A Submarine Snort Barometer Joins the Collection
A rare Negretti & Zambra snort barometer, made for Royal Navy submarines in the 1940s–1950s, has been added to the collection.
The collection has acquired a by , London, serial No. 17170, made to Admiralty order for diesel-electric submarines. Unlike a weather instrument, it measured the air pressure inside the boat while the diesels ran submerged on the snort. Coloured sectors on its 700–1200 mb scale mark the permitted vacuum limits; beyond them the head valve was shut and the engines stopped. The instrument has a non-magnetic copper case, a screen-printed aluminium dial and a temperature-compensated movement with a mechanical stop. A broad arrow hidden beneath the bezel marks it as British government property. Found in the Netherlands, it may have come from one of the British submarines that served under the Dutch flag after the war. A full catalogue description is available on its page.