Bertha

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 British 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.
The power is from a coal fired single cylinder steam engine providing steam at 40 pounds per square inch (280 kPa). 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 where it was restored. The Eyemouth Maritime Museum closed and Bertha is now in Bristol, but not on public display.

Time line after her bottom scraping life:
1972 Removed to Exeter for display afloat at Exeter Maritime Museum
1997 Removed to Bristol and then transferred with other vessels from the EISCA collection to Lowestoft and thence to Eyemouth
2015 Removed to Bristol after Eyemouth Maritime Museum closed down.
2019 Currently stored off-site and inaccessible to the public.
As he is still in operational cobndition, she is still considered 'ACTIVE'

sources: https://en.wikipedia.org and https://www.nationalhistoricships.org.uk