ARA Indomita
ARA Intrepida
ARA Defencia
[ARA Alerta war loss]
Indomita Class, Argentina Torpedo Boat laid down 1932
Displacement:
788 t light; 819 t standard; 891 t normal; 949 t full load
Dimensions: Length overall / water x beam x draught
290.71 ft / 285.43 ft x 31.50 ft x 7.71 ft (normal load)
88.61 m / 87.00 m x 9.60 m x 2.35 m
Armament:
4 - 3.94" / 100 mm guns (2x2 guns), 28.66lbs / 13.00kg shells, 1932 Model
Quick firing guns in deck mounts
on centreline ends, evenly spread
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on centreline, evenly spread, all raised mounts
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 122 lbs / 55 kg
Shells per gun, main battery: 180
4 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm 0.39" / 10 mm -
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 22,000 shp / 16,412 Kw = 32.00 kts
Range 2,500nm at 15.00 kts
Bunker at max displacement = 130 tons
Complement:
81 - 106
Cost:
£0.461 million / $1.845 million
Distribution of weights at normal displacement:
Armament: 16 tons, 1.8 %
Armour: 5 tons, 0.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 0.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 431 tons, 48.3 %
Hull, fittings & equipment: 301 tons, 33.8 %
Fuel, ammunition & stores: 103 tons, 11.6 %
Miscellaneous weights: 35 tons, 3.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
335 lbs / 152 Kg = 11.0 x 3.9 " / 100 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.29
Metacentric height 1.4 ft / 0.4 m
Roll period: 11.2 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.13
Seaboat quality (Average = 1.00): 0.80
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.450
Length to Beam Ratio: 9.06 : 1
'Natural speed' for length: 19.56 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 63
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: 19.69 ft / 6.00 m
- Forecastle (20 %): 18.37 ft / 5.60 m
- Mid (40 %): 18.37 ft / 5.60 m (10.66 ft / 3.25 m aft of break)
- Quarterdeck (13 %): 10.66 ft / 3.25 m
- Stern: 10.66 ft / 3.25 m
- Average freeboard: 13.85 ft / 4.22 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 174.5 %
- Above water (accommodation/working, high = better): 125.9 %
Waterplane Area: 5,957 Square feet or 553 Square metres
Displacement factor (Displacement / loading): 61 %
Structure weight / hull surface area: 28 lbs/sq ft or 136 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.38
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather
***
Indomita Class, Argentina Torpedo Boat laid down 1932
Displacement:
792 t light; 819 t standard; 891 t normal; 949 t full load
Dimensions: Length overall / water x beam x draught
290.71 ft / 285.43 ft x 31.50 ft x 7.71 ft (normal load)
88.61 m / 87.00 m x 9.60 m x 2.35 m
Armament:
6 - 2.17" / 55.0 mm guns (3x2 guns), 5.08lbs / 2.30kg shells, 1947 Model
Anti-aircraft guns in deck mounts
on centreline, evenly spread, 1 raised mount
Aft Main mounts separated by engine room
4 - 0.79" / 20.0 mm guns (2x2 guns), 0.24lbs / 0.11kg shells, 1936 Model
Anti-aircraft guns in deck mounts
on side, all aft, all raised mounts - superfiring
Weight of broadside 31 lbs / 14 kg
Shells per gun, main battery: 500
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm 0.59" / 15 mm -
2nd: 0.39" / 10 mm - -
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 22,000 shp / 16,412 Kw = 32.00 kts
Range 2,500nm at 15.00 kts
Bunker at max displacement = 130 tons
Complement:
81 - 106
Cost:
£0.430 million / $1.721 million
Distribution of weights at normal displacement:
Armament: 4 tons, 0.4 %
Armour: 5 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 455 tons, 51.0 %
Hull, fittings & equipment: 288 tons, 32.4 %
Fuel, ammunition & stores: 99 tons, 11.2 %
Miscellaneous weights: 40 tons, 4.5 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
336 lbs / 152 Kg = 66.2 x 2.2 " / 55 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.30
Metacentric height 1.4 ft / 0.4 m
Roll period: 11.1 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.04
Seaboat quality (Average = 1.00): 0.80
Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.450
Length to Beam Ratio: 9.06 : 1
'Natural speed' for length: 19.56 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 63
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: 19.69 ft / 6.00 m
- Forecastle (20 %): 18.37 ft / 5.60 m
- Mid (40 %): 18.37 ft / 5.60 m (10.66 ft / 3.25 m aft of break)
- Quarterdeck (13 %): 10.66 ft / 3.25 m
- Stern: 10.66 ft / 3.25 m
- Average freeboard: 13.85 ft / 4.22 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 173.8 %
- Above water (accommodation/working, high = better): 181.6 %
Waterplane Area: 5,957 Square feet or 553 Square metres
Displacement factor (Displacement / loading): 65 %
Structure weight / hull surface area: 27 lbs/sq ft or 130 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.24
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather
1948 Refit Notes
Twin 100mm DP and 37mm mounts replaced by twin 55mm AA mounts
Single 20mm mounts replaced by new twin mounts
Torpedo tubes removed
Langhiri-Florisson Asdic added
Refurbishment of internal fittings for life extension
Misc Weight
10 tons for German HA/LA director with FC RDF
5 tons for Chilean surface search RDF set
15 tons for one DCR and two DCT for 20x DC
10 tons for Asdic