This site is designated as a Historic Wreck under Protections of Wrecks Act 1973. The protected area around the wreck is a radius of 150m from the co-ordinate 53 12 46N 04 11 43W. Diving or any interference including filming, survey and excavation within the protected area of a designated wreck is a criminal offence unless a license has first been obtained from the Welsh Government. Cadw should be contacted in the first instance. http://www.cadw.wales.gov.uk/

The site consists of the remains of a small wooden vessel lying underneath a mound of hand-worked slate comprising the vessel's last cargo. The mound of slates continues to perform the very important function of trapping and preserving the remains of the vessel. The mound measures 9.4m long, 3m wide and is approximately 1.5m high. The mound sits on a sloping ledge in approximately 10m of water. There is an extensive spread of spilled slates on the down slope side of the wreck site, extending for more than 10m, before the ledge drops sharply down to depths in excess of 20m.

Event and Historical Information:
The identity of the vessel remains unknown, but may have been a type of `Ballinger'. It is likely that the vessel sank with its 20 ton cargo of some 40,000 slates whilst at anchor waiting for the tide to race through the Swellies.
The wreck site was found during a marine biological survey in March 1976. The following year, a pre-disturbance survey was undertaken by University College of North Wales (Bangor) and the Gwynedd British Sub Aqua Club. As a consequence of realizing the site's potential importance to the maritime and industrial history of Wales, the site was proposed for designation. The designation order came into operation on the 8 March 1978.
During the small-scale underwater excavation undertaken under licence in 1978, a sample of slates was recovered. Llanberis and the Nantile area were determined as their origin. The recovered slates were accessioned to local and national museum collections in the 1980s. Scientific dating (radio carbon 14) was undertaken on a small sample of recovered timbers. The results suggest a date for the sinking in the later half of the 16th century.
The discovery of the wreck encouraged the establishment of North Wales Marine Study group based at the Department of Extra-Mural Studies at University of Wales Bangor. The University group have continued to monitor the site and its marine biological communities through annual survey licences granted by Cadw.

Sources include:
Fenwick, V and Gale, G, 1998, Historic Shipwrecks: Discovered, Protected and Investigated, p 120-1.
Jones D C, 1977, A relic of the Slate Trade on the Menai Strait in Maritime Wales, Cymru a'r Mor, 2: p13-15
Jones, C, 1978 The Pwll Fanog wreck: a slate cargo in the Menai straits in International Journal of Nautical Archaeology (IJNA), Vol 7.2 pg 152-7.
Jones, C, 1980, The Riddle of the Slate Wreck in Diver, Vol 25.3, March 1980, p 44-5.
Roberts, O T P, 1979, Pwll Fanog Wreck, Menai Straits, North Wales in International Journal of Nautical Archaeology (IJNA), Notes and News, Vol 8.3, p249-54.
Statutory Instrument: 1978 No 199, Protection of Wrecks (Designation No 1) Order 1978.

Maritime Officer, 10 July 2007