Light Cruiser for 1917

[Sachmle]

Which, if either of these two do YOU think is better, and why. I'm trying to decide if either is worth building, and if the heavier one is worth the extra BP investment. Critique at will. Thanks.

First the lighter one.

Ersatz Köln, Brandenburg Kliener Kruezer laid down 1917 (Engine 1916)

Displacement:
   4,850 t light; 5,042 t standard; 5,844 t normal; 6,486 t full load

Dimensions: Length overall / water x beam x draught
   502.26 ft / 496.72 ft x 46.92 ft x 20.67 ft (normal load)
   153.09 m / 151.40 m x 14.30 m  x 6.30 m

Armament:
      4 - 5.91" / 150 mm guns in single mounts, 99.21lbs / 45.00kg shells, 1917 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 5.91" / 150 mm guns in single mounts, 99.21lbs / 45.00kg shells, 1917 Model
     Quick firing guns in deck mounts with hoists
     on side, all amidships
      1 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1917 Model
     Anti-aircraft gun in deck mount
     on centreline amidships, 1 raised gun
      2 - 1.46" / 37.0 mm guns in single mounts, 1.54lbs / 0.70kg shells, 1917 Model
     Anti-aircraft guns in deck mounts
     on side, all aft, all raised mounts - superfiring
      2 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1917 Model
     Machine guns in deck mounts
     on side, all forward, all raised mounts - superfiring
   Weight of broadside 819 lbs / 371 kg
   Shells per gun, main battery: 150
   4 - 19.7" / 500 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.95" / 75 mm   340.39 ft / 103.75 m   14.76 ft / 4.50 m
   Ends:   Unarmoured
     Main Belt covers 105 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.95" / 75 mm   0.98" / 25 mm      3.46" / 88 mm
   2nd:   2.95" / 75 mm   0.98" / 25 mm      3.46" / 88 mm

   - Armour deck: 0.98" / 25 mm, Conning tower: 2.95" / 75 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 42,195 shp / 31,477 Kw = 29.00 kts
   Range 6,700nm at 15.00 kts
   Bunker at max displacement = 1,444 tons

Complement:
   333 - 434

Cost:
   £0.871 million / $3.483 million

Distribution of weights at normal displacement:
   Armament: 106 tons, 1.8 %
   Armour: 961 tons, 16.4 %
      - Belts: 608 tons, 10.4 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 68 tons, 1.2 %
      - Armour Deck: 265 tons, 4.5 %
      - Conning Tower: 21 tons, 0.4 %
   Machinery: 1,572 tons, 26.9 %
   Hull, fittings & equipment: 2,061 tons, 35.3 %
   Fuel, ammunition & stores: 994 tons, 17.0 %
   Miscellaneous weights: 150 tons, 2.6 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5,721 lbs / 2,595 Kg = 55.6 x 5.9 " / 150 mm shells or 1.1 torpedoes
   Stability (Unstable if below 1.00): 1.15
   Metacentric height 2.1 ft / 0.6 m
   Roll period: 13.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.42
   Seaboat quality  (Average = 1.00): 1.23

Hull form characteristics:
   Hull has raised forecastle, rise forward of midbreak
   Block coefficient: 0.425
   Length to Beam Ratio: 10.59 : 1
   'Natural speed' for length: 22.29 kts
   Power going to wave formation at top speed: 52 %
   Trim (Max stability = 0, Max steadiness = 100): 57
   Bow angle (Positive = bow angles forward): 12.70 degrees
   Stern overhang: -1.97 ft / -0.60 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      24.61 ft / 7.50 m
      - Forecastle (20 %):   22.64 ft / 6.90 m (21.33 ft / 6.50 m aft of break)
      - Mid (35 %):      20.01 ft / 6.10 m (12.01 ft / 3.66 m aft of break)
      - Quarterdeck (15 %):   12.01 ft / 3.66 m
      - Stern:      12.01 ft / 3.66 m
      - Average freeboard:   15.59 ft / 4.75 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 104.4 %
      - Above water (accommodation/working, high = better): 104.6 %
   Waterplane Area: 14,577 Square feet or 1,354 Square metres
   Displacement factor (Displacement / loading): 115 %
   Structure weight / hull surface area: 80 lbs/sq ft or 393 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.49
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

Now, the heavier one:

Ersatz Emden, Brandenburg Kliener Kruezer laid down 1917 (Engine 1916)

Displacement:
   5,605 t light; 5,870 t standard; 6,800 t normal; 7,544 t full load

Dimensions: Length overall / water x beam x draught
   531.50 ft / 525.36 ft x 53.31 ft x 17.49 ft (normal load)
   162.00 m / 160.13 m x 16.25 m  x 5.33 m

Armament:
      4 - 5.91" / 150 mm guns in single mounts, 99.21lbs / 45.00kg shells, 1917 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 5.91" / 150 mm guns in single mounts, 99.21lbs / 45.00kg shells, 1917 Model
     Quick firing guns in deck mounts with hoists
     on side ends, evenly spread
      2 - 3.46" / 88.0 mm guns in single mounts, 20.79lbs / 9.43kg shells, 1917 Model
     Anti-aircraft guns in deck mounts
     on centreline, all amidships, all raised mounts - superfiring
      4 - 1.46" / 37.0 mm guns in single mounts, 1.55lbs / 0.70kg shells, 1917 Model
     Anti-aircraft guns in deck mounts
     on side ends, evenly spread, all raised mounts - superfiring
      4 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1917 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 841 lbs / 382 kg
   Shells per gun, main battery: 250
   4 - 19.7" / 500 mm above water torpedoes, 2 - 19.7" / 500 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.95" / 75 mm   393.70 ft / 120.00 m   14.76 ft / 4.50 m
   Ends:   Unarmoured
     Main Belt covers 115 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   2.95" / 75 mm   0.98" / 25 mm      3.46" / 88 mm
   2nd:   2.95" / 75 mm   0.98" / 25 mm      3.46" / 88 mm

   - Armour deck: 0.98" / 25 mm, Conning tower: 2.95" / 75 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 46,773 shp / 34,893 Kw = 29.00 kts
   Range 7,165nm at 15.00 kts
   Bunker at max displacement = 1,675 tons

Complement:
   373 - 486

Cost:
   £0.967 million / $3.867 million

Distribution of weights at normal displacement:
   Armament: 109 tons, 1.6 %
   Armour: 1,126 tons, 16.6 %
      - Belts: 699 tons, 10.3 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 68 tons, 1.0 %
      - Armour Deck: 336 tons, 4.9 %
      - Conning Tower: 23 tons, 0.3 %
   Machinery: 1,743 tons, 25.6 %
   Hull, fittings & equipment: 2,426 tons, 35.7 %
   Fuel, ammunition & stores: 1,195 tons, 17.6 %
   Miscellaneous weights: 202 tons, 3.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     7,809 lbs / 3,542 Kg = 75.8 x 5.9 " / 150 mm shells or 1.3 torpedoes
   Stability (Unstable if below 1.00): 1.25
   Metacentric height 2.9 ft / 0.9 m
   Roll period: 13.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.28
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has raised forecastle, rise forward of midbreak
   Block coefficient: 0.486
   Length to Beam Ratio: 9.85 : 1
   'Natural speed' for length: 22.92 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 14.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      24.61 ft / 7.50 m
      - Forecastle (20 %):   22.64 ft / 6.90 m (21.33 ft / 6.50 m aft of break)
      - Mid (45 %):      20.01 ft / 6.10 m (12.01 ft / 3.66 m aft of break)
      - Quarterdeck (15 %):   12.01 ft / 3.66 m
      - Stern:      12.01 ft / 3.66 m
      - Average freeboard:   16.46 ft / 5.02 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 102.9 %
      - Above water (accommodation/working, high = better): 131.9 %
   Waterplane Area: 18,426 Square feet or 1,712 Square metres
   Displacement factor (Displacement / loading): 120 %
   Structure weight / hull surface area: 84 lbs/sq ft or 408 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.98
      - Longitudinal: 1.19
      - 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
   Good seaboat, rides out heavy weather easily

[P3D]

What extra the second one has? I don't really see much that would argue for the heavier one - same firepower, slightly longer range, larger misc weight and that's it.

You have a deck ~4' above waterline. So have either 8-9' belt or 16-17'. Only 3' below WL is inadequate IMHO - light ship conditions, waves would expose vitals.

[Borys]

Ahoj!
I agree with P3D. I'd increase freeboard by 2', as to end up with a c.7' deck.

Borys

[Jefgte]

The second, Emden add 2 submerged TT.

That increase the ratio belt - 115%
For the first, Koln - 105%

IMO, the 2 submerged TT are not useful.
Add TTs on the 4800t deck


;)

[The Rock Doctor]

I'd vote for the lighter one, for similar reasons.

Now that I look again, I see the lighter one has a heavily optimized hull form - high L:W ratio, low BC, deep draught.  The heavier ship is less optimized in all respects...