Section 122(12)(c) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(c)Where an officer has been promoted to the rank of confirmed Lieutenant under the second proviso to cl. (b), such officer shall not be eligible for further promotion, whether acting or substantive, until he obtains the Naval Watchkeeping Certificate and he shall be required to obtain the same within one year of his becoming available for employment in the General Service.