Barge

A barge is a simple looking boat with a flat surface and long structure. Barges usually transport goods to different places.
In Great Britain, during the Industrial Revolution, a substantial network of narrow barges was developed from 1750 onwards.
From 1825 there was competition from the railways. Eventually the British rail system took over from canal traffic due to the higher speed, falling costs and route flexibility of rail transport. 
Barges carrying bulk and heavy cargoes continue to be viable. There is no cheaper way to move really heavy loads. Originally, British canals had locks only wide, so narrowboats could be no more than 6'10" wide if they were to be able to navigate the system. It was soon realised that narrow locks were too limiting, and later locks were doubled in width to . 
On the British canal system the term 'barge' is used to describe a "Thames [sailing barge], Duch [barge], or other styles of barge". The people who move barges are often known as lightermen. 
A narrowboat is a particular type of canal boat, built to fit the narrow locks of the United Kingdom.