Workers in this unit group command and navigate ships and hovercraft and direct marine services on shore for shipping company vessels arriving in port. Their functions include: taking complete charge of seagoing or inland waterway vessels; planning, supervising and co-ordinating deck and bridge-watch activities on vessels; navigating vessels into and out of ports and through channels, straits and other waters where special knowledge and skill are required; directing or arranging supply of ships' stores and equipment, recruitment of crews and provision of other services (except engineering) for company vessels arriving in port.