EP 1130-2-520
29 Nov 96
number, the TSOperator number (for usage in querying computer data), principal commodities
carried, the points or localities and waterways between which or on which operated and the number
of vessels reported by vessel type.
(c) Vessel characteristics - Volume 3 lists the vessel companies in alphabetical sequence and
describes each vessel surveyed by indicating its name and number, Coast Guard number, net
tonnage, VTCC code (vessel type, construction and characteristics, see Terminology), register and
overall length and breadth, loaded and light draft, horsepower, carrying capacity in short tons or
units of cargo and number of passengers, height of fixed superstructures, cargo handling
equipment, operating headquarters, and year built or rebuilt.
Q-2. Computation of Ton-miles.
(1) Water carriage ton-miles were first compiled and published in calendar year 1962. The
distances used are statute miles. Domestic ton-miles are calculated by multiplying the tons of
commerce being moved by the number of miles actually moved on the water (e.g., 50 short tons
moving 200 miles on a particular waterway would yield 10,000 ton-miles for that waterway). The
ton-mile parameter measures the total performance of a waterway. Ton-miles are not computed for
ports.
(2) For coastwise traffic this represents the safe navigation mileage between the point of
origin and destination.
(3) For rivers and inland waterways the distances were computed from waterway survey
maps and records of the Corps of Engineers.
(4) For the Great Lakes system the ton-miles are computed for movements of cargo west
of the international boundary of St. Regis, Quebec, Canada, to head of the lakes at
Duluth/Superior.
(5) For Canadian imports and exports, foreign ton-miles are computed as the tonnage times
the distance between the U.S. and Canadian ports. For lakewise domestic movements, ton-miles
equal the cargo tonnage times the distance between the U.S. Great Lakes ports.
(6) For overseas imports and exports, foreign ton-miles are computed by multiplying the
cargo tonnage by the miles carried on U.S. waterways and channels.
Q-2
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