''Bertha'' is a steam-powered boat built in 1844 to remove silt from the Port of Bridgwater in Somerset, England. It is the oldest operational steam vessel in Britain, and possibly in the world. It is part of the National Historic Fleet. The boat was built, of riveted iron, in Bristol by Lunnel, G & Co copying a design, by John McLean, developed by Isambard Kingdom Brunel to deal with silt in the Floating Harbour. It is a bed leveler or plough dredger, with a large metal blade, which could be lowered at the stern of the boat, below the water similar to a bulldozer on land. Bertha is long and wide, with a tonnage of 60 tons. The power is from a coal fired single cylinder steam engine providing steam at . A large flywheel and drive shaft drove a single-reduction spur wheel drive. It moved by being pulled along chains anchored on the quay. Bertha worked in Bridgwater Docks, after the connection of the

Bridgwater and Taunton Canal The Bridgwater and Taunton Canal is a canal in the south-west of England between Bridgwater and Taunton, opened in 1827 and linking the River Tone to the River Parrett. There were a number of abortive schemes to link the Bristol Channel ...

to the

River Parrett The River Parrett flows through the counties of Dorset and Somerset in South West England, from its source in the Thorney Mills springs in the hills around Chedington in Dorset. Flowing northwest through Somerset and the Somerset Levels to it ...

, from 1844 until 1969. The vessel was initially owned by the

Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...

and then

British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British rai ...

. She was then taken to the Exeter Maritime Museum, where she was shown working with the help of John Selby (welder and fabricator in Spaxton, Somerset). In 1997 it moved to the

World of Boats Eyemouth ( sco, Heymooth) is a small town and civil parish in Berwickshire, in the Scottish Borders area of Scotland. It is east of the main north–south A1 road and north of Berwick-upon-Tweed. The town's name comes from its location at the ...

at Eyemouth where it was restored. The Eyemouth Maritime Museum closed and Bertha is now in Bristol, but not on public display.

Notes

:1. It is unclear which type of ton is being referred to in the sources where a tonnage of 60 is reported. Gross register tonnage (GRT) represents the total internal volume of a vessel, where one register ton is equal to a volume of 100 cubic feet (2.83 m3)

References

{{Oldest surviving ships (pre-1919) Ships and vessels of the National Historic Fleet Bridgwater Ships designed by Isambard Kingdom Brunel