Wandenkolk served as Minister of the Navy during the government of president Deodoro da Fonseca.

[1][2] For his service in the war, Eduardo Wandenkolk was decorated with the silver medals of the Eastern Campaign for his participation at the Siege of Uruguaiana and the Passage of Humaitá.

[1] On November 17, 1875, he was promoted to frigate captain and took command of the Port Authority in the province of Rio Grande do Sul.

[1] He later joined the Club Militar which conspired against the Brazilian monarchy as well as a member of the Grande Oriente do Brasil.

The newly founded Brazilian Navy was bitter over the loss of the monarchy and when Floriano Peixoto was elected, Wandenkolk signed the Manifesto of the Thirteen Generals [pt] which called for a new election within the republic as well as criticizing Peixoto's methods on suppressing the rebellions within the Brazilian states.