 Following the aircraft experiments, "S-1" served as flagship for SubDiv 2 until July 1927, when she was transferred to SubDiv 4.While attached to this division, she made operational cruises to the Panama Canal Zone in 1928–1930, during the spring months.She visited ports at Cristobal, Canal Zone and Coco Solo, Canal Zone; Cartagena, Colombia; Kingston, Jamaica; and Guantánamo Bay, Cuba, during these cruises, and spent the remaining months of those years operating along the New England coast, out of New London.