In 1797 work on the canal itself was started by navvies. These were mainly Irish men who were reputed to be hard-living, hard-swearing and hard-drinking. The name "navvies" is a shortened version of "navigators".

When completed the canal was four and a half feet deep (about 1.5 metres) which was deeper than quoted on the original estimate, and ten yards (about 9 metres) wide.

Canal barges were capable of carrying twenty five tons of cargo.
The journey from Clydach to Brecon took one day in summer and two daysin winter.

More about the Brecon & Abergavenny canal...