Provision and use of radios
13.—(1) This regulation applies to—
(a)a vessel, other than a dumb craft, of 50 tons gross tonnage or more carrying a dangerous substance;
(b)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.
(2) The master of a vessel to which this regulation applies shall ensure that all times it is in a harbour area it is provided with a radio capable of receiving and transmitting in the very high frequency band.
(3) 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—
(a)when the vessel is at a berth; or
(b)for short periods when the radio is tuned to another frequency for operational purposes.