Penarth Dock exported 900,000 tons of coal in 1870 and by 1882 was exporting 2 million tons per year. The dock was enlarged in 1884. In February 1886
Isambard Kingdom Brunel's famous ship,
SS Great Britain, in her new role as a coal ship departed from Penarth Docks bound for
Panama. It was, however, to be her final voyage when, after a fire on board, she was diverted to the
Falkland Islands and remained there until 1937 as a storage vessel. The
Ely Subway, a pedestrian tunnel beneath the river, was opened in 1900 to provide a shortcut for workers walking between the dock and
Grangetown, and was in operation until 1963. Coal exports from Penarth peaked in 1913, with 4,660,648 tons exported in that year. Trade declined after the
Great War, despite all the coal production of the western
South Wales Valleys being sent via Penarth. In 1932 the
Earl of Plymouth had to forego his royalty payments to help keep the dock in business, but Penarth Dock finally closed in 1936 after annual exports had dropped to 685,000 tons. During the
Second World War the dock was revived as a training facility for
stevedores and, in 1943, became a base for the
United States Navy. == Closure and later use ==