Naval Enlisted Ranks

E-1 An E-1 in the USN is a seaman recruit. A seaman recruit has no insignia.
An E-2 in the USN is a seaman apprentice. His insignia is two parallel diagonal slashes.
An E-3 in the USN is a seaman. His insignia is three parallel diagonal slashes.
An E-4 in the USN is a petty officer third class. His insignia is one chevron below one eagle.
An E-5 in the USN is a petty officer second class. His insignia is two chevrons below one eagle.
An E-6 in the USN is a petty officer first class. His insignia is three chevrons below one eagle.
An E-7 in the USN is a chief petty officer. His insignia is three chevrons below one rocker below one eagle. In khaki uniform, his insignia will be a gold fouled anchor collar device with a silver 'USN' centered across the anchor.
An E-8 in the USN is a senior chief petty officer. His insignia is three chevrons below one rocker below one eagle below one star centered above the eagle. In khaki uniform, his insignia will be a gold fouled anchor collar device with a silver 'USN' centered across the anchor below one silver star.
An E-9 in the USN is a master chief petty officer. His insignia is three chevrons below one rocker below one eagle below two stars centered above the eagle. In khaki uniform, his insignia will be a gold fouled anchor collar device with a silver 'USN' centered across the anchor below two silver stars.
The master chief petty officer of the Navy is an E-9. His insignia is three chevrons below one rocker below one eagle below three stars centered above the eagle. In khaki uniform, his insignia will be a gold fouled anchor collar device with a silver 'USN' centered across the anchor below three silver stars.




Naval Warrant Officer Ranks

A W-2 is a chief warrant officer two. His insignia is a bar with a blue background and two gold breaks.
A W-3 is a chief warrant officer three. His insignia is a bar with a blue background and one silver break.
A W-4 is a chief warrant officer four. His insignia is a bar with a blue background and two silver breaks.




Naval Officer Ranks

An O-1 in the USN is an ensign. His insignia is a gold bar collar device or a gold one half inch stripe outboard of a gold five pointed star on black shoulder boards or a gold one half inch stripe below a gold five pointed star on the service dress blue uniform sleeves.
An O-2 in the USN is a lieutenant junior grade. His insignia is a silver bar collar device or a gold one half inch stripe outboard of a gold one quarter inch stripe outboard of a gold five pointed star on black shoulder boards or a gold one half inch stripe below a gold one quarter inch stripe below a gold five pointed star on the service dress blue uniform sleeves.
An O-3 in the USN is a lieutenant. His insignia is a two silver bar collar device or two gold one half inch stripes outboard of a gold five pointed star on black shoulder boards or two gold one half inch stripes below a gold five pointed star on the service dress blue uniform sleeves.
An O-4 in the USN is a lieutenant commander. His insignia is a gold oak leaf collar device or a gold one quarter inch stripe between two one half inch stripes outboard of a gold five pointed star on black shoulder boards or a gold one quarter inch stripe between two gold one half inch stripes below a gold five pointed star on the service dress blue uniform sleeves.
An O-5 in the USN is a commander. His insignia is a sliver oak leaf collar device or three gold one half inch stripes outboard of a gold five pointed star on black shoulder boards or three gold one half inch stripes below a gold five pointed star on the service dress blue uniform sleeves.
An O-6 in the USN is a captain. His insignia is a one silver eagle collar device or four gold one inch stripes outboard of a gold five pointed star on black shoulder boards or four one inch gold stripes below a gold five pointed star on the service dress blue uniform.
An O-7 in the USN is a rear admiral lower half. His insignia is a one silver five point star collar device or a gold shoulder board with one silver star outboard of a fouled anchor or a gold two inch stripe below a gold five pointed star on the service dress blue uniform sleeves.
An O-8 in the USN is a rear admiral. His insignia is a two silver five point star collar device or a gold shoulder board with two silver stars outboard of one fouled anchor or a gold two inch stripe below a gold one half inch stripe below a gold five pointed star on the service dress blue uniform sleeves.
An O-9 in the USN is a vice admiral. His insignia is a three silver five point star collar device or a gold shoulder board with three silver stars outboard of one fouled anchor or a gold two inch stripe below two gold one half inch stripes below one gold five pointed star on the service dress blue uniform sleeves.
An O-10 in the USN is an admiral. His insignia is a four silver five point star collar device or a gold shoulder board with four silver stars outboard of one fouled anchor or a gold two inch stripe below three gold one half inch stripes below a gold five pointed star on the service dress blue uniform sleeves.

Reference Site:  http://www.geocities.com/Pentagon/2086/ranks.htm