''Bertha'' is a steam-powered boat built in 1844 to remove silt from the Port of Bridgwater in

Somerset ( en, All The People of Somerset) , locator_map = , coordinates = , region = South West England , established_date = Ancient , established_by = , preceded_by = , origin = , lord_lieutenant_office =Lord Lieutenant of Somerset , lord_ ...

, England. It is the oldest operational steam vessel in Britain, and possibly in the world. It is part of the

National Historic Fleet The National Historic Fleet is a list of historic ships and vessels located in the United Kingdom, under the National Historic Ships register. National Historic Ships UK is an advisory body which advises the Secretary of State for Culture, Media ...

. The boat was built, of riveted iron, in

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...

by Lunnel, G & Co copying a design, by John McLean, developed by

Isambard Kingdom Brunel Isambard Kingdom Brunel (; 9 April 1806 – 15 September 1859) was a British civil engineer who is considered "one of the most ingenious and prolific figures in engineering history," "one of the 19th-century engineering giants," and "on ...

to deal with silt in the

Floating Harbour Bristol Harbour is the harbour in the city of Bristol, England. The harbour covers an area of . It is the former natural tidal river Avon through the city but was made into its current form in 1809 when the tide was prevented from going out perm ...

. 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 to the River Parrett, from 1844 until 1969. The vessel was initially owned by the Great Western Railway and then British Railways. 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 at

Eyemouth 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 ...

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 Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...

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