The Huddersfield Narrow Canal.
We were blown away by this last year, just after we took possession of Honey. But it was hard work. We spent more time aground than afloat on the Diggle Flight, and more time refilling pounds than using them on the Marsden Flight.
But BW (as it was then) did a lot of work over the winter, and the Eastern, Diggle side of the tunnel was a delight to navigate.
Still dredging to be done on the West side, though.