Section 289(12)(a) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(a)In the case of Executive Branch candidates:-(i)they must have passed the Higher Educational Test;(ii)they must not be older than 23 years on the 30th June of the year in which the Preliminary Selection Board is held;(iii)Seaman sailors must have passed for Leading Seaman;(iv)Communication sailors and Naval Airmen must have been employed for six months on the duties of Seaman sailors under sub-regulation (9) have passed professionally for Able Seaman (but need not hold any specialist qualification) and have held the Able '[Ranks] in their respective branches at least for a period of one year. If such sailors fail in the Preliminary Selection Board or at any stage of their training, they shall revert to their original duties but shall retain their [Rank] [Substitued by S.R.O. 192, dated 10th September, 1973]. In the case of sailors who have not yet qualified professionally for the Leading [Rank] [Substitued by S.R.O. 192, dated 10th September, 1973], special facilities shall be made available to them to qualify for that [Rank] [Substitued by S.R.O. 192, dated 10th September, 1973]