Glorious French cruisers

[Korpen]

As an aside - what would have prompted the move from 6" deck mounts to turrets?  Heavier shells?  Faster loading equipment?  Inability to design double mount-and-hoist deck mounts?

I think it really depends on which country we are talking about, some (Sweden) had ships with 15cm gun in twin enclosed mounts from around 1900.
But a big one is that is much better protected, and as cruisers increased in size, that became more important, at least that is my guess.

[P3D]

I think the main reason was fire control. If you put a rangefinder and FC on a light cruiser, it's better to put all that sensitive equipment and extra personnel protected from weather. And as you already have enclosed mounts, then armoring it and equipping it with power training is not a big step. Then you put two-three guns in the same turret to save on weight and personnel. With the powered hoists your sustained ROF would also be higher.

Also the ever increasing speed requirements increased light cruiser sizes, and if you set aside a given percentage of the displacement to armor and guns, it would increase as well.

[Korpen]

I think the main reason was fire control. If you put a rangefinder and FC on a light cruiser, it's better to put all that sensitive equipment and extra personnel protected from weather. And as you already have enclosed mounts, then armoring it and equipping it with power training is not a big step. Then you put two-three guns in the same turret to save on weight and personnel. With the powered hoists your sustained ROF would also be higher.

Maybe, but fire control did not increase the number of people at the guns themselves, as the gun layers did the same job, only in a different way (following a pointer rather then aiming on their own). But it is true that turrets allowed more and larger rangefinders to be mounted, reducing the need of calling out distance.

This would also explain why destroyers kept open mounts even after director controll was installed on them from mid-ww1.

[Borys]

Ahoj!
I think it was the progress in Fire Control.

And I am not sure whether  6 inchers really were "turret+barbette", and not "armoured box revolving on top of mount&hoist".
Borys

[Desertfox]

Welll the Omahas for one where "armoured box on top of mount & hoist". The Swiss 6" twins on the Auroras are basiclly the same thing.

[maddox]

The main reason why the 165mm guns got a single mount is the disappointment of the predecessors in the Ville Class light armored cruisers. Those twins were fitted in a deck mount and hoist with full weather protection and serious armor.  The gun themselfs are nice, hard hitting medium guns
165mm L50 type. But the cumbersome movement of the armored deck mount and the issues on reliability made the solution obvious.  Singles with lighter armor.

[Borys]

Ahoj!
The Swedish fleet probably put the 6 inchers in enclosed mounts due to weather.

The RN had twin 6 inchers, which they were unhappy with.

And it was a question of money. Weapons above 6 inches (more or less) had shells and propelant of such weight that mechanisation was needed. So a turret and barbette was more or less "inherent" to weapons of 8 inches and higher.
A single 6 incher in a casematte or in a mount&hoist ... well, mount, could get away with 100% manual operation, so why spend money? Especially in a large navy, smaller navies usually were more quality conscious, which might be another factor behind the Swedish enclosed 6 inchers. Italy and France also had (or ad designs for) enclosed mount secondaries of a calibre which othe navies put in casemattes.

Borys

[maddox]

The Rattlesnake cruiser aquired from the CSA will be rebuilded to French liking.

Crotalus Primus, French cruiser laid down 1907 (Engine 1909)

Displacement:
   4.716 t light; 4.984 t standard; 5.932 t normal; 6.690 t full load

Dimensions: Length overall / water x beam x draught
   470,00 ft / 470,00 ft x 50,00 ft x 19,00 ft (normal load)
   143,26 m / 143,26 m x 15,24 m  x 5,79 m

Armament:
      4 - 6,50" / 165 mm guns in single mounts, 143,30lbs / 65,00kg shells, 1907 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 6,50" / 165 mm guns in single mounts, 141,10lbs / 64,00kg shells, 1907 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, evenly spread
      8 - 2,76" / 70,0 mm guns in single mounts, 10,47lbs / 4,75kg shells, 1907 Model
     Quick firing guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
      4 - 0,98" / 25,0 mm guns in single mounts, 0,48lbs / 0,22kg shells, 1907 Model
     Machine guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 1.223 lbs / 555 kg
   Shells per gun, main battery: 200
   4 - 20,0" / 508 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   3,00" / 76 mm   340,00 ft / 103,63 m   12,00 ft / 3,66 m
   Ends:   Unarmoured
     Main Belt covers 111% of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1,00" / 25 mm   1,00" / 25 mm      3,00" / 76 mm
   2nd:   1,00" / 25 mm   1,00" / 25 mm      3,00" / 76 mm
   3rd:   1,00" / 25 mm   1,00" / 25 mm            -
   4th:   1,00" / 25 mm   1,00" / 25 mm            -

   - Armour deck: 2,00" / 51 mm, Conning tower: 3,00" / 76 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 21.235 shp / 15.841 Kw = 24,00 kts
   Range 8.000nm at 12,00 kts
   Bunker at max displacement = 1.706 tons (60% coal)

Complement:
   337 - 439

Cost:
   £0,432 million / $1,729 million

Distribution of weights at normal displacement:
   Armament: 148 tons, 2,5%
   Armour: 1.154 tons, 19,5%
      - Belts: 503 tons, 8,5%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 69 tons, 1,2%
      - Armour Deck: 562 tons, 9,5%
      - Conning Tower: 21 tons, 0,4%
   Machinery: 1.021 tons, 17,2%
   Hull, fittings & equipment: 2.324 tons, 39,2%
   Fuel, ammunition & stores: 1.216 tons, 20,5%
   Miscellaneous weights: 70 tons, 1,2%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     8.987 lbs / 4.077 Kg = 65,6 x 6,5 " / 165 mm shells or 1,5 torpedoes
   Stability (Unstable if below 1.00): 1,16
   Metacentric height 2,3 ft / 0,7 m
   Roll period: 13,7 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0,83
   Seaboat quality  (Average = 1.00): 2,00

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,465
   Length to Beam Ratio: 9,40 : 1
   'Natural speed' for length: 21,68 kts
   Power going to wave formation at top speed: 46 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): -5,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      24,00 ft / 7,32 m
      - Forecastle (20%):   20,00 ft / 6,10 m
      - Mid (50%):      18,00 ft / 5,49 m
      - Quarterdeck (15%):   18,00 ft / 5,49 m
      - Stern:      18,00 ft / 5,49 m
      - Average freeboard:   19,02 ft / 5,80 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 83,6%
      - Above water (accommodation/working, high = better): 158,4%
   Waterplane Area: 15.179 Square feet or 1.410 Square metres
   Displacement factor (Displacement / loading): 133%
   Structure weight / hull surface area: 84 lbs/sq ft or 412 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,91
      - Longitudinal: 2,35
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

The 5th rattlesnake cruiser from the confederated States of America, build in Halifax, as an export class of ships.

Rebuild to French specs in 1909

The typical French negatively angled bow, the exchange for the 6" guns to the bigger 165mm guns and the ubuqtous 70mm QF to replace the 4"

[maddox]

10K cruiser proposal from the Chantiers de St Nazaire.  Is it worth the effort?

Hannibal, French heavy cruiser laid down 1909

Displacement:
   10.010 t light; 10.564 t standard; 11.832 t normal; 12.847 t full load

Dimensions: Length overall / water x beam x draught
   497,05 ft / 492,13 ft x 78,74 ft x 19,69 ft (normal load)
   151,50 m / 150,00 m x 24,00 m  x 6,00 m

Armament:
      6 - 10,83" / 275 mm guns (3x2 guns), 661,39lbs / 300,00kg shells, 1909 Model
     Breech loading guns in turrets (on barbettes)
     on centreline, evenly spread
     Aft Main mounts separated by engine room
      12 - 5,51" / 140 mm guns in single mounts, 83,72lbs / 37,97kg shells, 1909 Model
     Quick firing guns in deck mounts with hoists
     on side, all amidships, 6 raised mounts - superfiring
      3 - 2,76" / 70,0 mm guns in single mounts, 10,47lbs / 4,75kg shells, 1909 Model
     Quick firing guns in deck mounts
     on centreline, evenly spread, all raised mounts
   Weight of broadside 5.004 lbs / 2.270 kg
   Shells per gun, main battery: 110

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   6,00" / 152 mm   319,88 ft / 97,50 m   10,65 ft / 3,25 m
   Ends:   4,00" / 102 mm   172,22 ft / 52,49 m   10,65 ft / 3,25 m
   Upper:   4,00" / 102 mm   319,88 ft / 97,50 m   8,00 ft / 2,44 m
     Main Belt covers 100% of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   5,00" / 127 mm   4,00" / 102 mm      6,00" / 152 mm
   2nd:   4,00" / 102 mm   2,00" / 51 mm      2,00" / 51 mm
   3rd:   0,50" / 13 mm         -               -

   - Armour deck: 1,00" / 25 mm, Conning tower: 6,00" / 152 mm

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 4 shafts, 34.795 shp / 25.957 Kw = 24,00 kts
   Range 9.000nm at 10,00 kts
   Bunker at max displacement = 2.283 tons (100% coal)

Complement:
   566 - 737

Cost:
   £1,102 million / $4,410 million

Distribution of weights at normal displacement:
   Armament: 605 tons, 5,1%
   Armour: 2.841 tons, 24,0%
      - Belts: 1.612 tons, 13,6%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 665 tons, 5,6%
      - Armour Deck: 497 tons, 4,2%
      - Conning Tower: 67 tons, 0,6%
   Machinery: 1.740 tons, 14,7%
   Hull, fittings & equipment: 4.724 tons, 39,9%
   Fuel, ammunition & stores: 1.822 tons, 15,4%
   Miscellaneous weights: 100 tons, 0,8%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     13.552 lbs / 6.147 Kg = 21,4 x 10,8 " / 275 mm shells or 2,2 torpedoes
   Stability (Unstable if below 1.00): 1,05
   Metacentric height 3,8 ft / 1,2 m
   Roll period: 16,9 seconds
   Steadiness   - As gun platform (Average = 50 %): 78 %
         - Recoil effect (Restricted arc if above 1.00): 0,51
   Seaboat quality  (Average = 1.00): 1,00

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,543
   Length to Beam Ratio: 6,25 : 1
   'Natural speed' for length: 22,18 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 78
   Bow angle (Positive = bow angles forward): -5,00 degrees
   Stern overhang: 4,92 ft / 1,50 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      22,97 ft / 7,00 m
      - Forecastle (20%):   16,40 ft / 5,00 m
      - Mid (50%):      14,47 ft / 4,41 m
      - Quarterdeck (15%):   14,47 ft / 4,41 m
      - Stern:      14,47 ft / 4,41 m
      - Average freeboard:   15,67 ft / 4,78 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 87,6%
      - Above water (accommodation/working, high = better): 134,8%
   Waterplane Area: 26.864 Square feet or 2.496 Square metres
   Displacement factor (Displacement / loading): 105%
   Structure weight / hull surface area: 133 lbs/sq ft or 647 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,96
      - Longitudinal: 1,39
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform

[Borys]

Ahoj!
I would not bother with Hanibal.
Unexceptional seakeeping, unexceptional stability.
Borys

[maddox]

But exceptional heavy armament, and exceptional range.  As a second class BB she does a good impression.

So, what changes do the Skoda engineers propose?

[Borys]

Ahoj!
Maybe there is a niche for them .... the Med.
Cut back on range and add 2 feet to Upper Belt.

The speed and firepower are the nice sides of this design. But the lack of seakeeping AND stability would lead me to redesign the ship completely. Increase freboard/ raised frecastle - improves seakeeping, worses stability. Increase beam = bigger displacement, worse seakeeping.

All in all I would start again, I think.

Borys

[Tanthalas]

the Italians would advise the use of tripple turrets instead of the twins chosen by the french team, and notes that with 2X3X10" she would be the spiting image of the Numidicas class.

[Ithekro]

The French may or may not yet have that ability.

[maddox]

The combined educational efforts by Rohan and Italy (also very willing to sel tripple turrets to France) will yield some results sooner or later.

(also, France does have the ability purely rulewise, I just want to have fun and not milk the rules )