Grand Admiral a naval rank in one of the highest in the several European navies that use this system, what system are they using?
Grand admiral Grand admiral is a historic naval rank, the highest rank in the several European navies that used it. It is best known for its use in Germany as "Großadmiral". A comparable rank in other navies is that of fleet admiral.
Unterleutnant Unterleutnant (NPA-original abbreviation "Ultn."; en: translation "Under-lieutenant" or "sub-lieutenant") was an officer of the German Democratic Republic's army (e.g. the National People's Army from 1956–1990) of the lowest commissioned officer (CO) rank comparable to NATO rank codes OF1c. It belonged to the rank group of lieutenants or subaltern officers. The equivalent OF1c-rank of the Volksmarine was Unterleutnant zur See (en: "sub-lieutenant at sea").