21 Prohibition on proceeding to sea without the appropriate documentation
1 No United Kingdom ship shall proceed to sea unless it has been surveyed and there is in force the following certificate or certificates:
(a) in the case of a passenger ship engaged on international voyages, a Passenger Ship Safety Certificate, or, if the ship is only engaged on short international voyages, a short international voyage Passenger Ship Safety Certificate;
(b) in the case of a cargo ship of 300 tons or over engaged on international voyages, a Cargo Ship Safety Radio Certificate;
(c) in the case of a cargo ship of 500 tons or over engaged on international voyages, a Cargo Ship Safety Equipment Certificate;
(d) in the case of a cargo ship of 500 tons or over engaged on international voayges, a Cargo Ship Safety Construction Certificate.
2 No ship registered in a country to which the 1974 SOLAS Convention applies shall proceed to sea from a port in the United Kingdom unless there is in force such Convention certificates that would be required if the ship was a United Kingdom ship. The extension provisions in regulation 15 shall apply to such certificates as if the ship was a United Kingdom ship and the Government of the country in which the ship is registered is substituted for the Secretary of State.
3 No cargo ship of 500 tons and over not engaged on international voyages shall proceed to sea from a port in the United Kingdom unless it has been surveyed and there is in force a United Kingdom Cargo Ship Safety Construction Certificate, unless there is in force a Cargo Ship Safety Construction Certificate as referred to in these Regulations;
4 No ship registered in a country to which the 1974 SOLAS Convention does not apply shall proceed to sea from a port in the United Kingdom unless the ship is in the possession of documentation which shows that either the ship has been surveyed for compliance with the relevant regulations applicable to the ship as though it was a United Kingdom ship or it has been surveyed and is in compliance with the relevant regulations applicable to the ship;
5 Where a certificate is issued subject to conditions, or specifies sea areas in which the ship is certified to operate, the owner and master shall ensure that all conditions are complied with, or, as the case may be, that the ship only operates in the specified sea areas.
6 The master of every ship shall produce to an officer of customs from whom a clearance for the ship is demanded for an international voyage the certificates or documentation referred to in this regulation.