Locks are an essential feature of any canal which needs to gain or lose height.
A few canals have no locks, such as the Gloucester and Sharpness Canal although it does have locks at either end. Locks were built to two main sets of dimensions, known as narrow locks and broad locks, though there are many locks with larger dimensions, especially on the river navigations. Narrow locks take one narrowboat which was up to 72 feet long and 7 foot beam. Most locks are between 6 and 10 feet deep but Tardebigge Top Lock on the Worcester and Birmingham falls 14 feet. Staircase locks and Flights of Locks Early canals placed locks wherever there was a contour change in the landscape, so that the canal channel could be built as easily as possible, and the spacing between locks varied greatly.