Mariz e Barros-class ironclad

The Mariz e Barros-class ironclads were a pair of armored corvettes originally ordered by Paraguay in 1864, but were sold to Brazil when Paraguay defaulted on the payments. Configured as central-battery ironclads, they served during the 1864–70 War of the Triple Alliance between Brazil, Argentina and Uruguay against Paraguay.

Design and description
The ships were 191 ft long, had a beam of 36 ft and drafts of 8.16 - 9.5 ft. They displaced 1196 - 1353 LT. The Mariz e Barros class had a pair of steam engines, each driving one propeller. The engines produced a total of 600 ihp and gave the ships a maximum speed of 9 kn. They carried 140 t of coal although nothing is known about their range or endurance. They were fully rigged with three masts. Their crew consisted of 125 officers and enlisted men.

Mariz e Barros was armed with two 120-pounder Whitworth rifled muzzle-loading guns and two smoothbore 68-pounder guns, while Herval had four 120-pounder guns. The ships had a complete waterline belt of wrought iron that ranged in thickness from 114 mm amidships to 76 mm at the ends of the ship.