REEFREP MANDATORY SHIP REPORTING SYSTEM (SRS) The ship reporting system area encloses Torres Strait and the Great Barrier Reef. For details and categories of ships required to participate see Mariners Handbook For Australian Waters AHP 20, Australia Pilot Volume III, NP 15 and Admiralty List of Radio Signals Volume 6(4). When reporting within the REEFREP area, vessels are to call 'Reef VTS' on VHF channels 11 or 14 depending on the ship's position. INMARSAT-C should be used for communicating with Reef VTS when VHF communications are limited.