They were based on the Royal Navy's Bridgewater-class sloops, but with a heavier armament and omitting the minelaying equipment of the British ships.

470 tons of oil were carried giving a range of 6,000 nautical miles (11,000 km; 6,900 mi) at 11 knots (20 km/h; 13 mph).

Four 2-pounder (40 mm) pom-pom anti-aircraft (AA) guns were fitted, while four depth charge throwers provided an anti-submarine armament.

As part of this programme, a contract was placed with the British shipbuilder Hawthorn Leslie for two sloops, to be named Gonçalo Velho and Gonçalves Zarco.

Portugal acquired new ships in the postwar era and Gonçalo Velho was broken up for scrap in June 1961.