Portugal was then forced to buy frigates of an already existing project due to the urgency in the acquisition of naval ships for the defense of African, Macanese and Timorese waters.

[2] However, due to their planned use in Portuguese colonies in the Pacific and African regions, they had additional equipment installed for tropical service.

The frigates were propelled by two shafts powered by four SEMT Pielstick V12 PC diesel engines creating 16,000 bhp (12,000 kW).

The frigates also sported two Bofors 40 mm (1.6 in)/60 guns in a twin turret situated in the "B" position on the centreline.

The 100 mm guns could fire a 13 kilograms (29 lb) shell 9 nmi (17 km; 10 mi) at 80° elevation.

The 40 mm guns could fire a 0.89 kg (2.0 lb) shell 6.6 nmi (12.2 km; 7.6 mi) at 90° elevation.

For anti-submarine warfare (ASW), the João Belo class were equipped with a single Mortier four-barrelled 305 mm (12.0 in) anti-submarine mortar with a range of 2,700 m (8,900 ft) firing a 227 kg (500 lb) projectile and two triple-mounted 550 mm (22 in) ASW torpedo tubes for LCAN L3 torpedoes.

[8] The four frigates of the class were ordered from the French shipyard Ateliers et chantiers de Bretagne (ACB) Nantes, with construction of the first ship beginning in 1965.

Comandante João Belo was the first ship to enter service and was sent on a mission to Bissau in January 1968.

In 1972, Comandante João Belo was among the Portuguese warships that sailed to Brazil for the nation's 150th anniversary of its independence.

Comandante Hermenegildo Capelo was chosen as a hull for the "Ocean Revival" program and stripped and decontaminated.