Profiting from its wartime experience with the little Goose, Grumman decided in 1944 to begin work on a similarly but larger amphibian as the G-66. This first flew in prototype form during October 1947, and offered greater payload than the Goose, while performance was considerably improved by the more powerful engines in combination with an airframe of exemplary aerodynamic clean lines. The type was order first by the US Navy, the initial UF-1 being joined later by her UF-2 with longer span wing of revised section, larger ailerons and tail surfaces, and a number of system improvements. Similar aircraft were ordered for the US Air Force as SA-16A and SA-16B and in 1962 these four models were redesigned HU-16A to HU-16D respectively. The UF-1F (HU-16E) was the Coast Guard version. The type was used mainly for SAR, though some smaller nations employ the type for coastal patrol. Some ex-military aircraft have entered service as airliners.