Seine Commercial craft (barges and push-tows) can use the river from Marcilly-sur-Seine, to its mouth. At Paris, there are 37 bridges. The river is only above sea level from its mouth, making it slow flowing and thus easily navigable. The Seine Maritime, from the English Channel at Le Havre to Rouen, is the only portion of the Seine used by ocean-going craft. The tidal section of the Seine Maritime is followed by a canalized section ("Basse Seine") with four large multiple locks until the mouth of the Oise at Conflans-Sainte-Honorine (170 km). Smaller locks at Bougival and at Suresnes lift the
Port of Tyne known as the Northumbrian Quay, to handle mail and cargo trade with Bergen in Norway. In 1968 the TIC was dissolved and replaced by the Port of Tyne Authority. Since then, with the decline in the coal industry, the port has switched to the export of cars manufactured in the northeast of England. The Port of Tyne is the navigation authority for the tidal reaches of the River Tyne, from the mouth to the Tidal Stone at Wylam, a distance of 17 miles. It also has jurisdiction for one mile past the roundheads at the piers at the river mouth.