WesWorld

Note: Names were assigned to active submarines in 1944.

IX-1 class (coastal - training) (1 unit) - 1921

I-2 class (coastal) (0 unit) - 1924

I-6/Satarka class (ocean-going) (3 units) - 1925-6

I-9/Parangata class (coastal) (3 units) - 1927

I-11/Sraddhalu class (ocean-going) (2 units) - 1927

I-15/Tamasika class (coastal) (6 units) - 1929

I-21/Pakka class (coastal atypical operations) (2 units) - 1930-31

I-22/Mazabuta class (coastal minelayer) (2 units) - 1930

I-24/Saktisali class (ocean-going) (3 units) - 1931

I-28/Sarvasrestha class (ocean-going minelayer) - (2 units) - 1932-3

I-30/Sangadila class (cruiser) (0 unit) - 1937

I-31/Athaka (ocean-going) (3 units) - 1937

I-34/Yasasvi (ocean-going) (2 units) - 1942

I-36/Prakopa (ocean-going) (4 units) - 1943

Durjeya class (ocean-going) (12 units) - 1945-6

IX-1 Class Coastal Submarine

IX-1, SS-1, laid down 1921

K-class, South African Submarine laid down 1917

Displacement:
457 t light; 470 t standard; 500 t normal; 525 t full load

Dimensions: Length overall / water x beam x draught
171,42 ft / 171,42 ft x 18,86 ft x 12,30 ft (normal load)
52,25 m / 52,25 m x 5,75 m x 3,75 m

Operational diving depth: 90 m
Emergency diving depth: 145
Crush depth: 225

Armament:
1 - 4,13" / 105 mm guns in single mounts, 35,32lbs / 16,02kg shells, 1917 Model
Breech loading gun in deck mount
on centreline forward
Weight of broadside 35 lbs / 16 kg
Shells per gun, main battery: 150
5 - 21,0" / 533 mm submerged torpedo tubes (4 fwd, 1 aft)

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 805 shp / 600 Kw = 13,93 kts
Range 4.500nm at 8,00 kts (Bunkerage = 55 tons)

Complement:
52 - 68

Cost:
£0,043 million / $0,173 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0,9%
Machinery: 30 tons, 5,9%
Hull, fittings & equipment: 318 tons, 63,5%
Fuel, ammunition & stores: 43 tons, 8,7%
Miscellaneous weights: 105 tons, 21,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
129 lbs / 59 Kg = 3,7 x 4,1 " / 105 mm shells or 0,2 torpedoes
Stability (Unstable if below 1.00): 1,05
Metacentric height 0,4 ft / 0,1 m
Roll period: 11,8 seconds
Steadiness - As gun platform (Average = 50 %): 2 %
- Recoil effect (Restricted arc if above 1.00): 0,00
Seaboat quality (Average = 1.00): 0,00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,440
Length to Beam Ratio: 9,09 : 1
'Natural speed' for length: 13,09 kts
Power going to wave formation at top speed: 42 %
Trim (Max stability = 0, Max steadiness = 100): 50
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: 0,16 ft / 0,05 m
- Forecastle (20%): 0,16 ft / 0,05 m
- Mid (50%): 0,16 ft / 0,05 m
- Quarterdeck (15%): 0,16 ft / 0,05 m
- Stern: 0,16 ft / 0,05 m
- Average freeboard: 0,16 ft / 0,05 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 142,2%
- Above water (accommodation/working, high = better): 1,2%
Waterplane Area: 2.046 Square feet or 190 Square metres
Displacement factor (Displacement / loading): 251%
Structure weight / hull surface area: 100 lbs/sq ft or 489 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3,72
- Longitudinal: 2,86
- Overall: 3,05
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

I-2 Class Coastal Submarine

I-2, SS-2, laid down 1924, to Persia 1937
I-3, SS-3, laid down 1924, to Persia 1937
I-4, SS-4, laid down 1924, to Persia 1937
I-5, SS-5, cancelled 1924

I-2, laid down 1924

Length, 51.8 m x Beam, 5.5 m x Depth, 3.7 m
525 tonnes normal displacement (463 tonnes standard)

Operational Depth: 80 m
Emergency Depth: 128 m
Crush Depth: 200 m

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 1.5-cm

Weight of broadside: 16 kg

5 TT, 50.0 cm (submerged) (4 Fwd, 1 aft)

Hull unarmored

Maximum speed for 1200 shaft kw = 16.48 knots
Approximate cruising radius, 4000 nm / 12 knots

Typical complement: 55-71


Estimated cost, $332,000 (£83,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 4 tonnes = 1 pct
Machinery ........................ 53 tonnes = 10 pct
Hull and fittings; equipment ..... 302 tonnes = 58 pct
Fuel, ammunition, stores ......... 75 tonnes = 14 pct
Miscellaneous weights ............ 90 tonnes = 17 pct
-----
525 tonnes = 100 pct

Estimated metacentric height, 0.1 m

Displacement summary:

Light ship: 450 tonnes
Standard displacement: 463 tonnes
Normal service: 525 tonnes
Full load: 572 tonnes

Loading submergence 180 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.07

Shellfire needed to sink: 48 kg = 3.0 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.34
Hull speed coefficient 'M' = 6.44
'Natural speed' for length = 13.0 knots
Power going to wave formation
at top speed: 53 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 161 percent

Relative accommodation and working space: 1 percent


Displacement factor: 227 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.60
(Structure weight per square
metre of hull surface: 477 kg)

Relative longitudinal hull strength: 2.43
(for 0.03 m average freeboard;
freeboard adjustment -2.53 m)

Relative composite hull strength: 2.68

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

170.00 x 18.00 x 12.00; 0.10 -- Dimensions
0.50 -- Block coefficient
1924 -- Year laid down
16.48 / 4000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
90 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
:
1 x 0.59; 0 -- Secondary battery; turrets
:
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
5 / 5 / 19.69 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.00 -- No battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-6/Satarka Class Ocean-going Submarine

Satarka (Alert), I-6, SS-6, laid down 1925
Savadhana (Careful), I-7, SS-7, laid down 1925
Nipuna (Accomplished), I-8, SS-8, laid down 1926

I-6, laid down 1925

Length, 70.1 m x Beam, 8.5 m x Depth, 5.8 m
1748 tonnes normal displacement (1355 tonnes standard)

Operating Depth: 84 m
Emergency Depth: 134 m
Crush Depth: 210 m

Main battery: 1 x 12.5-cm
Secondary battery: 1 x 3.5-cm
AA battery: 2 x 1.5-cm

Weight of broadside: 28 kg

8 TT, 50.0 cm (submerged) (6 Fwd, 2 aft)

Hull unarmored

Maximum speed for 2999 shaft kw = 17.64 knots
Approximate cruising radius, 13000 nm / 12 knots

Typical complement: 135-176


Estimated cost, $926,000 (£231,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 8 tonnes = 0 pct
Machinery ........................ 130 tonnes = 7 pct
Hull and fittings; equipment ..... 817 tonnes = 47 pct
Fuel, ammunition, stores ......... 433 tonnes = 25 pct
Miscellaneous weights ............ 360 tonnes = 21 pct
-----
1748 tonnes = 100 pct

Estimated metacentric height, 0.2 m

Displacement summary:

Light ship: 1315 tonnes
Standard displacement: 1355 tonnes
Normal service: 1748 tonnes
Full load: 2056 tonnes

Loading submergence 379 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.02

Shellfire needed to sink: 409 kg = 15.1 x 12.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.3
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.35
Hull speed coefficient 'M' = 5.84
'Natural speed' for length = 15.2 knots
Power going to wave formation
at top speed: 52 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 99 percent

Relative accommodation and working space: 1 percent


Displacement factor: 256 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.04
(Structure weight per square
metre of hull surface: 608 kg)

Relative longitudinal hull strength: 2.72
(for 0.03 m average freeboard;
freeboard adjustment -3.23 m)

Relative composite hull strength: 2.80

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

230.00 x 28.00 x 19.00; 0.10 -- Dimensions
0.50 -- Block coefficient
1925 -- Year laid down
17.64 / 13000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
360 tons -- Miscellaneous weights
++++++++++
1 x 4.92; 0 -- Main battery; turrets
Central positioning of guns
:
1 x 1.38; 0 -- Secondary battery; turrets
:
2 x 0.59 -- Tertiary (QF/AA) battery
:
0 -- No fourth (light) battery
8 / 8 / 19.69 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.00 -- No battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-9/Parangata Class Coastal Submarine

Parangata (Adept), I-9, laid down 1927
I-10, laid down 1927, lost 1941
Bahadura (Brave), I-12, laid down 1927
Saksama (Capable), I-14, laid down 1927

I-9, laid down 1927

Length, 51.8 m x Beam, 5.5 m x Depth, 3.7 m
525 tonnes normal displacement (465 tonnes standard)

Operational Depth: 82 m
Emergency Depth: 130 m
Crush Depth: 204 m

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 1.5-cm

Weight of broadside: 16 kg

5 TT, 50.0 cm (submerged) (4 fwd, 1 aft)

Hull unarmored

Maximum speed for 1200 shaft kw = 16.48 knots
Approximate cruising radius, 4000 nm / 12 knots

Typical complement: 55-71


Estimated cost, $387,000 (£97,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 4 tonnes = 1 pct
Machinery ........................ 51 tonnes = 10 pct
Hull and fittings; equipment ..... 306 tonnes = 58 pct
Fuel, ammunition, stores ......... 73 tonnes = 14 pct
Miscellaneous weights ............ 90 tonnes = 17 pct
-----
525 tonnes = 100 pct

Estimated metacentric height, 0.1 m

Displacement summary:

Light ship: 452 tonnes
Standard displacement: 465 tonnes
Normal service: 525 tonnes
Full load: 570 tonnes

Loading submergence 180 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.07

Shellfire needed to sink: 48 kg = 3.0 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.34
Hull speed coefficient 'M' = 6.44
'Natural speed' for length = 13.0 knots
Power going to wave formation
at top speed: 53 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 162 percent

Relative accommodation and working space: 1 percent


Displacement factor: 231 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.65
(Structure weight per square
metre of hull surface: 484 kg)

Relative longitudinal hull strength: 2.46
(for 0.03 m average freeboard;
freeboard adjustment -2.53 m)

Relative composite hull strength: 2.72

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

170.00 x 18.00 x 12.00; 0.10 -- Dimensions
0.50 -- Block coefficient
1927 -- Year laid down
16.48 / 4000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
90 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
:
1 x 0.59; 0 -- Secondary battery; turrets
:
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
5 / 5 / 19.69 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.00 -- No battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-11/Sraddhalu Class Ocean-Going Submarine

Sraddhalu (Trustful), I-11, laid down 1927
Kusala (Efficient), I-13, laid down 1927

Length, 66.0 m x Beam, 7.7 m x Depth, 5.5 m
1409 tonnes normal displacement (1067 tonnes standard)

Operational Depth: 85 m
Emergency Depth: 137 m
Crush Depth: 212 m

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm
AA battery: 2 x 1.5-cm

Weight of broadside: 17 kg

8 TT, 55.0 cm (submerged)

Hull unarmored

Battery armor:
Main, 3.0 cm shields / secondary, 2.0 cm shields
AA, 2.0 cm shields

Maximum speed for 1999 shaft kw = 16.37 knots
Approximate cruising radius, 13000 nm / 12 knots

Typical complement: 115-149


Estimated cost, $755,000 (£189,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 0 pct
Armor, total ..................... 1 tonnes = 0 pct

Armament 1 tonnes = 0 pct

Machinery ........................ 85 tonnes = 6 pct
Hull and fittings; equipment ..... 665 tonnes = 47 pct
Fuel, ammunition, stores ......... 374 tonnes = 27 pct
Miscellaneous weights ............ 280 tonnes = 20 pct
-----
1409 tonnes = 100 pct

Estimated metacentric height, 0.2 m

Displacement summary:

Light ship: 1035 tonnes
Standard displacement: 1067 tonnes
Normal service: 1409 tonnes
Full load: 1677 tonnes

Loading submergence 322 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.02

Shellfire needed to sink: 141 kg = 8.8 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.35
Hull speed coefficient 'M' = 5.90
'Natural speed' for length = 14.7 knots
Power going to wave formation
at top speed: 48 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 152 percent

Relative accommodation and working space: 1 percent


Displacement factor: 289 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.11
(Structure weight per square
metre of hull surface: 568 kg)

Relative longitudinal hull strength: 2.79
(for 0.03 m average freeboard;
freeboard adjustment -3.09 m)

Relative composite hull strength: 2.86

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

216.48 x 25.26 x 18.04; 0.10 -- Dimensions
0.50 -- Block coefficient
1927 -- Year laid down
16.37 / 13000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
280 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 1.38; 0 -- Secondary battery; turrets
Gun-shields
:
2 x 0.59 -- Tertiary (QF/AA) battery
Gun-shields
:
0 -- No fourth (light) battery
8 / 8 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
1.18 / 0.79 / 0.79 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-15/Tamasika Class Coastal Submarine



Top to Bottom:

I-15 class coastal submarine

I-21 class atypical operations submarine

I-22 class minelaying coastal submarine

A planned run of six boats. Officially reported as 450 t boats, the class is somewhat larger than the preceeding I-2 and I-9 classes on account of a greater operating radius, larger powerplant, and heavier armament.

Though technically coastal boats, there is an expectation that the class should be able to operate in the eastern Indian Ocean and the western Pacific, allowing the larger I-6 and I-11 classes to focus on the more distal western Indian Ocean.

Tamasika (Vengeful), I-15, laid down 1929
Upadravi (Rowdy), I-16, laid down 1929
Imanadara (Upright), I-17, laid down 1929
Jiddi (Stubborn), I-18, laid down 1929
Asanta (Turbulent), I-19, laid down 1930
Calaka (Clever), I-20, laid down 1930

Length, 59.0 m x Beam, 6.2 m x Depth, 4.0 m
590 tonnes normal displacement (466 tonnes standard)

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm

Weight of broadside: 17 kg

6 TT, 55.0 cm (submerged) (4F, 2A), 12 torpedoes

Hull unarmored

Battery armor:
Main, 2.0 cm shields / secondary, 2.0 cm shields


Maximum speed for 1798 shaft kw = 18.29 knots
Approximate cruising radius, 8000 nm / 12 knots

Operational Diving Depth: 53 m
Emergency Depth: 85 m
Crush Depth: 132 m

Typical complement: 60-78

Misc. Weight:
-12 t for six torpedo reloads
-108 t for ballast tanks (18.3% of normal weight)

Estimated cost, $480,000 (£120,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Magazines and engineering spaces are very cramped,
and lack adequate watertight subdivision.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 1 pct
Armor, total ..................... 1 tonnes = 0 pct

Armament 1 tonnes = 0 pct

Machinery ........................ 74 tonnes = 13 pct
Hull and fittings; equipment ..... 252 tonnes = 43 pct
Fuel, ammunition, stores ......... 139 tonnes = 24 pct
Miscellaneous weights ............ 120 tonnes = 20 pct
-----
590 tonnes = 100 pct

Estimated metacentric height, 0.1 m

Displacement summary:

Light ship: 451 tonnes
Standard displacement: 466 tonnes
Normal service: 590 tonnes
Full load: 687 tonnes

Loading submergence 200 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.00

Shellfire needed to sink: 23 kg = 1.4 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.0
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.40
Sharpness coefficient: 0.30
Hull speed coefficient 'M' = 7.05
'Natural speed' for length = 13.9 knots
Power going to wave formation
at top speed: 50 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 244 percent

Relative accommodation and working space: 1 percent


Displacement factor: 193 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 2.32
(Structure weight per square
metre of hull surface: 343 kg)

Relative longitudinal hull strength: 1.64
(for 0.03 m average freeboard;
freeboard adjustment -2.59 m)

Relative composite hull strength: 1.78

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

193.52 x 20.34 x 13.12; 0.10 -- Dimensions
0.40 -- Block coefficient
1929 -- Year laid down
18.29 / 8000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
120 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 1.38; 0 -- Secondary battery; turrets
Gun-shields
:
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
6 / 6 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.79 / 0.79 / 0.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-21/Pakka Class Submarine (Coastal Atypical Operations)

The I-21 class is a variation of the I-15 class; it includes a "shed" that can store two humasteered torpedoes or small boats, as well as bunk space for a squad of AOWWT (Atypical Operations, Weapons, and Warfare Team) naval infantry. This approach to inserting raiders will be evaluated in light of India's mixed success using destroyers and MTBs during the Filipino revolution. Such forces could be used for attacking warships in port, sabotage of enemy facilities, reconnaissance, and other missions.

Pakka (Obdurate), I-21, laid down 1930
Rocaka (Lively), I-25, laid down 1931

Length, 59.0 m x Beam, 6.2 m x Depth, 4.0 m
590 tonnes normal displacement (469 tonnes standard)

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm

Weight of broadside: 17 kg

2 TT, 55.0 cm (submerged)

Hull unarmored

Battery armor:
Main, 2.0 cm shields / secondary, 2.0 cm shields


Maximum speed for 1199 shaft kw = 16.47 knots
Approximate cruising radius, 8000 nm / 12 knots

Operational Diving Depth: 59 m
Emergency Depth: 94 m
Crush Depth: 149 m

Typical complement: 60-78

Misc. Weight:
-4 t for two torpedo reloads
-16 t for deck "shed", collapsible crane, and two human torpedos or small boats
-108 t for ballast tanks (18.3% of normal weight)


Estimated cost, $444,000 (£111,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are roomy, with superior
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 1 pct
Armor, total ..................... 1 tonnes = 0 pct

Armament 1 tonnes = 0 pct

Machinery ........................ 49 tonnes = 8 pct
Hull and fittings; equipment ..... 272 tonnes = 46 pct
Fuel, ammunition, stores ......... 136 tonnes = 23 pct
Miscellaneous weights ............ 128 tonnes = 22 pct
-----
590 tonnes = 100 pct

Estimated metacentric height, 0.1 m

Displacement summary:

Light ship: 454 tonnes
Standard displacement: 469 tonnes
Normal service: 590 tonnes
Full load: 685 tonnes

Loading submergence 200 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.00

Shellfire needed to sink: 180 kg = 11.2 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.4
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.40
Sharpness coefficient: 0.30
Hull speed coefficient 'M' = 7.05
'Natural speed' for length = 13.9 knots
Power going to wave formation
at top speed: 45 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 75 percent

Relative accommodation and working space: 1 percent


Displacement factor: 224 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 2.54
(Structure weight per square
metre of hull surface: 371 kg)

Relative longitudinal hull strength: 1.81
(for 0.03 m average freeboard;
freeboard adjustment -2.59 m)

Relative composite hull strength: 1.97

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

193.52 x 20.34 x 13.12; 0.10 -- Dimensions
0.40 -- Block coefficient
1930 -- Year laid down
16.47 / 8000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
128 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 1.38; 0 -- Secondary battery; turrets
Gun-shields
:
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
2 / 2 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.79 / 0.79 / 0.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-22/Mazabuta Class Submarine (Coastal Minelayer)

The I-22 class submarine has been planned for a while now: boats using vertical-tube launched mines to lay small minefields in enemy waters. Four tubes, each housing four mines, are located aft of the conning tower for this purpose. Two units will be laid down in 1930, with an eye towards another four to six similar boats if the initial class is deemed acceptable.

Mazabuta (Strong), I-22, laid down 1930
aniyantrita (Unruly), I-23, laid down 1930

Length, 59.0 m x Beam, 6.2 m x Depth, 4.0 m
590 tonnes normal displacement (467 tonnes standard)

Main battery: 2 x 3.5-cm

Weight of broadside: 1 kg

6 TT, 55.0 cm (submerged) (2 F, 4 amidships mine tubes)

Hull unarmored

Battery armor:
Main, 2.0 cm shields


Maximum speed for 1199 shaft kw = 16.47 knots
Approximate cruising radius, 8000 nm / 12 knots

Operational Diving Depth: 61 m
Emergency Depth: 97 m
Crush Depth: 152 m


Typical complement: 60-78

Misc. Weight:
-16 t for sixteen mines
-4 t for two torpedo reloads
-108 t for ballast tanks (18.3% of normal weight)


Estimated cost, $370,000 (£92,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Machinery ........................ 49 tonnes = 8 pct
Hull and fittings; equipment ..... 277 tonnes = 47 pct
Fuel, ammunition, stores ......... 136 tonnes = 23 pct
Miscellaneous weights ............ 128 tonnes = 22 pct
-----
590 tonnes = 100 pct

Estimated metacentric height, 0.1 m

Displacement summary:

Light ship: 455 tonnes
Standard displacement: 467 tonnes
Normal service: 590 tonnes
Full load: 687 tonnes

Loading submergence 200 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.02

Shellfire needed to sink: 41 kg = 68.5 x 3.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.0
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.40
Sharpness coefficient: 0.30
Hull speed coefficient 'M' = 7.05
'Natural speed' for length = 13.9 knots
Power going to wave formation
at top speed: 45 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 183 percent

Relative accommodation and working space: 1 percent


Displacement factor: 257 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 2.73
(Structure weight per square
metre of hull surface: 377 kg)

Relative longitudinal hull strength: 1.85
(for 0.03 m average freeboard;
freeboard adjustment -2.59 m)

Relative composite hull strength: 2.04

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

193.52 x 20.34 x 13.12; 0.10 -- Dimensions
0.40 -- Block coefficient
1930 -- Year laid down
16.47 / 8000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
128 tons -- Miscellaneous weights
++++++++++
2 x 1.38; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
0 -- No secondary battery
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
6 / 6 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.79 / 0.00 / 0.00 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-24/Saktisali Class Submarine (Ocean-going)

Incremental improvements on the I-11 class of 1927.

Saktisali (Powerful), I-24, laid down 1931
Vira (Heroic), I-26, laid down 1931
Utkrsta (Excellent), I-27, laid down 1931

Length, 66.0 m x Beam, 7.7 m x Depth, 5.5 m
1409 tonnes normal displacement (1084 tonnes standard)

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm
AA battery: 2 x 1.5-cm

Weight of broadside: 17 kg

8 TT, 55.0 cm (submerged)

Hull unarmored

Battery armor:
Main, 3.0 cm shields / secondary, 2.0 cm shields
AA, 2.0 cm shields

Maximum speed for 1999 shaft kw = 16.37 knots
Approximate cruising radius, 13000 nm / 12 knots

Operational Diving Depth: 88 m
Emergency Depth: 132 m
Crush Depth: 219 m

Typical complement: 115-149

Miscellaneous Weight:
-16 t for eight reload torpedoes
-274 t (19.4%) for ballast tanks


Estimated cost, $907,000 (£227,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 0 pct
Armor, total ..................... 1 tonnes = 0 pct

Armament 1 tonnes = 0 pct

Machinery ........................ 80 tonnes = 6 pct
Hull and fittings; equipment ..... 677 tonnes = 48 pct
Fuel, ammunition, stores ......... 356 tonnes = 25 pct
Miscellaneous weights ............ 290 tonnes = 21 pct
-----
1409 tonnes = 100 pct

Estimated metacentric height, 0.2 m

Displacement summary:

Light ship: 1053 tonnes
Standard displacement: 1084 tonnes
Normal service: 1409 tonnes
Full load: 1663 tonnes

Loading submergence 322 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.00

Shellfire needed to sink: 160 kg = 10.0 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.35
Hull speed coefficient 'M' = 5.90
'Natural speed' for length = 14.7 knots
Power going to wave formation
at top speed: 48 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 142 percent

Relative accommodation and working space: 1 percent


Displacement factor: 288 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.16
(Structure weight per square
metre of hull surface: 578 kg)

Relative longitudinal hull strength: 2.84
(for 0.03 m average freeboard;
freeboard adjustment -3.09 m)

Relative composite hull strength: 2.92

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

216.48 x 25.26 x 18.04; 0.10 -- Dimensions
0.50 -- Block coefficient
1931 -- Year laid down
16.37 / 13000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
290 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 1.38; 0 -- Secondary battery; turrets
Gun-shields
:
2 x 0.59 -- Tertiary (QF/AA) battery
Gun-shields
:
0 -- No fourth (light) battery
8 / 8 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
1.18 / 0.79 / 0.79 / 0.00 -- Battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-28/Sarvasrestha Class Submarine (Ocean-going Minelayer)

The largest submarine laid down by India so far, the I-28 is an ocean-going minelayer. I-28 and her planned sister will round out India's Class A submarine roster.

Sarvasrestha (Best), I-28, laid down 1932
Parama (Ultimate), I-29, projected for 1933

Length, 81.0 m x Beam, 8.2 m x Depth, 5.9 m
1976 tonnes normal displacement (1555 tonnes standard)

Main battery: 1 x 10.5-cm
Secondary battery: 1 x 3.5-cm
AA battery: 4 x 1.5-cm

Weight of broadside: 17 kg

12 TT, 55.0 cm (submerged) (2 F, 10 amidships mine tubes)

Hull unarmored

Maximum speed for 2199 shaft kw = 16.17 knots
Approximate cruising radius, 14000 nm / 12 knots

Operational Depth: 75.9 m
Emergency Depth: 121.4 m
Crush Depth: 189.7 m

Typical complement: 148-193

Misc weight:
-12 t: six torpedo reloads
-50 t: 50 mines
-358 t: ballast tanks (19%)


Estimated cost, $1.254 million (£314,000)

Remarks:

Caution: lacks seaworthiness -- very limited seakeeping ability.

Caution: Very cramped ship with excessively poor habitability;
lacks suitable working space.

Ship has quick, 'lively' roll; not a steady gun platform.

Magazines and engineering spaces are cramped, with poor
watertight subdivision.


Distribution of weights:
Percent
normal
displacement:

Armament ......................... 5 tonnes = 0 pct
Machinery ........................ 87 tonnes = 4 pct
Hull and fittings; equipment ..... 1001 tonnes = 51 pct
Fuel, ammunition, stores ......... 463 tonnes = 23 pct
Miscellaneous weights ............ 420 tonnes = 21 pct
-----
1976 tonnes = 100 pct

Estimated metacentric height, 0.2 m

Displacement summary:

Light ship: 1512 tonnes
Standard displacement: 1555 tonnes
Normal service: 1976 tonnes
Full load: 2304 tonnes

Loading submergence 421 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.00

Shellfire needed to sink: 205 kg = 12.8 x 10.5-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 0.1
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 1 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 0.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.33
Hull speed coefficient 'M' = 6.47
'Natural speed' for length = 16.3 knots
Power going to wave formation
at top speed: 40 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 149 percent

Relative accommodation and working space: 1 percent


Displacement factor: 313 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 3.37
(Structure weight per square
metre of hull surface: 652 kg)

Relative longitudinal hull strength: 2.29
(for 0.03 m average freeboard;
freeboard adjustment -3.31 m)

Relative composite hull strength: 2.53

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

265.68 x 26.90 x 19.35; 0.10 -- Dimensions
0.50 -- Block coefficient
1932 -- Year laid down
16.17 / 14000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
420 tons -- Miscellaneous weights
++++++++++
1 x 4.13; 0 -- Main battery; turrets
Central positioning of guns
:
1 x 1.38; 0 -- Secondary battery; turrets
:
4 x 0.59 -- Tertiary (QF/AA) battery
:
0 -- No fourth (light) battery
12 / 12 / 21.65 -- TT / submerged / size
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.00 -- No battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

I-30/Sangadila Class Submarine

Sangadila (Implacable), I-30, laid down 1937; to Japan, 1945

Displacement:
3,260 t light; 3,387 t standard; 3,983 t normal; 4,460 t full load

Dimensions: Length overall / water x beam x draught
361.00 ft / 360.89 ft x 29.53 ft (Bulges 36.09 ft) x 23.79 ft (normal load)
110.03 m / 110.00 m x 9.00 m (Bulges 11.00 m) x 7.25 m

Armament:
2 - 8.27" / 210 mm guns (1x2 guns), 282.57lbs / 128.17kg shells, 1937 Model
Breech loading guns in a turret (on a barbette)
on centreline forward
2 - 1.38" / 35.0 mm guns in single mounts, 1.31lbs / 0.59kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on centreline, evenly spread
4 - 0.59" / 15.0 mm guns (2x2 guns), 0.10lbs / 0.05kg shells, 1937 Model
Machine guns in deck mounts
on centreline, evenly spread
Weight of broadside 568 lbs / 258 kg
Shells per gun, main battery: 150
6 - 21.7" / 550 mm submerged torpedo tubes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 4.92" / 125 mm 1.18" / 30 mm 4.92" / 125 mm

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 6,205 shp / 4,629 Kw = 18.00 kts
Range 14,000nm at 12.00 kts
Bunker at max displacement = 1,073 tons

Complement:
249 - 325

Cost:
£1.079 million / $4.316 million

Distribution of weights at normal displacement:
Armament: 71 tons, 1.8 %
Armour: 34 tons, 0.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 29 tons, 0.7 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 4 tons, 0.1 %
Machinery: 172 tons, 4.3 %
Hull, fittings & equipment: 2,183 tons, 54.8 %
Fuel, ammunition & stores: 723 tons, 18.2 %
Miscellaneous weights: 800 tons, 20.1 %
Indian copy of Ninjatousaya System fitted.

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3,165 lbs / 1,436 Kg = 11.2 x 8.3 " / 210 mm shells or 1.3 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 0.8 ft / 0.2 m
Roll period: 16.9 seconds
Steadiness - As gun platform (Average = 50 %): 1 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.450
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 19.00 kts
Power going to wave formation at top speed: 36 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.10 ft / 0.03 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 0.10 ft / 0.03 m
- Forecastle (30 %): 0.10 ft / 0.03 m
- Mid (0 %): 0.10 ft / 0.03 m
- Quarterdeck (55 %): 0.10 ft / 0.03 m
- Stern: 0.10 ft / 0.03 m
- Average freeboard: 0.10 ft / 0.03 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 63.3 %
- Above water (accommodation/working, high = better): 0.5 %
Waterplane Area: 6,797 Square feet or 631 Square metres
Displacement factor (Displacement / loading): 228 %
Structure weight / hull surface area: 179 lbs/sq ft or 874 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 2.92
- Longitudinal: 1.99
- Overall: 2.19
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

I-31/Athaka class submarine (Ocean-going)

The I-31 submarine were build concurrently with the I-30 and all four subs rounded up the Ocean Going submarines roster allowed by the Karachi Agreement and the Australian Naval Agreement.

I-31, India Submarine laid down 1937

Athaka (Indefatigable), I-31, laid down 1937
Ajeya (Unstoppable), I-32, laid down 1937
Adamya (Indomitable), I-33, laid down 1937

Displacement:
1,475 t light; 1,519 t standard; 2,098 t normal; 2,560 t full load

Dimensions: Length overall / water x beam x draught
226.38 ft / 226.38 ft x 27.23 ft x 21.65 ft (normal load)
69.00 m / 69.00 m x 8.30 m x 6.60 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1937 Model
Breech loading gun in deck mount
on centreline forward
2 - 1.38" / 35.0 mm guns (1x2 guns), 1.31lbs / 0.59kg shells, 1937 Model
Anti-aircraft guns in deck mount
on side amidships
2 - 0.59" / 15.0 mm guns in single mounts, 0.10lbs / 0.05kg shells, 1937 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 38 lbs / 17 kg
Shells per gun, main battery: 100
10 - 21.7" / 550 mm submerged torpedo tubes (6 forward, 4 aft)

Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 4,478 shp / 3,340 Kw = 17.50 kts
Range 20,000nm at 12.00 kts
Bunker at max displacement = 1,041 tons

Complement:
154 - 201

Cost:
£0.410 million / $1.641 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.2 %
Machinery: 123 tons, 5.8 %
Hull, fittings & equipment: 948 tons, 45.2 %
Fuel, ammunition & stores: 623 tons, 29.7 %
Miscellaneous weights: 400 tons, 19.1 %
Indian copy of Ninjatousaya System fitted.

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
505 lbs / 229 Kg = 14.3 x 4.1 " / 105 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.00
Metacentric height 0.7 ft / 0.2 m
Roll period: 13.6 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.550
Length to Beam Ratio: 8.31 : 1
'Natural speed' for length: 15.05 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 50
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: 0.00 ft / 0.00 m
- Forecastle (20 %): 0.00 ft / 0.00 m
- Mid (50 %): 0.00 ft / 0.00 m
- Quarterdeck (15 %): 0.00 ft / 0.00 m
- Stern: 0.00 ft / 0.00 m
- Average freeboard: 0.00 ft / 0.00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 143.6 %
- Above water (accommodation/working, high = better): 0.0 %
Waterplane Area: 4,302 Square feet or 400 Square metres
Displacement factor (Displacement / loading): 307 %
Structure weight / hull surface area: 132 lbs/sq ft or 647 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3.18
- Longitudinal: 3.51
- Overall: 3.21
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

I-34/Yasasvi Class Ocean-going Submarine

The I-34 has a longer, slimmer hull form than the preceding I-31 type, allowing for a greater speed on surface. Greater ballast is also provided for, and the boat is more stable.

On the other hand, two fewer tubes are carried aft, and maximum diving depth is reduced.

Yasasvi (Glorious), I-34, laid down 1942
Ugra (Furious), I-35, laid down 1942

I-34, Indian SS laid down 1942

Displacement:
1,500 t light; 1,547 t standard; 1,877 t normal; 2,141 t full load

Dimensions: Length overall / water x beam x draught
265.91 ft / 265.91 ft x 29.53 ft x 16.73 ft (normal load)
81.05 m / 81.05 m x 9.00 m x 5.10 m

Armament:
1 - 4.92" / 125 mm guns in single mounts, 59.59lbs / 27.03kg shells, 1942 Model
Dual purpose gun in deck mount
on centreline forward
1 - 1.38" / 35.0 mm guns in single mounts, 1.31lbs / 0.59kg shells, 1942 Model
Anti-aircraft gun in deck mount
on centreline aft
4 - 0.59" / 15.0 mm guns (1x4 guns), 0.10lbs / 0.05kg shells, 1942 Model
Machine guns in deck mount
on centreline aft, all raised guns - superfiring
Weight of broadside 61 lbs / 28 kg
Shells per gun, main battery: 250
8 - 21.7" / 550 mm submerged torpedo tubes (6 F, 2 A)

Machinery:
Diesel Internal combustion engines plus batteries,
Electric cruising motors plus geared drives, 2 shafts, 6,703 shp / 5,000 Kw = 20.23 kts
Range 20,000nm at 10.00 kts (Bunkerage = 594 tons)

Complement:
142 - 185

Cost:
£0.531 million / $2.125 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.4 %
Machinery: 175 tons, 9.3 %
Hull, fittings & equipment: 888 tons, 47.3 %
Fuel, ammunition & stores: 376 tons, 20.1 %
Miscellaneous weights: 430 tons, 22.9 %
-365 t: Ballast (19.4% of normal displacement)
-32 t: Sixteen torpedo reloads (12 F, 4 A)
-10 t: Sonar
-10 t: Ninjatousaya/schnorkel
-13 t: Weight reserve

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
852 lbs / 386 Kg = 14.3 x 4.9 " / 125 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 0.9 ft / 0.3 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 0.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.500
Length to Beam Ratio: 9.01 : 1
'Natural speed' for length: 16.31 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 50
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: 0.00 ft / 0.00 m
- Forecastle (20 %): 0.00 ft / 0.00 m
- Mid (50 %): 0.00 ft / 0.00 m
- Quarterdeck (15 %): 0.00 ft / 0.00 m
- Stern: 0.00 ft / 0.00 m
- Average freeboard: 0.00 ft / 0.00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 106.6 %
- Above water (accommodation/working, high = better): 0.0 %
Waterplane Area: 5,231 Square feet or 486 Square metres
Displacement factor (Displacement / loading): 223 %
Structure weight / hull surface area: 119 lbs/sq ft or 581 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3.05
- Longitudinal: 1.59
- Overall: 1.87
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

I-36/Prakopa Class Ocean-Going Submarine

Prakopa (Wrathful), I-36, laid down 1943
Vijayi (Triumphant), I-37, laid down 1943
Saphala (Successful), I-38, laid down 1943
Banaila (Savage), I-39, laid down 1943

Date: 1943
Oceanic
Armament:
- Guns: 1x105mm LA, 1x35mm AA, 2x15mm MG
- Torpedoes: 8x550mm (6F/2A) + 12 reloads (simmed as 24 mines)
- Mines: 0
Electric HP: 5,500 hp
Diesel HP: 4,000 hp
Crew: 55
wt fuel&batts: 530
Light Displacement: 1,320 t
Loaded Displacement/Kerb Weight: 1,574 t
Full Displacement: 1,848 t
Reserve buoyancy: 15%
Max Surf Speed: 16.0 knots
Max Sub Speed: 12.1 knots

Length: 84.0 m
Beam: 8.0 m
Draft: 5.5 m
Crush depth: 300 m
Tons Oil: 230 t
Tons Battery: 300 t
Cruise speed: 12 knots
Submerged speed: 6 knots
Surface Range: 5,227 nm @ 15 knots; 8,168 nm @ 12 knots; 11,761 nm @ 10 kts
Submerged Range: 8 nm @ 12 knots; 22 nm @ 9 knots; 74 nm @ 6 knots

Other Features:
-Snort Mast (10 t miscellaneous weight)
-Sonar (10 t miscellaneous weight)
-Basic surface-search radar (5 t miscellaneous weight)
-35mm and 15mm guns (1 t miscellaneous weight)
-Weight reserve (4 t miscellaneous weight)

Durjeya Class Submarine (Oceanic)

The Durjeya class submarines are new ocean-going boats with substantially improved machinery and battery capacity, enabling longer and faster time spent underway. In conjunction with the Ninjatousaya, this should allow the boat to minimize time spent on the surface.

Armament has been revised somewhat over the previous Prakopa class, with the stern tubes and the major calibre gun being discarded. The latter is omitted in part for streamlining but also because the BNS is less concerned with conducting "Cruiser rules" trade warfare and more interested in hunting surface warships. Whether this proves to be a reasonable expectation remains to be seen.

A total of twelve boats are planned in 1945 and 1946, with the expectation that the six Satarka and Parangata class boats will be removed from active service at that time.

Durjeya, SS-40, laid down 1945
Sanadara, SS-41, laid down 1945
Mahana, SS-42, laid down 1945
Adarniya, SS-43, laid down 1945
Sammanita, SS-44, laid down 1945
Bhayanaka, SS-45, laid down, 1945
Bhayankara, SS-46, laid down 1946
Daravana, SS-47, laid down 1946
Sahasika, SS-48, laid down 1946
Nidara, SS-49, laid down 1946
Sahasi, SS-50, laid down 1946
Dabanga, SS-51, laid down 1946

Model: Durjeya/I-40 class
Date: 1945
Oceanic
Armament:
- Guns: 2x25mm
- Torpedoes: 6x550mm (6F/0A) + 18 reloads (simmed as 32 mines)
- Mines: Up to 32 in place of torpedoes
Electric HP: 7,000 hp
Diesel HP: 4,000 hp
Crew: 59
wt fuel&batts: 606
Light Displacement: 1,544 t
Loaded Displacement/Kerb Weight: 1,886 t
Full Displacement: 2,222 t
Reserve buoyancy: 15%
Max Surf Speed: 15.40 knots
Max Sub Speed: 17.9 knots

Length: 83.0 m
Beam: 8.5 m
Draft: 6.3 m
Crush depth: 317.5 m and not a centimetre more
Tons Oil: 306 t
Tons Battery: 300 t
Cruise speed: 12 knots
Submerged speed: 5 knots
Surface Range: 6,222 nm @ 15 knots; 9,722 nm @ 12 knots; 14,000 nm @ 10 kts
Submerged Range: 7 nm @ 17.9 knots; 15 nm @ 15 knots; 32 nm @ 12 knots; 317 nm @ 5 knots

Other Features:
-Snort Mast (10 t miscellaneous weight)
-Sonar (10 t miscellaneous weight)
-Basic surface-search radar (5 t miscellaneous weight)
-Streamlining on 25mm guns (2 t miscellaneous weight)
-Weight reserve (23 t miscellaneous weight)