 He served as the executive officer aboard the frigate , again as the commander of "Amazone", and as the shipyard director at the "Königliche Werft" (Royal Shipyard) in Danzig.During this period, Jachmann commanded a flotilla of ten gunboats during exercises in July and August 1851.In 1855, Jachmann was promoted to the rank of "Korvettenkapitän" (Corvette Captain).