The Naval Staff issued an Operational -Tactical Requirement (OTR) for a replacement Mendoza Class destroyer using the basic hull and powerplant but with war experience worked into the design and a new armament of 115mm dual-purpose guns. The OTR was then sent to Naval Constructors Board and the Scientific – Technical Research Committee. Naval Constructors Board assigned the OTR to the Fourth Project Design Team who specialises in destroyers.
The initial pre-design sketch by Project Design Team focused on the sixth Mendoza Class ship, Project 404M, which became the Cordoba which was completed with three twin 115mm DP mounts as a testbed ship. The sketch design replaced the midships mount with additional light AA guns and the internal spaces and bridge structure were altered. The pre-design sketch was then studied by Naval Constructors Board and Scientific – Technical Research Committee (STRC) and evaluated for weaknesses and cost. The STRC inputs any new technologies or ideas into the design and throughout the Project and building phase develop these new technologies further. A revised light AA director system was included to improve accuracy against fast low-flying aircraft and a more modern Italian commercial sonar set were added to the proposal by the STRC and the boilers were refined to reduce weight and three diesel generators were included. Two of these were to be outside the main machinery spaces.
The Technical - Tactical Requirement (TTR) then released to refine the design and the Project Number 419 was assigned work began on the main design with detailed internal space studies and the standard Mendoza powerplant system was refined further. The Project was then evaluated by the Naval Constructors Board and the Naval Staff. Both approved the design, although the Naval Constructors were sceptical of the new 115mm mount given its poor performance in heavy seas and maintenance issues. The Naval Constructors Board gave the go ahead for the Project Team to commence drawing work later the same month.
Project 419 Mendoza No 8 (Drummond), Argentina Destroyer laid down 1937
Displacement:
1,716 t light; 1,809 t standard; 2,030 t normal; 2,207 t full load
Dimensions: Length overall / water x beam x draught
369.19 ft / 361.55 ft x 33.79 ft x 13.78 ft (normal load)
112.53 m / 110.20 m x 10.30 m x 4.20 m
Armament:
4 - 4.53" / 115 mm guns (2x2 guns), 55.12lbs / 25.00kg shells, 1937 Model
Breech loading guns in deck mounts with hoists
on centreline ends, evenly spread, 1 raised mount
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
12 - 0.79" / 20.0 mm guns (2x6 guns), 0.24lbs / 0.11kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 230 lbs / 104 kg
Shells per gun, main battery: 400
8 - 23.6" / 600 mm above water torpedoes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.98" / 25 mm 1.97" / 50 mm
2nd: 0.59" / 15 mm 0.39" / 10 mm -
3rd: 0.47" / 12 mm - -
- Conning tower: 1.97" / 50 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 40,800 shp / 30,437 Kw = 34.02 kts
Range 5,000nm at 15.00 kts
Bunker at max displacement = 398 tons
Complement:
150 - 196
Cost:
£1.190 million / $4.761 million
Distribution of weights at normal displacement:
Armament: 24 tons, 1.2 %
Armour: 25 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 7 tons, 0.3 %
Machinery: 984 tons, 48.5 %
Hull, fittings & equipment: 597 tons, 29.4 %
Fuel, ammunition & stores: 314 tons, 15.5 %
Miscellaneous weights: 85 tons, 4.2 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
599 lbs / 272 Kg = 12.9 x 4.5 " / 115 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.25
Metacentric height 1.5 ft / 0.5 m
Roll period: 11.7 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.41
Seaboat quality (Average = 1.00): 1.05
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.422
Length to Beam Ratio: 10.70 : 1
'Natural speed' for length: 21.80 kts
Power going to wave formation at top speed: 67 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.00 ft / 6.40 m
- Forecastle (20 %): 20.34 ft / 6.20 m
- Mid (52 %): 20.34 ft / 6.20 m (10.50 ft / 3.20 m aft of break)
- Quarterdeck (15 %): 10.50 ft / 3.20 m
- Stern: 10.50 ft / 3.20 m
- Average freeboard: 15.67 ft / 4.78 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 172.2 %
- Above water (accommodation/working, high = better): 66.2 %
Waterplane Area: 7,919 Square feet or 736 Square metres
Displacement factor (Displacement / loading): 79 %
Structure weight / hull surface area: 36 lbs/sq ft or 175 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.22
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Misc Weight
20 tons Italian Sonar
30 tons DC fit (2 DCT 4 throwers)
12 tons torpedoes
Remainder growth weight
Here are the specs of the fourth Belgrano Class cruiser to be built from late 1936. Her specs differ slightly from the German baseline standard.
Almirante Domecq Garcia, Argentina/ Germany Light Cruiser laid down 1936
Displacement:
10,422 t light; 10,844 t standard; 11,886 t normal; 12,719 t full load
Dimensions: Length overall / water x beam x draught
637.98 ft / 623.36 ft x 65.62 ft x 20.34 ft (normal load)
194.46 m / 190.00 m x 20.00 m x 6.20 m
Armament:
15 - 5.91" / 150 mm guns (5x3 guns), 100.31lbs / 45.50kg shells, 1932 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, majority forward, 2 raised mounts - superfiring
8 - 3.94" / 100 mm guns (4x2 guns), 28.66lbs / 13.00kg shells, 1932 Model
Dual purpose guns in deck mounts with hoists
on side ends, evenly spread
14 - 1.46" / 37.0 mm guns (7x2 guns), 1.55lbs / 0.70kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, 6 raised mounts
24 - 0.79" / 20.0 mm guns (4x6 guns), 0.24lbs / 0.11kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 1,761 lbs / 799 kg
Shells per gun, main battery: 180
8 - 23.6" / 600 mm above water torpedoes
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.51" / 140 mm 393.70 ft / 120.00 m 9.71 ft / 2.96 m
Ends: Unarmoured
Main Belt covers 97 % of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4.72" / 120 mm 2.76" / 70 mm 4.72" / 120 mm
2nd: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
3rd: 0.39" / 10 mm 0.20" / 5 mm -
4th: 0.47" / 12 mm - -
- Armour deck: 2.36" / 60 mm, Conning tower: 4.72" / 120 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 85,458 shp / 63,752 Kw = 32.50 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 1,875 tons
Complement:
568 - 739
Cost:
£4.699 million / $18.796 million
Distribution of weights at normal displacement:
Armament: 227 tons, 1.9 %
Armour: 2,776 tons, 23.4 %
- Belts: 885 tons, 7.4 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 599 tons, 5.0 %
- Armour Deck: 1,239 tons, 10.4 %
- Conning Tower: 53 tons, 0.4 %
Machinery: 2,398 tons, 20.2 %
Hull, fittings & equipment: 4,921 tons, 41.4 %
Fuel, ammunition & stores: 1,464 tons, 12.3 %
Miscellaneous weights: 100 tons, 0.8 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
19,062 lbs / 8,646 Kg = 185.1 x 5.9 " / 150 mm shells or 2.2 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 3.1 ft / 1.0 m
Roll period: 15.6 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.46
Seaboat quality (Average = 1.00): 1.29
Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 9.50 : 1
'Natural speed' for length: 28.61 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.17 ft / 9.50 m
- Forecastle (20 %): 22.97 ft / 7.00 m
- Mid (45 %): 22.47 ft / 6.85 m
- Quarterdeck (15 %): 22.47 ft / 6.85 m
- Stern: 22.47 ft / 6.85 m
- Average freeboard: 23.29 ft / 7.10 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 82.1 %
- Above water (accommodation/working, high = better): 177.9 %
Waterplane Area: 28,340 Square feet or 2,633 Square metres
Displacement factor (Displacement / loading): 125 %
Structure weight / hull surface area: 109 lbs/sq ft or 531 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.62
- Overall: 0.99
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily