Bayandor-class corvette

The Bayandor class comprise four Iranian patrol frigates originally built for the US Navy as the PF-103 class. Only two are currently in service. Two were sunk in 1980 by Iraqi exocet ASM and aerial bombs.

USS Piedmont with Milanian (F-27) and Kahnamoie (F-28), circa 1969.
Class overview
Name:	Bayandor class
Builders:	Levingston Shipbuilding
Operators:	Iran
Building:	0
Completed:	4
Active:	2
Lost:	2
General characteristics
Type:	Corvette
Displacement:	900 tons (1135 tons full load)
Length:	84 m (276 ft)
Beam:	10.1 m (33 ft)
Draught:	3.1 m (10 ft)
Propulsion:	2 Fairbanks-Morse 38TD8 diesels on 2 shafts
Speed:	20 knots (37 km/h) on diesels
Range:	2,500 nmi (5,000 km)
Complement:	140
Armament:	4 × C-802 anti-ship cruise missiles 1 × 76/62 mm Fajr-27 dual purpose naval gun 1 × twin 40/56 mm AAA 2 × single 20 mm AAA 2 × 0.50cal machine guns 2 x triple light torpedo launchers

These corvettes were built in Texas under the MAP (Mutual Assistance Programme), wherein ships were built from US Navy funding and transferred immediately upon completion to allied navies. Two half-sisters serve in the Royal Thai navy.

As delivered, they were equipped with depth charge racks and Mk6 K-Guns aft; and a Mk10 Hedgehog forward. These were removed during the Iran-Iraq War. A ZU-23 anti-aircraft gun was added in 1982; this in turn was replaced by an Oerlikon 20 mm gun in 1990.

On 11 June 2013, after a 20-month refit and overhaul Iran's navy launched the corvette Bayandor, the program included repairing of the main engines, overhaul of the heat converters and fuel systems, modernizing of the monitoring systems and installation of new FCS and radar, and adding a Fajr-27 76 mm dual purpose Oto Melara type rapid fire cannon, and a dual 40 mm anti-aircraft cannon, in addition to two double canister Noor anti-ship missile launchers.[1][2][3]