The Savoia-Marchetti S.57 was an Italian single-engine biplane flying boat intended for aerial reconnaissance, built by Savoia-Marchetti for Regia Aeronautica after World War I.Of wooden construction with a single-step hull, with pilot and observer/gunner in tandem open cockpits in the bow, the S.57 was powered by a single 186 kW (249 hp) Isotta-Fraschini V.6.