Section 182(5)(c) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(c)state whether he elects to qualify for Commissioned Gunner, Commissioned Gunner (Torpedo & Anti-Submarine),Commissioned Boatswain, Commissioned Boatswain (Diving),Commissioned Boatswain (Plotter Radar) or Commissioned Physical Training Officer. The election made by a candidate on passing the seamanship examination for Branch Rank as to the branch in which he desires to qualify for promotion shall, as a general rule, be regarded as final; but transfers to the other branches may be allowed at the discretion of the Chief of the Naval Staff according to the requirements of the Service. The position on the roster of a candidate for undergoing the qualifying course who has been transferred from the roster of another rank, will be determined by the date of his transfer.