When the pre-dreadnought use for coastal protection "ll be too old, they could be replace by new coastal BBs.
This new kind of ships could be laid down in the 20's.
First type with 2T3x275
11500T coastal BB, Peru 2T3x275 laid down 1923 (Engine 1920)
Displacement:
11 500 t light; 12 129 t standard; 12 715 t normal; 13 183 t full load
Dimensions: Length overall / water x beam x draught
524.93 ft / 524.93 ft x 72.18 ft x 20.43 ft (normal load)
160.00 m / 160.00 m x 22.00 m x 6.23 m
Armament:
6 - 10.83" / 275 mm guns (2x3 guns), 661.39lbs / 300.00kg shells, 1923 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
12 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1923 Model
Breech loading guns in deck mounts with hoists
on side, evenly spread
8 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1923 Model
Quick firing guns in deck mounts
on centreline, all amidships, all raised mounts - superfiring
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1923 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 5 373 lbs / 2 437 kg
Shells per gun, main battery: 120
6 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 9.45" / 240 mm 354.33 ft / 108.00 m 9.84 ft / 3.00 m
Ends: 3.15" / 80 mm 144.36 ft / 44.00 m 8.01 ft / 2.44 m
26.25 ft / 8.00 m Unarmoured ends
Main Belt covers 104 % of normal length
- Torpedo Bulkhead:
1.57" / 40 mm 354.33 ft / 108.00 m 20.28 ft / 6.18 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 9.45" / 240 mm 3.94" / 100 mm 9.45" / 240 mm
2nd: 0.79" / 20 mm - -
3rd: 0.79" / 20 mm - -
4th: 0.50" / 13 mm - -
- Armour deck: 2.76" / 70 mm, Conning tower: 9.45" / 240 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 36 000 shp / 26 856 Kw = 24.14 kts
Range 5 500nm at 12.00 kts
Bunker at max displacement = 1 054 tons
Complement:
598 - 778
Cost:
£3.275 million / $13.102 million
Distribution of weights at normal displacement:
Armament: 651 tons, 5.1 %
Armour: 4 180 tons, 32.9 %
- Belts: 1 544 tons, 12.1 %
- Torpedo bulkhead: 419 tons, 3.3 %
- Armament: 727 tons, 5.7 %
- Armour Deck: 1 380 tons, 10.9 %
- Conning Tower: 111 tons, 0.9 %
Machinery: 1 259 tons, 9.9 %
Hull, fittings & equipment: 5 059 tons, 39.8 %
Fuel, ammunition & stores: 1 215 tons, 9.6 %
Miscellaneous weights: 350 tons, 2.8 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
17 963 lbs / 8 148 Kg = 28.3 x 10.8 " / 275 mm shells or 3.3 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 3.7 ft / 1.1 m
Roll period: 15.7 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.66
Seaboat quality (Average = 1.00): 1.21
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.575
Length to Beam Ratio: 7.27 : 1
'Natural speed' for length: 22.91 kts
Power going to wave formation at top speed: 51 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.62 ft / 7.20 m
- Forecastle (18 %): 19.36 ft / 5.90 m
- Mid (50 %): 15.75 ft / 4.80 m
- Quarterdeck (18 %): 15.75 ft / 4.80 m
- Stern: 15.75 ft / 4.80 m
- Average freeboard: 17.28 ft / 5.27 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 103.3 %
- Above water (accommodation/working, high = better): 127.9 %
Waterplane Area: 27 070 Square feet or 2 515 Square metres
Displacement factor (Displacement / loading): 104 %
Structure weight / hull surface area: 133 lbs/sq ft or 649 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
Good seaboat, rides out heavy weather easily
----------------------------------
Second type with 2T3x340
14000T coastal BB, Peru 2T3x340 laid down 1923 (Engine 1920)
Displacement:
14 000 t light; 14 759 t standard; 15 424 t normal; 15 956 t full load
Dimensions: Length overall / water x beam x draught
551.18 ft / 551.18 ft x 75.46 ft x 21.63 ft (normal load)
168.00 m / 168.00 m x 23.00 m x 6.59 m
Armament:
6 - 13.39" / 340 mm guns (2x3 guns), 1 199.24lbs / 543.97kg shells, 1923 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
12 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1923 Model
Breech loading guns in deck mounts with hoists
on side, evenly spread
8 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1923 Model
Quick firing guns in deck mounts
on centreline, all amidships, all raised mounts - superfiring
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1923 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 7 936 lbs / 3 600 kg
Shells per gun, main battery: 100
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 9.45" / 240 mm 393.70 ft / 120.00 m 9.84 ft / 3.00 m
Ends: 3.15" / 80 mm 144.36 ft / 44.00 m 8.01 ft / 2.44 m
13.12 ft / 4.00 m Unarmoured ends
Main Belt covers 110 % of normal length
- Torpedo Bulkhead:
1.57" / 40 mm 393.70 ft / 120.00 m 21.42 ft / 6.53 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 9.45" / 240 mm 3.94" / 100 mm 9.45" / 240 mm
2nd: 0.79" / 20 mm - -
3rd: 0.79" / 20 mm - -
4th: 0.50" / 13 mm - -
- Armour deck: 2.76" / 70 mm, Conning tower: 9.45" / 240 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 40 000 shp / 29 840 Kw = 24.10 kts
Range 5 500nm at 12.00 kts
Bunker at max displacement = 1 197 tons
Complement:
691 - 899
Cost:
£4.419 million / $17.677 million
Distribution of weights at normal displacement:
Armament: 992 tons, 6.4 %
Armour: 4 787 tons, 31.0 %
- Belts: 1 684 tons, 10.9 %
- Torpedo bulkhead: 491 tons, 3.2 %
- Armament: 934 tons, 6.1 %
- Armour Deck: 1 551 tons, 10.1 %
- Conning Tower: 126 tons, 0.8 %
Machinery: 1 399 tons, 9.1 %
Hull, fittings & equipment: 6 522 tons, 42.3 %
Fuel, ammunition & stores: 1 424 tons, 9.2 %
Miscellaneous weights: 300 tons, 1.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
19 613 lbs / 8 896 Kg = 16.4 x 13.4 " / 340 mm shells or 3.4 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 3.7 ft / 1.1 m
Roll period: 16.4 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.88
Seaboat quality (Average = 1.00): 1.20
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.600
Length to Beam Ratio: 7.30 : 1
'Natural speed' for length: 23.48 kts
Power going to wave formation at top speed: 50 %
Trim (Max stability = 0, Max steadiness = 100): 60
Bow angle (Positive = bow angles forward): 0.00 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 (18 %): 19.69 ft / 6.00 m
- Mid (50 %): 16.40 ft / 5.00 m
- Quarterdeck (18 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 17.87 ft / 5.45 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 108.9 %
- Above water (accommodation/working, high = better): 144.4 %
Waterplane Area: 30 420 Square feet or 2 826 Square metres
Displacement factor (Displacement / loading): 97 %
Structure weight / hull surface area: 153 lbs/sq ft or 748 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.42
- 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
I cannot say i like them, think you try and do too much and end up with a compromise that cannot really do anything.
What the two designs really are, is slow battlecruisers; their armour is excellent against older cruisers with <25cm guns, but not so impressive against even older BC with 30cm guns, and insufficient against BBs and later BCs (35cm+ guns).
Similar wit the speed, it is not fast enough to catch anything smaller, and not fast enough to run from larger things (something a CBB should never do IMO).
You could reduce speed to 18kts without and real impact on the CBB function. Similar with the armour, reducing the belt to 18-20cm will still give the ship reasonable protection against cruiser fire, while the threat from first rate guns is unaffected (drop the TB while you are at it as well to save weight). This would allow you to shrink the 34cm version to around 10kton and perhaps add a third gun tower (around 8000ton with just six guns).
The 27,5cm armed version is pointless IMO as the main function of a defence ship is to hurt the enemy, that version lacks that ability.
Think something like this is better value for money.
QuoteEnter ship name, Enter country Enter ship type laid down 1920
Displacement:
8 400 t light; 9 259 t standard; 9 765 t normal; 10 170 t full load
Dimensions: Length overall / water x beam x draught
360,89 ft / 360,89 ft x 68,90 ft x 19,69 ft (normal load)
110,00 m / 110,00 m x 21,00 m x 6,00 m
Armament:
6 - 13,39" / 340 mm guns (2x3 guns), 1 199,24lbs / 543,97kg shells, 1920 Model
Breech loading guns in turrets (on barbettes)
on centreline, evenly spread
12 - 4,72" / 120 mm guns in single mounts, 52,72lbs / 23,92kg shells, 1920 Model
Breech loading guns in deck mounts with hoists
on side, all amidships
Weight of broadside 7 828 lbs / 3 551 kg
Shells per gun, main battery: 150
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 7,87" / 200 mm 236,22 ft / 72,00 m 9,84 ft / 3,00 m
Ends: Unarmoured
Main Belt covers 101 % of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 9,45" / 240 mm 3,15" / 80 mm 7,09" / 180 mm
2nd: 2,95" / 75 mm 0,98" / 25 mm 1,97" / 50 mm
- Armour deck: 2,76" / 70 mm, Conning tower: 9,84" / 250 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 11 999 shp / 8 952 Kw = 18,00 kts
Range 5 500nm at 12,00 kts
Bunker at max displacement = 911 tons
Complement:
490 - 638
Cost:
£2,777 million / $11,106 million
Distribution of weights at normal displacement:
Armament: 979 tons, 10,0 %
Armour: 2 621 tons, 26,8 %
- Belts: 825 tons, 8,4 %
- Torpedo bulkhead: 0 tons, 0,0 %
- Armament: 684 tons, 7,0 %
- Armour Deck: 1 015 tons, 10,4 %
- Conning Tower: 97 tons, 1,0 %
Machinery: 420 tons, 4,3 %
Hull, fittings & equipment: 4 081 tons, 41,8 %
Fuel, ammunition & stores: 1 365 tons, 14,0 %
Miscellaneous weights: 300 tons, 3,1 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
9 628 lbs / 4 367 Kg = 8,0 x 13,4 " / 340 mm shells or 1,6 torpedoes
Stability (Unstable if below 1.00): 1,12
Metacentric height 3,6 ft / 1,1 m
Roll period: 15,3 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0,84
Seaboat quality (Average = 1.00): 1,12
Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,698
Length to Beam Ratio: 5,24 : 1
'Natural speed' for length: 19,00 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 0,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18,04 ft / 5,50 m
- Forecastle (20 %): 13,12 ft / 4,00 m
- Mid (50 %): 13,12 ft / 4,00 m
- Quarterdeck (15 %): 13,12 ft / 4,00 m
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 13,52 ft / 4,12 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 94,6 %
- Above water (accommodation/working, high = better): 101,5 %
Waterplane Area: 19 899 Square feet or 1 849 Square metres
Displacement factor (Displacement / loading): 84 %
Structure weight / hull surface area: 155 lbs/sq ft or 755 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,91
- Longitudinal: 2,27
- Overall: 1,00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Thanks for your comments & suggests.
Here is an other study with 2T3x6" for secondary armament:
- The disposition of the turrets is similar to BC Von der Tann.
- With this disposition, I could install 2x4 TTx533 protected by the upper deck.
- I increase the protection to 300mm.
- I decrease the speed to 22.2kts.
- Survivability approach 10 000kg.
14000T coastal BB, Peru 2T3x340+2T3x152 laid down 1923 (Engine 1920)
Displacement:
14 000 t light; 14 758 t standard; 15 426 t normal; 15 960 t full load
Dimensions: Length overall / water x beam x draught
535.83 ft / 531.50 ft x 78.74 ft x 20.94 ft (normal load)
163.32 m / 162.00 m x 24.00 m x 6.38 m
Armament:
6 - 13.39" / 340 mm guns (2x3 guns), 1 200.00lbs / 544.31kg shells, 1923 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
6 - 6.00" / 152 mm guns (2x3 guns), 108.00lbs / 48.99kg shells, 1923 Model
Breech loading guns in turrets (on barbettes)
on side, evenly spread
8 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1923 Model
Quick firing guns in deck mounts
on side, evenly spread, all raised mounts
4 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1923 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 7 956 lbs / 3 609 kg
Shells per gun, main battery: 100
8 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 11.8" / 300 mm 341.21 ft / 104.00 m 10.17 ft / 3.10 m
Ends: 2.36" / 60 mm 144.36 ft / 44.00 m 8.01 ft / 2.44 m
45.93 ft / 14.00 m Unarmoured ends
Main Belt covers 99 % of normal length
- Torpedo Bulkhead:
1.57" / 40 mm 341.21 ft / 104.00 m 20.80 ft / 6.34 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 11.8" / 300 mm 3.94" / 100 mm 11.0" / 280 mm
2nd: 3.15" / 80 mm 1.57" / 40 mm 2.36" / 60 mm
3rd: 0.79" / 20 mm - -
4th: 0.50" / 13 mm - -
- Armour deck: 2.95" / 75 mm, Conning tower: 11.81" / 300 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 30 000 shp / 22 380 Kw = 22.21 kts
Range 5 500nm at 12.00 kts
Bunker at max displacement = 1 202 tons
Complement:
691 - 899
Cost:
£4.282 million / $17.126 million
Distribution of weights at normal displacement:
Armament: 994 tons, 6.4 %
Armour: 5 229 tons, 33.9 %
- Belts: 1 891 tons, 12.3 %
- Torpedo bulkhead: 414 tons, 2.7 %
- Armament: 1 070 tons, 6.9 %
- Armour Deck: 1 697 tons, 11.0 %
- Conning Tower: 158 tons, 1.0 %
Machinery: 1 049 tons, 6.8 %
Hull, fittings & equipment: 6 428 tons, 41.7 %
Fuel, ammunition & stores: 1 426 tons, 9.2 %
Miscellaneous weights: 300 tons, 1.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
21 010 lbs / 9 530 Kg = 17.5 x 13.4 " / 340 mm shells or 3.9 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 4.2 ft / 1.3 m
Roll period: 16.2 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.68
Seaboat quality (Average = 1.00): 1.20
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.616
Length to Beam Ratio: 6.75 : 1
'Natural speed' for length: 23.05 kts
Power going to wave formation at top speed: 48 %
Trim (Max stability = 0, Max steadiness = 100): 60
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: 24.61 ft / 7.50 m
- Forecastle (19 %): 20.34 ft / 6.20 m
- Mid (50 %): 19.49 ft / 5.94 m (11.48 ft / 3.50 m aft of break)
- Quarterdeck (18 %): 11.48 ft / 3.50 m
- Stern: 11.48 ft / 3.50 m
- Average freeboard: 16.10 ft / 4.91 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 97.7 %
- Above water (accommodation/working, high = better): 116.2 %
Waterplane Area: 31 068 Square feet or 2 886 Square metres
Displacement factor (Displacement / loading): 99 %
Structure weight / hull surface area: 155 lbs/sq ft or 757 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.35
- 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
The last design is the strongest - but still very expensive for an essentially single purpose ship?
DK - what PDNs you have - but why not make them last another 10 years - with sensible but lmtd modernisation (as long as well protected but very slow ships have a function vs. ever increasing torpedo threat (from Sub, DD and Aircraft) )
- and invest all this $$$$$ - in proper (multi-purpose) ships - with 1916 Engine Tech - you can now build sexy BBCs - sorry I don't understand :D .....
The Dantons (http://www.navalism.org/index.php?topic=1545.msg16974#msg16974) are an example of a recently refitted PDN.
The lack of reasonable secundaries worries the admiral who has to work with those;
The ships are rather second-class battleships and a waste of BP, IMHO.
The question is can Peru afford a modern DN at all? If we assume No or with great difficulty then you start having to look at making accepting weakness in whatever you do build.
Michael