Section 231(a) in The Navy (Pay And Allowances) Regulations, 1966
(a)Advances payable under sub-clauses (i) and (iii) of clause (a) and under sub-clause (i) of clause (b) of regulation 229 shall be recovered in monthly instalments each equal to one-third of the total monthly emoluments of the individuals concerned. The recovery of advances under sub-clauses (i) and (iii) of clause (a) of regulation 229 shall commence from the pay for the month following that in which the advances are paid.