aside, I'll note the later Kriegsmarine apparently switched to to more conventional "Schlachtschiff" and "Schlachtkreuzer".

[Fingolfin_Noldor]

One thing about Spring Sharp I have found, is that it likely overestimates the weight of a lot of things. As such, it's quite possible a real life cruiser would have less armor, but yet the armor height is greater, but the armor tapers off. I'm not sure how Spring Sharp works out that bit.

In general, I adhere to a "armor height is 66% of the fore/aft freeboard" rule at the least. Hence, my 16,000 tonne cruiser has 9" belt, but 18ft in height, along with a 3" deck and 3" torpedo bulkhead, and also having a 60ft between beams to increase damage tolerance. Of course, I tend to over armor, because I prefer to emphasize on ship survivability over absolute firepower, while also affording some decent range and speed. The same ship in question makes 15kts for 10,000nm, with a top speed of 30kts.

Personally, my next cruiser killer would be quite close to the Alaska class battlecruisers.

[Steve]

What's her armament? She sounds like a smaller, less well-armed equivalent of my Lightning.

[Fingolfin_Noldor]

What's her armament? She sounds like a smaller, less well-armed equivalent of my Lightning.

9 8" guns, along with 12 5"/25s. Likely I will produce a model with 12 5"/38s, and maybe a slight improvement in main armament.

[Steve]

Hrm. Lightning has 9 10"/51 and 16 5"/43 DP, plus 24 40mm/40 AA guns. 13" belt, 5" deck, 33.5 knot top speed. But she's 30,000+ tons so you can build nearly two of your's for the same price, so to speak.

Lightning was built for "commerce defense" and in a pinch can be a fleet scout. She hunts down and kills raider cruisers or threats like the AMCs of Shepistan or the Grand Dominion, but her guns were intentionally kept small enough that not only could they have her lighter with a nice armament but that it would remove any temptation of admirals to put her into a line of battle. 10" guns, even 12" guns arguably, just aren't enough for such. It was intended to have the protection to face ships with similar armament to either kill them first or to escape with her powerful engines, 184,000hp in four shafts for 33.5 knots. And with fuel bunkers big enough for 10,000nm at 18 knots.

I'm contemplating a 1926 followup, Artemis.

[Fingolfin_Noldor]

My ship was meant both as commerce raider, though at 31knots, kill the other cruisers, with enough armor to soak up the punishment meted out, and at the same time serve as a picket ship for the battle line. The next follow up is likely to have some improvements to armament, as well as maybe speed.

A 9 12"/50 cruiser is in the works primarily to kill other cruisers, and make life miserable for any old dreadnought still in the land of the living. Which means my oldest 4 dreadnaughts can start kicking the bucket in stages.

[Steve]

Interesting. How secret is the project? Attempting to make a 9 12"/50 cruiser has generally forced me to go up to 35,000T, but I suppose if I cut the armor and engine plant size it could fit a 20-25,000T profile. (Also, I decided 12"/50 may be too much for the mission, though if I plausibly have to deal with 9" belts and such and thicker decks on certain cruisers I may do so.)

[Fingolfin_Noldor]

Interesting. How secret is the project? Attempting to make a 9 12"/50 cruiser has generally forced me to go up to 35,000T, but I suppose if I cut the armor and engine plant size it could fit a 20-25,000T profile. (Also, I decided 12"/50 may be too much for the mission, though if I plausibly have to deal with 9" belts and such and thicker decks on certain cruisers I may do so.)

I think rather i've been rather lazy at making story posts. I haven't bothered to announce the specs of the new ships at all.

But yeah, the tonnage of the ship hit 35,000 tonnes thereabouts. I posted the design up not too long ago actually.

Anyhow, reposting it here:

Colosseum, Byzantium Cruiser laid down 1928

Displacement:
32,576 t light; 34,429 t standard; 38,046 t normal; 40,940 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(804.96 ft / 771.00 ft) x 95.14 ft x (36.09 / 38.11 ft)
(245.35 m / 235.00 m) x 29.00 m x (11.00 / 11.62 m)

Armament:
9 - 12.00" / 305 mm 50.0 cal guns - 999.99lbs / 453.59kg shells, 120 per gun
Breech loading guns in turret on barbette mounts, 1928 Model
3 x 3-gun mounts on centreline ends, majority forward
1 raised mount - superfiring
12 - 5.00" / 127 mm 38.0 cal guns - 59.33lbs / 26.91kg shells, 1,000 per gun
Dual purpose guns in deck and hoist mounts, 1928 Model
8 x Twin mounts on sides, evenly spread
4 raised mounts
32 - 1.57" / 40.0 mm 60.0 cal guns - 2.14lbs / 0.97kg shells, 2,000 per gun
Anti-air guns in deck mounts, 1928 Model
8 x 4-gun mounts on sides, evenly spread
4 raised mounts
40 - 0.79" / 20.0 mm 39.0 cal guns - 0.22lbs / 0.10kg shells, 4,000 per gun
Anti-air guns in deck mounts, 1928 Model
10 x 4-gun mounts on sides, evenly spread
16 - 0.50" / 12.7 mm 12.0 cal guns - 0.04lbs / 0.02kg shells, 3,000 per gun
Machine guns in deck mounts, 1928 Model
16 x Single mounts on sides, evenly spread
Weight of broadside 9,790 lbs / 4,441 kg
Main Torpedoes
6 - 21.0" / 533 mm, 30.00 ft / 9.14 m torpedoes - 1.918 t each, 11.510 t total
In 12 sets of deck mounted carriage/fixed tubes
2nd Torpedoes
6 - 21.0" / 533 mm, 30.00 ft / 9.14 m torpedoes - 1.918 t each, 11.510 t total
In 12 sets of deck mounted carriage/fixed tubes
Mines
6 - 0.00 lbs / 0.00 kg mines + 6 reloads - 0.000 t total
in Above water - Stern racks/rails

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.5" / 318 mm 500.00 ft / 152.40 m 16.00 ft / 4.88 m
Ends: Unarmoured
Main Belt covers 100 % of normal length
Main Belt inclined 19.00 degrees (positive = in)

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 500.00 ft / 152.40 m 33.00 ft / 10.06 m
Beam between torpedo bulkheads 70.00 ft / 21.34 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 15.0" / 381 mm 10.0" / 254 mm 12.5" / 318 mm
2nd: 2.50" / 64 mm 2.50" / 64 mm 2.50" / 64 mm
3rd: 0.50" / 13 mm 0.50" / 13 mm -
4th: 0.50" / 13 mm 0.50" / 13 mm -
5th: 0.50" / 13 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 5.00" / 127 mm
Forecastle: 1.00" / 25 mm Quarter deck: 1.00" / 25 mm

- Conning towers: Forward 9.00" / 229 mm, Aft 4.00" / 102 mm

Machinery:
Oil fired boilers, steam turbines,
Electric motors, 4 shafts, 185,246 shp / 138,194 Kw = 33.00 kts
Range 12,000nm at 15.00 kts
Bunker at max displacement = 6,511 tons

Complement:
1,361 - 1,770

Cost:
£10.941 million / $43.763 million

Distribution of weights at normal displacement:
Armament: 2,191 tons, 5.8 %
- Guns: 2,162 tons, 5.7 %
- Weapons: 29 tons, 0.1 %
Armour: 12,463 tons, 32.8 %
- Belts: 4,206 tons, 11.1 %
- Torpedo bulkhead: 1,832 tons, 4.8 %
- Armament: 2,416 tons, 6.3 %
- Armour Deck: 3,693 tons, 9.7 %
- Conning Towers: 317 tons, 0.8 %
Machinery: 5,767 tons, 15.2 %
Hull, fittings & equipment: 12,079 tons, 31.7 %
Fuel, ammunition & stores: 5,470 tons, 14.4 %
Miscellaneous weights: 75 tons, 0.2 %
- On freeboard deck: 75 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
46,387 lbs / 21,041 Kg = 53.7 x 12.0 " / 305 mm shells or 5.0 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 4.6 ft / 1.4 m
Roll period: 18.6 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.58
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has a flush deck,
an extended bulbous bow and small transom stern
Block coefficient (normal/deep): 0.503 / 0.513
Length to Beam Ratio: 8.10 : 1
'Natural speed' for length: 30.08 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 68
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 13.12 ft / 4.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 30.00 %, 36.09 ft / 11.00 m, 26.25 ft / 8.00 m
- Forward deck: 25.00 %, 26.25 ft / 8.00 m, 19.69 ft / 6.00 m
- Aft deck: 30.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Quarter deck: 15.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Average freeboard: 23.65 ft / 7.21 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 99.4 %
- Above water (accommodation/working, high = better): 146.9 %
Waterplane Area: 50,185 Square feet or 4,662 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 172 lbs/sq ft or 842 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.45
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

I might retool the ship to have a thicker deck, but 5" might be sufficient.