UNITED STATES NAVY
Senior Chief Petty Officer is the eighth enlisted rank in the U.S. Navy and U.S. Coast Guard, just above Chief Petty Officer and below Master Chief Petty Officer, and is a non-commissioned officer. They are referred to as Senior Chief in most circumstances.
Advancement to Senior Chief Petty Officer is similar to that of Chief Petty Officer. It carries requirements of time in service, superior evaluation scores and peer review. It is the first promotion that is based entirely on proven leadership performance where test scores do not play a part. A Chief Petty Officer can only advance if a board of Master Chiefs approve, convened every year around March. Beginning in 2008, Chiefs will also be required to have at least an Associate's Degree before they can screen for this promotion.
As with Chief Petty Officers, a Senior Chief Petty Officer takes on more administrative duties. Their uniform changes to reflect this change of duty; becoming similar to that of an officer, albeit with different insignia than an officer.
Like Petty Officers, every chief has both a rate (rank) and rating (job, similar to an MOS in other branches). A chief's full title is a combination of the two. Thus, a Senior Chief Petty Officer, who has the rating of Machinist's Mate would properly be called a Senior Chief Machinist's Mate.
Each rating has an official abbreviation, such as MM for Machinist's Mate, BT for Boiler Technician, or YN for Yeoman. When combined with the petty officer level, this gives the short-hand for the chief's rank, such as BMCS for Boatswain's Mate Senior Chief. It is not uncommon practice to refer to the senior chief by this short hand in all but the most formal correspondence (such as printing and inscription on awards). They are commonly addressed as "Senior Chief" or even just "Senior" regardless of rating.
The rating insignia for a senior chief is an eagle with spread wings above three cheverons. The cheverons are topped by a rocker that goes behind the eagle (or "crow," as it is commonly called). An inverted star (a reference to the stars used on the sleeves of line officers) is placed above the crow. This is used on the Dress Blue uniform. On all over uniforms, the insignia used is the one that has become universally accepted as the symbol of the Chief Petty Officer. This is a fouled (entwined in the anchor chain) gold anchor superimposed with a silver "USN." Like the dress blue insignia, this is capped by an upside-down star.
Collectively, officers and chiefs are referred to as "khakis." This is a reference to the color of their most common uniforms, and is a direct contrast to those in paygrades E-6 and below (or, blueshirts).