Section 66(d) in The Merchant Shipping (Examination Of Engineers In The Merchant) Navy Rules, 1963
(d)A candidate may take Part 'B' or that Section of it from which he has not already been exempted at any time provided he holds a Second Class Certificate and has completed the necessary period of qualifying sea service, and provided also that he takes at the same time either the whole of Part 'A' of the examination or such subject, if any, in that Part, in which he has not already passed or from which he has not been exempted under (a) above.
