iE PORT ECONOMICS
The “ Register” Ton is an arbitrary standard of measurement
 equivalent to 100 cu. ft. of space and it is applied
to two methods of registration.
The Gross Registered Tonnage of a vessel is the volume
of its internal capacity, measured in units of 100 cu. ft., of
the whole of the under deck space, including that occupied
by machinery and also all enclosed spaces above the tonnage
 deck, subject to certain rules and exceptions specified
in the Merchant Shipping Act.
The Net Registered Tonnage is the residue after deducting
from the Gross Registered Tonnage various allowances for
crew and passenger space, officers’ quarters, navigating appliances,
 machinery, etc. It is usually some 60 to 70 per cent
of the Gross Registered Tonnage which, in turn, is roughly
about two-thirds of the deadweight carrying capacity.
As previously stated, cargo is usually charged for at
a net measurement rate of 40 cu. ft. to the ton, unless it
consists of goods heavier than this equivalent, in which
case the actual weight is generally charged for. A vessel
fully loaded with cargo measuring exactly 40 cu. ft. to the
ton would be carrying two and a half times its Net Registered
Tonnage. Owing, however, to the proportion of light goods
in an average cargo, the full load of a vessel may be roughly
taken as twice the Net Registered Tonnage.
Within seven days of a ship’s departure, it is obligatory
for the shipper to give the port collector of rates a complete
statement of the goods shipped, in a similar manner to
the lodgment of the “ entries ” in the case of imported goods.
DEPARTURE
The vessel, having been loaded with the goods to be
exported, is ready to depart, but, before doing so, must
satisfy the authorities that all the rates and charges have
been paid and must receive a Clearance Outwards from
the Customs officials. A vessel may be detained by the
port authority until all rates have been paid and a
distraint may be laid, if necessary.

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