Regulation 13 Provision and use of radios
This regulation applies to–
a vessel, other than a dumb craft, of 50 tons gross tonnage or more carrying a dangerous substance;
a vessel towing one or more dumb craft where the combined gross tonnage of all the dumb craft being towed is 50 tons or more and at least one is carrying a dangerous substance.
The master of a vessel to which this regulation applies shall ensure that all times it is in a harbour or harbour area it is provided with a radio capable of receiving and transmitting in the very high frequency band.
The master of a vessel to which this regulation applies shall ensure that a listening watch is kept on the operational frequency of the harbour authority at all times except–
when the vessel is at a berth; or
for short periods when the radio is tuned to another frequency for operational purposes.