Scale 1:12. An ozatrace copy of a plan showing the modifications made to the layout of the computer room on the sonar trials ship Matapan (1945). Matapan was originally a Battle class destroyer that was converted into a sonar trials ship in 1971. This drawing is noted as Sheet 3 of 3 and was drawn by R. Nelson [Draughtsman at Portsmouth Dockyard flourishing 1974].