As per SOLAS CH V, Regulation 19 (Carriage requirements for shipborne navigational systems and equipments)
All ships of 500 gross tonnage and upwards shall have, (Regln.184.108.40.206 of SOLAS CH V)
A gyro compass, to determine and display their heading by shipborne non-magnetic means, being clearly readable by the helmsman at the main steering position.
A gyro compass heading repeater, to supply heading information visually at the emergency steering position.
A gyro compass bearing repeater, to take bearings, over an arc of the horizon of 360º