Gloucester is floated on the water for the first time at Saul Junction.
A replica of a canalboat made at the same yard as the famous African Queen has been launched at Saul Junction.
The 45ft-long Gloucester is an exact copy of the original three vessels Sharpness, Worcester and Birmingham designed and built near Brimscombe Port by renowned firm Abdela and Mitchell between 1908 and 1912.
The company made the boat immortalised in the 1951 film African Queen, which starred Hollywood legends Humphrey Bogart and Katharine Hepburn.
Gloucester, commissioned in June 2007, is the fourth narrow-beam canal tunnel tug to be built in the West Country. It is undergoing sea trials before being sailed to her owner's home port of Cardiff.
She was commissioned by waterways enthusiast and medical statistician Dr Chris Poole.
The 36-year-old said the aim of the £90,000 project was to replicate the classic narrowboat shape in as accurate a way as possible.
There were no design drawings for the builders in Brimscombe, and later at Saul, to follow.
Dimensions and pictures were taken of Worcester, which is a working exhibit at the National Waterways Museum in Ellesmere Port. A hull template came from Birmingham, which is preserved on the canal bank in Tardebigge.
Dr Poole said: "It has been a bigger project than I ever envisaged. I didn't appreciate how difficult it would be to try and replicate a design for which there were no drawings.
"I think Isaac Abdela would have been fairly pleased with our efforts. I know I am."
Gloucester is 7ft wide and has a draft of 3ft. When fitted out Dr Poole and his family intend to use her for holidays and possibly hire.
The return of boat building to Brimscombe Port in readiness for the restoration of local canals has thrilled waterways enthusiasts, among them Brimscombe resident Ian Leighton-Boyce.
"Dr Poole's courage in commissioning such a difficult task almost defies belief," he said.
Mr Leighton-Boyce, a member of the Cotswold Canals Trust, added: "Despite many pitfalls he has achieved the almost impossible."
The Gloucester project was supported by British Waterways, which allowed Dr Poole to complete much of the work at the Boatshed in Brimscombe.