The Junior Engineer is directly responsible to the Chief Engineer in the discharge of his duties. Whilst engaged on watchkeeping duties, he is responsible for the operation of all machinery, pumps, valves and systems controlled from the Engine Room. He assists the Second Engineer, as required, with the preparation of spare gear and repair lists. He is responsible, through the Second Engineer, for the maintenance and repair of any items of machinery or equipment as may be required by the Chief or Second Engineers.

He must be familiar with all control piping systems, valves, electrical and hydraulic systems so that in an emergency, essential services can be quickly and safely restored. Moreover, he ensures that the work environment is safe and must be fully conversant with the methods of use of all safety equipment and emergency procedures.