Struncheon Hill Lock was built as a later addition to the Driffield Navigation in the East Riding of Yorkshire, England. It improved access to the next section of water during low tide conditions where the navigation meets the tidal River Hull. It is sometimes known as "Top Hill Low", which is the name of the large pumping station located there. Location Near the small hamlet of Hempholme, the lock is about south of Bethells Bridge. Access can be made by a footpath from Hempholme, or via the waterworks at Top Hill Low which is also a nature reserve. Situated on the Driffield Navigation Next Place Upstream: Bethells Bridge Next Place Downstream: Wilfholme Landing History During the navigation improvements of 1803–1811, a new lock cut was made to bypass a large meandering loop of the River Hull around Struncheon Hill. William Chapman, who looked after the works, built the lock to the standard dimensions of the rest of the navigation – to take vessels long, by wide. This is a standard known for Yorkshire Keels, however on further investigation it seems the lock was built to longer dimensions and in 2009 Michael Askin took a Royalty Class Narrow Boat Victoria of in length through the lock – though the boat would only fit pointing upstream due to low water levels not allowing enough depth over the top cill. The lock was originally built as a single lock, but like Snakeholme lock, it was found that at low tides there was not enough depth to get over the bottom cill, so a second chamber was added. To empty the chamber a large hole through one lock wall, and a wooden sluice was used. The lower lock was filled by emptying the upper lock. Originally made with oak gates, with handspike paddlegear, the top gates were replaced with unusual steel gates by Yorkshire Water, who looked after the navigation for drainage, and water supply. The gates instead of having balance beams to open them, had a complicated rack system which pulled them open with a windlass. The paddles were designed like weir sluices, and take many turns to open them. A weir was built at the lock to control the river level. Around the same time the top gates were replaced the weir was replaced by an automatically controlled structure. There is a small building next to the weir which houses water level