Protected Cruisers

[Carthaginian]

How are we going to sim the protected cruisers of the late 1800's?
Has anyone considered how to semi-accurately account for the differences in slope/flat thickness? I've always assumed that my slopes are 1/3 thicker than the flats...

[Tanthalas]

IDK I never even atempted to do a PC... on the deck armor for BC/BB/AC I always assumed that if I had a 2" deck it was 1" over the ends and 3 over the Vitals if that helps at all.

[Carthaginian]

Well, I'm not talking about the ends- I'm talking about the difference between the flat part of the deck and the sloped sides, not the ends versus the vitals.

[Jefgte]

I think to add a half deck belt 1.22m height. Same thickness



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Testing on the Milan cruiser
Milan, France cruiser laid down 1880

Displacement:
   2 000 t light; 2 080 t standard; 2 364 t normal; 2 591 t full load

Dimensions: Length overall / water x beam x draught
   255.91 ft / 255.91 ft x 39.37 ft x 14.67 ft (normal load)
   78.00 m / 78.00 m x 12.00 m  x 4.47 m

Armament:
     2 - 5.51" / 140 mm guns in single mounts, 71.17lbs / 32.28kg shells, 1880 Model
     Breech loading guns in deck mounts
     on centreline, evenly spread
     4 - 5.51" / 140 mm guns in single mounts, 71.17lbs / 32.28kg shells, 1880 Model
     Breech loading guns in deck mounts
     on side, evenly spread
     4 - 1.85" / 47.0 mm guns in single mounts, 2.69lbs / 1.22kg shells, 1880 Model
     Breech loading guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 438 lbs / 199 kg
   Shells per gun, main battery: 120
   2 - 13.8" / 350 mm above water torpedoes

Armour:
  - Belts:      Width (max)   Length (avg)      Height (avg)
   .Main:   1.97" / 50 mm   203.41 ft / 62.00 m   4.00 ft / 1.22 m.
   Ends:   Unarmoured
     Main Belt covers 122 % of normal length

  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.97" / 50 mm   1.57" / 40 mm            -
   2nd:   1.97" / 50 mm   1.57" / 40 mm            -
   3rd:   0.50" / 13 mm         -               -

 . - Armour deck: 1.97" / 50 mm.

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 2 shafts, 3 591 ihp / 2 679 Kw = 16.00 kts
   Range 3 000nm at 10.00 kts
   Bunker at max displacement = 511 tons (100% coal)

Complement:
   169 - 220

Cost:
   £0.220 million / $0.879 million

Distribution of weights at normal displacement:
   Armament: 55 tons, 2.3 %
   Armour: 373 tons, 15.8 %
      - Belts: 67 tons, 2.8 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 48 tons, 2.0 %
      - Armour Deck: 258 tons, 10.9 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 742 tons, 31.4 %
   Hull, fittings & equipment: 775 tons, 32.8 %
   Fuel, ammunition & stores: 364 tons, 15.4 %
   Miscellaneous weights: 55 tons, 2.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1 563 lbs / 709 Kg = 22.0 x 5.5 " / 140 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.32
   Metacentric height 2.0 ft / 0.6 m
   Roll period: 11.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.23
   Seaboat quality  (Average = 1.00): 1.99

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.560
   Length to Beam Ratio: 6.50 : 1
   'Natural speed' for length: 16.00 kts
   Power going to wave formation at top speed: 49 %
   Trim (Max stability = 0, Max steadiness = 100): 64
   Bow angle (Positive = bow angles forward): -10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      15.75 ft / 4.80 m
      - Forecastle (16 %):   15.75 ft / 4.80 m (11.81 ft / 3.60 m aft of break)
      - Mid (50 %):      11.81 ft / 3.60 m
      - Quarterdeck (12 %):   11.81 ft / 3.60 m
      - Stern:      11.81 ft / 3.60 m
      - Average freeboard:   12.44 ft / 3.79 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 122.0 %
      - Above water (accommodation/working, high = better): 88.9 %
   Waterplane Area: 7 098 Square feet or 659 Square metres
   Displacement factor (Displacement / loading): 101 %
   Structure weight / hull surface area: 68 lbs/sq ft or 333 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.91
      - Longitudinal: 2.50
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

This ship is also equipped with sails

[Tanthalas]

I like your idea jef, but wouldnt it make sence to make the half deck belts 30% heavier since from what little research I have done the belts apear to taper being thicker on the outside than in the middle?

[Jefgte]

With Pythagore,

We could think that the curved deck is the diagonal of rectangle made with the deck & the belt so, the weight & the thickness are not too stupid.




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[Carthaginian]

I think to add a half deck belt 1.22m height. Same thickness

Jef,

If the deck is there, why does it need a belt?
Unless we are making the deck be the thickness of the FLAT only, and the ADDING the thickness of the BELT to the DECK to come up with the total thickness of the SLOPE... like this:
FLAT DECK - 1" thick
         BELT - 1" thick
-------------------------
SLOPE DECK - 2" thick

I think it will still come out too heavy... but I'll try a few tonight.

[Tanthalas]

I have another PC question.  Anyone had any luck siming USS Olympia? I tryed to do it tonight and Honestly perhaps im missing somthing but I couldnt get it to work.  The machinery wouldnt even fit in the hull.

[Nobody]

About the slooped armor decks, I always calculated that the armor SS2 assumes to over bow and stern, but is not there, would be enough for the reinforced sloops.