<prompt> Pedzisa mutsara unotevera: Greer akasimudzirwa kuva lieutenant commander uye akashanda muUnited States Navy kubva muna 1862 kusvika muna 1863, uye akabva apiwa Rear Admiral David Dixon Porters Mississippi Squadron. Paakanga achitungamirira ngarava dzehondo dzesimbi uye, akapinda muhondo yeVicksburg nekupfura kwe  <response>: Grand Gulf pamwe chete neUnion Red River expedition yakatadza kubudirira mukuvamba kwa1864. 