2012:435 - BLIND HARBOUR, Broadhaven Bay, Mayo

In 2007 the Underwater Archaeology Unit (UAU) of the National Monuments Service received a report regarding the discovery of two previously unrecorded cannon on the seabed in Broadhaven Bay, Co. Mayo. A two-day dive and metal detection survey carried out by the UAU in August 2009 identified 6 iron cannon at the site. The UAU returned to the site in 2010, 2011 (Excavations 2011, No. 456) and 2012 to carry out further survey work to map the known extent of the wreck site. A small-scale rescue excavation was also carried out in 2011 and 2012 to try and ascertain the date and identity of the wreck and to retrieve artefacts in danger of being lost or washed away. The site is located at the north-eastern end of the Mullet peninsula on the west side of Broadhaven Bay at the entrance to Blind Harbour in approximately 4-8m of water.

To date, the underwater survey and excavation has resulted in the discovery of twelve iron cannon, a spread of concreted cannon balls, eight boat-shaped lead ingots, pewter bottle tops, bricks, two wooden barrels and a number of smaller artefacts. No structural remains of the ship have been discovered thus far. The heavily concreted cannon lie scattered and dispersed over a 40m stretch of the seabed in an apparently haphazard layout on the seabed. Some small-scale excavation and detailed survey work was carried out around some of the cannon in an attempt to record their form, calibre and to establish if any distinguishing marks or diagnostic features were present. All twelve cannon are cast iron muzzle-loaders varying in length from 2-2.48m. However, most of the guns are of similar size, being in or around 2.2m in length which indicates that they are likely to be small-medium sized guns, possibly ranging from minion to saker if English in origin, or 3 to 8 pounder if they are of the Dutch continental system. One of the guns may be a finbanker—a type of gun cast in Sweden mainly for the Dutch market, and the largest guns appears to be a 12-pounder gun measuring 2.48m long. Initial analysis of the cannon indicates that they are likely date to the mid-to late 17^th century.

Eight boat-shaped lead ingots were also found during the course of the survey (see entry in Excavations 2011). The presence of the ingots, the pewter bottle tops and other artefactual evidence all point towards the wreck being that of a mid-17^th-Century Dutch East Indiaman. The discovery of such a wreck in Irish waters is a unique find and there is a strong possibility that the records of the Dutch East India Company may contain the entire story of the ship and its loss. Further research and investigation is planned for 2013 to further determine the nature, extent and, if possible, the true identity of this wreck and to assist in the formulation of a definitive long-term management strategy for the site.

Blind Harbour, Broadhaven Bay, diver drawing concreted iron cannon on the seabed.