Subject to the provisions of this section the owner or master of a South African ship shall not permit a young person to work at night: Provided that-
(a) this subsection shall not apply-
(i) to the employment of a young person on such work as aforesaid in a school-ship or training-ship, if the work is of a kind approved by the Authority and is carried on subject to supervision by officers
approved or appointed by it;
(ii) if the effective training of the young person concerned would be impaired; or
(iii) if the specific nature of the training requires that the young person must perform duties at night.