"Legging" through the canal tunnel

A visit to the Maritime Museum in Gloucester, with excellent exhibits explaining the very important canal life of the late 1800's and 1900's.  Building the canals was labor intensive and tricky, using mostly might until engineering technology appeared.
The barges were pulled along the canal by horses from the "Tow Road" on the edge (and here I thought they were just recently created for cyclists!  How obtuse!).  But through the tunnels, the men had to use their own power, by pushing the boats through with their legs.  Not a pleasant task, with water from the tunnel dripping on them, and only a candle for light.