There are various different tasks which need to be perormed by sea transport workers.
Deck and Engine room Rating: Deck and engine-room workers are responsible for maintaining the exterior of the ship, lookout watches at sea, gangway duties in port and cleaning, repairing and ensuring that the ship's engine is kept in good working order. These workers are trained in the art of seamanship and general nautical knowledge.
Quartermaster: In addition to normal deck duties the quartermaster is responsible for manning the gangway in port, making deck rounds, checking moorings and steering in restricted water.
Boatswain: This is a petty officer in charge of the quartermasters and deck crew and takes orders from the first / chief officer of the ship.
Watchkeeper: In addition to normal engine-room duties, the watchkeeper assists the senior engineer officer on watch with watchkeeping duties, maintains the engine and supervises engine-room cleanliness.
Maintenance assistant: The engine-room leading hand is the petty officer in charge of the watchkeepers and engine-room crew. The maintenance assistant is responsible for checking, stowage and the security of engine-room stores and takes orders from the second engineer officer.