Brazilian monitor Parnaíba (U17)

Parnaíba (U-17) is a river monitor of the Brazilian Navy.

She was built by the Navy in Rio de Janeiro and commissioned on 9 March 1938. She participated in the Second World War and is currently the oldest ship in commission in the Brazilian Navy, as well as the oldest warship in the world still in active service (though HMS Victory of the Royal Navy is the oldest naval ship still in commission and the USS Constitution of the United States Navy is the oldest commissioned naval ship still floating). She is currently assigned to the Mato Grosso Flotilla.

Modernization
She underwent a modernization program at the Ladario Riverine Naval Base between January 1998 and 6 May 1999, which saw the replacement of her original reciprocating engine plant with diesel engines to increase her range and endurance. (One of her original engines was placed on display at the Sixth Naval District's Lieutenant Maximiano Memorial Hall.) A helicopter platform has been fitted over the fantail, allowing her to operate the IH-6B Bell Jet Ranger III, replacing the UH-12 Squirrel Helibrás Monoturbina.