The quartermaster is the enlisted member in charge of the watch-to-watch navigation and the maintenance, correction, and preparation of nautical charts and navigation publications. They are also responsible for navigational instruments and clocks and the training of ship's lookouts and helmsmen.
Quartermasters (QM) stand watch as assistants to Officers of the deck and navigators. They serve as helmsman and perform ship control, navigation and bridge watch duties. Your duties may include: Procure, correct, use and stow navigational and oceanographic publications and oceanographic charts.
By longstanding tradition, they are always commissioned from the ranks and hold the rank of captain or major (although until the 20th century the quartermaster was usually a lieutenant). Some units also have a technical quartermaster, who is in charge of technical stores.