The IMO Convention (1969) meant a transition from the
traditionally used terms gross register tons (grt) and net
register tons (nrt)
to gross tons (GT) and net tons (NT).
Gross tonnage forms the basis for manning regulations,
safety rules and registration fees. Both gross and net
tonnages are used to
calculate port dues.
The gross tonnage is a function of the moulded volume of all
enclosed spaces of the ship. The net tonnage is produced by
a formula
which is a function of the moulded volume of all cargo
spaces of the ship. The net tonnage shall not be taken as
less than 30 per cent
of the gross tonnage. |
