Underfall Yard

Talk by Andrew Blayney of the Underfall Yard Trust in February 2022. Report by Stephen Griffiths.

Many people will have heard of the Underfall Yard at the west end of Bristol’s floating harbour, but many of those will have no idea why it is so called. Originally, the weir that let excess harbour water flow into the river was called the ‘Overfall Dam’. So why ‘Underfall Yard’? Andrew Blayney zoomed in to the January meeting of the Society to explain all.

By the 1760s, Bristol was England’s second largest city, and a major port, but it was starting to lose trade to newer ports like Liverpool. The main problem was the large tidal range in the River Avon, which left ships stranded high and dry on the gloopy mud for long periods. At the start of the 19th century a new channel for the river was cut around Bristol and the old channel was blocked off by locks to make the floating harbour. But it was found that so much silt from the Avon and Frome rivers settled at the bottom of the harbour that it had to be drained and dug out by hand every six months.

Brunel was consulted in the 1830s and made some improvements, but it wasn’t until later in the century that docks engineer J W Girdlestone designed a solution. The Overfall Dam was replaced by gated channels built underground, so that water could be made to flow from the harbour depths, underneath the harbourmaster’s office, and into the river, scouring the silt out with it. Hence it became the ‘Underfall Yard’. The same scouring process is still performed every 2 weeks.

The 1880s saw the construction of the workshops and maintenance buildings that are in use today. The machinery workshop still contains the Victorian forges, lathes, shaping machines and steam engine, although these days an electric motor is used to drive the old machines during visitor demonstrations. Businesses of various kinds occupy the old buildings, but the most important are still the boat builders. You can have made by traditional methods a Bristol Channel Cutter (but you would have to sell your house first).

Of prime importance is the Victorian slipway, an area evocative of salty sea dogs and shanties. It was restored by the Underfall Yard Trust in the 1990s and is still used to get vessels out for inspection. You may even see the ‘Matthew’ out on the slipway for maintenance and repairs. Visitors are encouraged to wander around and take in all the busy activity of a working Victorian dockyard.

The red brick Victorian ‘Power House’ replaced an earlier pump house, now converted to the ‘Pump House’ pub, on the opposite side of the harbour. In the Power House are three large pumps which produce hydraulic power, stored in an accumulator, to drive the harbour’s lock gates, bridges, sluices etc. In 1907 the steam engines that drove the pumps were replaced with early electric motors which are demonstrated to visitors. The accumulator itself is fascinating as its use involves 80 tons of scrap metal. You’ll have to visit the Power House, now the Underfall Yard visitor centre, to find out how it works. They have a good web site to whet your appetite.

Many thanks to Andrew, who struggled manfully with ethernet and wi-fi (old nautical terms) to almost show us some 360 degree videos of the yard. Perhaps he would have had more success with hydraulic power.