Event/Activity EPM307 - Archaeological Watching Brief at National Museum of the Royal Navy, No. 6 Boathouse, Portsmouth Historic Dockyard

Wessex Archaeology carried out an archaeological watching brief on behalf of the National Museum of the Royal Navy at Boathouse No. 6 in Portsmouth Historic Dockyard on the 20th-28th January and the 1st-2nd of April 2025. Number 6 Boathouse (Building 1/23) and the slipway to the front is a Grade II* Listed Building and falls within Portsmouth City Council Conservation Area 22 H.M. Naval Base and St George's Square. The watching brief was carried out as part of a programme of archaeological works. The monitored works comprised three borehole test pits outside Boathouse No. 6 and three geotechnical investigation (GI) pits within the building excavated for structural engineering purposes. The test pits outside the building were located to the north, east and south of the boathouse. The pits were hand excavated prior to the drilling of three boreholes to obtain geotechincal data and acted as starting pits for the boreholes. Each pit measured 0.5m by 0.5m by 1m deep. The GI pits inside the building were cut through a concrete floor using a 0.30m diameter hollow drill and hand excavated to a depth of approximately 1m. The GI pits were located in the northwest corner of the building close to the front elevation, and to the northwest and southeast. No significant archaeological remains were encountered during the works. Rubble deposits recorded in two of the boreholes located to the east and south of the building may have related to dismantling and rebuilding following Second World War bomb damage. Layers of made ground observed within the GI pits excavated beneath the existing concrete floor inside the building may relate to the construction of Boathouse No. 6.