Mortar Wreck

Summary

The site comprises the remains of a C13 cargo vessel, located on the edge of the Swash Channel, in Poole Bay. The vessel foundered while outward bound with a cargo which included quarried Purbeck stone, several stone mortars as well as dressed stone grave slabs.

Reasons for Designation

The newly identified wooden wreck site, located on the edge of the Swash Channel, in Poole Bay, is designated as a Protected Wreck Site for the following principal reasons:

* Period: Dendrochronological analysis and interpretation of the finds assemblage indicates that the wreck is the remains of a C13 outgoing cargo vessel carrying worked and quarried stone from the Purbeck region;

* Rarity: Ships predating 1700 are extremely rare. There are no known wrecks of seagoing vessels from the C11 to the C14 known to survive in English territorial waters;

* Potential: The wreck still contains a portion of its cargo, and has potential to inform about the Purbeck stone trade during the C13;

* Vulnerability: Elements of the wreck and mobile artefacts exposed on the seabed remain vulnerable to uncontrolled salvage and theft.

* Group Value: The wreck shares group value with the nearby C16 Studland Bay wreck, and the C17 Swash Channel wreck, all three wrecks together helping us to better understand the types of vessels used in maritime trade off the coast of southern England.

History

The wreck was first identified by divers from Bournemouth University, who investigated a known obstruction on the edge of the Swash Channel in Poole Bay, on behalf of Trevor Small of Rocket Charters. The information was shared with Historic England, who worked in partnership with Bournemouth University to undertake further diving fieldwork, and DendroArch to undertake a dendrochronological assessment of the wreck.

Dendrochronological analysis of the hull planking indicates that they were derived from Irish oak trees, with a felling date of 1242-1265. The finds assemblage includes several Purbeck stone mortars which date to the mid C13 to C14, and decorated Purbeck stone grave slabs.

The tree-ring evidence, together with the interpretation of the finds assemblage, indicates that the wreck is the remains of a C13 outgoing cargo vessel carrying worked and quarried stone from the Purbeck region.

Details

Designation Order: 2022, No 535. Made 10th May 2022, Laid before Parliament: 12th May 2022, 2022 Coming into force: 2nd June 2022.

Restricted area: 50m radius within Latitude: 50.65845000, Longitude: -1.92592000.

The site covers an area approximately 20m by 15m, and is orientated NE-SW. The centre of the site comprises a large mound measuring approximately 1m high and approximately 8m in diameter, comprising unworked quarried stones, likely to be Purbeck stone. The mound covers the articulated remains of the port side of the vessel, which is comprised of frames and clinker planking.

Two complete decorated stone grave slabs, and one incomplete slab, can be seen on the seabed to the north-east of the main wreck mound. One of the slabs is decorated with a wheel headed cross, believed to be a style common in the early C13, while the second is decorated with a splayed arm cross, more common in the mid C13. The slabs remain unpolished, suggesting that the polishing would have occurred when they reached their intended destination.

Further disarticulated wooden remains are located away from the central wreck mound: a large timber measuring 4.5m long, interpreted as the stempost, is located to the north of the central mound; and a floor timber, measuring 3.4m long, is located to the west of the central mound.

The survey by Bournemouth University divers indicates that the site is being further revealed by sediment erosion, and that the timbers are under threat from marine boring organisms.

Following the diver investigation, the exposed features and artefacts were buried beneath a layer of Terram and sandbags.

Sources

Other
Bournemouth University (2020) Mortar Wreck, Undesignated Site Report
Nayling, N & Tyers, C (2020) Mortar Wreck, Poole, Dorset, Tree-ring Analysis of Oak Timbers. Historic England Research Report 252-2020
Historic England National Record of the Historic Environment (NRHE) No 832532
UKHO Wreck Report 19600

End of official list entry

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