Blisworth Tunnel has no tow path inside, but is wide enough for two narrowboats to pass in opposite directions. Work began in 1793, but errors by contractor left a wiggle in the tunnel, and after three years work it collapsed due to quicksand, claiming the lives of 14 men. It was then decided to begin again with a new tunnel. By the time the rest of the Grand Junction Canal had opened between London and Braunston, Northamptonshire in 1800, apart from the crossing of the River Great Ouse, the section of canal from Blisworth to the lower end of Stoke Bruerne locks
Canal tunnel would be propelled by legging. The term "canal tunnel" does not seem to be commonly applied to tunnels used to conduct water (for irrigation, water supply, etc.), such as the 48-kilometre-long Arpa-Sevan tunnel in Armenia (see List of longest tunnels), or a number of tunnels on the Irtysh–Karamay–Ürümqi Canal in China. For those, the term water tunnel is more commonly used. Canal tunnels were made in the Kingdom of Travancore as early as 1876. Canal tunnel A canal tunnel is a tunnel for a (shipping) canal. The longest canal tunnel in the world is the Rove Tunnel in France, currently