Dave, your photo shows the very old towpath bridge over the entrance to what was Samuel Barlows Coal Wharf, the transport yard there is situated on the site of the old wharf. the width of the 'Bridge Hole' is about six inches wider that the narrow boats were, and to make the turn easier there used to be a widening of the canal almost opposite, these were called 'Winding 'oles'... pronounced wind ing.