In December 1843, Voorhees joined Commodore Daniel Turner's Brazil Squadron blockading Montevideo in safeguarding U.S. trade during the Uruguayan Civil War. On September 29, 1844, Voorhees captured an armed Argentine schooner that delivered a mail to the Argentine commanding officer. This overreaction damaged the US-Argentina relation and resulted in a court martial for Voorhees. His impetuosity resulted in a few months suspension, for Voorhees, but did little damage to his career.