After Morgan was promoted from the rank of Chief Petty Officer to Lieutenant Commander for reportedly capturing the infamous "Kuro", and then making his way up to the rank of Captain, he became corrupted with his newfound fame and tyrannized the entire 153rd Branch and the town associated with it for three years, with his son Helmeppo taking advantage of this.
East Blue Saga
Romance Dawn Arc
Their reign of terror came to an end when Luffy and Zoro defeated Morgan. He was then dismissed and control of the base passed to Commander Ripper. Koby and Helmeppo were part of the staff of the base until the transfer of the imprisoned Morgan to Garp. During this, Morgan was able to escape and Koby and Helmeppo went under Garp's command and tutelage.
Fish-Man Island Saga
From the Decks of the World
During the two year timeskip, Ripper became a Marine officer and Rika joined the base as a waitress.