Trinity House Vessel Alert sailed from up the Thames Gravesend Town Pier on 9 March 2021 undertaking buoy maintenance in the Thames Estuary.
Later in the evening she returned to London as guests of the Royal Navy mooring at their base HMS President near Tower Bridge.
Rapid Intervention Vessel (RIV) THV Alert was designed with buoy handling, wreck marking, towing and multibeam and side scan hydrographic surveying capability. The vessel is usually based at Harwich, but undertakes work around the whole of the country.
Built in 2006, she measures 39.3m overall with a moulded breadth of 8m.
Photos by Fraser Grey