The two main functional areas in the Merchant Navy are those of navigation and engineering.
Navigating officers are responsible for the navigation of the ship, for efficient loading and discharge of cargo, and the safe operation of the ship. They also have to control large numbers of seamen as well as ensure the safety of the crew, and passengers, if any, and observance of the various national and international codes of conduct relating to sea transportation.
Marine engineers ensure that the ship runs smoothly and efficiently. They are responsible for the operation and maintenance of all installations in the ship, which includes electrical and refrigerating machinery, the main engines, auxiliary machinery and safety equipment.
They also supervise repairs at sea and overhauls in ports and are responsible for the work of engine-room staff on board the ships. Radio officers operate and maintain wireless equipment for receiving and transmitting messages.