exams attain certificate of competency of OICNW. Deck ratings Mariners without a certificate of competence are called ratings. They assist in all other tasks that can arise during a voyage. This includes for example, mooring, cleaning of the ship and its holds and repairing broken lines and ropes. These are physically challenging jobs and have to be done regardless of the weather. Boatswain The boatswain is the highest ranking unlicensed (rating) in the deck department. The boatswain generally carries out the tasks instructed by the chief mate, directing the able seamen and ordinary seamen. The boatswain generally does not stand a navigational watch. Able bodied seaman An able bodied seaman (AB) works under the boatswain, completing tasks such as working mooring lines, operating deck gear, standing anchor details, and working cargo. An able bodied seaman also stands a navigational watch, generally as a lookout or helmsman. Ordinary seaman The lowest ranking personnel in the deck department. An ordinary seaman (OS) generally helps out with work that able seamen do. Other tasks include standing lookout, and generally cleaning duties. Engine department Engineering officers The engineers are also called technical officers. They are responsible for keeping the ship and the machinery running. Today, ships are complex units that combine a lot of technology within a small space. This includes not only the engine and the propulsion system, but also, for example, the electrical power supply, devices for loading and discharging, garbage incineration and fresh water generators. An engineer is commonly considered a high officer in ranking in the ship. Chief engineer The chief engineer on a merchant vessel is the official title of someone qualified to oversee the engine department. The qualification for this position is colloquially called a "Chief's Ticket". The chief engineer, commonly referred to as "The chief", or just "chief", is responsible for all operations and maintenance that have to do with all machinery and equipment throughout the ship. He may be paid on par with the captain, and holds a similar rank as the captain. Second engineer The second engineer or first assistant engineer is the officer responsible for supervising the daily maintenance and operation of the engine department. He or she reports directly to the chief engineer. Third engineer The third engineer or second assistant engineer is usually in charge of boilers, fuel, auxiliary engines, condensate and feed systems, and is the third most senior marine engineer