Which Are the Cheapest Mooring Canals in the UK for Widebeam Boats?: A Complete Guide The problem of securing a relatively inexpensive mooring facility for a widebeam vessel, which generally has a width of between 10 to 12 feet, is perhaps the greatest obstacle facing UK liveaboards and leisure boating enthusiasts. Widebeams need wider lock chambers, deeper waters, and particular facilities, leading to costs that exceed those charged for normal narrowboat mooring facilities.