Large number of Russian submarines in northern waters in August 1943

American naval attaché at Moscow, Russia reported in August 1943 that there were more as 20 Soviet submarines in northern waters.

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.