Scale 1:24. A printed copy of a plan, showing the upper deck and accommodation arrangement, as fitted of the Type 1 Ham class inshore minesweeper Portisham (1955). The drawing was originally to be used for Frettenham but was reused for Portisham, both of which were Ham class inshore minesweepers. A J. Samuel White builder's stamp dated 23 November 1954 is printed on the drawing. This plan bears the signature of C. M. Jones [Draughtsman at Dorset Lake Shipyard flourishing 1956] dated 14 March 1956. The vessel's hull number 'IMS81' is printed on the drawing.