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.
Admiral (Australia) Admiral (abbreviated as ADML) is the highest active rank of the Royal Australian Navy and was created as a direct equivalent of the British Navy rank of admiral. It is a four-star rank. Since World War II, in general, the only time the rank is held is when the Chief of the Defence Force is a navy officer.