Rubuta ci gaba don wannan sakin layi - A farkon yakin Schleswig na biyu a 1864, yawancin jiragen ruwa na Prussian sun kasance a cikin Baltic Sea. Yarima Adalbert shi ne babban kwamandan sojan ruwa, kuma Jachmann, a matsayin babban kyaftin din, ya zama kwamandan rundunar, tare da "Arcona" a matsayin babban jirginsa. Mafi yawan manyan jiragen ruwa na Danish sun kewaye manyan tashar jiragen ruwa na Prussia, suna kama jiragen ruwa na Jachmann - "Arcona" da "Swinemünde". Ranar 17 ga watan Maris, Jachmann ya ɗauki jirgi biyu da jirgin ruwa mai dauke da makamai don kalubalanci sojojin Denmark. A cikin yakin Jasmund da ya biyo baya
a tsibirin Rügen, rundunar Jachmann ta ci nasara da rundunar sojojin Denmark mafi karfi kuma ta tilasta komawa baya. Wannan shi ne kawai babban yakin da aka yi a cikin Baltic a lokacin yakin. Duk da haka, an nada shi "Konteradmiral" (Rear Admiral) saboda mummunan aikinsa na rundunar jiragen ruwa a Jasmund. Zuwan wani jirgin ruwa na jirgin ruwa na Danish ya hana duk wani hare-haren da ake yi a kan jiragen ruwa na Danish, kamar yadda bindigogi na gargajiya da ke dauke da makamai na Jachmann ba su da amfani a kan jirgin ruwa.