I think you will find a waterman was a person involved with the navigation on the Rivers Severn, Wye, Bristol Avon and Warwickshire Avon. The craft on the Severn were generally known as Trow's and their masters were called Owners. The navigation of the Severn was enabled through periods of high water called Springs and the Trow owners worked between Shrewsbury and the river ports of Bridgnorth, Bewdley, Worcester, Gloucester, Newham and Lydney. Bristol was reached via the Avon and other coastal destinations in South Wales and Somerset were also reached. Trows were sailing vessels, but required to be bow hauled on occasion, such as passing up stream where halliers were employed. The completion of the Gloucester & Sharpness Canal enabled vessels to bypass the difficult sandbanks encountered on the tidal part south of Gloucester