law: 26. Certificates to be held by master and engineer of vessel of between forty and one hundred horse-power.-An inland 1[mechanically propelled vessel] having engines of 10[forty] or more nominal horse-power, but of less than 6[one hundred] nominal horse-power, shall not proceed on any voyage unless she has-
  (a) as her master a person possessing a second-class master's certificate granted under this Act, or any certificate referred to in clause (a) of section 25, and
  (b) as her engineer a person possessing a first-class engine-driver's certificate granted under this Act, or an engine-driver's 7[certificate granted or deemed to be granted under the Merchant Shipping Act, 1958 (44 of 1958)] or any certificate referred to in clause (b) of section 25: Provided that a 1[mechanically propelled vessel] shall be deemed to have complied with this section if she has as her master and engineer a person possessing both a certificate referred to in clause (a), and a certificate referred to in clause (b), of this section.