Taxes Consolidation Act 1997 Schedule 18B paragraph 31

Measurement of tonnage of ship

Paragraph 31 sets out how the gross and net tonnage of a ship is to be determined for tonnage tax purposes, and requires a valid tonnage certificate to be in force before a ship can be treated as a qualifying ship.

• A ship of 24 metres or longer is measured in accordance with the IMO International Convention on Tonnage Measurement of Ships 1969; a shorter ship is measured under tonnage regulations.
• A ship cannot be a qualifying ship unless it holds a valid International Tonnage Certificate (1969) or a valid certificate recording tonnage measured under tonnage regulations.
• Tonnage regulations are those made under section 91 of the Mercantile Marine Act 1955, or corresponding provisions of the law of a country or territory outside the State.
• The requirement for a valid certificate ensures that only ships with officially verified tonnage can enter the tonnage tax regime.