Dvina class river gunboat, laid down 1920
Length, 67.0 m x Beam, 6.8 m x Depth, 1.8 m
661 tonnes normal displacement (585 tonnes standard)
Main battery: 2 x 15.0-cm
Secondary
battery: 4 x 3.7-cm
Light battery: 8 x 1.3-cm
Weight of broadside: 97 kg
50 tons cargo/mines
Main belt, 3.0 cm; bow and stern, 2.0 cm
Upper belt, 3.0 cm
Armor deck, average 1.0 cm
Conning tower, 3.0 cm
Battery armor:
Main, 3.0 cm shields
/ secondary, 3.0 cm shields
light guns, 3.0 cm shields
Maximum speed for 752 shaft kw = 14.00 knots
Approximate cruising radius, 4000 nm / 12 knots
Typical complement: 65-85
Estimated cost, $441,000 (£110,000)
Remarks:
Relative extent of belt armor, 57 percent of 'typical' coverage.
Ship has slow, easy roll; a good, steady gun platform.
Good seaboat; rides out heavy weather easily.
Magazines and engineering spaces are roomy, with superior
watertight
subdivision.
Cramped ship; poor crew accommodation, limited working space.
Distribution of weights:
Percent
normal
displacement:
Armament ......................... 27
tonnes = 4 pct
Armor, total .....................
100 tonnes = 15 pct
Belt
62 tonnes = 9 pct
Deck
31 tonnes = 5 pct
C.T.
2 tonnes = 0 pct
Armament
6 tonnes = 1 pct
Machinery ........................ 35
tonnes = 5 pct
Hull and fittings; equipment .....
342 tonnes = 52 pct
Fuel, ammunition, stores .........
108 tonnes = 16 pct
Miscellaneous weights ............
50 tonnes = 8 pct
-----
661 tonnes = 100 pct
Estimated metacentric height, 0.2 m
Displacement summary:
Light ship:
554 tonnes
Standard displacement: 585 tonnes
Normal service:
661 tonnes
Full load:
720 tonnes
Loading submergence 396 tonnes/metre
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Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.04
Shellfire needed to sink: 618 kg = 13.2 x 15.0-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not
counting critical hits)
Torpedoes needed to sink: 1.0
(Approximates number of 'typical'
torpedo hits needed to sink ship)
Relative steadiness as gun platform, 70 percent
(50 percent is 'average')
Relative rocking effect from firing to beam, 0.57
Relative quality as a seaboat: 1.21
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Hull form characteristics:
Block coefficient: 0.80
Sharpness coefficient: 0.42
Hull speed coefficient 'M' = 7.71
'Natural speed' for length = 14.8 knots
Power going to wave formation
at top speed: 42 percent
Estimated hull characteristics and strength:
Relative underwater volume absorbed by
magazines and engineering spaces: 57 percent
Relative accommodation and working space: 89 percent
Displacement factor: 152 percent
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 1.47
(Structure weight per square
metre
of hull surface: 278 kg)
Relative longitudinal hull strength: 1.45
(for 2.20 m average freeboard;
freeboard
adjustment -0.48 m)
Relative composite hull strength: 1.46
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[Machine-readable parameters: Spring Style v. 1.2.1]
219.76 x 22.30 x 5.90; 7.22 -- Dimensions
0.80 -- Block coefficient
1920 -- Year laid down
14.00 / 4000 /
12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
50 tons -- Miscellaneous weights
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2
x 5.91; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
4
x 1.46; 0 -- Secondary battery; turrets
Gun-shields
:
0 -- No tertiary (QF/AA) battery
8
x 0.51 -- Fourth (light) battery
0 -- No torpedo armament
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1.18 / 0.79 / 1.18 / 0.00; 57 -- Belt armor;
relative extent
0.39 / 1.18 -- Deck / CT
1.18 / 1.18 / 0.00 / 1.18 -- Battery armor
(Note: For portability, values are stored in Anglo-American units)
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