(b)an engineer's or engine-driver's [certificate granted or deemed to be granted under the Merchant Shipping Act, 1958 (44 of 1958)] [Substituted by Act 35 of 1977, Section 20, for certain words (w.e.f. 1.5.1978)] shall not act as master or engineer, as the case may be, of an inland [mechanically propelled vessel] [Substituted by Act 35 of 1977, Section 5, for " steam-vessel" (w.e.f. 1.5.1978).] unless he also possesses-(i)in case (a), such a master's or serang's certificate granted under this Act as qualifies him under this Chapter to act as master of the [mechanically propelled vessel] [Substituted by Act 35 of 1977, Section 5, for " steam-vessel" (w.e.f. 1.5.1978).], or(ii)in case (b), such an engineer's or engine-driver's certificate granted under this Act as qualifies him under this Chapter to act as engineer of the [mechanically propelled vessel] [Substituted by Act 35 of 1977, Section 5, for " steam-vessel" (w.e.f. 1.5.1978).]:
