Zenit class seaplane carrier

Russian Seaplane/Submarine Tender, laid down 1924

Length, 110.0 m x Beam, 17.0 m x Depth, 5.0 m
4713 tonnes normal displacement (3350 tonnes standard)

Main battery: 3 x 13.0-cm (3 x 1)
Secondary battery: 4 x 7.6-cm
AA battery: 8 x 3.7-cm

Weight of broadside: 121 kg

Hull unarmored

Battery armor:
Main, 2.5 cm / secondary, 2.5 cm shields
AA, 2.5 cm shields

Aircraft - 16 Seaplanes, 2 Catapults (1 starboard, 1 port)

Sixteen is the number of aircraft the Seaplane Tender is designed to support - half a Patrol Squadron of twin-engined seaplanes, plus two Flights of four single-engined Scout seaplanes which are carried on board.

The twin-engine seaplanes are generally able to self-deploy, given their considerable range. The Tender sustains them for their operations.

It also carries diesel fuel and spare torpedos to support submarine operations.

Cargo - 1,250 metric tons 3,300 GRT

Maximum speed for 7785 shaft kw = 20.00 knots
Approximate cruising radius, 15000 nm / 15 knots

Typical complement: 284-370

Estimated cost, $2.341 million (£585,000)

Remarks:

Excellent seaboat; comfortable and able to fight her guns
in the heaviest weather.

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

Distribution of weights:
Percent
normal
displacement:

Armament ......................... 33 tonnes = 1 pct
Armor, total ..................... 28 tonnes = 1 pct

Armament 28 tonnes = 1 pct

Machinery ........................ 344 tonnes = 7 pct
Hull and fittings; equipment ..... 1328 tonnes = 28 pct
Fuel, ammunition, stores ......... 1480 tonnes = 31 pct
Miscellaneous weights ............ 1500 tonnes = 32 pct
-----
4713 tonnes = 100 pct

Estimated metacentric height, 0.9 m

Displacement summary:

Light ship: 3233 tonnes
Standard displacement: 3350 tonnes
Normal service: 4713 tonnes
Full load: 5785 tonnes

Loading submergence 1185 tonnes/metre

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

Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.24

Shellfire needed to sink: 3700 kg = 121.4 x 13.0-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 2.0
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 53 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.06

Relative quality as a seaboat: 1.51

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

Hull form characteristics:

Block coefficient: 0.50
Sharpness coefficient: 0.38
Hull speed coefficient 'M' = 6.58
'Natural speed' for length = 19.0 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: 65 percent

Relative accommodation and working space: 111 percent

Displacement factor: 190 percent
(Displacement relative to loading factors)

Relative cross-sectional hull strength: 0.95
(Structure weight per square
metre of hull surface: 345 kg)

Relative longitudinal hull strength: 1.58
(for 4.00 m average freeboard;
freeboard adjustment +0.03 m)

Relative composite hull strength: 1.00

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

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

360.80 x 55.76 x 16.40; 13.12 -- Dimensions
0.50 -- Block coefficient
1924 -- Year laid down
20.00 / 15000 / 15.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
1500 tons -- Miscellaneous weights
++++++++++
3 x 5.12; 3; 0 -- Main battery; turrets; superfiring
:
4 x 2.99; 0 -- Secondary battery; turrets
Gun-shields
:
8 x 1.46 -- Tertiary (QF/AA) battery
Gun-shields
:
0 -- No fourth (light) battery
0 -- No torpedo armament
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.98 / 0.98 / 0.98 / 0.00 -- Battery armor

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

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