WesWorld

Here is a small submarine used by the Institute for Maritime Research of the Russian Ministry of Marine. Its main uses so far have been to investigate the geography and flora and fauna of the sea, at depths previously unreached by man...

Znania class, Russian Research Submersible laid down 1920

Displacement:
63 t light; 64 t standard; 66 t normal; 68 t full load
Loading submergence 13 tons/feet

Dimensions:
66.27 ft x 9.51 ft x 6.23 ft (normal load)
20.20 m x 2.90 m x 1.90 m

Armament:
1 - 0.30" / 8 mm guns
Weight of broadside 0 lbs / 0 kg

Machinery:
Diesel Internal combustion generators plus batteries,
Electric motors, 1 shaft, 94 shp / 70 Kw = 10.00 kts
Range 600nm at 10.00 kts

Operational Depth - 168m/550 ft
Emergency Depth - 268m/880 ft
Crush Depth - 419m/1,375 ft

Complement:
5 - 8

Cost:
£0.006 million / $0.025 million

Distribution of weights at normal displacement:
Armament: 0 tons, 0.0 %
Machinery: 3 tons, 5.0 %
Hull, fittings & equipment: 48 tons, 73.1 %
Fuel, ammunition & stores: 4 tons, 5.3 %
Miscellaneous weights: 11 tons, 16.6 %

Metacentric height 0.2

Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.18
Shellfire needed to sink: 101 lbs / 46 Kg = 7,545.4 x 0.3 " / 8 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 0.6
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 0 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0.00
Relative quality as seaboat: 0.00

Hull form characteristics:
Block coefficient: 0.590
Sharpness coefficient: 0.41
Hull speed coefficient 'M': 5.00
'Natural speed' for length: 8.14 kts
Power going to wave formation at top speed: 58 %
Trim: 50
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 35.6 %
Relative accommodation and working space: 0.0 %
(Average = 100%)
Displacement factor: 377 %
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 5.49
(Structure weight / hull surface area: 72 lbs / square foot or 349 Kg / square metre)
Relative longitudinal hull strength: 5.50
(for 0.00 ft / 0.00 m average freeboard, freeboard adjustment -5.55 ft)
Relative composite hull strength: 5.50

How about forward, and with a mechanical arm attachment to grab the odd code book that just, by coincidence, happens to be found lying on the ocean floor...