Scale: Unknown. Model of a single frame of a wooden sailing vessel made with three timbers instead of two, as proposed by Sir Robert Seppings in 1820. The model is made entirely of wood and stained and varnished a uniform dark brown colour. The thickness of the frame tapers with the thicker part at the keel end of the frame. At this end, the three exposed timber ends each have dowels. The three timbers have been made in sections. A paper label marked "11" has been applied to the inner face of the frame, but is now partly missing.