A combination of rock-climbing skills and a spider crane is being used to repair a decades-old timber pier. The work at Sharpness Dock in Gloucestershire is a race against time and tides as the River Severn has the second largest tidal range in the world. The 689ft (210m) long pier dates back to 1874, when the dock was opened, and some of its massive 36ft (11m) tall wooden legs are original. As a gateway from the River Severn to the Gloucester and Sharpness Canal, the pier is exposed to huge tidal pressures, and mainly submerged, so a regular programme of repairs ensures it is kept in top condition. This year, engineers from the waterways charity Canal & River Trust are using a spider crane to bring in massive greenheart oak planks which will be fixed in place by a team lowered down on ropes suspended over the muddy riverbed. Sharpness is one of the most inland ports in Britain and each month the dock welcomes up to 250 ships bringing in supplies from mainland Europe.