Ships / Patrol boats / Osa class

Osa class

General Facts

  • TYPE
    Missile boat

  • ORIGIN
    USSR

  • NICKNAMES
    Project 205 (official Soviet designation)
    Tsunami (official Soviet nickname)

  • DESIGNED
    Early 1960's

  • DESIGNER
    Unknown

  • PRODUCTION
    Unknown

  • PRODUCERS
    China
    USSR

  • QUANTITY
    Over 400 have been produced

  • UNIT COST
    Unknown

  • CHARACTERISTICS
    High top and average speed
    Good self defense capabilities
    Limited production costs
    Average sea going capabilities
    Missiles currently outdated

Introduction

The Osa is a high speed missile boat of Soviet origin. It was developed in the early 1960's as a more capable alternative to the Komar class missile boat. The Osa is the world's most numerous missile boat. The official Soviet designation for this class is Project 205 Tsunami. The name Osa, which Russian for wasp, is the NATO designation. The improved Project 205U is known as Osa II.

Layout

The Osa class is a major improvement over the Komar missile boats. The Osa class is four times larger, is based on a steel hull, features 4 instead of 2 missiles, has a much improved air and self defense capability and better sea going performance. The improved Osa II features better engines and can fire a newer version of the SS-N-2 anti-ship missiles.

Firepower

The main armament of the Osa are the four SS-N-2 Styx anti-ship missiles. The Osa I fires the SS-N-2A and version while the Osa II may fire the larger longer range C model. Air defense is provided by two AK-230 turrets with two 30mm autocannon. One turret is fitted forward and the other aft. For an increased air defense capability the manually aimed quad launcher for the infra red guided SA-N-5 surface to air missiles was added to some vessels, mostly the Osa II.

Electronics

A Square Tie surface search radar is used for finding and plotting targets for the SS-N-2 Styx missiles. A Drum Tilt radar serves as fire control for the AK-230 turrets. IFF systems are fitted as well.

Mobility

To keep the design simple the Osa has three diesel engines each connected to its own shaft. The power to weight ratio is high and results in a maximum speed of 35 knots. The Osa II has more powerful engines and a slightly high maximum speed. Although the sea going capability is better than the Komar the Osa is not a true ocean going ship and is mostly used in coastal waters.

Users

The Osa was widely used by Soviet and Eastern European forces during the Cold War. It was also widely exported, mainly to Asia and the Middle East. Currently most remaining units suffer from old age and the SS-N-2 Styx missile is no longer considered to be a credible threat against modern frigates.

Variants

Osa I

The Project 205 Tsunami high speed missile boat has the NATO designation Osa I. The Osa I can be distinguished from the improved Osa II in having more squared missile launch tubes, whereas the Osa II has cylindrical missile tubes.

TypeMissile boat
Crew30
Displacement210 t standard, 245 t full load
Length38.6 m
Width7.6 m
Draught2.7 m
Height?
Machinery3x Type M503A diesel, 8.025 hp combined
Propulsion3 shafts
Speed35 kt
Range500 nm at 35 kt
SensorsSurface search: Square Tie
SystemsFCS: Drum Tilt radar for AK-230
IFF: High Pole B
IFF: Square Head
Countermeasures-
Aircraft-
Cargo-
Remarks-
WeaponsSSM: 4x SS-N-2 Styx
AA: 2x 30mm AK-230
SAM: 1x SA-N-5
Weapon1SS-N-2A Styx anti-ship missile
Four separate launchers middle and aft
4 rounds, all ready to fire
Weapon22x 30mm AK-230
Forward and aft
Weapon3-
Weapon4-
Weapon5-
Weapon6-
Weapon7-
Weapon8-

Osa II

The Project 205U Tsunami high speed missile boat has the NATO designation Osa II. The Osa II is an improved version of the Osa I. It has more powerful engines and is able to fire the larger and longer range SS-N-2C missile from its cylindrical shape missile launchers. Many Osa II are also fitted with the quad launcher for SA-N-5 surface to air missiles.

TypeMissile boat
Crew30
Displacement171 t standard, 245 t full load
Length38.6 m
Width7.6 m
Draught2.7 m
Height?
Machinery3x Type M504 diesel, 10.800 hp combined
Propulsion3 shafts
Speed37 kt
Range500 nm at 35 kt
SensorsSurface search: Square Tie
SystemsFCS: Drum Tilt radar for AK-230
IFF: High Pole B
IFF: Square Head
Countermeasures-
Aircraft-
Cargo-
Remarks-
WeaponsSSM: 4x SS-N-2 Styx
AA: 2x 30mm AK-230
SAM: 1x SA-N-5
Weapon1SS-N-2B Styx anti-ship missile
Four separate launchers middle and aft
4 rounds, all ready to fire
Weapon22x 30mm AK-230, Forward and aft
Weapon3SA-N-5 quad surface to air missile launcher
Middle of superstructure
16 rounds, 4 ready to fire
Weapon4-
Weapon5-
Weapon6-
Weapon7-
Weapon8-

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