After a year in Paraguay, Inhaúma had also become ill with a lingering disease (not positively identified, although malaria is suspected) and had fallen into depression, becoming what historian Francisco Doratioto themed "no more than a ghost of an admiral". By January 1868 Humaitá had been completely cut off from land reinforcement and the shallow-draft monitors had arrived. Both Inhaúma and his officers balked at putting the new vessels into action. It was Inhaúma's son-in-law, Captain of Sea and War Delfim Carlos de Carvalho (soon Baron of Passagem) who volunteered to lead a squadron. On 19 February, the Brazilian ironclads successfully made a passage up the Paraguay River under heavy fire, gaining full control of the river and thus isolating Humaitá from resupply by water.