WesWorld

The Bulgarian Navy is looking for two light cruisers with minelaying capability to replace the 30-year old cruisers Montana and Stara Zagora. Two new-built designs are being considered, but secondhand ships might also be of interest...

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General Comparison
------------- Design A3 ------- Design B3 --------Design C2
Weight: --8,073 t ----------- 9,431 t ----------- 9,357 t
Guns: -----9x6" ------------- 12x6" ------------- 12x5"
Speed: ---33 knots -------- 33.85 knots ----- 33.85 knots

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Design C2 and A3 appeal to me at the moment, C2 perhaps more because it has the 12x5" DP as its main battery.

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Quoted

DESIGN A3, Bulgarian Light Cruiser laid down 1936

Displacement:
6,973 t light; 7,262 t standard; 8,073 t normal; 8,722 t full load

Dimensions: Length overall / water x beam x draught
543.19 ft / 530.00 ft x 61.00 ft x 23.00 ft (normal load)
165.56 m / 161.54 m x 18.59 m x 7.01 m

Armament:
9 - 6.00" / 152 mm guns (3x3 guns), 108.00lbs / 48.99kg shells, 1936 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, majority forward, 1 raised mount - superfiring
12 - 4.00" / 102 mm guns (6x2 guns), 32.00lbs / 14.51kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
24 - 1.57" / 40.0 mm guns (6x4 guns), 1.95lbs / 0.89kg shells, 1936 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 1,403 lbs / 636 kg
Shells per gun, main battery: 150
6 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.00" / 76 mm 344.50 ft / 105.00 m 8.49 ft / 2.59 m
Ends: Unarmoured
Upper: 1.00" / 25 mm 344.50 ft / 105.00 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: 4.00" / 102 mm 2.00" / 51 mm 3.00" / 76 mm
2nd: 2.00" / 51 mm 1.00" / 25 mm -

- Armour deck: 1.50" / 38 mm, Conning tower: 4.00" / 102 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 70,866 shp / 52,866 Kw = 33.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 1,460 tons

Complement:
425 - 553

Cost:
£3.531 million / $14.126 million

Distribution of weights at normal displacement:
Armament: 175 tons, 2.2 %
Armour: 1,328 tons, 16.5 %
- Belts: 482 tons, 6.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 244 tons, 3.0 %
- Armour Deck: 568 tons, 7.0 %
- Conning Tower: 35 tons, 0.4 %
Machinery: 1,988 tons, 24.6 %
Hull, fittings & equipment: 3,382 tons, 41.9 %
Fuel, ammunition & stores: 1,100 tons, 13.6 %
Miscellaneous weights: 100 tons, 1.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
9,912 lbs / 4,496 Kg = 91.8 x 6.0 " / 152 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 2.9 ft / 0.9 m
Roll period: 15.0 seconds
Steadiness - As gun platform (Average = 50 %): 62 %
- Recoil effect (Restricted arc if above 1.00): 0.37
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 8.69 : 1
'Natural speed' for length: 27.05 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 59
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.00 ft / 0.91 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 28.00 ft / 8.53 m
- Forecastle (20 %): 18.00 ft / 5.49 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: 18.80 ft / 5.73 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 98.5 %
- Above water (accommodation/working, high = better): 143.9 %
Waterplane Area: 20,452 Square feet or 1,900 Square metres
Displacement factor (Displacement / loading): 119 %
Structure weight / hull surface area: 103 lbs/sq ft or 504 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.92
- Longitudinal: 1.98
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

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Quoted

DESIGN B3, Bulgarian Light Cruiser laid down 1936

Displacement:
8,188 t light; 8,531 t standard; 9,431 t normal; 10,151 t full load

Dimensions: Length overall / water x beam x draught
583.19 ft / 570.00 ft x 63.00 ft x 24.00 ft (normal load)
177.76 m / 173.74 m x 19.20 m x 7.32 m

Armament:
12 - 6.00" / 152 mm guns (4x3 guns), 108.00lbs / 48.99kg shells, 1936 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
12 - 4.00" / 102 mm guns (6x2 guns), 32.00lbs / 14.51kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
24 - 1.57" / 40.0 mm guns (6x4 guns), 1.95lbs / 0.88kg shells, 1936 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 1,727 lbs / 783 kg
Shells per gun, main battery: 150
6 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.00" / 76 mm 390.50 ft / 119.02 m 9.30 ft / 2.83 m
Ends: Unarmoured
Upper: 1.00" / 25 mm 370.50 ft / 112.93 m 8.00 ft / 2.44 m
Main Belt covers 105 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4.00" / 102 mm 2.00" / 51 mm 3.00" / 76 mm
2nd: 2.00" / 51 mm 1.00" / 25 mm -

- Armour deck: 1.50" / 38 mm, Conning tower: 4.00" / 102 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 84,149 shp / 62,775 Kw = 33.85 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 1,621 tons

Complement:
478 - 622

Cost:
£4.210 million / $16.840 million

Distribution of weights at normal displacement:
Armament: 216 tons, 2.3 %
Armour: 1,562 tons, 16.6 %
- Belts: 573 tons, 6.1 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 319 tons, 3.4 %
- Armour Deck: 631 tons, 6.7 %
- Conning Tower: 38 tons, 0.4 %
Machinery: 2,361 tons, 25.0 %
Hull, fittings & equipment: 3,948 tons, 41.9 %
Fuel, ammunition & stores: 1,243 tons, 13.2 %
Miscellaneous weights: 100 tons, 1.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
10,937 lbs / 4,961 Kg = 101.3 x 6.0 " / 152 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 3.0 ft / 0.9 m
Roll period: 15.3 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.41
Seaboat quality (Average = 1.00): 1.02

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.383
Length to Beam Ratio: 9.05 : 1
'Natural speed' for length: 27.94 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 59
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.00 ft / 0.91 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 28.00 ft / 8.53 m
- Forecastle (20 %): 18.00 ft / 5.49 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: 18.80 ft / 5.73 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 100.5 %
- Above water (accommodation/working, high = better): 144.4 %
Waterplane Area: 22,744 Square feet or 2,113 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 109 lbs/sq ft or 532 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.76
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

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Quoted

DESIGN C2, Bulgarian Light Cruiser laid down 1936

Displacement:
8,164 t light; 8,460 t standard; 9,357 t normal; 10,074 t full load

Dimensions: Length overall / water x beam x draught
583.19 ft / 570.00 ft x 63.00 ft x 24.00 ft (normal load)
177.76 m / 173.74 m x 19.20 m x 7.32 m

Armament:
12 - 5.00" / 127 mm guns (6x2 guns), 62.50lbs / 28.35kg shells, 1936 Model
Dual purpose guns in turrets (on barbettes)
on centreline ends, evenly spread, 4 raised mounts - superfiring
12 - 4.00" / 102 mm guns (6x2 guns), 32.00lbs / 14.51kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
24 - 1.57" / 40.0 mm guns (6x4 guns), 1.95lbs / 0.88kg shells, 1936 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 1,181 lbs / 536 kg
Shells per gun, main battery: 150
8 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.00" / 76 mm 390.50 ft / 119.02 m 9.30 ft / 2.83 m
Ends: Unarmoured
Upper: 1.00" / 25 mm 370.50 ft / 112.93 m 8.00 ft / 2.44 m
Main Belt covers 105 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4.00" / 102 mm 2.00" / 51 mm 3.00" / 76 mm
2nd: 2.00" / 51 mm 1.00" / 25 mm -

- Armour deck: 1.50" / 38 mm, Conning tower: 4.00" / 102 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 83,603 shp / 62,368 Kw = 33.85 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 1,614 tons

Complement:
475 - 618

Cost:
£3.892 million / $15.568 million

Distribution of weights at normal displacement:
Armament: 148 tons, 1.6 %
Armour: 1,558 tons, 16.7 %
- Belts: 573 tons, 6.1 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 316 tons, 3.4 %
- Armour Deck: 630 tons, 6.7 %
- Conning Tower: 38 tons, 0.4 %
Machinery: 2,346 tons, 25.1 %
Hull, fittings & equipment: 3,913 tons, 41.8 %
Fuel, ammunition & stores: 1,193 tons, 12.7 %
Miscellaneous weights: 200 tons, 2.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
11,433 lbs / 5,186 Kg = 182.9 x 5.0 " / 127 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 3.0 ft / 0.9 m
Roll period: 15.3 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.29
Seaboat quality (Average = 1.00): 1.04

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 9.05 : 1
'Natural speed' for length: 27.95 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.00 ft / 0.91 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 28.00 ft / 8.53 m
- Forecastle (20 %): 18.00 ft / 5.49 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: 18.80 ft / 5.73 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 96.4 %
- Above water (accommodation/working, high = better): 138.8 %
Waterplane Area: 22,717 Square feet or 2,110 Square metres
Displacement factor (Displacement / loading): 123 %
Structure weight / hull surface area: 108 lbs/sq ft or 528 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 1.78
- Overall: 1.05
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

In reguards to design C2, I'd ditch the 4" DP guns because you already have the 5" DP's. That said I don't see a huge need for an AA cruiser for Bulgaria.

A3 seems like the best design though I'd add more guns in the 20mm range and some smaller .30 or .50 cal weapons against smaller craft.

Turkey could offer the following design, which could be built in either Turkish or Bulgarian ports. The design can be modified to incorperate mines.

Ankara class Light Cruiser



Ankara, Istambul

Ankara, Turkish Light Cruiser laid down 1930
As simed by Hrolf Hakonson

Displacement:
6,943 t light; 7,223 t standard; 7,873 t normal; 8,393 t full load

Dimensions: Length overall / water x beam x draught
565.43 ft / 557.74 ft x 59.06 ft x 16.73 ft (normal load)
172.34 m / 170.00 m x 18.00 m x 5.10 m

Armament:
9 - 5.91" / 150 mm guns (3x3 guns), 102.98lbs / 46.71kg shells, 1928 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, majority forward, 1 raised mount - superfiring
2 - 3.46" / 88.0 mm guns (1x2 guns), 20.79lbs / 9.43kg shells, 1930 Model
Dual purpose guns in deck mount
on centreline aft, all raised guns - superfiring
8 - 3.46" / 88.0 mm guns (4x2 guns), 20.79lbs / 9.43kg shells, 1930 Model
Dual purpose guns in deck mounts
on side, evenly spread
8 - 1.46" / 37.0 mm guns (4x2 guns), 1.55lbs / 0.70kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1930 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 1,149 lbs / 521 kg
Shells per gun, main battery: 180
16 - 21.0" / 533 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.94" / 100 mm 356.96 ft / 108.80 m 9.22 ft / 2.81 m
Ends: Unarmoured
Main Belt covers 98 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4.72" / 120 mm 2.76" / 70 mm 3.94" / 100 mm
2nd: 1.57" / 40 mm 0.79" / 20 mm -
3rd: 1.57" / 40 mm 0.79" / 20 mm -
4th: 0.79" / 20 mm 0.39" / 10 mm -
5th: 0.39" / 10 mm - -

- Armour deck: 1.57" / 40 mm, Conning tower: 3.94" / 100 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 65,091 shp / 48,558 Kw = 32.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 1,170 tons

Complement:
417 - 543

Cost:
£2.676 million / $10.702 million

Distribution of weights at normal displacement:
Armament: 144 tons, 1.8 %
Armour: 1,521 tons, 19.3 %
- Belts: 543 tons, 6.9 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 279 tons, 3.5 %
- Armour Deck: 665 tons, 8.4 %
- Conning Tower: 34 tons, 0.4 %
Machinery: 1,972 tons, 25.1 %
Hull, fittings & equipment: 3,196 tons, 40.6 %
Fuel, ammunition & stores: 930 tons, 11.8 %
Miscellaneous weights: 110 tons, 1.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
10,902 lbs / 4,945 Kg = 105.9 x 5.9 " / 150 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.25
Metacentric height 3.4 ft / 1.0 m
Roll period: 13.4 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.25
Seaboat quality (Average = 1.00): 1.00

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 9.44 : 1
'Natural speed' for length: 27.07 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 28.71 ft / 8.75 m
- Forecastle (21 %): 21.33 ft / 6.50 m (17.22 ft / 5.25 m aft of break)
- Mid (60 %): 17.22 ft / 5.25 m
- Quarterdeck (15 %): 17.22 ft / 5.25 m
- Stern: 17.22 ft / 5.25 m
- Average freeboard: 18.71 ft / 5.70 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 97.6 %
- Above water (accommodation/working, high = better): 119.5 %
Waterplane Area: 22,822 Square feet or 2,120 Square metres
Displacement factor (Displacement / loading): 117 %
Structure weight / hull surface area: 94 lbs/sq ft or 460 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.97
- Longitudinal: 1.25
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate

80 tons reserved for aircraft facilities.

30 tons reserved for future growth.

Chester and Birkenhead are still nominally on the market, but unlikely to be an improvement.

Quoted

Originally posted by thesmilingassassin
Turkey could offer the following design, which could be built in either Turkish or Bulgarian ports. The design can be modified to incorperate mines.

Ankara class Light Cruiser

Ha, hm! Yes, I like the looks and stats on that one, very much...

All of the three designs presented have a block coefficient of abaout 0,38 which is way too low for a ship their size.

For comparison: The discussed RSAN designs in the other thread are quite similar but have a BC of 0,5 or higher which fits with the rules for SS.

I propose to re-design those Bulgarian cruisers with a higher BC.