You can read [url=http://onepiece.wikia.com/wiki/Marine_Ranks]this[/url] for more info:

I could be wrong about the "First Mate" "Second Mate" terminology, it's just something I picked up from watching Star Trek: TNG.

For a quick list:

Commissioned Officers:
Fleet Admiral
Admiral
Vice Admiral
Rear Admiral
Commodore
Captain - Ricden is now a Captain
Commander - Handel's highest rank before transfer to CP1
Lieutenant Commander - Ricden's rank before Handel's transfer
Lieutenant
Lieutenant Junior Grade
Ensign

Non-Commissioned Officers (Infantry and Sailor Division)
Warrant Officer
Master Chief Petty Officer
Chief Petty Officer
Petty Officer
Seaman First Class
Seaman Apprentice (Second Class)
Seaman Recruit (Third Class)
Chore Boy

Whew, done.