Perhaps this might help you a little bit:
These uniforms seem to be very early Imperial German ones from the 1870s.
As for the ranks, they are from the left to the right:
Unterleutnant (full-dress)
Kapitänleutnant (overcoat)
Admiral (full-dress)
Kapitän (full-dress)
Leutnant (overcoat)
Korvetten-Kapitän (overcoat)
Deckoffizier
Vize-Säbel-Kadett
Feldwebel
As for the uniform of an ordinary sailor, they wore white trousers and blue shirts.