Underwater acoustics (1938 – 1940)
On April 5, 1938, the Commission for Physical Armorment received a (very secret) assignment from the Dutch Department of Defence for research in underwater acoustics with the periphone and for studying the problem of noise reception under water. The underwater acoustic experiments took place in the Kanaal door Voorne, in the Westeinderplas (Aalsmeer), and at sea on board Hr. Ms. Mijnenveger M2 (Minesweeper).
The periphones developed by the laboratory consisted of magnetostrictive plates of nickel and Monel. They were successfully compared with a periphone from Atlas Werke A.G. affixed to the Dutch submarine O-16.
De door het laboratorium ontwikkelde perifonen bestaande uit magnetostrictieve nikkel- en Monelblikken zijn met succes vergeleken met een perifoon (periphone) van Atlas Werke A.G. aangebracht op de onderzeeër O-16.
At the outbreak of the war in May 1940, the research was discontinued for obvious reasons.