WesWorld

I-2 Class Coastal Submarine

I-2, SS-2, laid down 1924, scrapped 1947
I-3, SS-3, laid down 1924, scrapped 1947
I-4, SS-4, laid down 1924, scrapped 1947

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

Persia will buy the license from Germany in 1938. Thanks Hrolf for SIM.

Type I, Persian U-boat laid down 1938

I-5 laid down 1938
I-6 laid down 1938
I-7 laid down 1938
I-8 laid down 1938
I-9 laid down 1938
I-10 laid down 1940

Displacement:
414 t light; 424 t standard; 458 t normal; 485 t full load

Dimensions: Length overall / water x beam x draught
165.68 ft / 164.04 ft x 19.69 ft x 11.81 ft (normal load)
50.50 m / 50.00 m x 6.00 m x 3.60 m

Armament:
1 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1938 Model
Anti-aircraft gun in deck mount
on centreline aft
2 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1938 Model
Machine guns in deck mounts
on centreline, all amidships
Weight of broadside 2 lbs / 1 kg
Shells per gun, main battery: 450
4 - 21.0" / 533.4 mm submerged torpedo tubes

Armour:

- Conning tower: 0.79" / 20 mm

Machinery:
Diesel Internal combustion generators plus batteries,
Electric motors, 2 shafts, 1,019 shp / 760 Kw = 15.00 kts
Range 2,500nm at 12.00 kts
Bunker at max displacement = 61 tons

Complement:
49 - 64

Cost:
£0.080 million / $0.318 million

Distribution of weights at normal displacement:
Armament: 0 tons, 0.1 %
Armour: 1 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 0 tons, 0.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 1 tons, 0.2 %
Machinery: 31 tons, 6.7 %
Hull, fittings & equipment: 282 tons, 61.6 %
Fuel, ammunition & stores: 44 tons, 9.5 %
Miscellaneous weights: 100 tons, 21.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
239 lbs / 108 Kg = 154.6 x 1.5 " / 37 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 0.5 ft / 0.2 m
Roll period: 11.8 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: 0.420
Length to Beam Ratio: 8.33 : 1
'Natural speed' for length: 12.81 kts
Power going to wave formation at top speed: 47 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 1.64 ft / 0.50 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): 98.9 %
- Above water (accommodation/working, high = better): 0.0 %
Waterplane Area: 2,013 Square feet or 187 Square metres
Displacement factor (Displacement / loading): 278 %
Structure weight / hull surface area: 95 lbs/sq ft or 463 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 3.64
- Longitudinal: 2.71
- Overall: 2.92
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

All tubes are forward.

12 tons of the miscellaneous tonnage are for 8 reload torpedoes.