Man, in Victorian clothing, legging a narrow boat in a tunnel. Legging the tunnel was often the only way to move a horse drawn narrow boat through a tunnel. A simple solution, the canal boat was moved by the legger walking on the tunnel wall or roof. Most tunnels were too large for one man so two, lying on boards across the boat, would walk the boat through the tunnel. There is hardly any current in a canal. On long tunnels, professional legger teams would be employed. Over nearly 5 kilometres expert leggers could move a laden boat in 3 hours.