611X Deck LDO

611X is a United States Navy officer designator for a Surface Deck Limited Duty Officer (LDO). LDOs are technical managers in the field of seamanship and navigation.

They: Plan, supervise, and direct activities of deck and navigation personnel Plan, develop, and administer deck navigation training programs Other United States Navy officer designators include: 612X Operations (Surface) 613X Engineering/Repair (Surface) 615X Special Warfare (phased out as of July 2018)

Limited Duty Officers are separate from Chief Warrant Officers, but they are interchangeable up to the rank of Lieutenant Commander.