The Court reiterated the Millares ruling in Gu-Miro v. Adorable[19] where it held that a radio officer on board a vessel cannot be considered as a regular employee notwithstanding that the work he performs is necessary and desirable in the business of the company.            Thus, in the present case, the Court of Appeals erred in ruling that Tanchico was a regular employee of Petroleum Shipping.   On 13th Month Pay            The Court of Appeals premised its grant of 13th month pay on its ruling that Tanchico was a regular employee.  The Court of Appeals also ruled that petitioners are not exempt from the coverage of PD 851 which requires all employers to pay their employees a 13th month pay.            We do not agree with the Court of Appeals.  Again, Tanchico was a contractual, not a regular, employee.  Further, PD 851 does not apply to seafarers.  The WHEREAS clauses of PD 851 provides:            WHEREAS, it is necessary to further protect the level of real wages from ravages of world-wide inflation;              WHEREAS, there has been no increase in the legal minimum wage rates since 1970;              WHEREAS, the Christmas season is an opportune time for society to show its concern for the plight of the working masses so they may properly celebrate Christmas and New Year.            PD 851 contemplates the situation of land-based workers, and not of seafarers who generally earn more than domestic land-based workers.            Tanchico’s employment is governed by his Contract of Enlistment (“Contract”).[20] The Contract has been approved by the POEA in  accordance with Title I, Book  One  of  the  Labor Code and the POEA Rules Governing Employment.[21]   The coverage of the Contract includes Compensation, Overtime, Sundays and Holidays, Vacations, Living Allowance, Sickness, Injury and Death,