This is our only "staircase lock" on our trip, and it's a broad lock (which can accommodate two 7ft boats side-by-side). For significant elevational challenge over a short distance, the "staircase" is another wonder of canal enginering. The top gate of the first lock here (which you can see one half just being opened) forms the bottom gate of the second lock. Time and patience is required to get the sequence of paddle openings and closing right, otherwise you end up emptying the top level of canal into the bottom stretch, probably swamping the boats in the process!