You have asked for information on the POSTAL CLERK rating. The rating symbol is a Cancellation Mark from an Envelope
The U.S. Navy is made up of four distinct groups of technical rating specialist. These categories are:
Administrative and Medical
Aviation
Hull
Construction
The term SEABEE was originally coined to define the Naval combat construction forces assigned to the Naval Civil Engineering Corps, and the SEABEES became a recognized organization in 1942. The traditional SEABEE specialty ratings are made up of seven classifications shown as the top left seven on the home page. As SEABEES tend to be self sufficient in a combat zone or other deployed area, other ratings are assigned to the SEABEES to provide the skills necessary to accomplish this.
While any rating within the U.S. Navy can be billeted with a SEABEE group depending upon the nature of the task at hand, the home page includes thirteen typical other ratings that were most assigned to be part of a SEABEE unit during the Vietnam Era.
Postal Clerk (PC):
The Navy operates a large postal system manned by Navy PCs, who have similar duties to their civilian counterparts in the U.S. Postal Service. PCs send mail on its way; collect postage-due mail; prepare customs declarations; collect outgoing mail; cancel stamps. They also perform a variety of record-keeping and reporting duties, which include maintaining an up-to-date directory service and locator file.