Scale 1:48. A dyeline copy of a plan, showing the external plan views, as fitted for the Porpoise class submarines Porpoise (1956). There is a faded Vickers Armstrong builder's stamp dated 27 August 1959 printed on the drawing. A faded Portsmouth Dockyard Manager of Constructive Department dated January 1960 is also printed on the plan. A note on the drawing states this drawing was made during its 1969 refit and supercedes the previous plan.