*** Welcome to piglix ***

Osa-class missile boat

Osa I (Project 205) craft
Osa I (Project 205) craft
Class overview
Name: Osa (Project 205)
Operators: see below
Preceded by: Komar-class missile boat
Succeeded by: Tarantul-class corvette
Subclasses: Osa I, Osa II
Completed: 400+
General characteristics
Type: Fast attack craft
Displacement:
  • Osa I
  • 171.5 (with M-504B – 184) tons standard
  • 209 (with M-504B – 226) tons full load
  • Osa II
  • 192 tons standard
  • 235 tons full load
Length: 38.6 m (127 ft)
Beam: 7.64 m (25.1 ft)
Draught: 1.73 m (5.7 ft) (with M-504B – 1.84 m (6.0 ft))
Installed power:
  • 3 × 4000 hp M-503G diesel engines (205)
  • 3 × 5000 hp M-504B diesel engines (205U onwards)
Propulsion: 3 shafts
Speed:
  • 38.5 knots (M-503G)
  • 42 knots (M-504B)
Range:
  • 1,800 nmi (3,300 km) at 14 knots,
  • 800 nmi (1,500 km) at 30 knots,
  • 500 nmi (930 km) at 35 knots
Endurance: 5 days
Complement:
  • 28 (4 officers) (Osa I)
  • 29 (4 officers) (Osa II)
Sensors and
processing systems:
  • MR-331 Rangout (Square Tie) radar
  • Klyon fire-control system for P-15 Termit
  • Nickel IFF
  • MR-104 Rys (Drum Tilt) fire-control radar for AK-230
  • ARP-58SV radio direction finder
Electronic warfare
& decoys:
Nikhrom-RRM IFF/ESM
Armament:

The Project 205 Moskit (mosquito) more commonly known by their NATO reporting name Osa, are a class of missile boats developed for the Soviet Navy in the late 1950s. Until 1962 this was classified as a large torpedo boat. The Osa class is probably the most numerous class of missile boats ever built, with over 400 vessels constructed between 1960–1973 for both the Soviet Navy and for export to allied countries. "Osa" means "wasp" in Russian, but it is not an official name. The boats were designated as "large missile cutters" in the Soviet Navy.

While the earlier Komar class were cheap and efficient boats (and the first to sink a warship with guided missiles, destroying the Israeli Navy's Eilat), their endurance, sea keeping, and habitability were modest at best, and the missile box was vulnerable to damage from waves. Among their other weak points were the wooden hull, the radar set lacking a fire control unit, and an inadequate defensive armament consisting of two manually operated 25 mm guns with only a simple optical sight in a single turret. The Komars' offensive weapons were a pair of P-15 Termit (NATO: SS-N-2 "Styx") missiles, and there was insufficient capacity to hold the more modern longer-ranged P-15Ms. The sensors were not effective enough to use the maximum range of the missiles, and the crew of 17 was not large enough to employ all the systems efficiently.

In order to remedy all these shortcomings, it was felt that bigger boats were needed to mount the necessary equipment and to provide more space for a larger crew.

The Project 205 boats are bigger than the pioneering Project 183R (NATO: Komar class) boats, with a mass four times greater, and nearly double the crew. They were still meant to be 'minimal' ships for the planned tasks.

The hull was made of steel, with a low and wide superstructure made of lighter AMG alloys, continuous deck, and a high free-board. The edges of the deck were rounded and smooth to ease washing off radioactive contamination in case of nuclear war. The hull was quite wide, but the Project 205 boats could still achieve high speeds as they had three Zvezda M503 radial diesel engines capable of a combined 12,000 hp (15,000 hp on Project 205U onward) driving three shafts. The powerful engines allowed a maximum speed of about 40 knots together with reasonable endurance and reliability. There were also three diesel generators. Two main engines and one generator were placed in the forward engine room, the third main engine and two generators in the aft engine room. There was a control compartment between the two engine rooms.


...
Wikipedia

...