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1

Sunday, December 13th 2009, 10:12pm

Light Cruiser Design

I think I should start my first thread here with a modest design, so a 6000 t standard cruiser sounds good:



Enter ship name, France Light Cruiser laid down 1938

Displacement:
5,682 t light; 6,000 t standard; 6,974 t normal; 7,754 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(533.61 ft / 524.93 ft) x 52.49 ft x (17.72 / 19.15 ft)
(162.64 m / 160.00 m) x 16.00 m x (5.40 / 5.84 m)

Armament:
8 - 5.91" / 150 mm 60.0 cal guns - 110.23lbs / 50.00kg shells, 200 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
2 x Quad mounts on centreline, forward deck forward
1 raised mount - superfiring
12 - 3.94" / 100.0 mm 55.0 cal guns - 27.56lbs / 12.50kg shells, 300 per gun
Dual purpose guns in deck and hoist mounts, 1938 Model
6 x Twin mounts on sides, evenly spread
2 raised mounts
24 - 1.57" / 40.0 mm 60.0 cal guns - 2.12lbs / 0.96kg shells, 800 per gun
Anti-air guns in deck mounts, 1938 Model
6 x Quad mounts on sides, evenly spread
4 raised mounts
16 - 0.79" / 20.0 mm 80.0 cal guns - 0.28lbs / 0.13kg shells, 1,000 per gun
Anti-air guns in deck mounts, 1938 Model
8 x Twin mounts on sides, evenly spread
4 raised mounts
Weight of broadside 1,268 lbs / 575 kg
Main Torpedoes
8 - 21.7" / 550 mm, 27.07 ft / 8.25 m torpedoes - 1.894 t each, 15.152 t total
In 2 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 344.49 ft / 105.00 m 8.20 ft / 2.50 m
Ends: Unarmoured
Main Belt covers 101% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.95" / 75 mm 1.97" / 50 mm 2.95" / 75 mm
2nd: 1.97" / 50 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.79" / 20 mm - -
4th: 0.39" / 10 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 1.97" / 50 mm
Forecastle: 0.98" / 25 mm Quarter deck: 0.98" / 25 mm

- Conning towers: Forward 2.95" / 75 mm, Aft 0.98" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,812 shp / 37,906 Kw = 30.50 kts
Range 9,360nm at 15.00 kts
Bunker at max displacement = 1,754 tons

Complement:
381 - 496

Cost:
£3.154 million / $12.614 million

Distribution of weights at normal displacement:
Armament: 424 tons, 6.1%
- Guns: 405 tons, 5.8%
- Weapons: 19 tons, 0.3%
Armour: 1,200 tons, 17.2%
- Belts: 343 tons, 4.9%
- Armament: 191 tons, 2.7%
- Armour Deck: 636 tons, 9.1%
- Conning Towers: 31 tons, 0.4%
Machinery: 1,391 tons, 20.0%
Hull, fittings & equipment: 2,627 tons, 37.7%
Fuel, ammunition & stores: 1,292 tons, 18.5%
Miscellaneous weights: 40 tons, 0.6%
- Above deck: 40 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
9,184 lbs / 4,166 Kg = 89.2 x 5.9 " / 150 mm shells or 1.0 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 1.9 ft / 0.6 m
Roll period: 16.0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.65
Seaboat quality (Average = 1.00): 1.09

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.500 / 0.514
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 26.15 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 64
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00%, 26.25 ft / 8.00 m, 19.69 ft / 6.00 m
- Forward deck: 20.00%, 19.69 ft / 6.00 m, 16.40 ft / 5.00 m
- Aft deck: 45.00%, 16.40 ft / 5.00 m, 16.40 ft / 5.00 m
- Quarter deck: 15.00%, 16.40 ft / 5.00 m, 16.40 ft / 5.00 m
- Average freeboard: 17.91 ft / 5.46 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 87.8%
- Above water (accommodation/working, high = better): 158.1%
Waterplane Area: 19,093 Square feet or 1,774 Square metres
Displacement factor (Displacement / loading): 124%
Structure weight / hull surface area: 93 lbs/sq ft or 456 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 1.49
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform


Any feedback is welcomed. I have to admit that she's slow for a cruiser though...

This post has been edited 1 times, last edit by "gaiasabre11" (Dec 13th 2009, 10:15pm)


2

Sunday, December 13th 2009, 10:18pm

RE: Light Cruiser Design

Quoted

Originally posted by gaiasabre11
Stability (Unstable if below 1.00): 1.00

Warning! Danger, Will Robinson, danger!

Personally, I like to see Stability at 1.10 or higher. It's helpful when you're flooding on one beam and need that extra stability to keep from rolling.

Otherwise, I don't see any obvious errors...

3

Sunday, December 13th 2009, 10:30pm

RE: Light Cruiser Design

Quoted

Originally posted by Brockpaine
Warning! Danger, Will Robinson, danger!

Personally, I like to see Stability at 1.10 or higher. It's helpful when you're flooding on one beam and need that extra stability to keep from rolling.

Otherwise, I don't see any obvious errors...


Haha, I know that, but it says unstable when below 1.00, not when it's right on 1.00. :p I have to admit that I'm a bit greedy when it comes to guns/armor though.

Anyways, the stability problem can be solved by adjusting the trim, which is really no big deal.

This post has been edited 2 times, last edit by "gaiasabre11" (Dec 13th 2009, 10:33pm)


4

Monday, December 14th 2009, 12:03am

Yes, unstable below 1.00. Of course 1 good flooding hit and you're below 1.00, hence why most shoot for 1.10 at least.

5

Monday, December 14th 2009, 12:09am

Revised:


Enter ship name, France Light Cruiser laid down 1938

Displacement:
5,682 t light; 6,000 t standard; 6,974 t normal; 7,754 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(533.61 ft / 524.93 ft) x 52.49 ft x (17.72 / 19.15 ft)
(162.64 m / 160.00 m) x 16.00 m x (5.40 / 5.84 m)

Armament:
8 - 5.91" / 150 mm 60.0 cal guns - 110.23lbs / 50.00kg shells, 200 per gun
Breech loading guns in turret on barbette mounts, 1938 Model
2 x Quad mounts on centreline, forward deck forward
1 raised mount - superfiring
12 - 3.94" / 100.0 mm 55.0 cal guns - 27.56lbs / 12.50kg shells, 300 per gun
Dual purpose guns in deck and hoist mounts, 1938 Model
6 x Twin mounts on sides, evenly spread
2 raised mounts
24 - 1.57" / 40.0 mm 60.0 cal guns - 2.12lbs / 0.96kg shells, 800 per gun
Anti-air guns in deck mounts, 1938 Model
6 x Quad mounts on sides, evenly spread
4 raised mounts
16 - 0.79" / 20.0 mm 80.0 cal guns - 0.29lbs / 0.13kg shells, 1,000 per gun
Anti-air guns in deck mounts, 1938 Model
8 x Twin mounts on sides, evenly spread
4 raised mounts
Weight of broadside 1,268 lbs / 575 kg
Main Torpedoes
8 - 21.7" / 550 mm, 27.07 ft / 8.25 m torpedoes - 1.894 t each, 15.152 t total
In 2 sets of deck mounted carriage/fixed tubes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 344.49 ft / 105.00 m 8.20 ft / 2.50 m
Ends: Unarmoured
Main Belt covers 101% of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.95" / 75 mm 1.97" / 50 mm 2.95" / 75 mm
2nd: 1.97" / 50 mm 0.98" / 25 mm 0.98" / 25 mm
3rd: 0.79" / 20 mm - -
4th: 0.39" / 10 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 1.97" / 50 mm
Forecastle: 0.98" / 25 mm Quarter deck: 0.98" / 25 mm

- Conning towers: Forward 2.95" / 75 mm, Aft 0.98" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 50,812 shp / 37,906 Kw = 30.50 kts
Range 9,360nm at 15.00 kts
Bunker at max displacement = 1,754 tons

Complement:
381 - 496

Cost:
£3.154 million / $12.614 million

Distribution of weights at normal displacement:
Armament: 424 tons, 6.1%
- Guns: 405 tons, 5.8%
- Weapons: 19 tons, 0.3%
Armour: 1,200 tons, 17.2%
- Belts: 343 tons, 4.9%
- Armament: 191 tons, 2.7%
- Armour Deck: 636 tons, 9.1%
- Conning Towers: 31 tons, 0.4%
Machinery: 1,391 tons, 20.0%
Hull, fittings & equipment: 2,627 tons, 37.7%
Fuel, ammunition & stores: 1,292 tons, 18.5%
Miscellaneous weights: 40 tons, 0.6%
- Above deck: 40 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
9,646 lbs / 4,375 Kg = 93.7 x 5.9 " / 150 mm shells or 1.1 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 2.3 ft / 0.7 m
Roll period: 14.6 seconds
Steadiness - As gun platform (Average = 50 %): 55 %
- Recoil effect (Restricted arc if above 1.00): 0.53
Seaboat quality (Average = 1.00): 1.09

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.500 / 0.514
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 26.15 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00%, 26.25 ft / 8.00 m, 19.69 ft / 6.00 m
- Forward deck: 20.00%, 19.69 ft / 6.00 m, 16.40 ft / 5.00 m
- Aft deck: 45.00%, 16.40 ft / 5.00 m, 16.40 ft / 5.00 m
- Quarter deck: 15.00%, 16.40 ft / 5.00 m, 16.40 ft / 5.00 m
- Average freeboard: 17.91 ft / 5.46 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 87.8%
- Above water (accommodation/working, high = better): 158.1%
Waterplane Area: 19,093 Square feet or 1,774 Square metres
Displacement factor (Displacement / loading): 124%
Structure weight / hull surface area: 93 lbs/sq ft or 456 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 1.49
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room

6

Monday, December 14th 2009, 12:34am

Sim-wise, it looks pretty decent. I'm not sure that 16m (minus whatever for being forward of the widest part of the ship) beam is going to be enough for a quad 15cm, though. The DKM K-class is one of the narrower types with a triple 15cm, at 15.2m beam, so you might maybe be able to make it work by going to twin-twin mountings (like the bigger French quads). Otherwise, I'd say you'd need a wider ship (one of the downsides of quads, they do need a pretty big barbette).

7

Monday, December 14th 2009, 1:04am

Quoted

Originally posted by Hrolf Hakonson
Sim-wise, it looks pretty decent. I'm not sure that 16m (minus whatever for being forward of the widest part of the ship) beam is going to be enough for a quad 15cm, though. The DKM K-class is one of the narrower types with a triple 15cm, at 15.2m beam, so you might maybe be able to make it work by going to twin-twin mountings (like the bigger French quads). Otherwise, I'd say you'd need a wider ship (one of the downsides of quads, they do need a pretty big barbette).


This design is basically a baby Dunkerque, so yeah, the quads will most likely be similar to the much bigger French quads. ;)