Underfall Yard facts for kids

Underfall Yard's former pump room - redeveloped in the 2015 project to become the visitor centre

General view of Underfall Yard

The Underfall Yard is a historic boatyard in Bristol Harbour, England. It's located on Spike Island.

People often called it "The Underfalls." Its name comes from special water gates called sluices. The yard was first built in 1809 by William Jessop. Later, Isambard Kingdom Brunel made big improvements in the 1830s.

The Underfall Yard was fixed up in the 1990s. It is now a special historic site called a scheduled monument. Many of its buildings have been listed as Grade II Listed Buildings since the 1970s. The harbour and its equipment are still looked after. Many companies that work with boats are based there.

History of the Yard

In the early 1800s, an engineer named William Jessop helped the Bristol Dock Company. They wanted to create a Floating Harbour. This would stop ships from getting stuck in the mud when the tide was low.

Jessop built a lock to keep water in the harbour. This was finished in 1809. It allowed ships to float all the time, no matter the river's tide. Part of his plan included building a dam at the Underfall Yard. This dam had a weir (a small dam) called the Overfall. It let extra river water flow into the New Cut. The New Cut was a new channel that went around the Floating Harbour. It joined the River Avon near Temple Meads.

The place where the docks were maintained was set up on the land that appeared when the river was dammed. This maintenance facility is still in the same spot today. By the 1830s, the Floating Harbour had a big problem: too much mud and silt. Isambard Kingdom Brunel came up with a solution. He designed the underfall sluices based on Jessop's ideas. He also suggested using dredgers (machines that remove mud).

The Bristol Docks Company did not make much money. So, Bristol City Council took it over in 1848. In 1880, the Council bought the Slipway and yard. This was to make the docks' maintenance facilities bigger.

The 'Underfall' system was rebuilt in the 1880s with longer sluices. The yard above was also made larger. Brunel's way of removing silt is still used today. However, the silt is now carried in mud barges. Or it is pumped to the sluices through pipes from modern, more efficient 'Cutter-Suction' dredgers.

During the 1900s, parts of the yard were rented to a company called P & A Campbell Ltd. They ran paddle steamers and used the yard for maintenance. The yard has not changed much recently. One building, the 'A' block, was rebuilt. It was damaged by bombs in World War II.

The Underfall Yard has been fixed up by the Underfall Yard Trust. Many businesses are now based there. These include boat builders, a blacksmith, and a rigging company.

In 2015, a big project was announced to restore the yard. This work included building a cafe and a visitor centre. They also started collecting stories from people who worked there. School programs were introduced as part of the restoration.

Sadly, on May 6, 2023, a fire broke out at the yard. It destroyed several boats and a maintenance shed.

How the Underfall Sluices Work

The sluices

Jessop's first plans for the harbour had a dam with an 'overfall'. The water level was set by the dam's top. But mud and silt built up in the harbour. This often caused ships to get stuck. In 1832, Brunel was asked to solve this problem. He designed the sluice system, which is still used today. It helps remove extra silt and mud.

Instead of the Overfall, Brunel built three shallow sluices. He also built one deep scouring sluice. These sluices are between the harbour and the New Cut. He also created a special boat called a drag boat. This boat scraped silt away from the harbour walls. Sluices 1, 2, and 4 are 'shallow' and control the water level. Sluice 3 is 'deep' and removes the silt.

When the deep sluice opens at low tide, it creates a strong undertow. This undertow sucks the silt out of the harbour and into the river. The sluices have been changed and replaced many times. The current system was put in place in the 1880s. In March 1988, the sluice controls became computerised and automatic.

Buildings at the Yard

Most of the buildings and machines at the yard were built between 1880 and 1890. This was done under the direction of John Ward Girdlestone. Many of them are now listed buildings by English Heritage.

The octagonal brick chimney of the engine house is from 1888. It is a very important listed building (grade II*). The hydraulic engine house itself is also grade II* listed. It replaced the first pumping house, which is now The Pump House visitor centre. It is made of red brick with a slate roof. It first had two steam-powered pumps. These were replaced in 1907 by electric machines. The electric motors currently installed are from 1938-39. This engine house powered the docks' hydraulic system. This system operated cranes, bridges, and locks.

External Hydraulic accumulator

The tower holds a heavy weight called a hydraulic accumulator. This stores hydraulic energy. It makes sure the pressure is delivered smoothly. This means the pumps do not need to run all the time. The outside accumulator was added in 1954. Water is pumped from the harbour into a tank. Then it flows by gravity to the pumps. The working pressure is 750 lbf/in² (5.2 MPa).

Dock Maintenance Workshops

The Patent Slip, built in the 1890s

The dock maintenance workshops are from the 1880s. They were made bigger in the early 1900s. The brick building has a tiled roof. It has sliding doors at each end. These doors lead to the boiler and engine houses, and shops for blacksmiths and engineers. Much of the original machinery is still there. This includes steam-powered machines from the mid-1880s. There is also a steam hammer.

Pattern Maker's Shop

The old pattern-maker's shop and stores are from the same time. They are also listed buildings (grade II).

Many of the original wooden patterns still exist. Some are used for teaching. Some are on display. Others are still used for work. A business called RB Boatbuilding Ltd uses the shop. They build classic wooden boats from the late 1800s. This includes the Bristol Channel Pilot Cutter. The Slipway Co-operative Ltd helps move boats onto the slipway. They build, fix, and restore wooden boats. This includes the 14 feet (4 m) Bristol Jolly Boat.

The Slipway

The first slipway was built in 1890 by John Ward Girdlestone. It replaced an older one from the 1850s. It worked by floating a ship onto a special cradle. The cradle was then pulled out of the water by a steam-driven winch. This was a cheaper way to fix and maintain boats than using dry docks. This system was known as the Patent slipway. It was patented in 1819 by Thomas Morton.

The 1890 slipway was first powered by a hydraulic engine. This engine used the dock's hydraulic system. In 1924, an electric motor was put in. This motor still works today. The Bristol slipway is quite small. Its cradle is 100 feet (30 m) long. The track is 265 feet (81 m) long. It can lift boats up to 250 tons.

The three electronic pumping engines

The slipway stopped being used by 1974. By the 1990s, it was rotting. Members of the Slipway Co-operative and Underfall Trust rebuilt it in 1998–99. The underwater part of the track had to be completely replaced with steel. The track above water was relaid. The original cast iron rails were reused. The cradle was completely rebuilt to look like the original. The slipway working again was important for keeping the Underfall Yard as a historic site. It helped the Trust get money to maintain the slipway and buildings. It also helped the businesses there earn money from boats.

The Pump Room

The power house at Underfall Yard was built in 1887. It provided hydraulic power to the harbour. It was first powered by steam. The large chimney is from this system. The room that is now the visitor centre had three boilers. These powered steam hydraulic pumps. There are three electric pumps in the room next to the visitor centre. They are often run to show how they worked. These three pumps replaced the original ones in 1907.

The Big Shed

The Big Shed was originally used to build large items like lock gates. It is now used by boat businesses. It is not open to the public.

See also

• The Underfall Yard - This is an album by a British rock band called Big Big Train. It was inspired by the Underfall Yard and other projects by Victorian engineers.

Bristol Harbour Map