 Holes were then made in their hulls so that they filled with water, and over time silt has been laid down inside them.More boats have been added, including the schooner "Katherine Ellen" which was impounded in 1921 for running guns to the Irish Republican Army (IRA), the Kennet Canal barge "Harriett", and ferrocement barges built in World War II.The last boat was beached in 1965.