Built in 1952 by Vosper-Thornycroft at Southhampton, to a wartime design, RTTL 2748 was built as a fast air-sea-rescue vessel, to collect downed pilots and crews of aircraft ditched in the sea. Constructed of double and triple layers of planking on close frames with marine ply bulkheads and mostly aluminium brackets, she was designed to be strong, fast and manoeverable.