What is the collar device for a Seaman Recruit in the Navy?

The collar device for a Seaman Recruit in the Navy is indeed "None," which reflects the rank of a Seaman Recruit. This rank is the entry-level position within the enlisted ranks of the Navy, and as such, it does not have a collar device or insignia to denote rank.

In naval terminology, insignia typically signifies experience or rank and is an important means of identifying a service member’s position within the hierarchy. Higher ranks, such as Seaman Apprentice or Seaman, will have corresponding insignias that include various devices, such as gold or silver bars. However, since a Seaman Recruit is at the very beginning of their naval career, they do not wear any collar devices at this rank. This absence of insignia serves to delineate the training and progression that must still occur before they can wear identifiers that signify a higher rank.