As part of a large-scale replacement program the Ministry of Supply tasked the design of a new seaplane tender to J. I. Thornycroft & Sons. So confident was the ministry that the design would meet every requirement, they immediately ordered six craft to be built, and to be classed as range safety launches.
This was the first time a new boat had been built for the RAF without a prototype running exhaustive acceptance trials. The resulting craft was once again a development of an earlier design, that being the 41ft 6in seaplane tender, which is represented in our collection by ST 1502. Hence the new boats were similar, with the forward wheelhouse, a long four-berth cabin, twin Rolls Royce diesels housed in engine boxes on either side, and an open well deck aft. The bigger boat meant that a more spacious head could be housed ahead of the wheelhouse, and the radio room and galley moved to the front section of the main cabin, immediately behind the wheelhouse.
Their construction differed from other new boats utilising a combination of sawn and laminated frames with the latter very closely spaced. The RSLs had aluminium superstructures, and were tough seaworthy craft, very nimble and extremely responsive, and as such, ideal for teaching boat handling. In addition to range work, they carried out wet-winching drills, para-drop drills, and were the chosen craft for V.I.P. and P/R work.
Our own boat, RSL 1668, has been in private ownership for many years, and based in Penarth in South Wales. As a private launch, she was named “Pembrey.” She came to us via Berthon in Lymington where she was surveyed and had her numbers restored. Externally, she largely retains her RAF appearance, although with the addition of radar.