Question: Grand Admiral a naval rank in one of the highest in the several European navies that use this system, what system are they using? 
Sentence (from "Erich Raeder during World War II"): Raeder attained the highest possible naval rank—that of "Großadmiral" (Grand Admiral) — in 1939, becoming the first person to hold that rank since Alfred von Tirpitz.
Relevant evidence: No