What rank is designated as O-9 in the Navy?

The rank designated as O-9 in the Navy is Vice Admiral. This rank is two stars and is above Rear Admiral (which is O-8) and below Admiral (O-10). A Vice Admiral typically commands significant naval operations or holds important positions within the Navy and can serve in various high-level roles, including fleet commanders and senior staff positions.

The other ranks mentioned do not correspond to O-9. An Admiral is O-10, which is the highest rank in the Navy, while a Rear Admiral is O-8, positioned below the Vice Admiral. Fleet Admiral, while a recognized rank, is a special wartime rank that is designated as O-10 and has been used rarely in U.S. history.