The ship's design, the Vosper Mk 7 is a modified version of the Alvand-class frigate built for the Iranian Navy.

The ship had an extensive refit in Italy by CNR Riva Trigoso 1979–1980 when new sensors and missiles were installed.

Dat Assawari was a modified version of the Vosper Thornycroft Mark 7 design, based on the Alvand-class frigates constructed for the Iranian Navy.

The vessel was powered by a combined diesel or gas system composed of two Rolls-Royce Marine Olympus gas turbines turning two shafts rated at 34,600 kilowatts (46,400 shp), giving the frigate a maximum speed of 37.5 knots (69.5 km/h; 43.2 mph) and two Paxman Ventura 16Y JACM diesel engines rated at 2,600 kilowatts (3,500 bhp).

Dat Assawari had a range of 5,700 nautical miles (10,600 km; 6,600 mi) at 17 knots (31 km/h; 20 mph).

The Limbo mortar was removed, its well plated over, and four single Mk I Otomat anti-ship missiles and two triple 324 mm (12.75 in) ASW torpedo tubes fitted in the space thus created.