A large original pre war instructional board from Royal Navy Mining School HM Gunwharf on laying sea mines

A rare surviving instructional board from the Royal Navy mining school, HM Gunwharf, Portsmouth, and dates to the 1920s, which is unusual as a pre-war piece.  HM Gunwharf was a shore based training establishment and the mining school moved there in 1919 to train on the use and deployment of sea mines.    This board is dated 1921 to the back.   It is marked ‘Mining school, HM Gunwharf, Portsmouth’ and instructs on how sea mines are laid and deployed with a sinker and plummet which sets at what depth the mine will sit below the waterline.    HMS Vernon, the shore based establishment where the mining school was based, closed in the 1990s and this was one of the last pieces to be removed.  It is an important pieces of naval history and a truly rare survivor in untouched original condition including the original frame.

Measuring: 156 cm x 118 cm

English, 1920s