German submarines afraid for British patrol plane detection gear in 1942

American naval attaché at Paris, France reported in August 1942 that the Japanese naval attaché informed the French Intelligence that the British patrol plane detection gear performed such well that German submarines while operating in the Gulf of Gascony submerged at night and on surface during the day.

Source

National Archives USA. Record Group 38: Records of the Office of the Chief of Naval Operations. Series: Secret Naval Attaches Reports. Estimate of potential military strength (pt.). Summaries. Reports from London, Paris, Brussels, Rome and Berlin. Roll M975-001.