7 PORT ECONOMICS
become exempt from payment of further Light Dues for a
current year after having paid dues at a British port on
a certain number of voyages during that year, viz., for a
home trade ship, ten voyages, and for a foreign going ship,
six voyages.
Pilotage. The rate for pilotage is based at British ports
on the draught of the vessel, at so much per foot. Sometimes,
 in America, it is based on the gross tonnage. There
are charges both in respect of sea entrance pilotage and
river or dock pilotage, and both are generally incurred by a
vessel in making a port. Pilotage receipts do not usually
go to the port authority, they are paid into a fund appertaining
 to the local body of pilots who may, and, in most
instances do, work under licence from the authority. In
certain cases, the pilotage fund, as well as the service, is
under the administration of Trinity House.
Coming now to payments made to the port authority
itself, we have (1) dues or tolls on shipping, and (2) rates
or tolls on goods. The former are based on the tonnage
of vessels—hence called Tonnage Dues, and the latter on the
weight, or measurement, of the goods. The rates actually
leviable are limited in amount by a schedule of maximum
rates included in the Act of Parliament constituting the
port, or authorizing construction of its docks or quays,
but these rates may be modified by decisions of the
Ministry of Transport. During the war, all ports and
dock companies in this country were authorized by the
Ministry of Transport to increase their rates very considerably
 above the parliamentary standard, and, although
decreases have since been effected, the rates have not yet
come down to pre-war level.
DUES ON SHIPPING
Dues on vessels are computed as a rule on the net
register tonnage of the vessel, plus the deck space occupied
by cargo. Occasionally the gross tonnage is the basis,
but, in such cases, there is usually a fixed deduction