11.4.2 Traction, push-tow and lighters
Barges may be self-propelled or towed or pushed by tugs. On some contin-
ental canals diesel or electric tractors, or engines on a track along the
canal, have replaced the original form of traction by horses. On larger
canals and navigable waterways the traditional method of using tug boats,
pulling a number of barges, was replaced almost universally by 1970 by the
control of a group of barges by push boats (Section 11.2). This develop-
ment has been mainly due to the following advantages of the push-tow
(Cˇábelka and Gabriel, 1985).
- The resistance of a pushed barge train is lower than that of a towed
train of the same tonnage; it is therefore possible either to increase
the navigation speed or to reduce fuel consumption.
- The crew required is fewer in number and thus the organization of
labour and the living conditions of the crew are improved, and oper-
ating costs reduced.
- Investment costs are up to 40% lower than for comparable tug boats.
- The control and manoeuvrability of the whole train, and its safety,
are improved.
The advantages of the push-boat technology increase with the size of
the train which can navigate the waterways and pass through the locks
without being disconnected. The size of the push trains varies according to
the characteristics of the waterway (Section 11.2); on some larger ones
(e.g. the lower Mississippi) 48-barge push-tows with towboats exerting a
power over 5000 kW are not uncommon (Petersen, 1986).
With the development of international trade, intercontinental freight
transport acquires an ever-increasing importance on the principal water-
ways. After an extraordinarily speedy development of container transport,
the progressive method of international transport by means of floating
containers, called lighters, has begun to assert itself (Kubec, 1981).
This system is intended above all for the transport of goods whose
consigner and recipient are situated on navigable waterways of different
continents. Lighters, grouped on inland waterways into pushed trains, are
transported across the sea in special marine carriers provided with loading
and unloading equipment of their own (lighter aboard ship – LASH –
system).
A further development is the direct maritime link with cargo carried on
a ship which combines full sea-going capacity with dimensions allowing
maximum penetration of inland waterways – the river/sea ship – converting
sometimes previous inland ports to mixed barge and sea-going traffic (e.g.
Duisburg in Germany) (Hilling, 1999). The proposal for standardization of
ships and inland waterways for river/sea navigation (PIANC, 1996) led in
1997 to the creation of the European River–Sea Transport Union (ERSTU).
470 INLAND WATERWAYS
