2014:328 - Dun Laoghaire Harbour, Dublin

Archaeological investigations took place at two wreck site locations. The two wreck sites are included in the published Shipwreck Inventory of Ireland, as wrecksites W01966 and W01967. The former site’s location is charted at the harbour mouth against the East Pier and is a known shipwreck based on a dive report from 1996. The latter site’s location is charted within the main harbour and is a possible shipwreck based on an anomaly detected by the Irish National Seabed Survey.
Both locations are within potential impact zones associated with the proposed dredging of an approach channel into the harbour to facilitate future cruise ship movements.
Marine geophysical survey conducted for the overall project in May 2014 under licence 13R073 concluded that there was some correlation between the reported wreck site locations and side-scan sonar contact locations, which seemed to represent debris associated with the wrecks. It also observed slight deviations in the magnetometer data over the areas associated with both wreck sites.
Subsequent underwater inspection in September 2014 at the two charted wreck site locations concluded that there was wreck remains at both locations, which represented scattered remains with only sections of wreckage visible on the surface.
At the request of the DAHG, underwater investigation of both wreck site locations was required to further inform the nature and extent of the two sites. This work was to include detailed mapping where possible and the cutting of investigation trenches across both sites, to indicate stratigraphic depth; complexity of wreckage remains and the potential for dating each site.
ADCO was appointed to the project at this stage, and carried out a seven-day investigation project between 25 November and 4 December 2014 to meet the Department’s requirements. The work anticipated the presence of wrecks at both locations. However there was no wreckage located at either of the charted coordinates for W01966 or W01967. These observations were concluded following an extensive search and both probing and dredging at each location.
The search of a wide area beside both locations located wrecksite W01966, some 85m east of the charted location. Two pieces of exposed ironwork lay within metres of timberwork that was substantially buried. Two investigation trenches cut at the site revealed a composite array of ships’ timbers lying close against the foot of the East Pier's rock armour. The remains are largely buried in the covering sands, and appear to be the hull section of a large wooden vessel orientated north-west/south-east. The remains are wedged against the foot of the rock armour and run north of it in a sloping fashion. It was not possible to expose the full depth of the remains or their full extent. The removal of covering sands around one of two iron pieces lying beside the wreck revealed the presence of boulders underneath the iron. A scaled drawing has been made of the remains.
No remains were located that might be associated with W01967. Investigation at the charted location revealed an encrusted fish box that was partially exposed above the covering soft silts. Metal-detection survey did not highlight the presence of any anomalies. Consideration should be given to the possibility of changes in the seabed levels since the original record of a possible wreck was made. At that point in time, seabed levels were noted to be 8m depth. Today, seabed levels in this location are 10-11m deep.

ADCO, Brehon House, Kilkenny Road, Castlecomer, Co. Kilkenny