Passenger Vessel CORONIA was built as BRIT by Fellows & Co., Great Yarmouth, in 1935 for Longfield Brothers, who offered excursions from Great Yarmouth's Town Hall Quay and Britannia Quay. She was licensed to carry 200 passengers and spent her first five summers taking holidaymakers out to see the seals basking on the sandbanks along the north sea coast of Norfolk. She was powered by twin Crossley diesels. Following the outbreak of war, she was requisitioned by the Admiralty on 16 September 1939 for service as a tender. Renamed HMS Watchful , she became the base ship for the fleet and was repainted in battleship grey . On 29 May 1940, she was deployed to assist in the Dunkirk evacuation and reportedly rescued 900 troops.