The Gloucester and Sharpness Canal

At the site of the Purton Hulks there is less than 50 metres (160 ft) of land between the river and the Gloucester and Sharpness Canal (or Gloucester and Berkeley Canal). The 26.5-kilometre-long (16.5 mi) canal was dug between Gloucester and Sharpness; for much of its length it runs close to the tidal River Severn, but cuts off a significant loop in the river, at a once-dangerous bend near Arlingham. It was once the broadest and deepest canal in the world.^[6] Conceived in the Canal Mania period of the late 18th century, the Gloucester and Berkeley Ship Canal scheme was authorised by a 1793 Act of Parliament.^[7]

The canal opened in April 1827, having cost £440,000 (equivalent to £41,000,000 in 2021) in the course of its construction.^[8] The flood plain of the Severn hereabouts is very flat and so the elevation of the canal does not require any rise over its length. Outside the dock areas at each end, there are no locks.^[9] This encouraged the use of the canal for ships larger than on most other British canals, although there were a number of swing bridges to negotiate. As opened the canal was 86+1⁄2 feet (26.4 m) wide, 18 feet (5.5 m) deep and could take craft of up to 600 tons.^[8] In 1905 traffic exceeded one million tons for the first time.^[10] Oil was added to the list of cargoes carried by the canal, with bulk oil carriers taking fuel to storage tanks sited to the south of Gloucester.^[11]

Coastal defences

Stern of a ferro-cement barge

The stretch of canal from Sharpness to Purton runs very close to the river. At a high spring tide they were separated by little more than the width of the towpath. The canal also has no locks, and owing to its width, not even any stop locks. Any damage to the canal bank could thus render the entire canal unnavigable.

In 1909, following a collapse in the bank of the river,^[12] the canal company's chief engineer Mr A. J. Cullis called for old vessels to be run aground along the bank of the Severn, near Purton, to create a makeshift tidal erosion barrier to reinforce the narrow strip of land between the river and canal.^[13] Barges, trows and schooners were "hulked" at high tide, by towing them from the dock at Sharpness and releasing them to be carried up the bank on the tide. Holes were then made in their hulls so that they filled with water, and over time silt has been laid down inside them.^[13]

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.^[14] The last boat was beached in 1965.^[15] The ground level has built up over the years and some of the more recent additions are lying on top of those which had been beached earlier.^[13]

Preservation

In 1999, a local maritime historian, Paul Barnett, commenced a privately funded research project which saw the site's 86 vessels recorded and recognised as the largest ships' graveyard in mainland Britain.^[16] The Nautical Archaeology Society investigated the site in 2008 as part of its Diving into History Project,^[17][18] and carried out laser scanning of the remains.^[19] In 2010, British Waterways took control of the site in an attempt to protect it.^[20][12][21]

The only known surviving Kennet barge, Harriett, which was beached at Purton in 1964, has been scheduled as an ancient monument^[22] and included in the National Register of Historic Vessels,^[23] as are several ferro concrete barges. The remains of the vessels are not covered by the Protection of Wrecks Act 1973, as they are not on the seabed. But some of the other vessels may not be eligible for scheduling as ancient monuments, under the Ancient Monuments and Archaeological Areas Act 1979, because they are not inland.^[24] The issue and the responsibility of various statutory bodies in their protection was debated in the House of Commons in 2009.^[25]