the canal and the connected huddersfield broad canal were built to accept yorkshire keels coming up the aire and calder navigation. the first four locks on the lower calder and hebble, from fall ings to broad cut top lock have since been extended, and can accommodate boats which are , but the remainder restrict the size of boats that can use the navigation. they are among the shortest on the connected network of english and welsh inland waterways, but while wide beam boats are restricted to in length, it is possible for experienced boaters to fit narrowboats up to about long, but only wide, into the locks, by allowing them to sit diagonally in the restricted space. this may require expedients such as removing fenders, having shore parties pole the boat into position, and going down locks backwards. in particular, an inexperienced crew of any boat longer than about might find it impossible to negotiate the middle lock of the "salterhebble three", which is the shortest of all.