Until relatively recently, the Port wine trade was reliant on the river to bring the wines down from the vineyards to the ‘lodges’ of the Port shippers at Oporto near the coast. The earliest references to boats carrying wine along the Douro date from around 1200 when they were referred to as barcas taverneiras, or ‘taverner barges’. However, throughout most of the history of Port and until well into the 20th century, the vessels which carried out this work were the remarkable barcos rabelos.Until a series of dams were built across the river in the 20th century, the Douro was fast running. Calmer reaches alternated with treacherous shoals and turbulent rapids, some gushing through narrow sheer-sided gorges. Rapids were often grouped along the same stretch of river constituting a formidable sequence of obstacles which required great skill to negotiate successfully. To be able to navigate in these conditions, the barco rabelo had a flat bottomed hull and a long steering oar, operated from the top of a raised platform, which allowed the crew to carry out the very precise manoeuvres necessary to traverse the rapids.