Section 183(6) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(6)Before promotion to Branch Rank, a candidate must have served one year at sea as Yeoman of Signals or Petty Officer Telegraphist. A Leading Signalman or Leading Telegraphist shall be granted, after the qualifying course, the' [rank] of Acting Yeoman of Signals or Acting Petty Officer Telegraphist in sufficient time to ensure his having served in that capacity for a year before his turn of promotion is expected.
