The National Master 500/1600 Oceans (OC) or Near Coastal (NC) officers are responsible for vessels of less than 1600 GRT and its safe and efficient operation including, the ship's seaworthiness, safety and security conditions, cargo operations, navigation, and crew management. The National Master 500/1600 OC or NC officers set the course and speed, maneuver the vessel to avoid hazards and other ships, and periodically determine its position using navigation aids, celestial observations, and charts. They direct crew members who steer the vessel, operate engines, signal to other vessels, perform maintenance and handle lines, or operate towing or dredging gear. Masters ensure that proper procedures and safety practices are followed, ensure machinery and equipment are in reliable working order, and oversee the loading and unloading of cargo or passengers. They also maintain logs and other records of ships' movements and cargo carried. The Master is always in command of a merchant ship and regulates the proper daily transactions and handles the legal affairs on maritime issues. Candidates must meet a minimum sea service, training, and exam requirement.