Deck officers are responsible for the navigation and operation of a ship. They ensure the vessel's safe passage, manage the crew, and oversee the maintenance of the ship's equipment. Their duties include plotting courses, monitoring weather conditions, and communicating with other ships and port authorities. There are different ranks among deck officers, including second mate, first mate, and captain. Each rank has specific responsibilities, with the captain being the highest authority on board. Deck officers must have strong leadership skills and a thorough understanding of maritime laws and safety regulations to effectively perform their roles.